xnu-3248.60.10.tar.gz

[apple/xnu.git] / osfmk / vm / vm_resident.c

/*
 * Copyright (c) 2000-2009 Apple Inc. All rights reserved.
 *
 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. The rights granted to you under the License
 * may not be used to create, or enable the creation or redistribution of,
 * unlawful or unlicensed copies of an Apple operating system, or to
 * circumvent, violate, or enable the circumvention or violation of, any
 * terms of an Apple operating system software license agreement.
 * 
 * Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 */
/*
 *      File:   vm/vm_page.c
 *      Author: Avadis Tevanian, Jr., Michael Wayne Young
 *
 *      Resident memory management module.
 */

#include <debug.h>
#include <libkern/OSAtomic.h>
#include <libkern/OSDebug.h>

#include <mach/clock_types.h>
#include <mach/vm_prot.h>
#include <mach/vm_statistics.h>
#include <mach/sdt.h>
#include <kern/counters.h>
#include <kern/sched_prim.h>
#include <kern/task.h>
#include <kern/thread.h>
#include <kern/kalloc.h>
#include <kern/zalloc.h>
#include <kern/xpr.h>
#include <kern/ledger.h>
#include <vm/pmap.h>
#include <vm/vm_init.h>
#include <vm/vm_map.h>
#include <vm/vm_page.h>
#include <vm/vm_pageout.h>
#include <vm/vm_kern.h>                 /* kernel_memory_allocate() */
#include <kern/misc_protos.h>
#include <zone_debug.h>
#include <mach_debug/zone_info.h>
#include <vm/cpm.h>
#include <pexpert/pexpert.h>

#include <vm/vm_protos.h>
#include <vm/memory_object.h>
#include <vm/vm_purgeable_internal.h>
#include <vm/vm_compressor.h>

#if CONFIG_PHANTOM_CACHE
#include <vm/vm_phantom_cache.h>
#endif

#include <IOKit/IOHibernatePrivate.h>

#include <sys/kdebug.h>

boolean_t       hibernate_cleaning_in_progress = FALSE;
boolean_t       vm_page_free_verify = TRUE;

uint32_t        vm_lopage_free_count = 0;
uint32_t        vm_lopage_free_limit = 0;
uint32_t        vm_lopage_lowater    = 0;
boolean_t       vm_lopage_refill = FALSE;
boolean_t       vm_lopage_needed = FALSE;

lck_mtx_ext_t   vm_page_queue_lock_ext;
lck_mtx_ext_t   vm_page_queue_free_lock_ext;
lck_mtx_ext_t   vm_purgeable_queue_lock_ext;

int             speculative_age_index = 0;
int             speculative_steal_index = 0;
struct vm_speculative_age_q vm_page_queue_speculative[VM_PAGE_MAX_SPECULATIVE_AGE_Q + 1];


__private_extern__ void         vm_page_init_lck_grp(void);

static void             vm_page_free_prepare(vm_page_t  page);
static vm_page_t        vm_page_grab_fictitious_common(ppnum_t phys_addr);

static void vm_tag_init(void);

uint64_t        vm_min_kernel_and_kext_address = VM_MIN_KERNEL_AND_KEXT_ADDRESS;

/*
 *      Associated with page of user-allocatable memory is a
 *      page structure.
 */

/*
 *      These variables record the values returned by vm_page_bootstrap,
 *      for debugging purposes.  The implementation of pmap_steal_memory
 *      and pmap_startup here also uses them internally.
 */

vm_offset_t virtual_space_start;
vm_offset_t virtual_space_end;
uint32_t        vm_page_pages;

/*
 *      The vm_page_lookup() routine, which provides for fast
 *      (virtual memory object, offset) to page lookup, employs
 *      the following hash table.  The vm_page_{insert,remove}
 *      routines install and remove associations in the table.
 *      [This table is often called the virtual-to-physical,
 *      or VP, table.]
 */
typedef struct {
        vm_page_packed_t page_list;
#if     MACH_PAGE_HASH_STATS
        int             cur_count;              /* current count */
        int             hi_count;               /* high water mark */
#endif /* MACH_PAGE_HASH_STATS */
} vm_page_bucket_t;


#define BUCKETS_PER_LOCK        16

vm_page_bucket_t *vm_page_buckets;              /* Array of buckets */
unsigned int    vm_page_bucket_count = 0;       /* How big is array? */
unsigned int    vm_page_hash_mask;              /* Mask for hash function */
unsigned int    vm_page_hash_shift;             /* Shift for hash function */
uint32_t        vm_page_bucket_hash;            /* Basic bucket hash */
unsigned int    vm_page_bucket_lock_count = 0;          /* How big is array of locks? */

lck_spin_t      *vm_page_bucket_locks;
lck_spin_t      vm_objects_wired_lock;
lck_spin_t      vm_allocation_sites_lock;

#if VM_PAGE_BUCKETS_CHECK
boolean_t vm_page_buckets_check_ready = FALSE;
#if VM_PAGE_FAKE_BUCKETS
vm_page_bucket_t *vm_page_fake_buckets; /* decoy buckets */
vm_map_offset_t vm_page_fake_buckets_start, vm_page_fake_buckets_end;
#endif /* VM_PAGE_FAKE_BUCKETS */
#endif /* VM_PAGE_BUCKETS_CHECK */

extern int not_in_kdp;


#if     MACH_PAGE_HASH_STATS
/* This routine is only for debug.  It is intended to be called by
 * hand by a developer using a kernel debugger.  This routine prints
 * out vm_page_hash table statistics to the kernel debug console.
 */
void
hash_debug(void)
{
        int     i;
        int     numbuckets = 0;
        int     highsum = 0;
        int     maxdepth = 0;

        for (i = 0; i < vm_page_bucket_count; i++) {
                if (vm_page_buckets[i].hi_count) {
                        numbuckets++;
                        highsum += vm_page_buckets[i].hi_count;
                        if (vm_page_buckets[i].hi_count > maxdepth)
                                maxdepth = vm_page_buckets[i].hi_count;
                }
        }
        printf("Total number of buckets: %d\n", vm_page_bucket_count);
        printf("Number used buckets:     %d = %d%%\n",
                numbuckets, 100*numbuckets/vm_page_bucket_count);
        printf("Number unused buckets:   %d = %d%%\n",
                vm_page_bucket_count - numbuckets,
                100*(vm_page_bucket_count-numbuckets)/vm_page_bucket_count);
        printf("Sum of bucket max depth: %d\n", highsum);
        printf("Average bucket depth:    %d.%2d\n",
                highsum/vm_page_bucket_count,
                highsum%vm_page_bucket_count);
        printf("Maximum bucket depth:    %d\n", maxdepth);
}
#endif /* MACH_PAGE_HASH_STATS */

/*
 *      The virtual page size is currently implemented as a runtime
 *      variable, but is constant once initialized using vm_set_page_size.
 *      This initialization must be done in the machine-dependent
 *      bootstrap sequence, before calling other machine-independent
 *      initializations.
 *
 *      All references to the virtual page size outside this
 *      module must use the PAGE_SIZE, PAGE_MASK and PAGE_SHIFT
 *      constants.
 */
vm_size_t       page_size  = PAGE_SIZE;
vm_size_t       page_mask  = PAGE_MASK;
int             page_shift = PAGE_SHIFT;

/*
 *      Resident page structures are initialized from
 *      a template (see vm_page_alloc).
 *
 *      When adding a new field to the virtual memory
 *      object structure, be sure to add initialization
 *      (see vm_page_bootstrap).
 */
struct vm_page  vm_page_template;

vm_page_t       vm_pages = VM_PAGE_NULL;
unsigned int    vm_pages_count = 0;
ppnum_t         vm_page_lowest = 0;

/*
 *      Resident pages that represent real memory
 *      are allocated from a set of free lists,
 *      one per color.
 */
unsigned int    vm_colors;
unsigned int    vm_color_mask;                  /* mask is == (vm_colors-1) */
unsigned int    vm_cache_geometry_colors = 0;   /* set by hw dependent code during startup */
unsigned int    vm_free_magazine_refill_limit = 0;
queue_head_t    vm_page_queue_free[MAX_COLORS];
unsigned int    vm_page_free_wanted;
unsigned int    vm_page_free_wanted_privileged;
unsigned int    vm_page_free_count;
unsigned int    vm_page_fictitious_count;

/*
 *      Occasionally, the virtual memory system uses
 *      resident page structures that do not refer to
 *      real pages, for example to leave a page with
 *      important state information in the VP table.
 *
 *      These page structures are allocated the way
 *      most other kernel structures are.
 */
zone_t  vm_page_zone;
vm_locks_array_t vm_page_locks;
decl_lck_mtx_data(,vm_page_alloc_lock)
lck_mtx_ext_t vm_page_alloc_lock_ext;

unsigned int io_throttle_zero_fill;

unsigned int    vm_page_local_q_count = 0;
unsigned int    vm_page_local_q_soft_limit = 250;
unsigned int    vm_page_local_q_hard_limit = 500;
struct vplq     *vm_page_local_q = NULL;

/* N.B. Guard and fictitious pages must not
 * be assigned a zero phys_page value.
 */
/*
 *      Fictitious pages don't have a physical address,
 *      but we must initialize phys_page to something.
 *      For debugging, this should be a strange value
 *      that the pmap module can recognize in assertions.
 */
ppnum_t vm_page_fictitious_addr = (ppnum_t) -1;

/*
 *      Guard pages are not accessible so they don't
 *      need a physical address, but we need to enter
 *      one in the pmap.
 *      Let's make it recognizable and make sure that
 *      we don't use a real physical page with that
 *      physical address.
 */
ppnum_t vm_page_guard_addr = (ppnum_t) -2;

/*
 *      Resident page structures are also chained on
 *      queues that are used by the page replacement
 *      system (pageout daemon).  These queues are
 *      defined here, but are shared by the pageout
 *      module.  The inactive queue is broken into 
 *      file backed and anonymous for convenience as the 
 *      pageout daemon often assignes a higher 
 *      importance to anonymous pages (less likely to pick)
 */
queue_head_t    vm_page_queue_active;
queue_head_t    vm_page_queue_inactive;
queue_head_t    vm_page_queue_anonymous;        /* inactive memory queue for anonymous pages */
queue_head_t    vm_page_queue_throttled;

queue_head_t    vm_objects_wired;

unsigned int    vm_page_active_count;
unsigned int    vm_page_inactive_count;
unsigned int    vm_page_anonymous_count;
unsigned int    vm_page_throttled_count;
unsigned int    vm_page_speculative_count;

unsigned int    vm_page_wire_count;
unsigned int    vm_page_stolen_count;
unsigned int    vm_page_wire_count_initial;
unsigned int    vm_page_pages_initial;
unsigned int    vm_page_gobble_count = 0;

#define VM_PAGE_WIRE_COUNT_WARNING      0
#define VM_PAGE_GOBBLE_COUNT_WARNING    0

unsigned int    vm_page_purgeable_count = 0; /* # of pages purgeable now */
unsigned int    vm_page_purgeable_wired_count = 0; /* # of purgeable pages that are wired now */
uint64_t        vm_page_purged_count = 0;    /* total count of purged pages */

unsigned int    vm_page_xpmapped_external_count = 0;
unsigned int    vm_page_external_count = 0;
unsigned int    vm_page_internal_count = 0;
unsigned int    vm_page_pageable_external_count = 0;
unsigned int    vm_page_pageable_internal_count = 0;

#if DEVELOPMENT || DEBUG
unsigned int    vm_page_speculative_recreated = 0;
unsigned int    vm_page_speculative_created = 0;
unsigned int    vm_page_speculative_used = 0;
#endif

queue_head_t    vm_page_queue_cleaned;

unsigned int    vm_page_cleaned_count = 0;
unsigned int    vm_pageout_enqueued_cleaned = 0;

uint64_t        max_valid_dma_address = 0xffffffffffffffffULL;
ppnum_t         max_valid_low_ppnum = 0xffffffff;


/*
 *      Several page replacement parameters are also
 *      shared with this module, so that page allocation
 *      (done here in vm_page_alloc) can trigger the
 *      pageout daemon.
 */
unsigned int    vm_page_free_target = 0;
unsigned int    vm_page_free_min = 0;
unsigned int    vm_page_throttle_limit = 0;
unsigned int    vm_page_inactive_target = 0;
unsigned int    vm_page_anonymous_min = 0;
unsigned int    vm_page_inactive_min = 0;
unsigned int    vm_page_free_reserved = 0;
unsigned int    vm_page_throttle_count = 0;


/*
 *      The VM system has a couple of heuristics for deciding
 *      that pages are "uninteresting" and should be placed
 *      on the inactive queue as likely candidates for replacement.
 *      These variables let the heuristics be controlled at run-time
 *      to make experimentation easier.
 */

boolean_t vm_page_deactivate_hint = TRUE;

struct vm_page_stats_reusable vm_page_stats_reusable;
        
/*
 *      vm_set_page_size:
 *
 *      Sets the page size, perhaps based upon the memory
 *      size.  Must be called before any use of page-size
 *      dependent functions.
 *
 *      Sets page_shift and page_mask from page_size.
 */
void
vm_set_page_size(void)
{
        page_size  = PAGE_SIZE;
        page_mask  = PAGE_MASK;
        page_shift = PAGE_SHIFT;

        if ((page_mask & page_size) != 0)
                panic("vm_set_page_size: page size not a power of two");

        for (page_shift = 0; ; page_shift++)
                if ((1U << page_shift) == page_size)
                        break;
}

#define COLOR_GROUPS_TO_STEAL   4


/* Called once during statup, once the cache geometry is known.
 */
static void
vm_page_set_colors( void )
{
        unsigned int    n, override;
        
        if ( PE_parse_boot_argn("colors", &override, sizeof (override)) )               /* colors specified as a boot-arg? */
                n = override;   
        else if ( vm_cache_geometry_colors )                    /* do we know what the cache geometry is? */
                n = vm_cache_geometry_colors;
        else    n = DEFAULT_COLORS;                             /* use default if all else fails */

        if ( n == 0 )
                n = 1;
        if ( n > MAX_COLORS )
                n = MAX_COLORS;
                
        /* the count must be a power of 2  */
        if ( ( n & (n - 1)) != 0  )
                panic("vm_page_set_colors");
        
        vm_colors = n;
        vm_color_mask = n - 1;

        vm_free_magazine_refill_limit = vm_colors * COLOR_GROUPS_TO_STEAL;
}


lck_grp_t               vm_page_lck_grp_free;
lck_grp_t               vm_page_lck_grp_queue;
lck_grp_t               vm_page_lck_grp_local;
lck_grp_t               vm_page_lck_grp_purge;
lck_grp_t               vm_page_lck_grp_alloc;
lck_grp_t               vm_page_lck_grp_bucket;
lck_grp_attr_t          vm_page_lck_grp_attr;
lck_attr_t              vm_page_lck_attr;


__private_extern__ void
vm_page_init_lck_grp(void)
{
        /*
         * initialze the vm_page lock world
         */
        lck_grp_attr_setdefault(&vm_page_lck_grp_attr);
        lck_grp_init(&vm_page_lck_grp_free, "vm_page_free", &vm_page_lck_grp_attr);
        lck_grp_init(&vm_page_lck_grp_queue, "vm_page_queue", &vm_page_lck_grp_attr);
        lck_grp_init(&vm_page_lck_grp_local, "vm_page_queue_local", &vm_page_lck_grp_attr);
        lck_grp_init(&vm_page_lck_grp_purge, "vm_page_purge", &vm_page_lck_grp_attr);
        lck_grp_init(&vm_page_lck_grp_alloc, "vm_page_alloc", &vm_page_lck_grp_attr);
        lck_grp_init(&vm_page_lck_grp_bucket, "vm_page_bucket", &vm_page_lck_grp_attr);
        lck_attr_setdefault(&vm_page_lck_attr);
        lck_mtx_init_ext(&vm_page_alloc_lock, &vm_page_alloc_lock_ext, &vm_page_lck_grp_alloc, &vm_page_lck_attr);

        vm_compressor_init_locks();
}

void
vm_page_init_local_q()
{
        unsigned int            num_cpus;
        unsigned int            i;
        struct vplq             *t_local_q;

        num_cpus = ml_get_max_cpus();

        /*
         * no point in this for a uni-processor system
         */
        if (num_cpus >= 2) {
                t_local_q = (struct vplq *)kalloc(num_cpus * sizeof(struct vplq));

                for (i = 0; i < num_cpus; i++) {
                        struct vpl      *lq;

                        lq = &t_local_q[i].vpl_un.vpl;
                        VPL_LOCK_INIT(lq, &vm_page_lck_grp_local, &vm_page_lck_attr);
                        queue_init(&lq->vpl_queue);
                        lq->vpl_count = 0;
                        lq->vpl_internal_count = 0;
                        lq->vpl_external_count = 0;
                }
                vm_page_local_q_count = num_cpus;

                vm_page_local_q = (struct vplq *)t_local_q;
        }
}


/*
 *      vm_page_bootstrap:
 *
 *      Initializes the resident memory module.
 *
 *      Allocates memory for the page cells, and
 *      for the object/offset-to-page hash table headers.
 *      Each page cell is initialized and placed on the free list.
 *      Returns the range of available kernel virtual memory.
 */

void
vm_page_bootstrap(
        vm_offset_t             *startp,
        vm_offset_t             *endp)
{
        register vm_page_t      m;
        unsigned int            i;
        unsigned int            log1;
        unsigned int            log2;
        unsigned int            size;

        /*
         *      Initialize the vm_page template.
         */

        m = &vm_page_template;
        bzero(m, sizeof (*m));

        m->pageq.next = NULL;
        m->pageq.prev = NULL;
        m->listq.next = NULL;
        m->listq.prev = NULL;
        m->next_m = VM_PAGE_PACK_PTR(VM_PAGE_NULL);

        m->object = VM_OBJECT_NULL;             /* reset later */
        m->offset = (vm_object_offset_t) -1;    /* reset later */

        m->wire_count = 0;
        m->local = FALSE;
        m->inactive = FALSE;
        m->active = FALSE;
        m->pageout_queue = FALSE;
        m->speculative = FALSE;
        m->laundry = FALSE;
        m->free = FALSE;
        m->reference = FALSE;
        m->gobbled = FALSE;
        m->private = FALSE;
        m->throttled = FALSE;
        m->__unused_pageq_bits = 0;

        m->phys_page = 0;               /* reset later */

        m->busy = TRUE;
        m->wanted = FALSE;
        m->tabled = FALSE;
        m->hashed = FALSE;
        m->fictitious = FALSE;
        m->pmapped = FALSE;
        m->wpmapped = FALSE;
        m->pageout = FALSE;
        m->absent = FALSE;
        m->error = FALSE;
        m->dirty = FALSE;
        m->cleaning = FALSE;
        m->precious = FALSE;
        m->clustered = FALSE;
        m->overwriting = FALSE;
        m->restart = FALSE;
        m->unusual = FALSE;
        m->encrypted = FALSE;
        m->encrypted_cleaning = FALSE;
        m->cs_validated = FALSE;
        m->cs_tainted = FALSE;
        m->cs_nx = FALSE;
        m->no_cache = FALSE;
        m->reusable = FALSE;
        m->slid = FALSE;
        m->xpmapped = FALSE;
        m->compressor = FALSE;
        m->written_by_kernel = FALSE;
        m->__unused_object_bits = 0;

        /*
         *      Initialize the page queues.
         */
        vm_page_init_lck_grp();
        
        lck_mtx_init_ext(&vm_page_queue_free_lock, &vm_page_queue_free_lock_ext, &vm_page_lck_grp_free, &vm_page_lck_attr);
        lck_mtx_init_ext(&vm_page_queue_lock, &vm_page_queue_lock_ext, &vm_page_lck_grp_queue, &vm_page_lck_attr);
        lck_mtx_init_ext(&vm_purgeable_queue_lock, &vm_purgeable_queue_lock_ext, &vm_page_lck_grp_purge, &vm_page_lck_attr);
    
        for (i = 0; i < PURGEABLE_Q_TYPE_MAX; i++) {
                int group;

                purgeable_queues[i].token_q_head = 0;
                purgeable_queues[i].token_q_tail = 0;
                for (group = 0; group < NUM_VOLATILE_GROUPS; group++)
                        queue_init(&purgeable_queues[i].objq[group]);

                purgeable_queues[i].type = i;
                purgeable_queues[i].new_pages = 0;
#if MACH_ASSERT
                purgeable_queues[i].debug_count_tokens = 0;
                purgeable_queues[i].debug_count_objects = 0;
#endif
        };
        purgeable_nonvolatile_count = 0;
        queue_init(&purgeable_nonvolatile_queue);
    
        for (i = 0; i < MAX_COLORS; i++ )
                queue_init(&vm_page_queue_free[i]);

        queue_init(&vm_lopage_queue_free);
        queue_init(&vm_page_queue_active);
        queue_init(&vm_page_queue_inactive);
        queue_init(&vm_page_queue_cleaned);
        queue_init(&vm_page_queue_throttled);
        queue_init(&vm_page_queue_anonymous);
        queue_init(&vm_objects_wired);

        for ( i = 0; i <= VM_PAGE_MAX_SPECULATIVE_AGE_Q; i++ ) {
                queue_init(&vm_page_queue_speculative[i].age_q);

                vm_page_queue_speculative[i].age_ts.tv_sec = 0;
                vm_page_queue_speculative[i].age_ts.tv_nsec = 0;
        }
        vm_page_free_wanted = 0;
        vm_page_free_wanted_privileged = 0;
        
        vm_page_set_colors();


        /*
         *      Steal memory for the map and zone subsystems.
         */
        kernel_debug_string_simple("zone_steal_memory");
        zone_steal_memory();
        kernel_debug_string_simple("vm_map_steal_memory");
        vm_map_steal_memory();

        /*
         *      Allocate (and initialize) the virtual-to-physical
         *      table hash buckets.
         *
         *      The number of buckets should be a power of two to
         *      get a good hash function.  The following computation
         *      chooses the first power of two that is greater
         *      than the number of physical pages in the system.
         */

        if (vm_page_bucket_count == 0) {
                unsigned int npages = pmap_free_pages();

                vm_page_bucket_count = 1;
                while (vm_page_bucket_count < npages)
                        vm_page_bucket_count <<= 1;
        }
        vm_page_bucket_lock_count = (vm_page_bucket_count + BUCKETS_PER_LOCK - 1) / BUCKETS_PER_LOCK;

        vm_page_hash_mask = vm_page_bucket_count - 1;

        /*
         *      Calculate object shift value for hashing algorithm:
         *              O = log2(sizeof(struct vm_object))
         *              B = log2(vm_page_bucket_count)
         *              hash shifts the object left by
         *              B/2 - O
         */
        size = vm_page_bucket_count;
        for (log1 = 0; size > 1; log1++) 
                size /= 2;
        size = sizeof(struct vm_object);
        for (log2 = 0; size > 1; log2++) 
                size /= 2;
        vm_page_hash_shift = log1/2 - log2 + 1;
        
        vm_page_bucket_hash = 1 << ((log1 + 1) >> 1);           /* Get (ceiling of sqrt of table size) */
        vm_page_bucket_hash |= 1 << ((log1 + 1) >> 2);          /* Get (ceiling of quadroot of table size) */
        vm_page_bucket_hash |= 1;                                                       /* Set bit and add 1 - always must be 1 to insure unique series */

        if (vm_page_hash_mask & vm_page_bucket_count)
                printf("vm_page_bootstrap: WARNING -- strange page hash\n");

#if VM_PAGE_BUCKETS_CHECK
#if VM_PAGE_FAKE_BUCKETS
        /*
         * Allocate a decoy set of page buckets, to detect
         * any stomping there.
         */
        vm_page_fake_buckets = (vm_page_bucket_t *)
                pmap_steal_memory(vm_page_bucket_count *
                                  sizeof(vm_page_bucket_t));
        vm_page_fake_buckets_start = (vm_map_offset_t) vm_page_fake_buckets;
        vm_page_fake_buckets_end =
                vm_map_round_page((vm_page_fake_buckets_start +
                                   (vm_page_bucket_count *
                                    sizeof (vm_page_bucket_t))),
                                  PAGE_MASK);
        char *cp;
        for (cp = (char *)vm_page_fake_buckets_start;
             cp < (char *)vm_page_fake_buckets_end;
             cp++) {
                *cp = 0x5a;
        }
#endif /* VM_PAGE_FAKE_BUCKETS */
#endif /* VM_PAGE_BUCKETS_CHECK */

        kernel_debug_string_simple("vm_page_buckets");
        vm_page_buckets = (vm_page_bucket_t *)
                pmap_steal_memory(vm_page_bucket_count *
                                  sizeof(vm_page_bucket_t));

        kernel_debug_string_simple("vm_page_bucket_locks");
        vm_page_bucket_locks = (lck_spin_t *)
                pmap_steal_memory(vm_page_bucket_lock_count *
                                  sizeof(lck_spin_t));

        for (i = 0; i < vm_page_bucket_count; i++) {
                register vm_page_bucket_t *bucket = &vm_page_buckets[i];

                bucket->page_list = VM_PAGE_PACK_PTR(VM_PAGE_NULL);
#if     MACH_PAGE_HASH_STATS
                bucket->cur_count = 0;
                bucket->hi_count = 0;
#endif /* MACH_PAGE_HASH_STATS */
        }

        for (i = 0; i < vm_page_bucket_lock_count; i++)
                lck_spin_init(&vm_page_bucket_locks[i], &vm_page_lck_grp_bucket, &vm_page_lck_attr);

        lck_spin_init(&vm_objects_wired_lock, &vm_page_lck_grp_bucket, &vm_page_lck_attr);
        lck_spin_init(&vm_allocation_sites_lock, &vm_page_lck_grp_bucket, &vm_page_lck_attr);
        vm_tag_init();

#if VM_PAGE_BUCKETS_CHECK
        vm_page_buckets_check_ready = TRUE;
#endif /* VM_PAGE_BUCKETS_CHECK */

        /*
         *      Machine-dependent code allocates the resident page table.
         *      It uses vm_page_init to initialize the page frames.
         *      The code also returns to us the virtual space available
         *      to the kernel.  We don't trust the pmap module
         *      to get the alignment right.
         */

        kernel_debug_string_simple("pmap_startup");
        pmap_startup(&virtual_space_start, &virtual_space_end);
        virtual_space_start = round_page(virtual_space_start);
        virtual_space_end = trunc_page(virtual_space_end);

        *startp = virtual_space_start;
        *endp = virtual_space_end;

        /*
         *      Compute the initial "wire" count.
         *      Up until now, the pages which have been set aside are not under 
         *      the VM system's control, so although they aren't explicitly
         *      wired, they nonetheless can't be moved. At this moment,
         *      all VM managed pages are "free", courtesy of pmap_startup.
         */
        assert((unsigned int) atop_64(max_mem) == atop_64(max_mem));
        vm_page_wire_count = ((unsigned int) atop_64(max_mem)) - vm_page_free_count - vm_lopage_free_count;     /* initial value */
        vm_page_wire_count_initial = vm_page_wire_count;
        vm_page_pages_initial = vm_page_pages;

        printf("vm_page_bootstrap: %d free pages and %d wired pages\n",
               vm_page_free_count, vm_page_wire_count);

        kernel_debug_string_simple("vm_page_bootstrap complete");
        simple_lock_init(&vm_paging_lock, 0);
}

#ifndef MACHINE_PAGES
/*
 *      We implement pmap_steal_memory and pmap_startup with the help
 *      of two simpler functions, pmap_virtual_space and pmap_next_page.
 */

void *
pmap_steal_memory(
        vm_size_t size)
{
        vm_offset_t addr, vaddr;
        ppnum_t phys_page;

        /*
         *      We round the size to a round multiple.
         */

        size = (size + sizeof (void *) - 1) &~ (sizeof (void *) - 1);

        /*
         *      If this is the first call to pmap_steal_memory,
         *      we have to initialize ourself.
         */

        if (virtual_space_start == virtual_space_end) {
                pmap_virtual_space(&virtual_space_start, &virtual_space_end);

                /*
                 *      The initial values must be aligned properly, and
                 *      we don't trust the pmap module to do it right.
                 */

                virtual_space_start = round_page(virtual_space_start);
                virtual_space_end = trunc_page(virtual_space_end);
        }

        /*
         *      Allocate virtual memory for this request.
         */

        addr = virtual_space_start;
        virtual_space_start += size;

        //kprintf("pmap_steal_memory: %08lX - %08lX; size=%08lX\n", (long)addr, (long)virtual_space_start, (long)size); /* (TEST/DEBUG) */

        /*
         *      Allocate and map physical pages to back new virtual pages.
         */

        for (vaddr = round_page(addr);
             vaddr < addr + size;
             vaddr += PAGE_SIZE) {

                if (!pmap_next_page_hi(&phys_page))
                        panic("pmap_steal_memory");

                /*
                 *      XXX Logically, these mappings should be wired,
                 *      but some pmap modules barf if they are.
                 */
#if defined(__LP64__)
                pmap_pre_expand(kernel_pmap, vaddr);
#endif

                pmap_enter(kernel_pmap, vaddr, phys_page,
                           VM_PROT_READ|VM_PROT_WRITE, VM_PROT_NONE,
                                VM_WIMG_USE_DEFAULT, FALSE);
                /*
                 * Account for newly stolen memory
                 */
                vm_page_wire_count++;
                vm_page_stolen_count++;
        }

        return (void *) addr;
}

void vm_page_release_startup(vm_page_t mem);
void
pmap_startup(
        vm_offset_t *startp,
        vm_offset_t *endp)
{
        unsigned int i, npages, pages_initialized, fill, fillval;
        ppnum_t         phys_page;
        addr64_t        tmpaddr;


#if    defined(__LP64__)
        /*
         * struct vm_page must be of size 64 due to VM_PAGE_PACK_PTR use
         */
        assert(sizeof(struct vm_page) == 64);

        /*
         * make sure we are aligned on a 64 byte boundary
         * for VM_PAGE_PACK_PTR (it clips off the low-order
         * 6 bits of the pointer)
         */
        if (virtual_space_start != virtual_space_end)
                virtual_space_start = round_page(virtual_space_start);
#endif

        /*
         *      We calculate how many page frames we will have
         *      and then allocate the page structures in one chunk.
         */

        tmpaddr = (addr64_t)pmap_free_pages() * (addr64_t)PAGE_SIZE;    /* Get the amount of memory left */
        tmpaddr = tmpaddr + (addr64_t)(round_page(virtual_space_start) - virtual_space_start);  /* Account for any slop */
        npages = (unsigned int)(tmpaddr / (addr64_t)(PAGE_SIZE + sizeof(*vm_pages)));   /* Figure size of all vm_page_ts, including enough to hold the vm_page_ts */

        vm_pages = (vm_page_t) pmap_steal_memory(npages * sizeof *vm_pages);

        /*
         *      Initialize the page frames.
         */
        kernel_debug_string_simple("Initialize the page frames");
        for (i = 0, pages_initialized = 0; i < npages; i++) {
                if (!pmap_next_page(&phys_page))
                        break;
                if (pages_initialized == 0 || phys_page < vm_page_lowest)
                        vm_page_lowest = phys_page;

                vm_page_init(&vm_pages[i], phys_page, FALSE);
                vm_page_pages++;
                pages_initialized++;
        }
        vm_pages_count = pages_initialized;

#if    defined(__LP64__)

        if (VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(&vm_pages[0])) != &vm_pages[0])
                panic("VM_PAGE_PACK_PTR failed on &vm_pages[0] - %p", (void *)&vm_pages[0]);

        if (VM_PAGE_UNPACK_PTR(VM_PAGE_PACK_PTR(&vm_pages[vm_pages_count-1])) != &vm_pages[vm_pages_count-1])
                panic("VM_PAGE_PACK_PTR failed on &vm_pages[vm_pages_count-1] - %p", (void *)&vm_pages[vm_pages_count-1]);
#endif
        kernel_debug_string_simple("page fill/release");
        /*
         * Check if we want to initialize pages to a known value
         */
        fill = 0;                                                               /* Assume no fill */
        if (PE_parse_boot_argn("fill", &fillval, sizeof (fillval))) fill = 1;                   /* Set fill */
#if     DEBUG
        /* This slows down booting the DEBUG kernel, particularly on
         * large memory systems, but is worthwhile in deterministically
         * trapping uninitialized memory usage.
         */
        if (fill == 0) {
                fill = 1;
                fillval = 0xDEB8F177;
        }
#endif
        if (fill)
                kprintf("Filling vm_pages with pattern: 0x%x\n", fillval);
        // -debug code remove
        if (2 == vm_himemory_mode) {
                // free low -> high so high is preferred
                for (i = 1; i <= pages_initialized; i++) {
                        if(fill) fillPage(vm_pages[i - 1].phys_page, fillval);          /* Fill the page with a know value if requested at boot */                      
                        vm_page_release_startup(&vm_pages[i - 1]);
                }
        }
        else
        // debug code remove-

        /*
         * Release pages in reverse order so that physical pages
         * initially get allocated in ascending addresses. This keeps
         * the devices (which must address physical memory) happy if
         * they require several consecutive pages.
         */
        for (i = pages_initialized; i > 0; i--) {
                if(fill) fillPage(vm_pages[i - 1].phys_page, fillval);          /* Fill the page with a know value if requested at boot */                      
                vm_page_release_startup(&vm_pages[i - 1]);
        }

        VM_CHECK_MEMORYSTATUS;
        
#if 0
        {
                vm_page_t xx, xxo, xxl;
                int i, j, k, l;
        
                j = 0;                                                                                                  /* (BRINGUP) */
                xxl = 0;
                
                for( i = 0; i < vm_colors; i++ ) {
                        queue_iterate(&vm_page_queue_free[i],
                                      xx,
                                      vm_page_t,
                                      pageq) {  /* BRINGUP */
                                j++;                                                                                            /* (BRINGUP) */
                                if(j > vm_page_free_count) {                                            /* (BRINGUP) */
                                        panic("pmap_startup: too many pages, xx = %08X, xxl = %08X\n", xx, xxl);
                                }
                                
                                l = vm_page_free_count - j;                                                     /* (BRINGUP) */
                                k = 0;                                                                                          /* (BRINGUP) */
                                
                                if(((j - 1) & 0xFFFF) == 0) kprintf("checking number %d of %d\n", j, vm_page_free_count);

                                for(xxo = xx->pageq.next; xxo != &vm_page_queue_free[i]; xxo = xxo->pageq.next) {       /* (BRINGUP) */
                                        k++;
                                        if(k > l) panic("pmap_startup: too many in secondary check %d %d\n", k, l);
                                        if((xx->phys_page & 0xFFFFFFFF) == (xxo->phys_page & 0xFFFFFFFF)) {     /* (BRINGUP) */
                                                panic("pmap_startup: duplicate physaddr, xx = %08X, xxo = %08X\n", xx, xxo);
                                        }
                                }

                                xxl = xx;
                        }
                }
                
                if(j != vm_page_free_count) {                                           /* (BRINGUP) */
                        panic("pmap_startup: vm_page_free_count does not match, calc =  %d, vm_page_free_count = %08X\n", j, vm_page_free_count);
                }
        }
#endif


        /*
         *      We have to re-align virtual_space_start,
         *      because pmap_steal_memory has been using it.
         */

        virtual_space_start = round_page(virtual_space_start);

        *startp = virtual_space_start;
        *endp = virtual_space_end;
}
#endif  /* MACHINE_PAGES */

/*
 *      Routine:        vm_page_module_init
 *      Purpose:
 *              Second initialization pass, to be done after
 *              the basic VM system is ready.
 */
void
vm_page_module_init(void)
{
        uint64_t vm_page_zone_pages, vm_page_zone_data_size;
        vm_page_zone = zinit((vm_size_t) sizeof(struct vm_page),
                             0, PAGE_SIZE, "vm pages");

#if     ZONE_DEBUG
        zone_debug_disable(vm_page_zone);
#endif  /* ZONE_DEBUG */

        zone_change(vm_page_zone, Z_CALLERACCT, FALSE);
        zone_change(vm_page_zone, Z_EXPAND, FALSE);
        zone_change(vm_page_zone, Z_EXHAUST, TRUE);
        zone_change(vm_page_zone, Z_FOREIGN, TRUE);
        zone_change(vm_page_zone, Z_GZALLOC_EXEMPT, TRUE);
        /*
         * Adjust zone statistics to account for the real pages allocated
         * in vm_page_create(). [Q: is this really what we want?]
         */
        vm_page_zone->count += vm_page_pages;
        vm_page_zone->sum_count += vm_page_pages;
        vm_page_zone_data_size = vm_page_pages * vm_page_zone->elem_size;
        vm_page_zone->cur_size += vm_page_zone_data_size;
        vm_page_zone_pages = ((round_page(vm_page_zone_data_size)) / PAGE_SIZE);
        OSAddAtomic64(vm_page_zone_pages, &(vm_page_zone->page_count));
        /* since zone accounts for these, take them out of stolen */
        VM_PAGE_MOVE_STOLEN(vm_page_zone_pages);
}

/*
 *      Routine:        vm_page_create
 *      Purpose:
 *              After the VM system is up, machine-dependent code
 *              may stumble across more physical memory.  For example,
 *              memory that it was reserving for a frame buffer.
 *              vm_page_create turns this memory into available pages.
 */

void
vm_page_create(
        ppnum_t start,
        ppnum_t end)
{
        ppnum_t         phys_page;
        vm_page_t       m;

        for (phys_page = start;
             phys_page < end;
             phys_page++) {
                while ((m = (vm_page_t) vm_page_grab_fictitious_common(phys_page))
                        == VM_PAGE_NULL)
                        vm_page_more_fictitious();

                m->fictitious = FALSE;
                pmap_clear_noencrypt(phys_page);

                vm_page_pages++;
                vm_page_release(m);
        }
}

/*
 *      vm_page_hash:
 *
 *      Distributes the object/offset key pair among hash buckets.
 *
 *      NOTE:   The bucket count must be a power of 2
 */
#define vm_page_hash(object, offset) (\
        ( (natural_t)((uintptr_t)object * vm_page_bucket_hash) + ((uint32_t)atop_64(offset) ^ vm_page_bucket_hash))\
         & vm_page_hash_mask)


/*
 *      vm_page_insert:         [ internal use only ]
 *
 *      Inserts the given mem entry into the object/object-page
 *      table and object list.
 *
 *      The object must be locked.
 */
void
vm_page_insert(
        vm_page_t               mem,
        vm_object_t             object,
        vm_object_offset_t      offset)
{
        vm_page_insert_internal(mem, object, offset, VM_KERN_MEMORY_NONE, FALSE, TRUE, FALSE, FALSE, NULL);
}

void
vm_page_insert_wired(
        vm_page_t               mem,
        vm_object_t             object,
        vm_object_offset_t      offset,
        vm_tag_t                tag)
{
        vm_page_insert_internal(mem, object, offset, tag, FALSE, TRUE, FALSE, FALSE, NULL);
}

void
vm_page_insert_internal(
        vm_page_t               mem,
        vm_object_t             object,
        vm_object_offset_t      offset,
        vm_tag_t                tag,
        boolean_t               queues_lock_held,
        boolean_t               insert_in_hash,
        boolean_t               batch_pmap_op,
        boolean_t               batch_accounting,
        uint64_t                *delayed_ledger_update)
{
        vm_page_bucket_t        *bucket;
        lck_spin_t              *bucket_lock;
        int                     hash_id;
        task_t                  owner;

        XPR(XPR_VM_PAGE,
                "vm_page_insert, object 0x%X offset 0x%X page 0x%X\n",
                object, offset, mem, 0,0);
#if 0
        /*
         * we may not hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(mem);
#endif

        assert(page_aligned(offset));

        assert(!VM_PAGE_WIRED(mem) || mem->private || mem->fictitious || (tag != VM_KERN_MEMORY_NONE));

        /* the vm_submap_object is only a placeholder for submaps */
        assert(object != vm_submap_object);

        vm_object_lock_assert_exclusive(object);
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock,
                       queues_lock_held ? LCK_MTX_ASSERT_OWNED
                                        : LCK_MTX_ASSERT_NOTOWNED);
#endif  /* DEBUG */

        if (insert_in_hash == TRUE) {
#if DEBUG || VM_PAGE_CHECK_BUCKETS
                if (mem->tabled || mem->object != VM_OBJECT_NULL)
                        panic("vm_page_insert: page %p for (obj=%p,off=0x%llx) "
                              "already in (obj=%p,off=0x%llx)",
                              mem, object, offset, mem->object, mem->offset);
#endif
                assert(!object->internal || offset < object->vo_size);

                /* only insert "pageout" pages into "pageout" objects,
                 * and normal pages into normal objects */
#if 00
                /*
                 * For some reason, this assertion gets tripped
                 * but it's mostly harmless, so let's disable it
                 * for now.
                 */
                assert(object->pageout == mem->pageout);
#endif /* 00 */

                assert(vm_page_lookup(object, offset) == VM_PAGE_NULL);
                
                /*
                 *      Record the object/offset pair in this page
                 */

                mem->object = object;
                mem->offset = offset;

                /*
                 *      Insert it into the object_object/offset hash table
                 */
                hash_id = vm_page_hash(object, offset);
                bucket = &vm_page_buckets[hash_id];
                bucket_lock = &vm_page_bucket_locks[hash_id / BUCKETS_PER_LOCK];
        
                lck_spin_lock(bucket_lock);

                mem->next_m = bucket->page_list;
                bucket->page_list = VM_PAGE_PACK_PTR(mem);
                assert(mem == VM_PAGE_UNPACK_PTR(bucket->page_list));

#if     MACH_PAGE_HASH_STATS
                if (++bucket->cur_count > bucket->hi_count)
                        bucket->hi_count = bucket->cur_count;
#endif /* MACH_PAGE_HASH_STATS */
                mem->hashed = TRUE;
                lck_spin_unlock(bucket_lock);
        }

        {       
                unsigned int    cache_attr;

                cache_attr = object->wimg_bits & VM_WIMG_MASK;

                if (cache_attr != VM_WIMG_USE_DEFAULT) {
                        PMAP_SET_CACHE_ATTR(mem, object, cache_attr, batch_pmap_op);
                }
        }
        /*
         *      Now link into the object's list of backed pages.
         */
        queue_enter(&object->memq, mem, vm_page_t, listq);
        object->memq_hint = mem;
        mem->tabled = TRUE;

        /*
         *      Show that the object has one more resident page.
         */

        object->resident_page_count++;
        if (VM_PAGE_WIRED(mem)) {
            if (!mem->private && !mem->fictitious) 
            {
                if (!object->wired_page_count)
                {
                    assert(VM_KERN_MEMORY_NONE != tag);
                    object->wire_tag = tag;
                    VM_OBJECT_WIRED(object);
                }
            }
            object->wired_page_count++;
        }
        assert(object->resident_page_count >= object->wired_page_count);

        if (batch_accounting == FALSE) {
                if (object->internal) {
                        OSAddAtomic(1, &vm_page_internal_count);
                } else {
                        OSAddAtomic(1, &vm_page_external_count);
                }
        }

        /*
         * It wouldn't make sense to insert a "reusable" page in
         * an object (the page would have been marked "reusable" only
         * at the time of a madvise(MADV_FREE_REUSABLE) if it was already
         * in the object at that time).
         * But a page could be inserted in a "all_reusable" object, if
         * something faults it in (a vm_read() from another task or a
         * "use-after-free" issue in user space, for example).  It can
         * also happen if we're relocating a page from that object to
         * a different physical page during a physically-contiguous
         * allocation.
         */
        assert(!mem->reusable);
        if (mem->object->all_reusable) {
                OSAddAtomic(+1, &vm_page_stats_reusable.reusable_count);
        }

        if (object->purgable == VM_PURGABLE_DENY) {
                owner = TASK_NULL;
        } else {
                owner = object->vo_purgeable_owner;
        }
        if (owner &&
            (object->purgable == VM_PURGABLE_NONVOLATILE ||
             VM_PAGE_WIRED(mem))) {

                if (delayed_ledger_update)
                        *delayed_ledger_update += PAGE_SIZE;
                else {
                        /* more non-volatile bytes */
                        ledger_credit(owner->ledger,
                                      task_ledgers.purgeable_nonvolatile,
                                      PAGE_SIZE);
                        /* more footprint */
                        ledger_credit(owner->ledger,
                                      task_ledgers.phys_footprint,
                                      PAGE_SIZE);
                }

        } else if (owner &&
                   (object->purgable == VM_PURGABLE_VOLATILE ||
                    object->purgable == VM_PURGABLE_EMPTY)) {
                assert(! VM_PAGE_WIRED(mem));
                /* more volatile bytes */
                ledger_credit(owner->ledger,
                              task_ledgers.purgeable_volatile,
                              PAGE_SIZE);
        }

        if (object->purgable == VM_PURGABLE_VOLATILE) {
                if (VM_PAGE_WIRED(mem)) {
                        OSAddAtomic(+1, &vm_page_purgeable_wired_count);
                } else {
                        OSAddAtomic(+1, &vm_page_purgeable_count);
                }
        } else if (object->purgable == VM_PURGABLE_EMPTY &&
                   mem->throttled) {
                /*
                 * This page belongs to a purged VM object but hasn't
                 * been purged (because it was "busy").
                 * It's in the "throttled" queue and hence not
                 * visible to vm_pageout_scan().  Move it to a pageable
                 * queue, so that it can eventually be reclaimed, instead
                 * of lingering in the "empty" object.
                 */
                if (queues_lock_held == FALSE)
                        vm_page_lockspin_queues();
                vm_page_deactivate(mem);
                if (queues_lock_held == FALSE)
                        vm_page_unlock_queues();
        }

#if VM_OBJECT_TRACKING_OP_MODIFIED
        if (vm_object_tracking_inited &&
            object->internal &&
            object->resident_page_count == 0 &&
            object->pager == NULL &&
            object->shadow != NULL &&
            object->shadow->copy == object) {
                void *bt[VM_OBJECT_TRACKING_BTDEPTH];
                int numsaved = 0;

                numsaved =OSBacktrace(bt, VM_OBJECT_TRACKING_BTDEPTH);
                btlog_add_entry(vm_object_tracking_btlog,
                                object,
                                VM_OBJECT_TRACKING_OP_MODIFIED,
                                bt,
                                numsaved);
        }
#endif /* VM_OBJECT_TRACKING_OP_MODIFIED */
}

/*
 *      vm_page_replace:
 *
 *      Exactly like vm_page_insert, except that we first
 *      remove any existing page at the given offset in object.
 *
 *      The object must be locked.
 */
void
vm_page_replace(
        register vm_page_t              mem,
        register vm_object_t            object,
        register vm_object_offset_t     offset)
{
        vm_page_bucket_t *bucket;
        vm_page_t        found_m = VM_PAGE_NULL;
        lck_spin_t      *bucket_lock;
        int             hash_id;

#if 0
        /*
         * we don't hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(mem);
#endif
        vm_object_lock_assert_exclusive(object);
#if DEBUG || VM_PAGE_CHECK_BUCKETS
        if (mem->tabled || mem->object != VM_OBJECT_NULL)
                panic("vm_page_replace: page %p for (obj=%p,off=0x%llx) "
                      "already in (obj=%p,off=0x%llx)",
                      mem, object, offset, mem->object, mem->offset);
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_NOTOWNED);
#endif
        /*
         *      Record the object/offset pair in this page
         */

        mem->object = object;
        mem->offset = offset;

        /*
         *      Insert it into the object_object/offset hash table,
         *      replacing any page that might have been there.
         */

        hash_id = vm_page_hash(object, offset);
        bucket = &vm_page_buckets[hash_id];
        bucket_lock = &vm_page_bucket_locks[hash_id / BUCKETS_PER_LOCK];

        lck_spin_lock(bucket_lock);

        if (bucket->page_list) {
                vm_page_packed_t *mp = &bucket->page_list;
                vm_page_t m = VM_PAGE_UNPACK_PTR(*mp);

                do {
                        if (m->object == object && m->offset == offset) {
                                /*
                                 * Remove old page from hash list
                                 */
                                *mp = m->next_m;
                                m->hashed = FALSE;

                                found_m = m;
                                break;
                        }
                        mp = &m->next_m;
                } while ((m = VM_PAGE_UNPACK_PTR(*mp)));

                mem->next_m = bucket->page_list;
        } else {
                mem->next_m = VM_PAGE_PACK_PTR(VM_PAGE_NULL);
        }
        /*
         * insert new page at head of hash list
         */
        bucket->page_list = VM_PAGE_PACK_PTR(mem);
        mem->hashed = TRUE;

        lck_spin_unlock(bucket_lock);

        if (found_m) {
                /*
                 * there was already a page at the specified
                 * offset for this object... remove it from
                 * the object and free it back to the free list
                 */
                vm_page_free_unlocked(found_m, FALSE);
        }
        vm_page_insert_internal(mem, object, offset, VM_KERN_MEMORY_NONE, FALSE, FALSE, FALSE, FALSE, NULL);
}

/*
 *      vm_page_remove:         [ internal use only ]
 *
 *      Removes the given mem entry from the object/offset-page
 *      table and the object page list.
 *
 *      The object must be locked.
 */

void
vm_page_remove(
        vm_page_t       mem,
        boolean_t       remove_from_hash)
{
        vm_page_bucket_t *bucket;
        vm_page_t       this;
        lck_spin_t      *bucket_lock;
        int             hash_id;
        task_t          owner;

        XPR(XPR_VM_PAGE,
                "vm_page_remove, object 0x%X offset 0x%X page 0x%X\n",
                mem->object, mem->offset, 
                mem, 0,0);

        vm_object_lock_assert_exclusive(mem->object);
        assert(mem->tabled);
        assert(!mem->cleaning);
        assert(!mem->laundry);
#if 0
        /*
         * we don't hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(mem);
#endif
        if (remove_from_hash == TRUE) {
                /*
                 *      Remove from the object_object/offset hash table
                 */
                hash_id = vm_page_hash(mem->object, mem->offset);
                bucket = &vm_page_buckets[hash_id];
                bucket_lock = &vm_page_bucket_locks[hash_id / BUCKETS_PER_LOCK];

                lck_spin_lock(bucket_lock);

                if ((this = VM_PAGE_UNPACK_PTR(bucket->page_list)) == mem) {
                        /* optimize for common case */

                        bucket->page_list = mem->next_m;
                } else {
                        vm_page_packed_t        *prev;

                        for (prev = &this->next_m;
                             (this = VM_PAGE_UNPACK_PTR(*prev)) != mem;
                             prev = &this->next_m)
                                continue;
                        *prev = this->next_m;
                }
#if     MACH_PAGE_HASH_STATS
                bucket->cur_count--;
#endif /* MACH_PAGE_HASH_STATS */
                mem->hashed = FALSE;
                lck_spin_unlock(bucket_lock);
        }
        /*
         *      Now remove from the object's list of backed pages.
         */

        vm_page_remove_internal(mem);

        /*
         *      And show that the object has one fewer resident
         *      page.
         */

        assert(mem->object->resident_page_count > 0);
        mem->object->resident_page_count--;

        if (mem->object->internal) {
#if DEBUG
                assert(vm_page_internal_count);
#endif /* DEBUG */

                OSAddAtomic(-1, &vm_page_internal_count);
        } else {
                assert(vm_page_external_count);
                OSAddAtomic(-1, &vm_page_external_count);

                if (mem->xpmapped) {
                        assert(vm_page_xpmapped_external_count);
                        OSAddAtomic(-1, &vm_page_xpmapped_external_count);
                }
        }
        if (!mem->object->internal && (mem->object->objq.next || mem->object->objq.prev)) {
                if (mem->object->resident_page_count == 0)
                        vm_object_cache_remove(mem->object);
        }

        if (VM_PAGE_WIRED(mem)) {
                assert(mem->object->wired_page_count > 0);
                mem->object->wired_page_count--;
                if (!mem->object->wired_page_count) {
                    VM_OBJECT_UNWIRED(mem->object);
                }
        }
        assert(mem->object->resident_page_count >=
               mem->object->wired_page_count);
        if (mem->reusable) {
                assert(mem->object->reusable_page_count > 0);
                mem->object->reusable_page_count--;
                assert(mem->object->reusable_page_count <=
                       mem->object->resident_page_count);
                mem->reusable = FALSE;
                OSAddAtomic(-1, &vm_page_stats_reusable.reusable_count);
                vm_page_stats_reusable.reused_remove++;
        } else if (mem->object->all_reusable) {
                OSAddAtomic(-1, &vm_page_stats_reusable.reusable_count);
                vm_page_stats_reusable.reused_remove++;
        }

        if (mem->object->purgable == VM_PURGABLE_DENY) {
                owner = TASK_NULL;
        } else {
                owner = mem->object->vo_purgeable_owner;
        }
        if (owner &&
            (mem->object->purgable == VM_PURGABLE_NONVOLATILE ||
             VM_PAGE_WIRED(mem))) {
                /* less non-volatile bytes */
                ledger_debit(owner->ledger,
                             task_ledgers.purgeable_nonvolatile,
                             PAGE_SIZE);
                /* less footprint */
                ledger_debit(owner->ledger,
                             task_ledgers.phys_footprint,
                             PAGE_SIZE);
        } else if (owner &&
                   (mem->object->purgable == VM_PURGABLE_VOLATILE ||
                    mem->object->purgable == VM_PURGABLE_EMPTY)) {
                assert(! VM_PAGE_WIRED(mem));
                /* less volatile bytes */
                ledger_debit(owner->ledger,
                             task_ledgers.purgeable_volatile,
                             PAGE_SIZE);
        }
        if (mem->object->purgable == VM_PURGABLE_VOLATILE) {
                if (VM_PAGE_WIRED(mem)) {
                        assert(vm_page_purgeable_wired_count > 0);
                        OSAddAtomic(-1, &vm_page_purgeable_wired_count);
                } else {
                        assert(vm_page_purgeable_count > 0);
                        OSAddAtomic(-1, &vm_page_purgeable_count);
                }
        }
        if (mem->object->set_cache_attr == TRUE)
                pmap_set_cache_attributes(mem->phys_page, 0);

        mem->tabled = FALSE;
        mem->object = VM_OBJECT_NULL;
        mem->offset = (vm_object_offset_t) -1;
}


/*
 *      vm_page_lookup:
 *
 *      Returns the page associated with the object/offset
 *      pair specified; if none is found, VM_PAGE_NULL is returned.
 *
 *      The object must be locked.  No side effects.
 */

#define VM_PAGE_HASH_LOOKUP_THRESHOLD   10

#if DEBUG_VM_PAGE_LOOKUP

struct {
        uint64_t        vpl_total;
        uint64_t        vpl_empty_obj;
        uint64_t        vpl_bucket_NULL;
        uint64_t        vpl_hit_hint;
        uint64_t        vpl_hit_hint_next;
        uint64_t        vpl_hit_hint_prev;
        uint64_t        vpl_fast;
        uint64_t        vpl_slow;
        uint64_t        vpl_hit;
        uint64_t        vpl_miss;

        uint64_t        vpl_fast_elapsed;
        uint64_t        vpl_slow_elapsed;
} vm_page_lookup_stats __attribute__((aligned(8)));

#endif

#define KDP_VM_PAGE_WALK_MAX    1000

vm_page_t
kdp_vm_page_lookup(
        vm_object_t             object,
        vm_object_offset_t      offset)
{
        vm_page_t cur_page;
        int num_traversed = 0;

        if (not_in_kdp) {
                panic("panic: kdp_vm_page_lookup done outside of kernel debugger");
        }

        queue_iterate(&object->memq, cur_page, vm_page_t, listq) {
                if (cur_page->offset == offset) {
                        return cur_page;
                }
                num_traversed++;

                if (num_traversed >= KDP_VM_PAGE_WALK_MAX) {
                        return VM_PAGE_NULL;
                }
        }

        return VM_PAGE_NULL;
}

vm_page_t
vm_page_lookup(
        vm_object_t             object,
        vm_object_offset_t      offset)
{
        vm_page_t       mem;
        vm_page_bucket_t *bucket;
        queue_entry_t   qe;
        lck_spin_t      *bucket_lock = NULL;
        int             hash_id;
#if DEBUG_VM_PAGE_LOOKUP
        uint64_t        start, elapsed;

        OSAddAtomic64(1, &vm_page_lookup_stats.vpl_total);
#endif
        vm_object_lock_assert_held(object);

        if (object->resident_page_count == 0) {
#if DEBUG_VM_PAGE_LOOKUP
                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_empty_obj);
#endif
                return (VM_PAGE_NULL);
        }

        mem = object->memq_hint;

        if (mem != VM_PAGE_NULL) {
                assert(mem->object == object);

                if (mem->offset == offset) {
#if DEBUG_VM_PAGE_LOOKUP
                        OSAddAtomic64(1, &vm_page_lookup_stats.vpl_hit_hint);
#endif
                        return (mem);
                }
                qe = queue_next(&mem->listq);

                if (! queue_end(&object->memq, qe)) {
                        vm_page_t       next_page;

                        next_page = (vm_page_t) qe;
                        assert(next_page->object == object);

                        if (next_page->offset == offset) {
                                object->memq_hint = next_page; /* new hint */
#if DEBUG_VM_PAGE_LOOKUP
                                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_hit_hint_next);
#endif
                                return (next_page);
                        }
                }
                qe = queue_prev(&mem->listq);

                if (! queue_end(&object->memq, qe)) {
                        vm_page_t prev_page;

                        prev_page = (vm_page_t) qe;
                        assert(prev_page->object == object);

                        if (prev_page->offset == offset) {
                                object->memq_hint = prev_page; /* new hint */
#if DEBUG_VM_PAGE_LOOKUP
                                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_hit_hint_prev);
#endif
                                return (prev_page);
                        }
                }
        }
        /*
         * Search the hash table for this object/offset pair
         */
        hash_id = vm_page_hash(object, offset);
        bucket = &vm_page_buckets[hash_id];

        /*
         * since we hold the object lock, we are guaranteed that no
         * new pages can be inserted into this object... this in turn
         * guarantess that the page we're looking for can't exist
         * if the bucket it hashes to is currently NULL even when looked
         * at outside the scope of the hash bucket lock... this is a 
         * really cheap optimiztion to avoid taking the lock
         */
        if (!bucket->page_list) {
#if DEBUG_VM_PAGE_LOOKUP
                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_bucket_NULL);
#endif
                return (VM_PAGE_NULL);
        }

#if DEBUG_VM_PAGE_LOOKUP
        start = mach_absolute_time();
#endif
        if (object->resident_page_count <= VM_PAGE_HASH_LOOKUP_THRESHOLD) {
                /*
                 * on average, it's roughly 3 times faster to run a short memq list
                 * than to take the spin lock and go through the hash list
                 */
                mem = (vm_page_t)queue_first(&object->memq);

                while (!queue_end(&object->memq, (queue_entry_t)mem)) {

                        if (mem->offset == offset)
                                break;

                        mem = (vm_page_t)queue_next(&mem->listq);
                }
                if (queue_end(&object->memq, (queue_entry_t)mem))
                        mem = NULL;
        } else {

                bucket_lock = &vm_page_bucket_locks[hash_id / BUCKETS_PER_LOCK];

                lck_spin_lock(bucket_lock);

                for (mem = VM_PAGE_UNPACK_PTR(bucket->page_list); mem != VM_PAGE_NULL; mem = VM_PAGE_UNPACK_PTR(mem->next_m)) {
#if 0
                        /*
                         * we don't hold the page queue lock
                         * so this check isn't safe to make
                         */
                        VM_PAGE_CHECK(mem);
#endif
                        if ((mem->object == object) && (mem->offset == offset))
                                break;
                }
                lck_spin_unlock(bucket_lock);
        }

#if DEBUG_VM_PAGE_LOOKUP
        elapsed = mach_absolute_time() - start;

        if (bucket_lock) {
                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_slow);
                OSAddAtomic64(elapsed, &vm_page_lookup_stats.vpl_slow_elapsed);
        } else {
                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_fast);
                OSAddAtomic64(elapsed, &vm_page_lookup_stats.vpl_fast_elapsed);
        }
        if (mem != VM_PAGE_NULL)
                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_hit);
        else
                OSAddAtomic64(1, &vm_page_lookup_stats.vpl_miss);
#endif
        if (mem != VM_PAGE_NULL) {
                assert(mem->object == object);

                object->memq_hint = mem;
        }
        return (mem);
}


/*
 *      vm_page_rename:
 *
 *      Move the given memory entry from its
 *      current object to the specified target object/offset.
 *
 *      The object must be locked.
 */
void
vm_page_rename(
        register vm_page_t              mem,
        register vm_object_t            new_object,
        vm_object_offset_t              new_offset,
        boolean_t                       encrypted_ok)
{
        boolean_t internal_to_external, external_to_internal;
        vm_tag_t  tag;

        assert(mem->object != new_object);

        assert(mem->object);

        /*
         * ENCRYPTED SWAP:
         * The encryption key is based on the page's memory object
         * (aka "pager") and paging offset.  Moving the page to
         * another VM object changes its "pager" and "paging_offset"
         * so it has to be decrypted first, or we would lose the key.
         *
         * One exception is VM object collapsing, where we transfer pages
         * from one backing object to its parent object.  This operation also
         * transfers the paging information, so the <pager,paging_offset> info
         * should remain consistent.  The caller (vm_object_do_collapse())
         * sets "encrypted_ok" in this case.
         */
        if (!encrypted_ok && mem->encrypted) {
                panic("vm_page_rename: page %p is encrypted\n", mem);
        }

        XPR(XPR_VM_PAGE,
                "vm_page_rename, new object 0x%X, offset 0x%X page 0x%X\n",
                new_object, new_offset, 
                mem, 0,0);

        /*
         *      Changes to mem->object require the page lock because
         *      the pageout daemon uses that lock to get the object.
         */
        vm_page_lockspin_queues();

        internal_to_external = FALSE;
        external_to_internal = FALSE;

        if (mem->local) {
                /*
                 * it's much easier to get the vm_page_pageable_xxx accounting correct
                 * if we first move the page to the active queue... it's going to end
                 * up there anyway, and we don't do vm_page_rename's frequently enough
                 * for this to matter.
                 */
                vm_page_queues_remove(mem);
                vm_page_activate(mem);
        }
        if (mem->active || mem->inactive || mem->speculative) {
                if (mem->object->internal && !new_object->internal) {
                        internal_to_external = TRUE;
                }
                if (!mem->object->internal && new_object->internal) {
                        external_to_internal = TRUE;
                }
        }

        tag = mem->object->wire_tag;
        vm_page_remove(mem, TRUE);
        vm_page_insert_internal(mem, new_object, new_offset, tag, TRUE, TRUE, FALSE, FALSE, NULL);

        if (internal_to_external) {
                vm_page_pageable_internal_count--;
                vm_page_pageable_external_count++;
        } else if (external_to_internal) {
                vm_page_pageable_external_count--;
                vm_page_pageable_internal_count++;
        }

        vm_page_unlock_queues();
}

/*
 *      vm_page_init:
 *
 *      Initialize the fields in a new page.
 *      This takes a structure with random values and initializes it
 *      so that it can be given to vm_page_release or vm_page_insert.
 */
void
vm_page_init(
        vm_page_t       mem,
        ppnum_t         phys_page,
        boolean_t       lopage)
{
        assert(phys_page);

#if     DEBUG
        if ((phys_page != vm_page_fictitious_addr) && (phys_page != vm_page_guard_addr)) {
                if (!(pmap_valid_page(phys_page))) {
                        panic("vm_page_init: non-DRAM phys_page 0x%x\n", phys_page);
                }
        }
#endif
        *mem = vm_page_template;
        mem->phys_page = phys_page;
#if 0
        /*
         * we're leaving this turned off for now... currently pages
         * come off the free list and are either immediately dirtied/referenced
         * due to zero-fill or COW faults, or are used to read or write files...
         * in the file I/O case, the UPL mechanism takes care of clearing
         * the state of the HW ref/mod bits in a somewhat fragile way.
         * Since we may change the way this works in the future (to toughen it up),
         * I'm leaving this as a reminder of where these bits could get cleared
         */

        /*
         * make sure both the h/w referenced and modified bits are
         * clear at this point... we are especially dependent on 
         * not finding a 'stale' h/w modified in a number of spots
         * once this page goes back into use
         */
        pmap_clear_refmod(phys_page, VM_MEM_MODIFIED | VM_MEM_REFERENCED);
#endif
        mem->lopage = lopage;
}

/*
 *      vm_page_grab_fictitious:
 *
 *      Remove a fictitious page from the free list.
 *      Returns VM_PAGE_NULL if there are no free pages.
 */
int     c_vm_page_grab_fictitious = 0;
int     c_vm_page_grab_fictitious_failed = 0;
int     c_vm_page_release_fictitious = 0;
int     c_vm_page_more_fictitious = 0;

vm_page_t
vm_page_grab_fictitious_common(
        ppnum_t phys_addr)
{
        vm_page_t       m;

        if ((m = (vm_page_t)zget(vm_page_zone))) {

                vm_page_init(m, phys_addr, FALSE);
                m->fictitious = TRUE;

                c_vm_page_grab_fictitious++;
        } else
                c_vm_page_grab_fictitious_failed++;

        return m;
}

vm_page_t
vm_page_grab_fictitious(void)
{
        return vm_page_grab_fictitious_common(vm_page_fictitious_addr);
}

vm_page_t
vm_page_grab_guard(void)
{
        return vm_page_grab_fictitious_common(vm_page_guard_addr);
}


/*
 *      vm_page_release_fictitious:
 *
 *      Release a fictitious page to the zone pool
 */
void
vm_page_release_fictitious(
        vm_page_t m)
{
        assert(!m->free);
        assert(m->fictitious);
        assert(m->phys_page == vm_page_fictitious_addr ||
               m->phys_page == vm_page_guard_addr);

        c_vm_page_release_fictitious++;

        zfree(vm_page_zone, m);
}

/*
 *      vm_page_more_fictitious:
 *
 *      Add more fictitious pages to the zone.
 *      Allowed to block. This routine is way intimate
 *      with the zones code, for several reasons:
 *      1. we need to carve some page structures out of physical
 *         memory before zones work, so they _cannot_ come from
 *         the zone_map.
 *      2. the zone needs to be collectable in order to prevent
 *         growth without bound. These structures are used by
 *         the device pager (by the hundreds and thousands), as
 *         private pages for pageout, and as blocking pages for
 *         pagein. Temporary bursts in demand should not result in
 *         permanent allocation of a resource.
 *      3. To smooth allocation humps, we allocate single pages
 *         with kernel_memory_allocate(), and cram them into the
 *         zone.
 */

void vm_page_more_fictitious(void)
{
        vm_offset_t     addr;
        kern_return_t   retval;

        c_vm_page_more_fictitious++;

        /*
         * Allocate a single page from the zone_map. Do not wait if no physical
         * pages are immediately available, and do not zero the space. We need
         * our own blocking lock here to prevent having multiple,
         * simultaneous requests from piling up on the zone_map lock. Exactly
         * one (of our) threads should be potentially waiting on the map lock.
         * If winner is not vm-privileged, then the page allocation will fail,
         * and it will temporarily block here in the vm_page_wait().
         */
        lck_mtx_lock(&vm_page_alloc_lock);
        /*
         * If another thread allocated space, just bail out now.
         */
        if (zone_free_count(vm_page_zone) > 5) {
                /*
                 * The number "5" is a small number that is larger than the
                 * number of fictitious pages that any single caller will
                 * attempt to allocate. Otherwise, a thread will attempt to
                 * acquire a fictitious page (vm_page_grab_fictitious), fail,
                 * release all of the resources and locks already acquired,
                 * and then call this routine. This routine finds the pages
                 * that the caller released, so fails to allocate new space.
                 * The process repeats infinitely. The largest known number
                 * of fictitious pages required in this manner is 2. 5 is
                 * simply a somewhat larger number.
                 */
                lck_mtx_unlock(&vm_page_alloc_lock);
                return;
        }

        retval = kernel_memory_allocate(zone_map,
                                        &addr, PAGE_SIZE, VM_PROT_ALL,
                                        KMA_KOBJECT|KMA_NOPAGEWAIT, VM_KERN_MEMORY_ZONE);
        if (retval != KERN_SUCCESS) { 
                /*
                 * No page was available. Drop the
                 * lock to give another thread a chance at it, and
                 * wait for the pageout daemon to make progress.
                 */
                lck_mtx_unlock(&vm_page_alloc_lock);
                vm_page_wait(THREAD_UNINT);
                return;
        }

        zcram(vm_page_zone, addr, PAGE_SIZE);

        lck_mtx_unlock(&vm_page_alloc_lock);
}


/*
 *      vm_pool_low():
 *
 *      Return true if it is not likely that a non-vm_privileged thread
 *      can get memory without blocking.  Advisory only, since the
 *      situation may change under us.
 */
int
vm_pool_low(void)
{
        /* No locking, at worst we will fib. */
        return( vm_page_free_count <= vm_page_free_reserved );
}



/*
 * this is an interface to support bring-up of drivers
 * on platforms with physical memory > 4G...
 */
int             vm_himemory_mode = 2;


/*
 * this interface exists to support hardware controllers
 * incapable of generating DMAs with more than 32 bits
 * of address on platforms with physical memory > 4G...
 */
unsigned int    vm_lopages_allocated_q = 0;
unsigned int    vm_lopages_allocated_cpm_success = 0;
unsigned int    vm_lopages_allocated_cpm_failed = 0;
queue_head_t    vm_lopage_queue_free;

vm_page_t
vm_page_grablo(void)
{
        vm_page_t       mem;

        if (vm_lopage_needed == FALSE)
                return (vm_page_grab());

        lck_mtx_lock_spin(&vm_page_queue_free_lock);

        if ( !queue_empty(&vm_lopage_queue_free)) {
                queue_remove_first(&vm_lopage_queue_free,
                                   mem,
                                   vm_page_t,
                                   pageq);
                assert(vm_lopage_free_count);

                vm_lopage_free_count--;
                vm_lopages_allocated_q++;

                if (vm_lopage_free_count < vm_lopage_lowater)
                        vm_lopage_refill = TRUE;

                lck_mtx_unlock(&vm_page_queue_free_lock);
        } else {
                lck_mtx_unlock(&vm_page_queue_free_lock);

                if (cpm_allocate(PAGE_SIZE, &mem, atop(0xffffffff), 0, FALSE, KMA_LOMEM) != KERN_SUCCESS) {

                        lck_mtx_lock_spin(&vm_page_queue_free_lock);
                        vm_lopages_allocated_cpm_failed++;
                        lck_mtx_unlock(&vm_page_queue_free_lock);

                        return (VM_PAGE_NULL);
                }
                mem->busy = TRUE;

                vm_page_lockspin_queues();
                
                mem->gobbled = FALSE;
                vm_page_gobble_count--;
                vm_page_wire_count--;

                vm_lopages_allocated_cpm_success++;
                vm_page_unlock_queues();
        }
        assert(mem->busy);
        assert(!mem->free);
        assert(!mem->pmapped);
        assert(!mem->wpmapped);
        assert(!pmap_is_noencrypt(mem->phys_page));

        mem->pageq.next = NULL;
        mem->pageq.prev = NULL;

        return (mem);
}


/*
 *      vm_page_grab:
 *
 *      first try to grab a page from the per-cpu free list...
 *      this must be done while pre-emption is disabled... if
 *      a page is available, we're done... 
 *      if no page is available, grab the vm_page_queue_free_lock
 *      and see if current number of free pages would allow us
 *      to grab at least 1... if not, return VM_PAGE_NULL as before... 
 *      if there are pages available, disable preemption and
 *      recheck the state of the per-cpu free list... we could
 *      have been preempted and moved to a different cpu, or
 *      some other thread could have re-filled it... if still
 *      empty, figure out how many pages we can steal from the
 *      global free queue and move to the per-cpu queue...
 *      return 1 of these pages when done... only wakeup the
 *      pageout_scan thread if we moved pages from the global
 *      list... no need for the wakeup if we've satisfied the
 *      request from the per-cpu queue.
 */


vm_page_t
vm_page_grab( void )
{
        vm_page_t       mem;


        disable_preemption();

        if ((mem = PROCESSOR_DATA(current_processor(), free_pages))) {
return_page_from_cpu_list:
                PROCESSOR_DATA(current_processor(), page_grab_count) += 1;
                PROCESSOR_DATA(current_processor(), free_pages) = mem->pageq.next;

                enable_preemption();
                mem->pageq.next = NULL;

                assert(mem->listq.next == NULL && mem->listq.prev == NULL);
                assert(mem->tabled == FALSE);
                assert(mem->object == VM_OBJECT_NULL);
                assert(!mem->laundry);
                assert(!mem->free);
                assert(pmap_verify_free(mem->phys_page));
                assert(mem->busy);
                assert(!mem->encrypted);
                assert(!mem->pmapped);
                assert(!mem->wpmapped);
                assert(!mem->active);
                assert(!mem->inactive);
                assert(!mem->throttled);
                assert(!mem->speculative);
                assert(!pmap_is_noencrypt(mem->phys_page));

                return mem;
        }
        enable_preemption();


        /*
         *      Optionally produce warnings if the wire or gobble
         *      counts exceed some threshold.
         */
#if VM_PAGE_WIRE_COUNT_WARNING
        if (vm_page_wire_count >= VM_PAGE_WIRE_COUNT_WARNING) {
                printf("mk: vm_page_grab(): high wired page count of %d\n",
                        vm_page_wire_count);
        }
#endif
#if VM_PAGE_GOBBLE_COUNT_WARNING
        if (vm_page_gobble_count >= VM_PAGE_GOBBLE_COUNT_WARNING) {
                printf("mk: vm_page_grab(): high gobbled page count of %d\n",
                        vm_page_gobble_count);
        }
#endif
        lck_mtx_lock_spin(&vm_page_queue_free_lock);

        /*
         *      Only let privileged threads (involved in pageout)
         *      dip into the reserved pool.
         */
        if ((vm_page_free_count < vm_page_free_reserved) &&
            !(current_thread()->options & TH_OPT_VMPRIV)) {
                lck_mtx_unlock(&vm_page_queue_free_lock);
                mem = VM_PAGE_NULL;
        }
        else {
               vm_page_t        head;
               vm_page_t        tail;
               unsigned int     pages_to_steal;
               unsigned int     color;

               while ( vm_page_free_count == 0 ) {

                        lck_mtx_unlock(&vm_page_queue_free_lock);
                        /*
                         * must be a privileged thread to be
                         * in this state since a non-privileged 
                         * thread would have bailed if we were
                         * under the vm_page_free_reserved mark
                         */
                        VM_PAGE_WAIT();
                        lck_mtx_lock_spin(&vm_page_queue_free_lock);
                }

                disable_preemption();

                if ((mem = PROCESSOR_DATA(current_processor(), free_pages))) {
                        lck_mtx_unlock(&vm_page_queue_free_lock);

                        /*
                         * we got preempted and moved to another processor
                         * or we got preempted and someone else ran and filled the cache
                         */
                        goto return_page_from_cpu_list;
                }
                if (vm_page_free_count <= vm_page_free_reserved)
                        pages_to_steal = 1;
                else {
                        if (vm_free_magazine_refill_limit <= (vm_page_free_count - vm_page_free_reserved))
                                pages_to_steal = vm_free_magazine_refill_limit;
                        else
                                pages_to_steal = (vm_page_free_count - vm_page_free_reserved);
                }
                color = PROCESSOR_DATA(current_processor(), start_color);
                head = tail = NULL;

                vm_page_free_count -= pages_to_steal;

                while (pages_to_steal--) {

                        while (queue_empty(&vm_page_queue_free[color]))
                                color = (color + 1) & vm_color_mask;
                
                        queue_remove_first(&vm_page_queue_free[color],
                                           mem,
                                           vm_page_t,
                                           pageq);
                        mem->pageq.next = NULL;
                        mem->pageq.prev = NULL;

                        assert(!mem->active);
                        assert(!mem->inactive);
                        assert(!mem->throttled);
                        assert(!mem->speculative);                      

                        color = (color + 1) & vm_color_mask;

                        if (head == NULL)
                                head = mem;
                        else
                                tail->pageq.next = (queue_t)mem;
                        tail = mem;

                        assert(mem->listq.next == NULL && mem->listq.prev == NULL);
                        assert(mem->tabled == FALSE);
                        assert(mem->object == VM_OBJECT_NULL);
                        assert(!mem->laundry);
                        assert(mem->free);
                        mem->free = FALSE;

                        assert(pmap_verify_free(mem->phys_page));
                        assert(mem->busy);
                        assert(!mem->free);
                        assert(!mem->encrypted);
                        assert(!mem->pmapped);
                        assert(!mem->wpmapped);
                        assert(!pmap_is_noencrypt(mem->phys_page));
                }
                lck_mtx_unlock(&vm_page_queue_free_lock);

                PROCESSOR_DATA(current_processor(), free_pages) = head->pageq.next;
                PROCESSOR_DATA(current_processor(), start_color) = color;

                /*
                 * satisfy this request
                 */
                PROCESSOR_DATA(current_processor(), page_grab_count) += 1;
                mem = head;
                mem->pageq.next = NULL;

                enable_preemption();
        }
        /*
         *      Decide if we should poke the pageout daemon.
         *      We do this if the free count is less than the low
         *      water mark, or if the free count is less than the high
         *      water mark (but above the low water mark) and the inactive
         *      count is less than its target.
         *
         *      We don't have the counts locked ... if they change a little,
         *      it doesn't really matter.
         */
        if ((vm_page_free_count < vm_page_free_min) ||
             ((vm_page_free_count < vm_page_free_target) &&
              ((vm_page_inactive_count + vm_page_speculative_count) < vm_page_inactive_min)))
                 thread_wakeup((event_t) &vm_page_free_wanted);

        VM_CHECK_MEMORYSTATUS;
        
//      dbgLog(mem->phys_page, vm_page_free_count, vm_page_wire_count, 4);      /* (TEST/DEBUG) */

        return mem;
}

/*
 *      vm_page_release:
 *
 *      Return a page to the free list.
 */

void
vm_page_release(
        register vm_page_t      mem)
{
        unsigned int    color;
        int     need_wakeup = 0;
        int     need_priv_wakeup = 0;


        assert(!mem->private && !mem->fictitious);
        if (vm_page_free_verify) {
                assert(pmap_verify_free(mem->phys_page));
        }
//      dbgLog(mem->phys_page, vm_page_free_count, vm_page_wire_count, 5);      /* (TEST/DEBUG) */

        pmap_clear_noencrypt(mem->phys_page);

        lck_mtx_lock_spin(&vm_page_queue_free_lock);
#if DEBUG
        if (mem->free)
                panic("vm_page_release");
#endif

        assert(mem->busy);
        assert(!mem->laundry);
        assert(mem->object == VM_OBJECT_NULL);
        assert(mem->pageq.next == NULL &&
               mem->pageq.prev == NULL);
        assert(mem->listq.next == NULL &&
               mem->listq.prev == NULL);
        
        if ((mem->lopage == TRUE || vm_lopage_refill == TRUE) &&
            vm_lopage_free_count < vm_lopage_free_limit &&
            mem->phys_page < max_valid_low_ppnum) {
                /*
                 * this exists to support hardware controllers
                 * incapable of generating DMAs with more than 32 bits
                 * of address on platforms with physical memory > 4G...
                 */
                queue_enter_first(&vm_lopage_queue_free,
                                  mem,
                                  vm_page_t,
                                  pageq);
                vm_lopage_free_count++;

                if (vm_lopage_free_count >= vm_lopage_free_limit)
                        vm_lopage_refill = FALSE;

                mem->lopage = TRUE;
        } else {          
                mem->lopage = FALSE;
                mem->free = TRUE;

                color = mem->phys_page & vm_color_mask;
                queue_enter_first(&vm_page_queue_free[color],
                                  mem,
                                  vm_page_t,
                                  pageq);
                vm_page_free_count++;
                /*
                 *      Check if we should wake up someone waiting for page.
                 *      But don't bother waking them unless they can allocate.
                 *
                 *      We wakeup only one thread, to prevent starvation.
                 *      Because the scheduling system handles wait queues FIFO,
                 *      if we wakeup all waiting threads, one greedy thread
                 *      can starve multiple niceguy threads.  When the threads
                 *      all wakeup, the greedy threads runs first, grabs the page,
                 *      and waits for another page.  It will be the first to run
                 *      when the next page is freed.
                 *
                 *      However, there is a slight danger here.
                 *      The thread we wake might not use the free page.
                 *      Then the other threads could wait indefinitely
                 *      while the page goes unused.  To forestall this,
                 *      the pageout daemon will keep making free pages
                 *      as long as vm_page_free_wanted is non-zero.
                 */

                assert(vm_page_free_count > 0);
                if (vm_page_free_wanted_privileged > 0) {
                        vm_page_free_wanted_privileged--;
                        need_priv_wakeup = 1;
                } else if (vm_page_free_wanted > 0 &&
                           vm_page_free_count > vm_page_free_reserved) {
                        vm_page_free_wanted--;
                        need_wakeup = 1;
                }
        }
        lck_mtx_unlock(&vm_page_queue_free_lock);

        if (need_priv_wakeup)
                thread_wakeup_one((event_t) &vm_page_free_wanted_privileged);
        else if (need_wakeup)
                thread_wakeup_one((event_t) &vm_page_free_count);

        VM_CHECK_MEMORYSTATUS;
}

/*
 * This version of vm_page_release() is used only at startup
 * when we are single-threaded and pages are being released 
 * for the first time. Hence, no locking or unnecessary checks are made.
 * Note: VM_CHECK_MEMORYSTATUS invoked by the caller.
 */
void
vm_page_release_startup(
        register vm_page_t      mem)
{
        queue_t queue_free;

        if (vm_lopage_free_count < vm_lopage_free_limit &&
            mem->phys_page < max_valid_low_ppnum) {
                mem->lopage = TRUE;
                vm_lopage_free_count++;
                queue_free = &vm_lopage_queue_free;
        } else {          
                mem->lopage = FALSE;
                mem->free = TRUE;
                vm_page_free_count++;
                queue_free = &vm_page_queue_free[mem->phys_page & vm_color_mask];
        }
        queue_enter_first(queue_free, mem, vm_page_t, pageq);
}

/*
 *      vm_page_wait:
 *
 *      Wait for a page to become available.
 *      If there are plenty of free pages, then we don't sleep.
 *
 *      Returns:
 *              TRUE:  There may be another page, try again
 *              FALSE: We were interrupted out of our wait, don't try again
 */

boolean_t
vm_page_wait(
        int     interruptible )
{
        /*
         *      We can't use vm_page_free_reserved to make this
         *      determination.  Consider: some thread might
         *      need to allocate two pages.  The first allocation
         *      succeeds, the second fails.  After the first page is freed,
         *      a call to vm_page_wait must really block.
         */
        kern_return_t   wait_result;
        int             need_wakeup = 0;
        int             is_privileged = current_thread()->options & TH_OPT_VMPRIV;

        lck_mtx_lock_spin(&vm_page_queue_free_lock);

        if (is_privileged && vm_page_free_count) {
                lck_mtx_unlock(&vm_page_queue_free_lock);
                return TRUE;
        }
        if (vm_page_free_count < vm_page_free_target) {

                if (is_privileged) {
                        if (vm_page_free_wanted_privileged++ == 0)
                                need_wakeup = 1;
                        wait_result = assert_wait((event_t)&vm_page_free_wanted_privileged, interruptible);
                } else {
                        if (vm_page_free_wanted++ == 0)
                                need_wakeup = 1;
                        wait_result = assert_wait((event_t)&vm_page_free_count, interruptible);
                }
                lck_mtx_unlock(&vm_page_queue_free_lock);
                counter(c_vm_page_wait_block++);

                if (need_wakeup)
                        thread_wakeup((event_t)&vm_page_free_wanted);

                if (wait_result == THREAD_WAITING) {
                        VM_DEBUG_EVENT(vm_page_wait_block, VM_PAGE_WAIT_BLOCK, DBG_FUNC_START,
                                       vm_page_free_wanted_privileged, vm_page_free_wanted, 0, 0);
                        wait_result = thread_block(THREAD_CONTINUE_NULL);
                        VM_DEBUG_EVENT(vm_page_wait_block, VM_PAGE_WAIT_BLOCK, DBG_FUNC_END, 0, 0, 0, 0);
                }

                return(wait_result == THREAD_AWAKENED);
        } else {
                lck_mtx_unlock(&vm_page_queue_free_lock);
                return TRUE;
        }
}

/*
 *      vm_page_alloc:
 *
 *      Allocate and return a memory cell associated
 *      with this VM object/offset pair.
 *
 *      Object must be locked.
 */

vm_page_t
vm_page_alloc(
        vm_object_t             object,
        vm_object_offset_t      offset)
{
        register vm_page_t      mem;

        vm_object_lock_assert_exclusive(object);
        mem = vm_page_grab();
        if (mem == VM_PAGE_NULL)
                return VM_PAGE_NULL;

        vm_page_insert(mem, object, offset);

        return(mem);
}

/*
 *      vm_page_alloc_guard:
 *      
 *      Allocate a fictitious page which will be used
 *      as a guard page.  The page will be inserted into
 *      the object and returned to the caller.
 */

vm_page_t
vm_page_alloc_guard(
        vm_object_t             object,
        vm_object_offset_t      offset)
{
        register vm_page_t      mem;

        vm_object_lock_assert_exclusive(object);
        mem = vm_page_grab_guard();
        if (mem == VM_PAGE_NULL)
                return VM_PAGE_NULL;

        vm_page_insert(mem, object, offset);

        return(mem);
}


counter(unsigned int c_laundry_pages_freed = 0;)

/*
 *      vm_page_free_prepare:
 *
 *      Removes page from any queue it may be on
 *      and disassociates it from its VM object.
 *
 *      Object and page queues must be locked prior to entry.
 */
static void
vm_page_free_prepare(
        vm_page_t       mem)
{
        vm_page_free_prepare_queues(mem);
        vm_page_free_prepare_object(mem, TRUE);
}


void
vm_page_free_prepare_queues(
        vm_page_t       mem)
{
        VM_PAGE_CHECK(mem);
        assert(!mem->free);
        assert(!mem->cleaning);

#if MACH_ASSERT || DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
        if (mem->free)
                panic("vm_page_free: freeing page on free list\n");
#endif /* MACH_ASSERT || DEBUG */
        if (mem->object) {
                vm_object_lock_assert_exclusive(mem->object);
        }
        if (mem->laundry) {
                /*
                 * We may have to free a page while it's being laundered
                 * if we lost its pager (due to a forced unmount, for example).
                 * We need to call vm_pageout_steal_laundry() before removing
                 * the page from its VM object, so that we can remove it
                 * from its pageout queue and adjust the laundry accounting
                 */
                vm_pageout_steal_laundry(mem, TRUE);
                counter(++c_laundry_pages_freed);
        }
        
        vm_page_queues_remove(mem);     /* clears local/active/inactive/throttled/speculative */

        if (VM_PAGE_WIRED(mem)) {
                if (mem->object) {
                        assert(mem->object->wired_page_count > 0);
                        mem->object->wired_page_count--;
                        if (!mem->object->wired_page_count) {
                            VM_OBJECT_UNWIRED(mem->object);
                        }

                        assert(mem->object->resident_page_count >=
                               mem->object->wired_page_count);

                        if (mem->object->purgable == VM_PURGABLE_VOLATILE) {
                                OSAddAtomic(+1, &vm_page_purgeable_count);
                                assert(vm_page_purgeable_wired_count > 0);
                                OSAddAtomic(-1, &vm_page_purgeable_wired_count);
                        }
                        if ((mem->object->purgable == VM_PURGABLE_VOLATILE ||
                             mem->object->purgable == VM_PURGABLE_EMPTY) &&
                            mem->object->vo_purgeable_owner != TASK_NULL) {
                                task_t owner;

                                owner = mem->object->vo_purgeable_owner;
                                /*
                                 * While wired, this page was accounted
                                 * as "non-volatile" but it should now
                                 * be accounted as "volatile".
                                 */
                                /* one less "non-volatile"... */
                                ledger_debit(owner->ledger,
                                             task_ledgers.purgeable_nonvolatile,
                                             PAGE_SIZE);
                                /* ... and "phys_footprint" */
                                ledger_debit(owner->ledger,
                                             task_ledgers.phys_footprint,
                                             PAGE_SIZE);
                                /* one more "volatile" */
                                ledger_credit(owner->ledger,
                                              task_ledgers.purgeable_volatile,
                                              PAGE_SIZE);
                        }
                }
                if (!mem->private && !mem->fictitious)
                        vm_page_wire_count--;
                mem->wire_count = 0;
                assert(!mem->gobbled);
        } else if (mem->gobbled) {
                if (!mem->private && !mem->fictitious)
                        vm_page_wire_count--;
                vm_page_gobble_count--;
        }
}


void
vm_page_free_prepare_object(
        vm_page_t       mem,
        boolean_t       remove_from_hash)
{
        if (mem->tabled)
                vm_page_remove(mem, remove_from_hash);  /* clears tabled, object, offset */

        PAGE_WAKEUP(mem);               /* clears wanted */

        if (mem->private) {
                mem->private = FALSE;
                mem->fictitious = TRUE;
                mem->phys_page = vm_page_fictitious_addr;
        }
        if ( !mem->fictitious) {
                vm_page_init(mem, mem->phys_page, mem->lopage);
        }
}


/*
 *      vm_page_free:
 *
 *      Returns the given page to the free list,
 *      disassociating it with any VM object.
 *
 *      Object and page queues must be locked prior to entry.
 */
void
vm_page_free(
        vm_page_t       mem)
{
        vm_page_free_prepare(mem);

        if (mem->fictitious) {
                vm_page_release_fictitious(mem);
        } else {
                vm_page_release(mem);
        }
}


void
vm_page_free_unlocked(
        vm_page_t       mem,
        boolean_t       remove_from_hash)
{
        vm_page_lockspin_queues();
        vm_page_free_prepare_queues(mem);
        vm_page_unlock_queues();

        vm_page_free_prepare_object(mem, remove_from_hash);

        if (mem->fictitious) {
                vm_page_release_fictitious(mem);
        } else {
                vm_page_release(mem);
        }
}


/*
 * Free a list of pages.  The list can be up to several hundred pages,
 * as blocked up by vm_pageout_scan().
 * The big win is not having to take the free list lock once
 * per page.
 */
void
vm_page_free_list(
        vm_page_t       freeq,
        boolean_t       prepare_object)
{
        vm_page_t       mem;
        vm_page_t       nxt;
        vm_page_t       local_freeq;
        int             pg_count;

        while (freeq) {

                pg_count = 0;
                local_freeq = VM_PAGE_NULL;
                mem = freeq;

                /*
                 * break up the processing into smaller chunks so
                 * that we can 'pipeline' the pages onto the
                 * free list w/o introducing too much
                 * contention on the global free queue lock
                 */
                while (mem && pg_count < 64) {

                        assert(!mem->inactive);
                        assert(!mem->active);
                        assert(!mem->throttled);
                        assert(!mem->free);
                        assert(!mem->speculative);
                        assert(!VM_PAGE_WIRED(mem));
                        assert(mem->pageq.prev == NULL);

                        nxt = (vm_page_t)(mem->pageq.next);
                
                        if (vm_page_free_verify && !mem->fictitious && !mem->private) {
                                assert(pmap_verify_free(mem->phys_page));
                        }
                        if (prepare_object == TRUE)
                                vm_page_free_prepare_object(mem, TRUE);

                        if (!mem->fictitious) {
                                assert(mem->busy);

                                if ((mem->lopage == TRUE || vm_lopage_refill == TRUE) &&
                                    vm_lopage_free_count < vm_lopage_free_limit &&
                                    mem->phys_page < max_valid_low_ppnum) {
                                        mem->pageq.next = NULL;
                                        vm_page_release(mem);
                                } else {
                                        /*
                                         * IMPORTANT: we can't set the page "free" here
                                         * because that would make the page eligible for
                                         * a physically-contiguous allocation (see
                                         * vm_page_find_contiguous()) right away (we don't
                                         * hold the vm_page_queue_free lock).  That would
                                         * cause trouble because the page is not actually
                                         * in the free queue yet...
                                         */
                                        mem->pageq.next = (queue_entry_t)local_freeq;
                                        local_freeq = mem;
                                        pg_count++;

                                        pmap_clear_noencrypt(mem->phys_page);
                                }
                        } else {
                                assert(mem->phys_page == vm_page_fictitious_addr ||
                                       mem->phys_page == vm_page_guard_addr);
                                vm_page_release_fictitious(mem);
                        }
                        mem = nxt;
                }
                freeq = mem;

                if ( (mem = local_freeq) ) {
                        unsigned int    avail_free_count;
                        unsigned int    need_wakeup = 0;
                        unsigned int    need_priv_wakeup = 0;
          
                        lck_mtx_lock_spin(&vm_page_queue_free_lock);

                        while (mem) {
                                int     color;

                                nxt = (vm_page_t)(mem->pageq.next);

                                assert(!mem->free);
                                assert(mem->busy);
                                mem->free = TRUE;

                                color = mem->phys_page & vm_color_mask;
                                queue_enter_first(&vm_page_queue_free[color],
                                                  mem,
                                                  vm_page_t,
                                                  pageq);
                                mem = nxt;
                        }
                        vm_page_free_count += pg_count;
                        avail_free_count = vm_page_free_count;

                        if (vm_page_free_wanted_privileged > 0 && avail_free_count > 0) {

                                if (avail_free_count < vm_page_free_wanted_privileged) {
                                        need_priv_wakeup = avail_free_count;
                                        vm_page_free_wanted_privileged -= avail_free_count;
                                        avail_free_count = 0;
                                } else {
                                        need_priv_wakeup = vm_page_free_wanted_privileged;
                                        vm_page_free_wanted_privileged = 0;
                                        avail_free_count -= vm_page_free_wanted_privileged;
                                }
                        }
                        if (vm_page_free_wanted > 0 && avail_free_count > vm_page_free_reserved) {
                                unsigned int  available_pages;

                                available_pages = avail_free_count - vm_page_free_reserved;

                                if (available_pages >= vm_page_free_wanted) {
                                        need_wakeup = vm_page_free_wanted;
                                        vm_page_free_wanted = 0;
                                } else {
                                        need_wakeup = available_pages;
                                        vm_page_free_wanted -= available_pages;
                                }
                        }
                        lck_mtx_unlock(&vm_page_queue_free_lock);

                        if (need_priv_wakeup != 0) {
                                /*
                                 * There shouldn't be that many VM-privileged threads,
                                 * so let's wake them all up, even if we don't quite
                                 * have enough pages to satisfy them all.
                                 */
                                thread_wakeup((event_t)&vm_page_free_wanted_privileged);
                        }
                        if (need_wakeup != 0 && vm_page_free_wanted == 0) {
                                /*
                                 * We don't expect to have any more waiters
                                 * after this, so let's wake them all up at
                                 * once.
                                 */
                                thread_wakeup((event_t) &vm_page_free_count);
                        } else for (; need_wakeup != 0; need_wakeup--) {
                                /*
                                 * Wake up one waiter per page we just released.
                                 */
                                thread_wakeup_one((event_t) &vm_page_free_count);
                        }

                        VM_CHECK_MEMORYSTATUS;
                }
        }
}


/*
 *      vm_page_wire:
 *
 *      Mark this page as wired down by yet
 *      another map, removing it from paging queues
 *      as necessary.
 *
 *      The page's object and the page queues must be locked.
 */


void
vm_page_wire(
        register vm_page_t mem,
        vm_tag_t           tag,
        boolean_t          check_memorystatus)
{

//      dbgLog(current_thread(), mem->offset, mem->object, 1);  /* (TEST/DEBUG) */

        VM_PAGE_CHECK(mem);
        if (mem->object) {
                vm_object_lock_assert_exclusive(mem->object);
        } else {
                /*
                 * In theory, the page should be in an object before it
                 * gets wired, since we need to hold the object lock
                 * to update some fields in the page structure.
                 * However, some code (i386 pmap, for example) might want
                 * to wire a page before it gets inserted into an object.
                 * That's somewhat OK, as long as nobody else can get to
                 * that page and update it at the same time.
                 */
        }
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        if ( !VM_PAGE_WIRED(mem)) {

                if (mem->pageout_queue) {
                        mem->pageout = FALSE;
                        vm_pageout_throttle_up(mem);
                }
                vm_page_queues_remove(mem);

                if (mem->object) {

                        if (!mem->private && !mem->fictitious) 
                        {
                            if (!mem->object->wired_page_count)
                            {
                                assert(VM_KERN_MEMORY_NONE != tag);
                                mem->object->wire_tag = tag;
                                VM_OBJECT_WIRED(mem->object);
                            }
                        }
                        mem->object->wired_page_count++;

                        assert(mem->object->resident_page_count >=
                               mem->object->wired_page_count);
                        if (mem->object->purgable == VM_PURGABLE_VOLATILE) {
                                assert(vm_page_purgeable_count > 0);
                                OSAddAtomic(-1, &vm_page_purgeable_count);
                                OSAddAtomic(1, &vm_page_purgeable_wired_count);
                        }
                        if ((mem->object->purgable == VM_PURGABLE_VOLATILE ||
                             mem->object->purgable == VM_PURGABLE_EMPTY) &&
                            mem->object->vo_purgeable_owner != TASK_NULL) {
                                task_t owner;

                                owner = mem->object->vo_purgeable_owner;
                                /* less volatile bytes */
                                ledger_debit(owner->ledger,
                                             task_ledgers.purgeable_volatile,
                                             PAGE_SIZE);
                                /* more not-quite-volatile bytes */
                                ledger_credit(owner->ledger,
                                              task_ledgers.purgeable_nonvolatile,
                                              PAGE_SIZE);
                                /* more footprint */
                                ledger_credit(owner->ledger,
                                              task_ledgers.phys_footprint,
                                              PAGE_SIZE);
                        }
                        if (mem->object->all_reusable) {
                                /*
                                 * Wired pages are not counted as "re-usable"
                                 * in "all_reusable" VM objects, so nothing
                                 * to do here.
                                 */
                        } else if (mem->reusable) {
                                /*
                                 * This page is not "re-usable" when it's
                                 * wired, so adjust its state and the
                                 * accounting.
                                 */
                                vm_object_reuse_pages(mem->object,
                                                      mem->offset,
                                                      mem->offset+PAGE_SIZE_64,
                                                      FALSE);
                        }
                }
                assert(!mem->reusable);

                if (!mem->private && !mem->fictitious && !mem->gobbled)
                        vm_page_wire_count++;
                if (mem->gobbled)
                        vm_page_gobble_count--;
                mem->gobbled = FALSE;

                if (check_memorystatus == TRUE) {
                        VM_CHECK_MEMORYSTATUS;
                }
                /* 
                 * ENCRYPTED SWAP:
                 * The page could be encrypted, but
                 * We don't have to decrypt it here
                 * because we don't guarantee that the
                 * data is actually valid at this point.
                 * The page will get decrypted in
                 * vm_fault_wire() if needed.
                 */
        }
        assert(!mem->gobbled);
        mem->wire_count++;
        VM_PAGE_CHECK(mem);
}

/*
 *      vm_page_unwire:
 *
 *      Release one wiring of this page, potentially
 *      enabling it to be paged again.
 *
 *      The page's object and the page queues must be locked.
 */
void
vm_page_unwire(
        vm_page_t       mem,
        boolean_t       queueit)
{

//      dbgLog(current_thread(), mem->offset, mem->object, 0);  /* (TEST/DEBUG) */

        VM_PAGE_CHECK(mem);
        assert(VM_PAGE_WIRED(mem));
        assert(!mem->gobbled);
        assert(mem->object != VM_OBJECT_NULL);
#if DEBUG
        vm_object_lock_assert_exclusive(mem->object);
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        if (--mem->wire_count == 0) {
                if (!mem->private && !mem->fictitious) {
                        vm_page_wire_count--;
                }
                assert(mem->object->wired_page_count > 0);
                mem->object->wired_page_count--;
                if (!mem->object->wired_page_count) {
                    VM_OBJECT_UNWIRED(mem->object);
                }
                assert(mem->object->resident_page_count >=
                       mem->object->wired_page_count);
                if (mem->object->purgable == VM_PURGABLE_VOLATILE) {
                        OSAddAtomic(+1, &vm_page_purgeable_count);
                        assert(vm_page_purgeable_wired_count > 0);
                        OSAddAtomic(-1, &vm_page_purgeable_wired_count);
                }
                if ((mem->object->purgable == VM_PURGABLE_VOLATILE ||
                     mem->object->purgable == VM_PURGABLE_EMPTY) &&
                    mem->object->vo_purgeable_owner != TASK_NULL) {
                        task_t owner;

                        owner = mem->object->vo_purgeable_owner;
                        /* more volatile bytes */
                        ledger_credit(owner->ledger,
                                      task_ledgers.purgeable_volatile,
                                      PAGE_SIZE);
                        /* less not-quite-volatile bytes */
                        ledger_debit(owner->ledger,
                                     task_ledgers.purgeable_nonvolatile,
                                     PAGE_SIZE);
                        /* less footprint */
                        ledger_debit(owner->ledger,
                                     task_ledgers.phys_footprint,
                                     PAGE_SIZE);
                }
                assert(mem->object != kernel_object);
                assert(mem->pageq.next == NULL && mem->pageq.prev == NULL);

                if (queueit == TRUE) {
                        if (mem->object->purgable == VM_PURGABLE_EMPTY) {
                                vm_page_deactivate(mem);
                        } else {
                                vm_page_activate(mem);
                        }
                }

                VM_CHECK_MEMORYSTATUS;
                
        }
        VM_PAGE_CHECK(mem);
}

/*
 *      vm_page_deactivate:
 *
 *      Returns the given page to the inactive list,
 *      indicating that no physical maps have access
 *      to this page.  [Used by the physical mapping system.]
 *
 *      The page queues must be locked.
 */
void
vm_page_deactivate(
        vm_page_t       m)
{
        vm_page_deactivate_internal(m, TRUE);
}


void
vm_page_deactivate_internal(
        vm_page_t       m,
        boolean_t       clear_hw_reference)
{

        VM_PAGE_CHECK(m);
        assert(m->object != kernel_object);
        assert(m->phys_page != vm_page_guard_addr);

//      dbgLog(m->phys_page, vm_page_free_count, vm_page_wire_count, 6);        /* (TEST/DEBUG) */
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        /*
         *      This page is no longer very interesting.  If it was
         *      interesting (active or inactive/referenced), then we
         *      clear the reference bit and (re)enter it in the
         *      inactive queue.  Note wired pages should not have
         *      their reference bit cleared.
         */
        assert ( !(m->absent && !m->unusual));

        if (m->gobbled) {               /* can this happen? */
                assert( !VM_PAGE_WIRED(m));

                if (!m->private && !m->fictitious)
                        vm_page_wire_count--;
                vm_page_gobble_count--;
                m->gobbled = FALSE;
        }
        /*
         * if this page is currently on the pageout queue, we can't do the
         * vm_page_queues_remove (which doesn't handle the pageout queue case)
         * and we can't remove it manually since we would need the object lock
         * (which is not required here) to decrement the activity_in_progress
         * reference which is held on the object while the page is in the pageout queue...
         * just let the normal laundry processing proceed
         */
        if (m->laundry || m->pageout_queue || m->private || m->fictitious || m->compressor || (VM_PAGE_WIRED(m)))
                return;

        if (!m->absent && clear_hw_reference == TRUE)
                pmap_clear_reference(m->phys_page);

        m->reference = FALSE;
        m->no_cache = FALSE;

        if (!m->inactive) {
                vm_page_queues_remove(m);

                if (!VM_DYNAMIC_PAGING_ENABLED(memory_manager_default) &&
                    m->dirty && m->object->internal &&
                    (m->object->purgable == VM_PURGABLE_DENY ||
                     m->object->purgable == VM_PURGABLE_NONVOLATILE ||
                     m->object->purgable == VM_PURGABLE_VOLATILE)) {
                        vm_page_check_pageable_safe(m);
                        queue_enter(&vm_page_queue_throttled, m, vm_page_t, pageq);
                        m->throttled = TRUE;
                        vm_page_throttled_count++;
                } else {
                        if (m->object->named && m->object->ref_count == 1) {
                                vm_page_speculate(m, FALSE);
#if DEVELOPMENT || DEBUG
                                vm_page_speculative_recreated++;
#endif
                        } else {
                                vm_page_enqueue_inactive(m, FALSE);
                        }
                }
        }
}

/*
 * vm_page_enqueue_cleaned
 *
 * Put the page on the cleaned queue, mark it cleaned, etc.
 * Being on the cleaned queue (and having m->clean_queue set)
 * does ** NOT ** guarantee that the page is clean!
 *
 * Call with the queues lock held.
 */

void vm_page_enqueue_cleaned(vm_page_t m)
{
        assert(m->phys_page != vm_page_guard_addr);
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        assert( !(m->absent && !m->unusual));

        if (m->gobbled) {
                assert( !VM_PAGE_WIRED(m));
                if (!m->private && !m->fictitious)
                        vm_page_wire_count--;
                vm_page_gobble_count--;
                m->gobbled = FALSE;
        }
        /*
         * if this page is currently on the pageout queue, we can't do the
         * vm_page_queues_remove (which doesn't handle the pageout queue case)
         * and we can't remove it manually since we would need the object lock
         * (which is not required here) to decrement the activity_in_progress
         * reference which is held on the object while the page is in the pageout queue...
         * just let the normal laundry processing proceed
         */
        if (m->laundry || m->clean_queue || m->pageout_queue || m->private || m->fictitious)
                return;

        vm_page_queues_remove(m);

        vm_page_check_pageable_safe(m);
        queue_enter(&vm_page_queue_cleaned, m, vm_page_t, pageq);
        m->clean_queue = TRUE;
        vm_page_cleaned_count++;

        m->inactive = TRUE;
        vm_page_inactive_count++;
        if (m->object->internal) {
                vm_page_pageable_internal_count++;
        } else {
                vm_page_pageable_external_count++;
        }

        vm_pageout_enqueued_cleaned++;
}

/*
 *      vm_page_activate:
 *
 *      Put the specified page on the active list (if appropriate).
 *
 *      The page queues must be locked.
 */

void
vm_page_activate(
        register vm_page_t      m)
{
        VM_PAGE_CHECK(m);
#ifdef  FIXME_4778297
        assert(m->object != kernel_object);
#endif
        assert(m->phys_page != vm_page_guard_addr);
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        assert( !(m->absent && !m->unusual));

        if (m->gobbled) {
                assert( !VM_PAGE_WIRED(m));
                if (!m->private && !m->fictitious)
                        vm_page_wire_count--;
                vm_page_gobble_count--;
                m->gobbled = FALSE;
        }
        /*
         * if this page is currently on the pageout queue, we can't do the
         * vm_page_queues_remove (which doesn't handle the pageout queue case)
         * and we can't remove it manually since we would need the object lock
         * (which is not required here) to decrement the activity_in_progress
         * reference which is held on the object while the page is in the pageout queue...
         * just let the normal laundry processing proceed
         */
        if (m->laundry || m->pageout_queue || m->private || m->fictitious || m->compressor)
                return;

#if DEBUG
        if (m->active)
                panic("vm_page_activate: already active");
#endif

        if (m->speculative) {
                DTRACE_VM2(pgrec, int, 1, (uint64_t *), NULL);
                DTRACE_VM2(pgfrec, int, 1, (uint64_t *), NULL);
        }
        
        vm_page_queues_remove(m);

        if ( !VM_PAGE_WIRED(m)) {
                vm_page_check_pageable_safe(m);
                if (!VM_DYNAMIC_PAGING_ENABLED(memory_manager_default) && 
                    m->dirty && m->object->internal && 
                    (m->object->purgable == VM_PURGABLE_DENY ||
                     m->object->purgable == VM_PURGABLE_NONVOLATILE ||
                     m->object->purgable == VM_PURGABLE_VOLATILE)) {
                        queue_enter(&vm_page_queue_throttled, m, vm_page_t, pageq);
                        m->throttled = TRUE;
                        vm_page_throttled_count++;
                } else {
                        queue_enter(&vm_page_queue_active, m, vm_page_t, pageq);
                        m->active = TRUE;
                        vm_page_active_count++;
                        if (m->object->internal) {
                                vm_page_pageable_internal_count++;
                        } else {
                                vm_page_pageable_external_count++;
                        }
                }
                m->reference = TRUE;
                m->no_cache = FALSE;
        }
        VM_PAGE_CHECK(m);
}


/*
 *      vm_page_speculate:
 *
 *      Put the specified page on the speculative list (if appropriate).
 *
 *      The page queues must be locked.
 */
void
vm_page_speculate(
        vm_page_t       m,
        boolean_t       new)
{
        struct vm_speculative_age_q     *aq;

        VM_PAGE_CHECK(m);
        vm_page_check_pageable_safe(m);

        assert(m->phys_page != vm_page_guard_addr);
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        assert( !(m->absent && !m->unusual));

        /*
         * if this page is currently on the pageout queue, we can't do the
         * vm_page_queues_remove (which doesn't handle the pageout queue case)
         * and we can't remove it manually since we would need the object lock
         * (which is not required here) to decrement the activity_in_progress
         * reference which is held on the object while the page is in the pageout queue...
         * just let the normal laundry processing proceed
         */
        if (m->laundry || m->pageout_queue || m->private || m->fictitious || m->compressor)
                return;

        vm_page_queues_remove(m);

        if ( !VM_PAGE_WIRED(m)) {
                mach_timespec_t         ts;
                clock_sec_t sec;
                clock_nsec_t nsec;

                clock_get_system_nanotime(&sec, &nsec);
                ts.tv_sec = (unsigned int) sec;
                ts.tv_nsec = nsec;

                if (vm_page_speculative_count == 0) {

                        speculative_age_index = VM_PAGE_MIN_SPECULATIVE_AGE_Q;
                        speculative_steal_index = VM_PAGE_MIN_SPECULATIVE_AGE_Q;

                        aq = &vm_page_queue_speculative[speculative_age_index];

                        /*
                         * set the timer to begin a new group
                         */
                        aq->age_ts.tv_sec = vm_page_speculative_q_age_ms / 1000;
                        aq->age_ts.tv_nsec = (vm_page_speculative_q_age_ms % 1000) * 1000 * NSEC_PER_USEC;

                        ADD_MACH_TIMESPEC(&aq->age_ts, &ts);
                } else {
                        aq = &vm_page_queue_speculative[speculative_age_index];

                        if (CMP_MACH_TIMESPEC(&ts, &aq->age_ts) >= 0) {

                                speculative_age_index++;

                                if (speculative_age_index > VM_PAGE_MAX_SPECULATIVE_AGE_Q)
                                        speculative_age_index = VM_PAGE_MIN_SPECULATIVE_AGE_Q;
                                if (speculative_age_index == speculative_steal_index) {
                                        speculative_steal_index = speculative_age_index + 1;

                                        if (speculative_steal_index > VM_PAGE_MAX_SPECULATIVE_AGE_Q)
                                                speculative_steal_index = VM_PAGE_MIN_SPECULATIVE_AGE_Q;
                                }
                                aq = &vm_page_queue_speculative[speculative_age_index];

                                if (!queue_empty(&aq->age_q))
                                        vm_page_speculate_ageit(aq);

                                aq->age_ts.tv_sec = vm_page_speculative_q_age_ms / 1000;
                                aq->age_ts.tv_nsec = (vm_page_speculative_q_age_ms % 1000) * 1000 * NSEC_PER_USEC;

                                ADD_MACH_TIMESPEC(&aq->age_ts, &ts);
                        }
                }
                enqueue_tail(&aq->age_q, &m->pageq);
                m->speculative = TRUE;
                vm_page_speculative_count++;
                if (m->object->internal) {
                        vm_page_pageable_internal_count++;
                } else {
                        vm_page_pageable_external_count++;
                }

                if (new == TRUE) {
                        vm_object_lock_assert_exclusive(m->object);

                        m->object->pages_created++;
#if DEVELOPMENT || DEBUG
                        vm_page_speculative_created++;
#endif
                }
        }
        VM_PAGE_CHECK(m);
}


/*
 * move pages from the specified aging bin to
 * the speculative bin that pageout_scan claims from
 *
 *      The page queues must be locked.
 */
void
vm_page_speculate_ageit(struct vm_speculative_age_q *aq)
{
        struct vm_speculative_age_q     *sq;
        vm_page_t       t;

        sq = &vm_page_queue_speculative[VM_PAGE_SPECULATIVE_AGED_Q];

        if (queue_empty(&sq->age_q)) {
                sq->age_q.next = aq->age_q.next;
                sq->age_q.prev = aq->age_q.prev;
                
                t = (vm_page_t)sq->age_q.next;
                t->pageq.prev = &sq->age_q;

                t = (vm_page_t)sq->age_q.prev;
                t->pageq.next = &sq->age_q;
        } else {
                t = (vm_page_t)sq->age_q.prev;
                t->pageq.next = aq->age_q.next;
                                                
                t = (vm_page_t)aq->age_q.next;
                t->pageq.prev = sq->age_q.prev;

                t = (vm_page_t)aq->age_q.prev;
                t->pageq.next = &sq->age_q;

                sq->age_q.prev = aq->age_q.prev;
        }
        queue_init(&aq->age_q);
}


void
vm_page_lru(
        vm_page_t       m)
{
        VM_PAGE_CHECK(m);
        assert(m->object != kernel_object);
        assert(m->phys_page != vm_page_guard_addr);

#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        /*
         * if this page is currently on the pageout queue, we can't do the
         * vm_page_queues_remove (which doesn't handle the pageout queue case)
         * and we can't remove it manually since we would need the object lock
         * (which is not required here) to decrement the activity_in_progress
         * reference which is held on the object while the page is in the pageout queue...
         * just let the normal laundry processing proceed
         */
        if (m->laundry || m->pageout_queue || m->private || m->compressor || (VM_PAGE_WIRED(m)))
                return;

        m->no_cache = FALSE;

        vm_page_queues_remove(m);

        vm_page_enqueue_inactive(m, FALSE);
}


void
vm_page_reactivate_all_throttled(void)
{
        vm_page_t       first_throttled, last_throttled;
        vm_page_t       first_active;
        vm_page_t       m;
        int             extra_active_count;
        int             extra_internal_count, extra_external_count;

        if (!VM_DYNAMIC_PAGING_ENABLED(memory_manager_default))
                return;

        extra_active_count = 0;
        extra_internal_count = 0;
        extra_external_count = 0;
        vm_page_lock_queues();
        if (! queue_empty(&vm_page_queue_throttled)) {
                /*
                 * Switch "throttled" pages to "active".
                 */
                queue_iterate(&vm_page_queue_throttled, m, vm_page_t, pageq) {
                        VM_PAGE_CHECK(m);
                        assert(m->throttled);
                        assert(!m->active);
                        assert(!m->inactive);
                        assert(!m->speculative);
                        assert(!VM_PAGE_WIRED(m));

                        extra_active_count++;
                        if (m->object->internal) {
                                extra_internal_count++;
                        } else {
                                extra_external_count++;
                        }

                        m->throttled = FALSE;
                        m->active = TRUE;
                        VM_PAGE_CHECK(m);
                }

                /*
                 * Transfer the entire throttled queue to a regular LRU page queues.
                 * We insert it at the head of the active queue, so that these pages
                 * get re-evaluated by the LRU algorithm first, since they've been
                 * completely out of it until now.
                 */
                first_throttled = (vm_page_t) queue_first(&vm_page_queue_throttled);
                last_throttled = (vm_page_t) queue_last(&vm_page_queue_throttled);
                first_active = (vm_page_t) queue_first(&vm_page_queue_active);
                if (queue_empty(&vm_page_queue_active)) {
                        queue_last(&vm_page_queue_active) = (queue_entry_t) last_throttled;
                } else {
                        queue_prev(&first_active->pageq) = (queue_entry_t) last_throttled;
                }
                queue_first(&vm_page_queue_active) = (queue_entry_t) first_throttled;
                queue_prev(&first_throttled->pageq) = (queue_entry_t) &vm_page_queue_active;
                queue_next(&last_throttled->pageq) = (queue_entry_t) first_active;

#if DEBUG
                printf("reactivated %d throttled pages\n", vm_page_throttled_count);
#endif
                queue_init(&vm_page_queue_throttled);
                /*
                 * Adjust the global page counts.
                 */
                vm_page_active_count += extra_active_count;
                vm_page_pageable_internal_count += extra_internal_count;
                vm_page_pageable_external_count += extra_external_count;
                vm_page_throttled_count = 0;
        }
        assert(vm_page_throttled_count == 0);
        assert(queue_empty(&vm_page_queue_throttled));
        vm_page_unlock_queues();
}


/*
 * move pages from the indicated local queue to the global active queue
 * its ok to fail if we're below the hard limit and force == FALSE
 * the nolocks == TRUE case is to allow this function to be run on
 * the hibernate path
 */

void
vm_page_reactivate_local(uint32_t lid, boolean_t force, boolean_t nolocks)
{
        struct vpl      *lq;
        vm_page_t       first_local, last_local;
        vm_page_t       first_active;
        vm_page_t       m;
        uint32_t        count = 0;

        if (vm_page_local_q == NULL)
                return;

        lq = &vm_page_local_q[lid].vpl_un.vpl;

        if (nolocks == FALSE) {
                if (lq->vpl_count < vm_page_local_q_hard_limit && force == FALSE) {
                        if ( !vm_page_trylockspin_queues())
                                return;
                } else
                        vm_page_lockspin_queues();

                VPL_LOCK(&lq->vpl_lock);
        }
        if (lq->vpl_count) {
                /*
                 * Switch "local" pages to "active".
                 */
                assert(!queue_empty(&lq->vpl_queue));

                queue_iterate(&lq->vpl_queue, m, vm_page_t, pageq) {
                        VM_PAGE_CHECK(m);
                        vm_page_check_pageable_safe(m);
                        assert(m->local);
                        assert(!m->active);
                        assert(!m->inactive);
                        assert(!m->speculative);
                        assert(!VM_PAGE_WIRED(m));
                        assert(!m->throttled);
                        assert(!m->fictitious);

                        if (m->local_id != lid)
                                panic("vm_page_reactivate_local: found vm_page_t(%p) with wrong cpuid", m);
                        
                        m->local_id = 0;
                        m->local = FALSE;
                        m->active = TRUE;
                        VM_PAGE_CHECK(m);

                        count++;
                }
                if (count != lq->vpl_count)
                        panic("vm_page_reactivate_local: count = %d, vm_page_local_count = %d\n", count, lq->vpl_count);

                /*
                 * Transfer the entire local queue to a regular LRU page queues.
                 */
                first_local = (vm_page_t) queue_first(&lq->vpl_queue);
                last_local = (vm_page_t) queue_last(&lq->vpl_queue);
                first_active = (vm_page_t) queue_first(&vm_page_queue_active);

                if (queue_empty(&vm_page_queue_active)) {
                        queue_last(&vm_page_queue_active) = (queue_entry_t) last_local;
                } else {
                        queue_prev(&first_active->pageq) = (queue_entry_t) last_local;
                }
                queue_first(&vm_page_queue_active) = (queue_entry_t) first_local;
                queue_prev(&first_local->pageq) = (queue_entry_t) &vm_page_queue_active;
                queue_next(&last_local->pageq) = (queue_entry_t) first_active;

                queue_init(&lq->vpl_queue);
                /*
                 * Adjust the global page counts.
                 */
                vm_page_active_count += lq->vpl_count;
                vm_page_pageable_internal_count += lq->vpl_internal_count;
                vm_page_pageable_external_count += lq->vpl_external_count;
                lq->vpl_count = 0;
                lq->vpl_internal_count = 0;
                lq->vpl_external_count = 0;
        }
        assert(queue_empty(&lq->vpl_queue));

        if (nolocks == FALSE) {
                VPL_UNLOCK(&lq->vpl_lock);
                vm_page_unlock_queues();
        }
}

/*
 *      vm_page_part_zero_fill:
 *
 *      Zero-fill a part of the page.
 */
#define PMAP_ZERO_PART_PAGE_IMPLEMENTED
void
vm_page_part_zero_fill(
        vm_page_t       m,
        vm_offset_t     m_pa,
        vm_size_t       len)
{

#if 0
        /*
         * we don't hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(m);
#endif

#ifdef PMAP_ZERO_PART_PAGE_IMPLEMENTED
        pmap_zero_part_page(m->phys_page, m_pa, len);
#else
        vm_page_t       tmp;
        while (1) {
                tmp = vm_page_grab();
                if (tmp == VM_PAGE_NULL) {
                        vm_page_wait(THREAD_UNINT);
                        continue;
                }
                break;  
        }
        vm_page_zero_fill(tmp);
        if(m_pa != 0) {
                vm_page_part_copy(m, 0, tmp, 0, m_pa);
        }
        if((m_pa + len) <  PAGE_SIZE) {
                vm_page_part_copy(m, m_pa + len, tmp, 
                                m_pa + len, PAGE_SIZE - (m_pa + len));
        }
        vm_page_copy(tmp,m);
        VM_PAGE_FREE(tmp); 
#endif

}

/*
 *      vm_page_zero_fill:
 *
 *      Zero-fill the specified page.
 */
void
vm_page_zero_fill(
        vm_page_t       m)
{
        XPR(XPR_VM_PAGE,
                "vm_page_zero_fill, object 0x%X offset 0x%X page 0x%X\n",
                m->object, m->offset, m, 0,0);
#if 0
        /*
         * we don't hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(m);
#endif

//      dbgTrace(0xAEAEAEAE, m->phys_page, 0);          /* (BRINGUP) */
        pmap_zero_page(m->phys_page);
}

/*
 *      vm_page_part_copy:
 *
 *      copy part of one page to another
 */

void
vm_page_part_copy(
        vm_page_t       src_m,
        vm_offset_t     src_pa,
        vm_page_t       dst_m,
        vm_offset_t     dst_pa,
        vm_size_t       len)
{
#if 0
        /*
         * we don't hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(src_m);
        VM_PAGE_CHECK(dst_m);
#endif
        pmap_copy_part_page(src_m->phys_page, src_pa,
                        dst_m->phys_page, dst_pa, len);
}

/*
 *      vm_page_copy:
 *
 *      Copy one page to another
 *
 * ENCRYPTED SWAP:
 * The source page should not be encrypted.  The caller should
 * make sure the page is decrypted first, if necessary.
 */

int vm_page_copy_cs_validations = 0;
int vm_page_copy_cs_tainted = 0;

void
vm_page_copy(
        vm_page_t       src_m,
        vm_page_t       dest_m)
{
        XPR(XPR_VM_PAGE,
        "vm_page_copy, object 0x%X offset 0x%X to object 0x%X offset 0x%X\n",
        src_m->object, src_m->offset, 
        dest_m->object, dest_m->offset,
        0);
#if 0
        /*
         * we don't hold the page queue lock
         * so this check isn't safe to make
         */
        VM_PAGE_CHECK(src_m);
        VM_PAGE_CHECK(dest_m);
#endif
        vm_object_lock_assert_held(src_m->object);

        /*
         * ENCRYPTED SWAP:
         * The source page should not be encrypted at this point.
         * The destination page will therefore not contain encrypted
         * data after the copy.
         */
        if (src_m->encrypted) {
                panic("vm_page_copy: source page %p is encrypted\n", src_m);
        }
        dest_m->encrypted = FALSE;

        if (src_m->object != VM_OBJECT_NULL &&
            src_m->object->code_signed) {
                /*
                 * We're copying a page from a code-signed object.
                 * Whoever ends up mapping the copy page might care about
                 * the original page's integrity, so let's validate the
                 * source page now.
                 */
                vm_page_copy_cs_validations++;
                vm_page_validate_cs(src_m);
        }

        if (vm_page_is_slideable(src_m)) {
                boolean_t was_busy = src_m->busy;
                src_m->busy = TRUE;
                (void) vm_page_slide(src_m, 0);
                assert(src_m->busy);
                if (!was_busy) {
                        PAGE_WAKEUP_DONE(src_m);
                }
        }

        /*
         * Propagate the cs_tainted bit to the copy page. Do not propagate
         * the cs_validated bit.
         */
        dest_m->cs_tainted = src_m->cs_tainted;
        if (dest_m->cs_tainted) {
                vm_page_copy_cs_tainted++;
        }
        dest_m->slid = src_m->slid;
        dest_m->error = src_m->error; /* sliding src_m might have failed... */
        pmap_copy_page(src_m->phys_page, dest_m->phys_page);
}

#if MACH_ASSERT
static void
_vm_page_print(
        vm_page_t       p)
{
        printf("vm_page %p: \n", p);
        printf("  pageq: next=%p prev=%p\n", p->pageq.next, p->pageq.prev);
        printf("  listq: next=%p prev=%p\n", p->listq.next, p->listq.prev);
        printf("  next=%p\n", VM_PAGE_UNPACK_PTR(p->next_m));
        printf("  object=%p offset=0x%llx\n", p->object, p->offset);
        printf("  wire_count=%u\n", p->wire_count);

        printf("  %slocal, %sinactive, %sactive, %spageout_queue, %sspeculative, %slaundry\n",
               (p->local ? "" : "!"),
               (p->inactive ? "" : "!"),
               (p->active ? "" : "!"),
               (p->pageout_queue ? "" : "!"),
               (p->speculative ? "" : "!"),
               (p->laundry ? "" : "!"));
        printf("  %sfree, %sref, %sgobbled, %sprivate, %sthrottled\n",
               (p->free ? "" : "!"),
               (p->reference ? "" : "!"),
               (p->gobbled ? "" : "!"),
               (p->private ? "" : "!"),
               (p->throttled ? "" : "!"));
        printf("  %sbusy, %swanted, %stabled, %sfictitious, %spmapped, %swpmapped\n",
                (p->busy ? "" : "!"),
                (p->wanted ? "" : "!"),
                (p->tabled ? "" : "!"),
                (p->fictitious ? "" : "!"),
                (p->pmapped ? "" : "!"),
                (p->wpmapped ? "" : "!"));
        printf("  %spageout, %sabsent, %serror, %sdirty, %scleaning, %sprecious, %sclustered\n",
               (p->pageout ? "" : "!"),
               (p->absent ? "" : "!"),
               (p->error ? "" : "!"),
               (p->dirty ? "" : "!"),
               (p->cleaning ? "" : "!"),
               (p->precious ? "" : "!"),
               (p->clustered ? "" : "!"));
        printf("  %soverwriting, %srestart, %sunusual, %sencrypted, %sencrypted_cleaning\n",
               (p->overwriting ? "" : "!"),
               (p->restart ? "" : "!"),
               (p->unusual ? "" : "!"),
               (p->encrypted ? "" : "!"),
               (p->encrypted_cleaning ? "" : "!"));
        printf("  %scs_validated, %scs_tainted, %scs_nx, %sno_cache\n",
               (p->cs_validated ? "" : "!"),
               (p->cs_tainted ? "" : "!"),
               (p->cs_nx ? "" : "!"),
               (p->no_cache ? "" : "!"));

        printf("phys_page=0x%x\n", p->phys_page);
}

/*
 *      Check that the list of pages is ordered by
 *      ascending physical address and has no holes.
 */
static int
vm_page_verify_contiguous(
        vm_page_t       pages,
        unsigned int    npages)
{
        register vm_page_t      m;
        unsigned int            page_count;
        vm_offset_t             prev_addr;

        prev_addr = pages->phys_page;
        page_count = 1;
        for (m = NEXT_PAGE(pages); m != VM_PAGE_NULL; m = NEXT_PAGE(m)) {
                if (m->phys_page != prev_addr + 1) {
                        printf("m %p prev_addr 0x%lx, current addr 0x%x\n",
                               m, (long)prev_addr, m->phys_page);
                        printf("pages %p page_count %d npages %d\n", pages, page_count, npages);
                        panic("vm_page_verify_contiguous:  not contiguous!");
                }
                prev_addr = m->phys_page;
                ++page_count;
        }
        if (page_count != npages) {
                printf("pages %p actual count 0x%x but requested 0x%x\n",
                       pages, page_count, npages);
                panic("vm_page_verify_contiguous:  count error");
        }
        return 1;
}


/*
 *      Check the free lists for proper length etc.
 */
static boolean_t vm_page_verify_this_free_list_enabled = FALSE;
static unsigned int
vm_page_verify_free_list(
        queue_head_t    *vm_page_queue,
        unsigned int    color,
        vm_page_t       look_for_page,
        boolean_t       expect_page)
{
        unsigned int    npages;
        vm_page_t       m;
        vm_page_t       prev_m;
        boolean_t       found_page;

        if (! vm_page_verify_this_free_list_enabled)
                return 0;

        found_page = FALSE;
        npages = 0;
        prev_m = (vm_page_t) vm_page_queue;
        queue_iterate(vm_page_queue,
                      m,
                      vm_page_t,
                      pageq) {

                if (m == look_for_page) {
                        found_page = TRUE;
                }
                if ((vm_page_t) m->pageq.prev != prev_m)
                        panic("vm_page_verify_free_list(color=%u, npages=%u): page %p corrupted prev ptr %p instead of %p\n",
                              color, npages, m, m->pageq.prev, prev_m);
                if ( ! m->busy )
                        panic("vm_page_verify_free_list(color=%u, npages=%u): page %p not busy\n",
                              color, npages, m);
                if (color != (unsigned int) -1) {
                        if ((m->phys_page & vm_color_mask) != color)
                                panic("vm_page_verify_free_list(color=%u, npages=%u): page %p wrong color %u instead of %u\n",
                                      color, npages, m, m->phys_page & vm_color_mask, color);
                        if ( ! m->free )
                                panic("vm_page_verify_free_list(color=%u, npages=%u): page %p not free\n",
                                      color, npages, m);
                }
                ++npages;
                prev_m = m;
        }
        if (look_for_page != VM_PAGE_NULL) {
                unsigned int other_color;

                if (expect_page && !found_page) {
                        printf("vm_page_verify_free_list(color=%u, npages=%u): page %p not found phys=%u\n",
                               color, npages, look_for_page, look_for_page->phys_page);
                        _vm_page_print(look_for_page);
                        for (other_color = 0;
                             other_color < vm_colors;
                             other_color++) {
                                if (other_color == color)
                                        continue;
                                vm_page_verify_free_list(&vm_page_queue_free[other_color],
                                                         other_color, look_for_page, FALSE);
                        }
                        if (color == (unsigned int) -1) {
                                vm_page_verify_free_list(&vm_lopage_queue_free,
                                                         (unsigned int) -1, look_for_page, FALSE);
                        }
                        panic("vm_page_verify_free_list(color=%u)\n", color);
                }
                if (!expect_page && found_page) {
                        printf("vm_page_verify_free_list(color=%u, npages=%u): page %p found phys=%u\n",
                               color, npages, look_for_page, look_for_page->phys_page);
                }
        }
        return npages;
}

static boolean_t vm_page_verify_all_free_lists_enabled = FALSE;
static void
vm_page_verify_free_lists( void )
{
        unsigned int    color, npages, nlopages;
        boolean_t       toggle = TRUE;

        if (! vm_page_verify_all_free_lists_enabled)
                return;

        npages = 0;

        lck_mtx_lock(&vm_page_queue_free_lock);
        
        if (vm_page_verify_this_free_list_enabled == TRUE) {
                /*
                 * This variable has been set globally for extra checking of
                 * each free list Q. Since we didn't set it, we don't own it
                 * and we shouldn't toggle it.
                 */
                toggle = FALSE;
        }

        if (toggle == TRUE) {
                vm_page_verify_this_free_list_enabled = TRUE;
        }

        for( color = 0; color < vm_colors; color++ ) {
                npages += vm_page_verify_free_list(&vm_page_queue_free[color],
                                                   color, VM_PAGE_NULL, FALSE);
        }
        nlopages = vm_page_verify_free_list(&vm_lopage_queue_free,
                                            (unsigned int) -1,
                                            VM_PAGE_NULL, FALSE);
        if (npages != vm_page_free_count || nlopages != vm_lopage_free_count)
                panic("vm_page_verify_free_lists:  "
                      "npages %u free_count %d nlopages %u lo_free_count %u",
                      npages, vm_page_free_count, nlopages, vm_lopage_free_count);

        if (toggle == TRUE) {
                vm_page_verify_this_free_list_enabled = FALSE;
        }

        lck_mtx_unlock(&vm_page_queue_free_lock);
}

void
vm_page_queues_assert(
        vm_page_t       mem,
        int             val)
{
#if DEBUG
        lck_mtx_assert(&vm_page_queue_lock, LCK_MTX_ASSERT_OWNED);
#endif
        if (mem->free + mem->active + mem->inactive + mem->speculative +
            mem->throttled + mem->pageout_queue > (val)) {
                _vm_page_print(mem);
                panic("vm_page_queues_assert(%p, %d)\n", mem, val);
        }
        if (VM_PAGE_WIRED(mem)) {
                assert(!mem->active);
                assert(!mem->inactive);
                assert(!mem->speculative);
                assert(!mem->throttled);
                assert(!mem->pageout_queue);
        }
}
#endif  /* MACH_ASSERT */





extern boolean_t (* volatile consider_buffer_cache_collect)(int);

/*
 *      CONTIGUOUS PAGE ALLOCATION
 *
 *      Find a region large enough to contain at least n pages
 *      of contiguous physical memory.
 *
 *      This is done by traversing the vm_page_t array in a linear fashion
 *      we assume that the vm_page_t array has the avaiable physical pages in an
 *      ordered, ascending list... this is currently true of all our implementations
 *      and must remain so... there can be 'holes' in the array...  we also can
 *      no longer tolerate the vm_page_t's in the list being 'freed' and reclaimed
 *      which use to happen via 'vm_page_convert'... that function was no longer
 *      being called and was removed...
 *      
 *      The basic flow consists of stabilizing some of the interesting state of 
 *      a vm_page_t behind the vm_page_queue and vm_page_free locks... we start our
 *      sweep at the beginning of the array looking for pages that meet our criterea
 *      for a 'stealable' page... currently we are pretty conservative... if the page
 *      meets this criterea and is physically contiguous to the previous page in the 'run'
 *      we keep developing it.  If we hit a page that doesn't fit, we reset our state
 *      and start to develop a new run... if at this point we've already considered
 *      at least MAX_CONSIDERED_BEFORE_YIELD pages, we'll drop the 2 locks we hold,
 *      and mutex_pause (which will yield the processor), to keep the latency low w/r 
 *      to other threads trying to acquire free pages (or move pages from q to q),
 *      and then continue from the spot we left off... we only make 1 pass through the
 *      array.  Once we have a 'run' that is long enough, we'll go into the loop which
 *      which steals the pages from the queues they're currently on... pages on the free
 *      queue can be stolen directly... pages that are on any of the other queues
 *      must be removed from the object they are tabled on... this requires taking the
 *      object lock... we do this as a 'try' to prevent deadlocks... if the 'try' fails
 *      or if the state of the page behind the vm_object lock is no longer viable, we'll
 *      dump the pages we've currently stolen back to the free list, and pick up our
 *      scan from the point where we aborted the 'current' run.
 *
 *
 *      Requirements:
 *              - neither vm_page_queue nor vm_free_list lock can be held on entry
 *
 *      Returns a pointer to a list of gobbled/wired pages or VM_PAGE_NULL.
 *
 * Algorithm:
 */

#define MAX_CONSIDERED_BEFORE_YIELD     1000


#define RESET_STATE_OF_RUN()    \
        MACRO_BEGIN             \
        prevcontaddr = -2;      \
        start_pnum = -1;        \
        free_considered = 0;    \
        substitute_needed = 0;  \
        npages = 0;             \
        MACRO_END                       

/*
 * Can we steal in-use (i.e. not free) pages when searching for
 * physically-contiguous pages ?
 */
#define VM_PAGE_FIND_CONTIGUOUS_CAN_STEAL 1

static unsigned int vm_page_find_contiguous_last_idx = 0,  vm_page_lomem_find_contiguous_last_idx = 0;
#if DEBUG
int vm_page_find_contig_debug = 0;
#endif

static vm_page_t
vm_page_find_contiguous(
        unsigned int    contig_pages,
        ppnum_t         max_pnum,
        ppnum_t     pnum_mask,
        boolean_t       wire,
        int             flags)
{
        vm_page_t       m = NULL;
        ppnum_t         prevcontaddr;
        ppnum_t         start_pnum;
        unsigned int    npages, considered, scanned;
        unsigned int    page_idx, start_idx, last_idx, orig_last_idx;
        unsigned int    idx_last_contig_page_found = 0;
        int             free_considered, free_available;
        int             substitute_needed;
        boolean_t       wrapped, zone_gc_called = FALSE;
#if DEBUG
        clock_sec_t     tv_start_sec, tv_end_sec;
        clock_usec_t    tv_start_usec, tv_end_usec;
#endif

        int             yielded = 0;
        int             dumped_run = 0;
        int             stolen_pages = 0;
        int             compressed_pages = 0;


        if (contig_pages == 0)
                return VM_PAGE_NULL;

full_scan_again:

#if MACH_ASSERT
        vm_page_verify_free_lists();
#endif
#if DEBUG
        clock_get_system_microtime(&tv_start_sec, &tv_start_usec);
#endif
        PAGE_REPLACEMENT_ALLOWED(TRUE);

        vm_page_lock_queues();


        lck_mtx_lock(&vm_page_queue_free_lock);

        RESET_STATE_OF_RUN();

        scanned = 0;
        considered = 0;
        free_available = vm_page_free_count - vm_page_free_reserved;

        wrapped = FALSE;
        
        if(flags & KMA_LOMEM) 
                idx_last_contig_page_found = vm_page_lomem_find_contiguous_last_idx;
        else
                idx_last_contig_page_found =  vm_page_find_contiguous_last_idx;

        orig_last_idx = idx_last_contig_page_found;
        last_idx = orig_last_idx;

        for (page_idx = last_idx, start_idx = last_idx;
             npages < contig_pages && page_idx < vm_pages_count;
             page_idx++) {
retry:
                if (wrapped &&
                    npages == 0 &&
                    page_idx >= orig_last_idx) {
                        /*
                         * We're back where we started and we haven't
                         * found any suitable contiguous range.  Let's
                         * give up.
                         */
                        break;
                }
                scanned++;
                m = &vm_pages[page_idx];

                assert(!m->fictitious);
                assert(!m->private);

                if (max_pnum && m->phys_page > max_pnum) {
                        /* no more low pages... */
                        break;
                }
                if (!npages & ((m->phys_page & pnum_mask) != 0)) {
                        /*
                         * not aligned
                         */
                        RESET_STATE_OF_RUN();

                } else if (VM_PAGE_WIRED(m) || m->gobbled ||
                           m->encrypted_cleaning ||
                           m->pageout_queue || m->laundry || m->wanted ||
                           m->cleaning || m->overwriting || m->pageout) {
                        /*
                         * page is in a transient state
                         * or a state we don't want to deal
                         * with, so don't consider it which
                         * means starting a new run
                         */
                        RESET_STATE_OF_RUN();

                } else if (!m->free && !m->active && !m->inactive && !m->speculative && !m->throttled && !m->compressor) {
                        /*
                         * page needs to be on one of our queues
                         * or it needs to belong to the compressor pool
                         * in order for it to be stable behind the
                         * locks we hold at this point...
                         * if not, don't consider it which
                         * means starting a new run
                         */
                        RESET_STATE_OF_RUN();

                } else if (!m->free && (!m->tabled || m->busy)) {
                        /*
                         * pages on the free list are always 'busy'
                         * so we couldn't test for 'busy' in the check
                         * for the transient states... pages that are
                         * 'free' are never 'tabled', so we also couldn't
                         * test for 'tabled'.  So we check here to make
                         * sure that a non-free page is not busy and is
                         * tabled on an object... 
                         * if not, don't consider it which
                         * means starting a new run
                         */
                        RESET_STATE_OF_RUN();

                } else {
                        if (m->phys_page != prevcontaddr + 1) {
                                if ((m->phys_page & pnum_mask) != 0) {
                                        RESET_STATE_OF_RUN();
                                        goto did_consider;
                                } else {
                                        npages = 1;
                                        start_idx = page_idx;
                                        start_pnum = m->phys_page;
                                }
                        } else {
                                npages++;
                        }
                        prevcontaddr = m->phys_page;
                        
                        VM_PAGE_CHECK(m);
                        if (m->free) {
                                free_considered++;
                        } else {
                                /*
                                 * This page is not free.
                                 * If we can't steal used pages,
                                 * we have to give up this run
                                 * and keep looking.
                                 * Otherwise, we might need to
                                 * move the contents of this page
                                 * into a substitute page.
                                 */
#if VM_PAGE_FIND_CONTIGUOUS_CAN_STEAL
                                if (m->pmapped || m->dirty || m->precious) {
                                        substitute_needed++;
                                }
#else
                                RESET_STATE_OF_RUN();
#endif
                        }

                        if ((free_considered + substitute_needed) > free_available) {   
                                /*
                                 * if we let this run continue
                                 * we will end up dropping the vm_page_free_count
                                 * below the reserve limit... we need to abort
                                 * this run, but we can at least re-consider this
                                 * page... thus the jump back to 'retry'
                                 */
                                RESET_STATE_OF_RUN();

                                if (free_available && considered <= MAX_CONSIDERED_BEFORE_YIELD) {
                                        considered++;
                                        goto retry;
                                }
                                /*
                                 * free_available == 0
                                 * so can't consider any free pages... if
                                 * we went to retry in this case, we'd
                                 * get stuck looking at the same page
                                 * w/o making any forward progress
                                 * we also want to take this path if we've already
                                 * reached our limit that controls the lock latency
                                 */
                        }
                }
did_consider:
                if (considered > MAX_CONSIDERED_BEFORE_YIELD && npages <= 1) {

                        PAGE_REPLACEMENT_ALLOWED(FALSE);

                        lck_mtx_unlock(&vm_page_queue_free_lock);
                        vm_page_unlock_queues();

                        mutex_pause(0);

                        PAGE_REPLACEMENT_ALLOWED(TRUE);

                        vm_page_lock_queues();
                        lck_mtx_lock(&vm_page_queue_free_lock);

                        RESET_STATE_OF_RUN();
                        /*
                         * reset our free page limit since we
                         * dropped the lock protecting the vm_page_free_queue
                         */
                        free_available = vm_page_free_count - vm_page_free_reserved;
                        considered = 0;

                        yielded++;

                        goto retry;
                }
                considered++;
        }
        m = VM_PAGE_NULL;

        if (npages != contig_pages) {
                if (!wrapped) {
                        /*
                         * We didn't find a contiguous range but we didn't
                         * start from the very first page.
                         * Start again from the very first page.
                         */
                        RESET_STATE_OF_RUN();
                        if( flags & KMA_LOMEM)
                                idx_last_contig_page_found  = vm_page_lomem_find_contiguous_last_idx = 0;
                        else
                                idx_last_contig_page_found = vm_page_find_contiguous_last_idx = 0;
                        last_idx = 0;
                        page_idx = last_idx;
                        wrapped = TRUE;
                        goto retry;
                }
                lck_mtx_unlock(&vm_page_queue_free_lock);
        } else {
                vm_page_t       m1;
                vm_page_t       m2;
                unsigned int    cur_idx;
                unsigned int    tmp_start_idx;
                vm_object_t     locked_object = VM_OBJECT_NULL;
                boolean_t       abort_run = FALSE;
                
                assert(page_idx - start_idx == contig_pages);

                tmp_start_idx = start_idx;

                /*
                 * first pass through to pull the free pages
                 * off of the free queue so that in case we
                 * need substitute pages, we won't grab any 
                 * of the free pages in the run... we'll clear
                 * the 'free' bit in the 2nd pass, and even in
                 * an abort_run case, we'll collect all of the
                 * free pages in this run and return them to the free list
                 */
                while (start_idx < page_idx) {

                        m1 = &vm_pages[start_idx++];

#if !VM_PAGE_FIND_CONTIGUOUS_CAN_STEAL
                        assert(m1->free);
#endif

                        if (m1->free) {
                                unsigned int color;

                                color = m1->phys_page & vm_color_mask;
#if MACH_ASSERT
                                vm_page_verify_free_list(&vm_page_queue_free[color], color, m1, TRUE);
#endif
                                queue_remove(&vm_page_queue_free[color],
                                             m1,
                                             vm_page_t,
                                             pageq);
                                m1->pageq.next = NULL;
                                m1->pageq.prev = NULL;
#if MACH_ASSERT
                                vm_page_verify_free_list(&vm_page_queue_free[color], color, VM_PAGE_NULL, FALSE);
#endif
                                /*
                                 * Clear the "free" bit so that this page
                                 * does not get considered for another
                                 * concurrent physically-contiguous allocation.
                                 */
                                m1->free = FALSE; 
                                assert(m1->busy);

                                vm_page_free_count--;
                        }
                }
                if( flags & KMA_LOMEM)
                        vm_page_lomem_find_contiguous_last_idx = page_idx;
                else 
                        vm_page_find_contiguous_last_idx = page_idx;
                
                /*
                 * we can drop the free queue lock at this point since
                 * we've pulled any 'free' candidates off of the list
                 * we need it dropped so that we can do a vm_page_grab
                 * when substituing for pmapped/dirty pages
                 */
                lck_mtx_unlock(&vm_page_queue_free_lock);

                start_idx = tmp_start_idx;
                cur_idx = page_idx - 1;

                while (start_idx++ < page_idx) {
                        /*
                         * must go through the list from back to front
                         * so that the page list is created in the
                         * correct order - low -> high phys addresses
                         */
                        m1 = &vm_pages[cur_idx--];

                        assert(!m1->free);

                        if (m1->object == VM_OBJECT_NULL) {
                                /*
                                 * page has already been removed from
                                 * the free list in the 1st pass
                                 */
                                assert(m1->offset == (vm_object_offset_t) -1);
                                assert(m1->busy);
                                assert(!m1->wanted);
                                assert(!m1->laundry);
                        } else {
                                vm_object_t object;
                                int refmod;
                                boolean_t disconnected, reusable;

                                if (abort_run == TRUE)
                                        continue;

                                object = m1->object;

                                if (object != locked_object) {
                                        if (locked_object) {
                                                vm_object_unlock(locked_object);
                                                locked_object = VM_OBJECT_NULL;
                                        }
                                        if (vm_object_lock_try(object))
                                                locked_object = object;
                                }
                                if (locked_object == VM_OBJECT_NULL || 
                                    (VM_PAGE_WIRED(m1) || m1->gobbled ||
                                     m1->encrypted_cleaning ||
                                     m1->pageout_queue || m1->laundry || m1->wanted ||
                                     m1->cleaning || m1->overwriting || m1->pageout || m1->busy)) {

                                        if (locked_object) {
                                                vm_object_unlock(locked_object);
                                                locked_object = VM_OBJECT_NULL;
                                        }
                                        tmp_start_idx = cur_idx;
                                        abort_run = TRUE;
                                        continue;
                                }

                                disconnected = FALSE;
                                reusable = FALSE;

                                if ((m1->reusable ||
                                     m1->object->all_reusable) &&
                                    m1->inactive &&
                                    !m1->dirty &&
                                    !m1->reference) {
                                        /* reusable page... */
                                        refmod = pmap_disconnect(m1->phys_page);
                                        disconnected = TRUE;
                                        if (refmod == 0) {
                                                /*
                                                 * ... not reused: can steal
                                                 * without relocating contents.
                                                 */
                                                reusable = TRUE;
                                        }
                                }

                                if ((m1->pmapped &&
                                     ! reusable) ||
                                    m1->dirty ||
                                    m1->precious) {
                                        vm_object_offset_t offset;

                                        m2 = vm_page_grab();

                                        if (m2 == VM_PAGE_NULL) {
                                                if (locked_object) {
                                                        vm_object_unlock(locked_object);
                                                        locked_object = VM_OBJECT_NULL;
                                                }
                                                tmp_start_idx = cur_idx;
                                                abort_run = TRUE;
                                                continue;
                                        }
                                        if (! disconnected) {
                                                if (m1->pmapped)
                                                        refmod = pmap_disconnect(m1->phys_page);
                                                else
                                                        refmod = 0;
                                        }

                                        /* copy the page's contents */
                                        pmap_copy_page(m1->phys_page, m2->phys_page);
                                        /* copy the page's state */
                                        assert(!VM_PAGE_WIRED(m1));
                                        assert(!m1->free);
                                        assert(!m1->pageout_queue);
                                        assert(!m1->laundry);
                                        m2->reference   = m1->reference;
                                        assert(!m1->gobbled);
                                        assert(!m1->private);
                                        m2->no_cache    = m1->no_cache;
                                        m2->xpmapped    = 0;
                                        assert(!m1->busy);
                                        assert(!m1->wanted);
                                        assert(!m1->fictitious);
                                        m2->pmapped     = m1->pmapped; /* should flush cache ? */
                                        m2->wpmapped    = m1->wpmapped;
                                        assert(!m1->pageout);
                                        m2->absent      = m1->absent;
                                        m2->error       = m1->error;
                                        m2->dirty       = m1->dirty;
                                        assert(!m1->cleaning);
                                        m2->precious    = m1->precious;
                                        m2->clustered   = m1->clustered;
                                        assert(!m1->overwriting);
                                        m2->restart     = m1->restart;
                                        m2->unusual     = m1->unusual;
                                        m2->encrypted   = m1->encrypted;
                                        assert(!m1->encrypted_cleaning);
                                        m2->cs_validated = m1->cs_validated;
                                        m2->cs_tainted  = m1->cs_tainted;
                                        m2->cs_nx       = m1->cs_nx;

                                        /*
                                         * If m1 had really been reusable,
                                         * we would have just stolen it, so
                                         * let's not propagate it's "reusable"
                                         * bit and assert that m2 is not
                                         * marked as "reusable".
                                         */
                                        // m2->reusable = m1->reusable;
                                        assert(!m2->reusable);

                                        assert(!m1->lopage);
                                        m2->slid        = m1->slid;
                                        m2->compressor  = m1->compressor;

                                        /*
                                         * page may need to be flushed if
                                         * it is marshalled into a UPL
                                         * that is going to be used by a device
                                         * that doesn't support coherency
                                         */
                                        m2->written_by_kernel = TRUE;

                                        /*
                                         * make sure we clear the ref/mod state
                                         * from the pmap layer... else we risk
                                         * inheriting state from the last time
                                         * this page was used...
                                         */
                                        pmap_clear_refmod(m2->phys_page, VM_MEM_MODIFIED | VM_MEM_REFERENCED);

                                        if (refmod & VM_MEM_REFERENCED)
                                                m2->reference = TRUE;
                                        if (refmod & VM_MEM_MODIFIED) {
                                                SET_PAGE_DIRTY(m2, TRUE);
                                        }
                                        offset = m1->offset;

                                        /*
                                         * completely cleans up the state
                                         * of the page so that it is ready
                                         * to be put onto the free list, or
                                         * for this purpose it looks like it
                                         * just came off of the free list
                                         */
                                        vm_page_free_prepare(m1);

                                        /*
                                         * now put the substitute page
                                         * on the object
                                         */
                                        vm_page_insert_internal(m2, locked_object, offset, VM_KERN_MEMORY_NONE, TRUE, TRUE, FALSE, FALSE, NULL);

                                        if (m2->compressor) {
                                                m2->pmapped = TRUE;
                                                m2->wpmapped = TRUE;

                                                PMAP_ENTER(kernel_pmap, m2->offset, m2,
                                                           VM_PROT_READ | VM_PROT_WRITE, VM_PROT_NONE, 0, TRUE);

                                                compressed_pages++;

                                        } else {
                                                if (m2->reference)
                                                        vm_page_activate(m2);
                                                else
                                                        vm_page_deactivate(m2);
                                        }
                                        PAGE_WAKEUP_DONE(m2);

                                } else {
                                        assert(!m1->compressor);

                                        /*
                                         * completely cleans up the state
                                         * of the page so that it is ready
                                         * to be put onto the free list, or
                                         * for this purpose it looks like it
                                         * just came off of the free list
                                         */
                                        vm_page_free_prepare(m1);
                                }

                                stolen_pages++;

                        }
                        m1->pageq.next = (queue_entry_t) m;
                        m1->pageq.prev = NULL;
                        m = m1;
                }
                if (locked_object) {
                        vm_object_unlock(locked_object);
                        locked_object = VM_OBJECT_NULL;
                }

                if (abort_run == TRUE) {
                        if (m != VM_PAGE_NULL) {
                                vm_page_free_list(m, FALSE);
                        }

                        dumped_run++;

                        /*
                         * want the index of the last
                         * page in this run that was
                         * successfully 'stolen', so back
                         * it up 1 for the auto-decrement on use
                         * and 1 more to bump back over this page
                         */
                        page_idx = tmp_start_idx + 2;
                        if (page_idx >= vm_pages_count) {
                                if (wrapped)
                                        goto done_scanning;
                                page_idx = last_idx = 0;
                                wrapped = TRUE;
                        }
                        abort_run = FALSE;
                
                        /*
                         * We didn't find a contiguous range but we didn't
                         * start from the very first page.
                         * Start again from the very first page.
                         */
                        RESET_STATE_OF_RUN();
                        
                        if( flags & KMA_LOMEM)
                                idx_last_contig_page_found  = vm_page_lomem_find_contiguous_last_idx = page_idx;
                        else
                                idx_last_contig_page_found = vm_page_find_contiguous_last_idx = page_idx;
                        
                        last_idx = page_idx;
                        
                        lck_mtx_lock(&vm_page_queue_free_lock);
                        /*
                        * reset our free page limit since we
                        * dropped the lock protecting the vm_page_free_queue
                        */
                        free_available = vm_page_free_count - vm_page_free_reserved;
                        goto retry;
                }

                for (m1 = m; m1 != VM_PAGE_NULL; m1 = NEXT_PAGE(m1)) {

                        if (wire == TRUE)
                                m1->wire_count++;
                        else
                                m1->gobbled = TRUE;
                }
                if (wire == FALSE)
                        vm_page_gobble_count += npages;

                /*
                 * gobbled pages are also counted as wired pages
                 */
                vm_page_wire_count += npages;

                assert(vm_page_verify_contiguous(m, npages));
        }
done_scanning:
        PAGE_REPLACEMENT_ALLOWED(FALSE);

        vm_page_unlock_queues();

#if DEBUG
        clock_get_system_microtime(&tv_end_sec, &tv_end_usec);

        tv_end_sec -= tv_start_sec;
        if (tv_end_usec < tv_start_usec) {
                tv_end_sec--;
                tv_end_usec += 1000000;
        }
        tv_end_usec -= tv_start_usec;
        if (tv_end_usec >= 1000000) {
                tv_end_sec++;
                tv_end_sec -= 1000000;
        }
        if (vm_page_find_contig_debug) {
                printf("%s(num=%d,low=%d): found %d pages at 0x%llx in %ld.%06ds...  started at %d...  scanned %d pages...  yielded %d times...  dumped run %d times... stole %d pages... stole %d compressed pages\n",
                       __func__, contig_pages, max_pnum, npages, (vm_object_offset_t)start_pnum << PAGE_SHIFT,
                       (long)tv_end_sec, tv_end_usec, orig_last_idx,
                       scanned, yielded, dumped_run, stolen_pages, compressed_pages);
        }

#endif
#if MACH_ASSERT
        vm_page_verify_free_lists();
#endif
        if (m == NULL && zone_gc_called == FALSE) {
                printf("%s(num=%d,low=%d): found %d pages at 0x%llx...scanned %d pages...  yielded %d times...  dumped run %d times... stole %d pages... stole %d compressed pages... wired count is %d\n",
                       __func__, contig_pages, max_pnum, npages, (vm_object_offset_t)start_pnum << PAGE_SHIFT,
                       scanned, yielded, dumped_run, stolen_pages, compressed_pages, vm_page_wire_count);

                if (consider_buffer_cache_collect != NULL) {
                        (void)(*consider_buffer_cache_collect)(1);
                }

                consider_zone_gc(TRUE);

                zone_gc_called = TRUE;

                printf("vm_page_find_contiguous: zone_gc called... wired count is %d\n", vm_page_wire_count);
                goto full_scan_again;
        }

        return m;
}

/*
 *      Allocate a list of contiguous, wired pages.
 */
kern_return_t
cpm_allocate(
        vm_size_t       size,
        vm_page_t       *list,
        ppnum_t         max_pnum,
        ppnum_t         pnum_mask,
        boolean_t       wire,
        int             flags)
{
        vm_page_t               pages;
        unsigned int            npages;

        if (size % PAGE_SIZE != 0)
                return KERN_INVALID_ARGUMENT;

        npages = (unsigned int) (size / PAGE_SIZE);
        if (npages != size / PAGE_SIZE) {
                /* 32-bit overflow */
                return KERN_INVALID_ARGUMENT;
        }

        /*
         *      Obtain a pointer to a subset of the free
         *      list large enough to satisfy the request;
         *      the region will be physically contiguous.
         */
        pages = vm_page_find_contiguous(npages, max_pnum, pnum_mask, wire, flags);

        if (pages == VM_PAGE_NULL)
                return KERN_NO_SPACE;
        /*
         * determine need for wakeups
         */
        if ((vm_page_free_count < vm_page_free_min) ||
             ((vm_page_free_count < vm_page_free_target) &&
              ((vm_page_inactive_count + vm_page_speculative_count) < vm_page_inactive_min)))
                 thread_wakeup((event_t) &vm_page_free_wanted);
                
        VM_CHECK_MEMORYSTATUS;
        
        /*
         *      The CPM pages should now be available and
         *      ordered by ascending physical address.
         */
        assert(vm_page_verify_contiguous(pages, npages));

        *list = pages;
        return KERN_SUCCESS;
}


unsigned int vm_max_delayed_work_limit = DEFAULT_DELAYED_WORK_LIMIT;

/*
 * when working on a 'run' of pages, it is necessary to hold 
 * the vm_page_queue_lock (a hot global lock) for certain operations
 * on the page... however, the majority of the work can be done
 * while merely holding the object lock... in fact there are certain
 * collections of pages that don't require any work brokered by the
 * vm_page_queue_lock... to mitigate the time spent behind the global
 * lock, go to a 2 pass algorithm... collect pages up to DELAYED_WORK_LIMIT
 * while doing all of the work that doesn't require the vm_page_queue_lock...
 * then call vm_page_do_delayed_work to acquire the vm_page_queue_lock and do the
 * necessary work for each page... we will grab the busy bit on the page
 * if it's not already held so that vm_page_do_delayed_work can drop the object lock
 * if it can't immediately take the vm_page_queue_lock in order to compete
 * for the locks in the same order that vm_pageout_scan takes them.
 * the operation names are modeled after the names of the routines that
 * need to be called in order to make the changes very obvious in the
 * original loop
 */

void
vm_page_do_delayed_work(
        vm_object_t     object,
        vm_tag_t        tag,
        struct vm_page_delayed_work *dwp,
        int             dw_count)
{
        int             j;
        vm_page_t       m;
        vm_page_t       local_free_q = VM_PAGE_NULL;

        /*
         * pageout_scan takes the vm_page_lock_queues first
         * then tries for the object lock... to avoid what
         * is effectively a lock inversion, we'll go to the
         * trouble of taking them in that same order... otherwise
         * if this object contains the majority of the pages resident
         * in the UBC (or a small set of large objects actively being
         * worked on contain the majority of the pages), we could
         * cause the pageout_scan thread to 'starve' in its attempt
         * to find pages to move to the free queue, since it has to
         * successfully acquire the object lock of any candidate page
         * before it can steal/clean it.
         */
        if (!vm_page_trylockspin_queues()) {
                vm_object_unlock(object);

                vm_page_lockspin_queues();

                for (j = 0; ; j++) {
                        if (!vm_object_lock_avoid(object) &&
                            _vm_object_lock_try(object))
                                break;
                        vm_page_unlock_queues();
                        mutex_pause(j);
                        vm_page_lockspin_queues();
                }
        }
        for (j = 0; j < dw_count; j++, dwp++) {

                m = dwp->dw_m;

                if (dwp->dw_mask & DW_vm_pageout_throttle_up)
                        vm_pageout_throttle_up(m);
#if CONFIG_PHANTOM_CACHE
                if (dwp->dw_mask & DW_vm_phantom_cache_update)
                        vm_phantom_cache_update(m);
#endif
                if (dwp->dw_mask & DW_vm_page_wire)
                        vm_page_wire(m, tag, FALSE);
                else if (dwp->dw_mask & DW_vm_page_unwire) {
                        boolean_t       queueit;

                        queueit = (dwp->dw_mask & (DW_vm_page_free | DW_vm_page_deactivate_internal)) ? FALSE : TRUE;

                        vm_page_unwire(m, queueit);
                }
                if (dwp->dw_mask & DW_vm_page_free) {
                        vm_page_free_prepare_queues(m);

                        assert(m->pageq.next == NULL && m->pageq.prev == NULL);
                        /*
                         * Add this page to our list of reclaimed pages,
                         * to be freed later.
                         */
                        m->pageq.next = (queue_entry_t) local_free_q;
                        local_free_q = m;
                } else {
                        if (dwp->dw_mask & DW_vm_page_deactivate_internal)
                                vm_page_deactivate_internal(m, FALSE);
                        else if (dwp->dw_mask & DW_vm_page_activate) {
                                if (m->active == FALSE) {
                                        vm_page_activate(m);
                                }
                        }
                        else if (dwp->dw_mask & DW_vm_page_speculate)
                                vm_page_speculate(m, TRUE);
                        else if (dwp->dw_mask & DW_enqueue_cleaned) {
                                /*
                                 * if we didn't hold the object lock and did this,
                                 * we might disconnect the page, then someone might
                                 * soft fault it back in, then we would put it on the
                                 * cleaned queue, and so we would have a referenced (maybe even dirty)
                                 * page on that queue, which we don't want
                                 */
                                int refmod_state = pmap_disconnect(m->phys_page);

                                if ((refmod_state & VM_MEM_REFERENCED)) {
                                        /*
                                         * this page has been touched since it got cleaned; let's activate it
                                         * if it hasn't already been
                                         */
                                        vm_pageout_enqueued_cleaned++;
                                        vm_pageout_cleaned_reactivated++;
                                        vm_pageout_cleaned_commit_reactivated++;

                                        if (m->active == FALSE)
                                                vm_page_activate(m);
                                } else {
                                        m->reference = FALSE;
                                        vm_page_enqueue_cleaned(m);
                                }
                        }
                        else if (dwp->dw_mask & DW_vm_page_lru)
                                vm_page_lru(m);
                        else if (dwp->dw_mask & DW_VM_PAGE_QUEUES_REMOVE) {
                                if ( !m->pageout_queue)
                                        vm_page_queues_remove(m);
                        }
                        if (dwp->dw_mask & DW_set_reference)
                                m->reference = TRUE;
                        else if (dwp->dw_mask & DW_clear_reference)
                                m->reference = FALSE;

                        if (dwp->dw_mask & DW_move_page) {
                                if ( !m->pageout_queue) {
                                        vm_page_queues_remove(m);

                                        assert(m->object != kernel_object);

                                        vm_page_enqueue_inactive(m, FALSE);
                                }
                        }
                        if (dwp->dw_mask & DW_clear_busy)
                                m->busy = FALSE;

                        if (dwp->dw_mask & DW_PAGE_WAKEUP)
                                PAGE_WAKEUP(m);
                }
        }
        vm_page_unlock_queues();

        if (local_free_q)
                vm_page_free_list(local_free_q, TRUE);
        
        VM_CHECK_MEMORYSTATUS;

}

kern_return_t
vm_page_alloc_list(
        int     page_count,
        int     flags,
        vm_page_t *list)
{
        vm_page_t       lo_page_list = VM_PAGE_NULL;
        vm_page_t       mem;
        int             i;

        if ( !(flags & KMA_LOMEM))
                panic("vm_page_alloc_list: called w/o KMA_LOMEM");

        for (i = 0; i < page_count; i++) {

                mem = vm_page_grablo();

                if (mem == VM_PAGE_NULL) {
                        if (lo_page_list)
                                vm_page_free_list(lo_page_list, FALSE);

                        *list = VM_PAGE_NULL;

                        return (KERN_RESOURCE_SHORTAGE);
                }
                mem->pageq.next = (queue_entry_t) lo_page_list;
                lo_page_list = mem;
        }
        *list = lo_page_list;

        return (KERN_SUCCESS);
}

void
vm_page_set_offset(vm_page_t page, vm_object_offset_t offset)
{
        page->offset = offset;
}

vm_page_t
vm_page_get_next(vm_page_t page)
{
        return ((vm_page_t) page->pageq.next);
}

vm_object_offset_t
vm_page_get_offset(vm_page_t page)
{
        return (page->offset);
}

ppnum_t
vm_page_get_phys_page(vm_page_t page)
{
        return (page->phys_page);
}
        
        
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#if HIBERNATION

static vm_page_t hibernate_gobble_queue;

static int  hibernate_drain_pageout_queue(struct vm_pageout_queue *);
static int  hibernate_flush_dirty_pages(int);
static int  hibernate_flush_queue(queue_head_t *, int);

void hibernate_flush_wait(void);
void hibernate_mark_in_progress(void);
void hibernate_clear_in_progress(void);

void            hibernate_free_range(int, int);
void            hibernate_hash_insert_page(vm_page_t);
uint32_t        hibernate_mark_as_unneeded(addr64_t, addr64_t, hibernate_page_list_t *, hibernate_page_list_t *);
void            hibernate_rebuild_vm_structs(void);
uint32_t        hibernate_teardown_vm_structs(hibernate_page_list_t *, hibernate_page_list_t *);
ppnum_t         hibernate_lookup_paddr(unsigned int);

struct hibernate_statistics {
        int hibernate_considered;
        int hibernate_reentered_on_q;
        int hibernate_found_dirty;
        int hibernate_skipped_cleaning;
        int hibernate_skipped_transient;
        int hibernate_skipped_precious;
        int hibernate_skipped_external;
        int hibernate_queue_nolock;
        int hibernate_queue_paused;
        int hibernate_throttled;
        int hibernate_throttle_timeout;
        int hibernate_drained;
        int hibernate_drain_timeout;
        int cd_lock_failed;
        int cd_found_precious;
        int cd_found_wired;
        int cd_found_busy;
        int cd_found_unusual;
        int cd_found_cleaning;
        int cd_found_laundry;
        int cd_found_dirty;
        int cd_found_xpmapped;
        int cd_skipped_xpmapped;
        int cd_local_free;
        int cd_total_free;
        int cd_vm_page_wire_count;
        int cd_vm_struct_pages_unneeded;
        int cd_pages;
        int cd_discarded;
        int cd_count_wire;
} hibernate_stats;


/*
 * clamp the number of 'xpmapped' pages we'll sweep into the hibernation image
 * so that we don't overrun the estimated image size, which would
 * result in a hibernation failure.
 */
#define HIBERNATE_XPMAPPED_LIMIT        40000


static int
hibernate_drain_pageout_queue(struct vm_pageout_queue *q)
{
        wait_result_t   wait_result;

        vm_page_lock_queues();

        while ( !queue_empty(&q->pgo_pending) ) {

                q->pgo_draining = TRUE;

                assert_wait_timeout((event_t) (&q->pgo_laundry+1), THREAD_INTERRUPTIBLE, 5000, 1000*NSEC_PER_USEC);

                vm_page_unlock_queues();

                wait_result = thread_block(THREAD_CONTINUE_NULL);

                if (wait_result == THREAD_TIMED_OUT && !queue_empty(&q->pgo_pending)) {
                        hibernate_stats.hibernate_drain_timeout++;
                        
                        if (q == &vm_pageout_queue_external)
                                return (0);
                        
                        return (1);
                }
                vm_page_lock_queues();

                hibernate_stats.hibernate_drained++;
        }
        vm_page_unlock_queues();

        return (0);
}


boolean_t hibernate_skip_external = FALSE;

static int
hibernate_flush_queue(queue_head_t *q, int qcount)
{
        vm_page_t       m;
        vm_object_t     l_object = NULL;
        vm_object_t     m_object = NULL;
        int             refmod_state = 0;
        int             try_failed_count = 0;
        int             retval = 0;
        int             current_run = 0;
        struct  vm_pageout_queue *iq;
        struct  vm_pageout_queue *eq;
        struct  vm_pageout_queue *tq;


        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 4) | DBG_FUNC_START, q, qcount, 0, 0, 0);
        
        iq = &vm_pageout_queue_internal;
        eq = &vm_pageout_queue_external;

        vm_page_lock_queues();

        while (qcount && !queue_empty(q)) {

                if (current_run++ == 1000) {
                        if (hibernate_should_abort()) {
                                retval = 1;
                                break;
                        }
                        current_run = 0;
                }

                m = (vm_page_t) queue_first(q);
                m_object = m->object;

                /*
                 * check to see if we currently are working
                 * with the same object... if so, we've
                 * already got the lock
                 */
                if (m_object != l_object) {
                        /*
                         * the object associated with candidate page is 
                         * different from the one we were just working
                         * with... dump the lock if we still own it
                         */
                        if (l_object != NULL) {
                                vm_object_unlock(l_object);
                                l_object = NULL;
                        }
                        /*
                         * Try to lock object; since we've alread got the
                         * page queues lock, we can only 'try' for this one.
                         * if the 'try' fails, we need to do a mutex_pause
                         * to allow the owner of the object lock a chance to
                         * run... 
                         */
                        if ( !vm_object_lock_try_scan(m_object)) {

                                if (try_failed_count > 20) {
                                        hibernate_stats.hibernate_queue_nolock++;

                                        goto reenter_pg_on_q;
                                }

                                vm_page_unlock_queues();
                                mutex_pause(try_failed_count++);
                                vm_page_lock_queues();

                                hibernate_stats.hibernate_queue_paused++;
                                continue;
                        } else {
                                l_object = m_object;
                        }
                }
                if ( !m_object->alive || m->encrypted_cleaning || m->cleaning || m->laundry || m->busy || m->absent || m->error) {
                        /*
                         * page is not to be cleaned
                         * put it back on the head of its queue
                         */
                        if (m->cleaning)
                                hibernate_stats.hibernate_skipped_cleaning++;
                        else
                                hibernate_stats.hibernate_skipped_transient++;

                        goto reenter_pg_on_q;
                }
                if (m_object->copy == VM_OBJECT_NULL) {
                        if (m_object->purgable == VM_PURGABLE_VOLATILE || m_object->purgable == VM_PURGABLE_EMPTY) {
                                /*
                                 * let the normal hibernate image path
                                 * deal with these
                                 */
                                goto reenter_pg_on_q;
                        }
                }
                if ( !m->dirty && m->pmapped) {
                        refmod_state = pmap_get_refmod(m->phys_page);

                        if ((refmod_state & VM_MEM_MODIFIED)) {
                                SET_PAGE_DIRTY(m, FALSE);
                        }
                } else
                        refmod_state = 0;

                if ( !m->dirty) {
                        /*
                         * page is not to be cleaned
                         * put it back on the head of its queue
                         */
                        if (m->precious)
                                hibernate_stats.hibernate_skipped_precious++;

                        goto reenter_pg_on_q;
                }

                if (hibernate_skip_external == TRUE && !m_object->internal) {

                        hibernate_stats.hibernate_skipped_external++;
                        
                        goto reenter_pg_on_q;
                }
                tq = NULL;

                if (m_object->internal) {
                        if (VM_PAGE_Q_THROTTLED(iq))
                                tq = iq;
                } else if (VM_PAGE_Q_THROTTLED(eq))
                        tq = eq;

                if (tq != NULL) {
                        wait_result_t   wait_result;
                        int             wait_count = 5;

                        if (l_object != NULL) {
                                vm_object_unlock(l_object);
                                l_object = NULL;
                        }

                        while (retval == 0) {

                                tq->pgo_throttled = TRUE;

                                assert_wait_timeout((event_t) &tq->pgo_laundry, THREAD_INTERRUPTIBLE, 1000, 1000*NSEC_PER_USEC);

                                vm_page_unlock_queues();

                                wait_result = thread_block(THREAD_CONTINUE_NULL);

                                vm_page_lock_queues();

                                if (wait_result != THREAD_TIMED_OUT)
                                        break;
                                if (!VM_PAGE_Q_THROTTLED(tq))
                                        break;

                                if (hibernate_should_abort())
                                        retval = 1;

                                if (--wait_count == 0) {

                                        hibernate_stats.hibernate_throttle_timeout++;

                                        if (tq == eq) {
                                                hibernate_skip_external = TRUE;
                                                break;
                                        }
                                        retval = 1;
                                }
                        }
                        if (retval)
                                break;

                        hibernate_stats.hibernate_throttled++;

                        continue;
                }
                /*
                 * we've already factored out pages in the laundry which
                 * means this page can't be on the pageout queue so it's
                 * safe to do the vm_page_queues_remove
                 */
                assert(!m->pageout_queue);

                vm_page_queues_remove(m);

                if (COMPRESSED_PAGER_IS_ACTIVE && m_object->internal == TRUE)
                        pmap_disconnect_options(m->phys_page, PMAP_OPTIONS_COMPRESSOR, NULL);

                (void)vm_pageout_cluster(m, FALSE, FALSE, FALSE);

                hibernate_stats.hibernate_found_dirty++;

                goto next_pg;

reenter_pg_on_q:
                queue_remove(q, m, vm_page_t, pageq);
                queue_enter(q, m, vm_page_t, pageq);

                hibernate_stats.hibernate_reentered_on_q++;
next_pg:
                hibernate_stats.hibernate_considered++;

                qcount--;
                try_failed_count = 0;
        }
        if (l_object != NULL) {
                vm_object_unlock(l_object);
                l_object = NULL;
        }

        vm_page_unlock_queues();

        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 4) | DBG_FUNC_END, hibernate_stats.hibernate_found_dirty, retval, 0, 0, 0);

        return (retval);
}


static int
hibernate_flush_dirty_pages(int pass)
{
        struct vm_speculative_age_q     *aq;
        uint32_t        i;

        if (vm_page_local_q) {
                for (i = 0; i < vm_page_local_q_count; i++)
                        vm_page_reactivate_local(i, TRUE, FALSE);
        }

        for (i = 0; i <= VM_PAGE_MAX_SPECULATIVE_AGE_Q; i++) {
                int             qcount;
                vm_page_t       m;

                aq = &vm_page_queue_speculative[i];

                if (queue_empty(&aq->age_q))
                        continue;
                qcount = 0;

                vm_page_lockspin_queues();

                queue_iterate(&aq->age_q,
                              m,
                              vm_page_t,
                              pageq)
                {
                        qcount++;
                }
                vm_page_unlock_queues();

                if (qcount) {
                        if (hibernate_flush_queue(&aq->age_q, qcount))
                                return (1);
                }
        }
        if (hibernate_flush_queue(&vm_page_queue_inactive, vm_page_inactive_count - vm_page_anonymous_count - vm_page_cleaned_count))
                return (1);
        if (hibernate_flush_queue(&vm_page_queue_anonymous, vm_page_anonymous_count))
                return (1);
        if (hibernate_flush_queue(&vm_page_queue_cleaned, vm_page_cleaned_count))
                return (1);
        if (hibernate_drain_pageout_queue(&vm_pageout_queue_internal))
                return (1);

        if (COMPRESSED_PAGER_IS_ACTIVE && pass == 1)
                vm_compressor_record_warmup_start();

        if (hibernate_flush_queue(&vm_page_queue_active, vm_page_active_count)) {
                if (COMPRESSED_PAGER_IS_ACTIVE && pass == 1)
                        vm_compressor_record_warmup_end();
                return (1);
        }
        if (hibernate_drain_pageout_queue(&vm_pageout_queue_internal)) {
                if (COMPRESSED_PAGER_IS_ACTIVE && pass == 1)
                        vm_compressor_record_warmup_end();
                return (1);
        }
        if (COMPRESSED_PAGER_IS_ACTIVE && pass == 1)
                vm_compressor_record_warmup_end();

        if (hibernate_skip_external == FALSE && hibernate_drain_pageout_queue(&vm_pageout_queue_external))
                return (1);

        return (0);
}


void
hibernate_reset_stats()
{
        bzero(&hibernate_stats, sizeof(struct hibernate_statistics));
}


int
hibernate_flush_memory()
{
        int     retval;

        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 3) | DBG_FUNC_START, vm_page_free_count, 0, 0, 0, 0);

        hibernate_cleaning_in_progress = TRUE;
        hibernate_skip_external = FALSE;

        if ((retval = hibernate_flush_dirty_pages(1)) == 0) {

                if (COMPRESSED_PAGER_IS_ACTIVE) {

                                KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 10) | DBG_FUNC_START, VM_PAGE_COMPRESSOR_COUNT, 0, 0, 0, 0);

                                vm_compressor_flush();

                                KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 10) | DBG_FUNC_END, VM_PAGE_COMPRESSOR_COUNT, 0, 0, 0, 0);
                }
                if (consider_buffer_cache_collect != NULL) {
                        unsigned int orig_wire_count;

                        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 7) | DBG_FUNC_START, 0, 0, 0, 0, 0);
                        orig_wire_count = vm_page_wire_count;
                        
                        (void)(*consider_buffer_cache_collect)(1);
                        consider_zone_gc(TRUE);

                        HIBLOG("hibernate_flush_memory: buffer_cache_gc freed up %d wired pages\n", orig_wire_count - vm_page_wire_count);

                        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 7) | DBG_FUNC_END, orig_wire_count - vm_page_wire_count, 0, 0, 0, 0);
                }
        }
        hibernate_cleaning_in_progress = FALSE;

        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 3) | DBG_FUNC_END, vm_page_free_count, hibernate_stats.hibernate_found_dirty, retval, 0, 0);

        if (retval && COMPRESSED_PAGER_IS_ACTIVE)
                HIBLOG("hibernate_flush_memory() failed to finish - vm_page_compressor_count(%d)\n", VM_PAGE_COMPRESSOR_COUNT);


    HIBPRINT("hibernate_flush_memory() considered(%d) reentered_on_q(%d) found_dirty(%d)\n",
                hibernate_stats.hibernate_considered,
                hibernate_stats.hibernate_reentered_on_q,
                hibernate_stats.hibernate_found_dirty);
    HIBPRINT("   skipped_cleaning(%d) skipped_transient(%d) skipped_precious(%d) skipped_external(%d) queue_nolock(%d)\n",
                hibernate_stats.hibernate_skipped_cleaning,
                hibernate_stats.hibernate_skipped_transient,
                hibernate_stats.hibernate_skipped_precious,
                hibernate_stats.hibernate_skipped_external,
                hibernate_stats.hibernate_queue_nolock);
    HIBPRINT("   queue_paused(%d) throttled(%d) throttle_timeout(%d) drained(%d) drain_timeout(%d)\n",
                hibernate_stats.hibernate_queue_paused,
                hibernate_stats.hibernate_throttled,
                hibernate_stats.hibernate_throttle_timeout,
                hibernate_stats.hibernate_drained,
                hibernate_stats.hibernate_drain_timeout);

        return (retval);
}


static void
hibernate_page_list_zero(hibernate_page_list_t *list)
{
    uint32_t             bank;
    hibernate_bitmap_t * bitmap;

    bitmap = &list->bank_bitmap[0];
    for (bank = 0; bank < list->bank_count; bank++)
    {
        uint32_t last_bit;

        bzero((void *) &bitmap->bitmap[0], bitmap->bitmapwords << 2); 
        // set out-of-bound bits at end of bitmap.
        last_bit = ((bitmap->last_page - bitmap->first_page + 1) & 31);
        if (last_bit)
            bitmap->bitmap[bitmap->bitmapwords - 1] = (0xFFFFFFFF >> last_bit);

        bitmap = (hibernate_bitmap_t *) &bitmap->bitmap[bitmap->bitmapwords];
    }
}

void
hibernate_free_gobble_pages(void)
{
    vm_page_t m, next;
    uint32_t  count = 0;

    m = (vm_page_t) hibernate_gobble_queue;
    while(m)
    {
        next = (vm_page_t) m->pageq.next;
        vm_page_free(m);
        count++;
        m = next;
    }
    hibernate_gobble_queue = VM_PAGE_NULL;
    
    if (count)
        HIBLOG("Freed %d pages\n", count);
}

static boolean_t 
hibernate_consider_discard(vm_page_t m, boolean_t preflight)
{
    vm_object_t object = NULL;
    int                  refmod_state;
    boolean_t            discard = FALSE;

    do
    {
        if (m->private)
            panic("hibernate_consider_discard: private");

        if (!vm_object_lock_try(m->object)) {
            if (!preflight) hibernate_stats.cd_lock_failed++;
            break;
        }
        object = m->object;

        if (VM_PAGE_WIRED(m)) {
            if (!preflight) hibernate_stats.cd_found_wired++;
            break;
        }
        if (m->precious) {
            if (!preflight) hibernate_stats.cd_found_precious++;
            break;
        }
        if (m->busy || !object->alive) {
           /*
            *   Somebody is playing with this page.
            */
            if (!preflight) hibernate_stats.cd_found_busy++;
            break;
        }
        if (m->absent || m->unusual || m->error) {
           /*
            * If it's unusual in anyway, ignore it
            */
            if (!preflight) hibernate_stats.cd_found_unusual++;
            break;
        }
        if (m->cleaning) {
            if (!preflight) hibernate_stats.cd_found_cleaning++;
            break;
        }
        if (m->laundry) {
            if (!preflight) hibernate_stats.cd_found_laundry++;
            break;
        }
        if (!m->dirty)
        {
            refmod_state = pmap_get_refmod(m->phys_page);
        
            if (refmod_state & VM_MEM_REFERENCED)
                m->reference = TRUE;
            if (refmod_state & VM_MEM_MODIFIED) {
                SET_PAGE_DIRTY(m, FALSE);
            }
        }
   
        /*
         * If it's clean or purgeable we can discard the page on wakeup.
         */
        discard = (!m->dirty) 
                    || (VM_PURGABLE_VOLATILE == object->purgable)
                    || (VM_PURGABLE_EMPTY    == object->purgable);


        if (discard == FALSE) {
                if (!preflight)
                        hibernate_stats.cd_found_dirty++;
        } else if (m->xpmapped && m->reference && !object->internal) {
                if (hibernate_stats.cd_found_xpmapped < HIBERNATE_XPMAPPED_LIMIT) {
                        if (!preflight)
                                hibernate_stats.cd_found_xpmapped++;
                        discard = FALSE;
                } else {
                        if (!preflight)
                                hibernate_stats.cd_skipped_xpmapped++;
                }
        }
    }
    while (FALSE);

    if (object)
        vm_object_unlock(object);

    return (discard);
}


static void
hibernate_discard_page(vm_page_t m)
{
    if (m->absent || m->unusual || m->error)
       /*
        * If it's unusual in anyway, ignore
        */
        return;

#if MACH_ASSERT || DEBUG
    vm_object_t object = m->object;
    if (!vm_object_lock_try(m->object))
        panic("hibernate_discard_page(%p) !vm_object_lock_try", m);
#else
    /* No need to lock page queue for token delete, hibernate_vm_unlock() 
       makes sure these locks are uncontended before sleep */
#endif /* MACH_ASSERT || DEBUG */

    if (m->pmapped == TRUE) 
    {
        __unused int refmod_state = pmap_disconnect(m->phys_page);
    }

    if (m->laundry)
        panic("hibernate_discard_page(%p) laundry", m);
    if (m->private)
        panic("hibernate_discard_page(%p) private", m);
    if (m->fictitious)
        panic("hibernate_discard_page(%p) fictitious", m);

    if (VM_PURGABLE_VOLATILE == m->object->purgable)
    {
        /* object should be on a queue */
        assert((m->object->objq.next != NULL) && (m->object->objq.prev != NULL));
        purgeable_q_t old_queue = vm_purgeable_object_remove(m->object);
        assert(old_queue);
        if (m->object->purgeable_when_ripe) {
                vm_purgeable_token_delete_first(old_queue);
        }
        m->object->purgable = VM_PURGABLE_EMPTY;

        /*
         * Purgeable ledgers:  pages of VOLATILE and EMPTY objects are
         * accounted in the "volatile" ledger, so no change here.
         * We have to update vm_page_purgeable_count, though, since we're
         * effectively purging this object.
         */
        unsigned int delta;
        assert(m->object->resident_page_count >= m->object->wired_page_count);
        delta = (m->object->resident_page_count - m->object->wired_page_count);
        assert(vm_page_purgeable_count >= delta);
        assert(delta > 0);
        OSAddAtomic(-delta, (SInt32 *)&vm_page_purgeable_count);
    }
        
    vm_page_free(m);

#if MACH_ASSERT || DEBUG
    vm_object_unlock(object);
#endif  /* MACH_ASSERT || DEBUG */
}

/*
 Grab locks for hibernate_page_list_setall()
*/
void
hibernate_vm_lock_queues(void)
{
    vm_object_lock(compressor_object);
    vm_page_lock_queues();
    lck_mtx_lock(&vm_page_queue_free_lock);

    if (vm_page_local_q) {
        uint32_t  i;
        for (i = 0; i < vm_page_local_q_count; i++) {
            struct vpl  *lq;
            lq = &vm_page_local_q[i].vpl_un.vpl;
            VPL_LOCK(&lq->vpl_lock);
        }
    }
}

void
hibernate_vm_unlock_queues(void)
{
    if (vm_page_local_q) {
        uint32_t  i;
        for (i = 0; i < vm_page_local_q_count; i++) {
            struct vpl  *lq;
            lq = &vm_page_local_q[i].vpl_un.vpl;
            VPL_UNLOCK(&lq->vpl_lock);
        }
    }
    lck_mtx_unlock(&vm_page_queue_free_lock);
    vm_page_unlock_queues();
    vm_object_unlock(compressor_object);
}

/*
 Bits zero in the bitmaps => page needs to be saved. All pages default to be saved,
 pages known to VM to not need saving are subtracted.
 Wired pages to be saved are present in page_list_wired, pageable in page_list.
*/

void
hibernate_page_list_setall(hibernate_page_list_t * page_list,
                           hibernate_page_list_t * page_list_wired,
                           hibernate_page_list_t * page_list_pal,
                           boolean_t preflight, 
                           boolean_t will_discard,
                           uint32_t * pagesOut)
{
    uint64_t start, end, nsec;
    vm_page_t m;
    vm_page_t next;
    uint32_t pages = page_list->page_count;
    uint32_t count_anonymous = 0, count_throttled = 0, count_compressor = 0;
    uint32_t count_inactive = 0, count_active = 0, count_speculative = 0, count_cleaned = 0;
    uint32_t count_wire = pages;
    uint32_t count_discard_active    = 0;
    uint32_t count_discard_inactive  = 0;
    uint32_t count_discard_cleaned   = 0;
    uint32_t count_discard_purgeable = 0;
    uint32_t count_discard_speculative = 0;
    uint32_t count_discard_vm_struct_pages = 0;
    uint32_t i;
    uint32_t             bank;
    hibernate_bitmap_t * bitmap;
    hibernate_bitmap_t * bitmap_wired;
    boolean_t                    discard_all;
    boolean_t            discard;

    HIBLOG("hibernate_page_list_setall(preflight %d) start\n", preflight);

    if (preflight) {
        page_list       = NULL;
        page_list_wired = NULL;
        page_list_pal   = NULL;
                discard_all     = FALSE;
    } else {
                discard_all     = will_discard;
    }

#if MACH_ASSERT || DEBUG
    if (!preflight)
    {
        vm_page_lock_queues();
        if (vm_page_local_q) {
            for (i = 0; i < vm_page_local_q_count; i++) {
                struct vpl      *lq;
                lq = &vm_page_local_q[i].vpl_un.vpl;
                VPL_LOCK(&lq->vpl_lock);
            }
        }
    }
#endif  /* MACH_ASSERT || DEBUG */


    KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 8) | DBG_FUNC_START, count_wire, 0, 0, 0, 0);

    clock_get_uptime(&start);

    if (!preflight) {
        hibernate_page_list_zero(page_list);
        hibernate_page_list_zero(page_list_wired);
        hibernate_page_list_zero(page_list_pal);
    
        hibernate_stats.cd_vm_page_wire_count = vm_page_wire_count;
        hibernate_stats.cd_pages = pages;
    }

    if (vm_page_local_q) {
            for (i = 0; i < vm_page_local_q_count; i++)
                    vm_page_reactivate_local(i, TRUE, !preflight);
    }

    if (preflight) {
        vm_object_lock(compressor_object);
        vm_page_lock_queues();
        lck_mtx_lock(&vm_page_queue_free_lock);
    }

    m = (vm_page_t) hibernate_gobble_queue;
    while (m)
    {
        pages--;
        count_wire--;
        if (!preflight) {
            hibernate_page_bitset(page_list,       TRUE, m->phys_page);
            hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
        }
        m = (vm_page_t) m->pageq.next;
    }

    if (!preflight) for( i = 0; i < real_ncpus; i++ )
    {
        if (cpu_data_ptr[i] && cpu_data_ptr[i]->cpu_processor)
        {
            for (m = PROCESSOR_DATA(cpu_data_ptr[i]->cpu_processor, free_pages); m; m = (vm_page_t)m->pageq.next)
            {
                pages--;
                count_wire--;
                hibernate_page_bitset(page_list,       TRUE, m->phys_page);
                hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);

                hibernate_stats.cd_local_free++;
                hibernate_stats.cd_total_free++;
            }
        }
    }

    for( i = 0; i < vm_colors; i++ )
    {
        queue_iterate(&vm_page_queue_free[i],
                      m,
                      vm_page_t,
                      pageq)
        {
            pages--;
            count_wire--;
            if (!preflight) {
                hibernate_page_bitset(page_list,       TRUE, m->phys_page);
                hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
    
                hibernate_stats.cd_total_free++;
            }
        }
    }

    queue_iterate(&vm_lopage_queue_free,
                  m,
                  vm_page_t,
                  pageq)
    {
        pages--;
        count_wire--;
        if (!preflight) {
            hibernate_page_bitset(page_list,       TRUE, m->phys_page);
            hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
    
            hibernate_stats.cd_total_free++;
        }
    }

    m = (vm_page_t) queue_first(&vm_page_queue_throttled);
    while (m && !queue_end(&vm_page_queue_throttled, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        discard = FALSE;
        if ((kIOHibernateModeDiscardCleanInactive & gIOHibernateMode) 
         && hibernate_consider_discard(m, preflight))
        {
            if (!preflight) hibernate_page_bitset(page_list, TRUE, m->phys_page);
            count_discard_inactive++;
            discard = discard_all;
        }
        else
            count_throttled++;
        count_wire--;
        if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);

        if (discard) hibernate_discard_page(m);
        m = next;
    }

    m = (vm_page_t) queue_first(&vm_page_queue_anonymous);
    while (m && !queue_end(&vm_page_queue_anonymous, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        discard = FALSE;
        if ((kIOHibernateModeDiscardCleanInactive & gIOHibernateMode) 
         && hibernate_consider_discard(m, preflight))
        {
            if (!preflight) hibernate_page_bitset(page_list, TRUE, m->phys_page);
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_inactive++;
            discard = discard_all;
        }
        else
            count_anonymous++;
        count_wire--;
        if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
        if (discard)    hibernate_discard_page(m);
        m = next;
    }

    m = (vm_page_t) queue_first(&vm_page_queue_cleaned);
    while (m && !queue_end(&vm_page_queue_cleaned, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        discard = FALSE;
        if ((kIOHibernateModeDiscardCleanInactive & gIOHibernateMode) 
         && hibernate_consider_discard(m, preflight))
        {
            if (!preflight) hibernate_page_bitset(page_list, TRUE, m->phys_page);
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_cleaned++;
            discard = discard_all;
        }
        else
            count_cleaned++;
        count_wire--;
        if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
        if (discard)    hibernate_discard_page(m);
        m = next;
    }

    m = (vm_page_t) queue_first(&vm_page_queue_active);
    while (m && !queue_end(&vm_page_queue_active, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        discard = FALSE;
        if ((kIOHibernateModeDiscardCleanActive & gIOHibernateMode) 
         && hibernate_consider_discard(m, preflight))
        {
            if (!preflight) hibernate_page_bitset(page_list, TRUE, m->phys_page);
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_active++;
            discard = discard_all;
        }
        else
            count_active++;
        count_wire--;
        if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
        if (discard)    hibernate_discard_page(m);
        m = next;
    }

    m = (vm_page_t) queue_first(&vm_page_queue_inactive);
    while (m && !queue_end(&vm_page_queue_inactive, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        discard = FALSE;
        if ((kIOHibernateModeDiscardCleanInactive & gIOHibernateMode) 
         && hibernate_consider_discard(m, preflight))
        {
            if (!preflight) hibernate_page_bitset(page_list, TRUE, m->phys_page);
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_inactive++;
            discard = discard_all;
        }
        else
            count_inactive++;
        count_wire--;
        if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
        if (discard)    hibernate_discard_page(m);
        m = next;
    }

    for( i = 0; i <= VM_PAGE_MAX_SPECULATIVE_AGE_Q; i++ )
    {
        m = (vm_page_t) queue_first(&vm_page_queue_speculative[i].age_q);
        while (m && !queue_end(&vm_page_queue_speculative[i].age_q, (queue_entry_t)m))
        {
            next = (vm_page_t) m->pageq.next;
            discard = FALSE;
            if ((kIOHibernateModeDiscardCleanInactive & gIOHibernateMode) 
             && hibernate_consider_discard(m, preflight))
            {
                if (!preflight) hibernate_page_bitset(page_list, TRUE, m->phys_page);
                count_discard_speculative++;
                discard = discard_all;
            }
            else
                count_speculative++;
            count_wire--;
            if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
            if (discard)    hibernate_discard_page(m);
            m = next;
        }
    }

    queue_iterate(&compressor_object->memq, m, vm_page_t, listq)
    {
        count_compressor++;
        count_wire--;
        if (!preflight) hibernate_page_bitset(page_list_wired, TRUE, m->phys_page);
    }

    if (preflight == FALSE && discard_all == TRUE) {
            KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 12) | DBG_FUNC_START, 0, 0, 0, 0, 0);

            HIBLOG("hibernate_teardown started\n");
            count_discard_vm_struct_pages = hibernate_teardown_vm_structs(page_list, page_list_wired);
            HIBLOG("hibernate_teardown completed - discarded %d\n", count_discard_vm_struct_pages);

            pages -= count_discard_vm_struct_pages;
            count_wire -= count_discard_vm_struct_pages;

            hibernate_stats.cd_vm_struct_pages_unneeded = count_discard_vm_struct_pages;

            KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 13) | DBG_FUNC_END, 0, 0, 0, 0, 0);
    }

    if (!preflight) {
        // pull wired from hibernate_bitmap
        bitmap = &page_list->bank_bitmap[0];
        bitmap_wired = &page_list_wired->bank_bitmap[0];
        for (bank = 0; bank < page_list->bank_count; bank++)
        {
            for (i = 0; i < bitmap->bitmapwords; i++)
                bitmap->bitmap[i] = bitmap->bitmap[i] | ~bitmap_wired->bitmap[i];
            bitmap       = (hibernate_bitmap_t *) &bitmap->bitmap      [bitmap->bitmapwords];
            bitmap_wired = (hibernate_bitmap_t *) &bitmap_wired->bitmap[bitmap_wired->bitmapwords];
        }
    }

    // machine dependent adjustments
    hibernate_page_list_setall_machine(page_list, page_list_wired, preflight, &pages);

    if (!preflight) {
        hibernate_stats.cd_count_wire = count_wire;
        hibernate_stats.cd_discarded = count_discard_active + count_discard_inactive + count_discard_purgeable +
                count_discard_speculative + count_discard_cleaned + count_discard_vm_struct_pages;
    }

    clock_get_uptime(&end);
    absolutetime_to_nanoseconds(end - start, &nsec);
    HIBLOG("hibernate_page_list_setall time: %qd ms\n", nsec / 1000000ULL);

    HIBLOG("pages %d, wire %d, act %d, inact %d, cleaned %d spec %d, zf %d, throt %d, compr %d, xpmapped %d\n  %s discard act %d inact %d purgeable %d spec %d cleaned %d\n", 
           pages, count_wire, count_active, count_inactive, count_cleaned, count_speculative, count_anonymous, count_throttled, count_compressor, hibernate_stats.cd_found_xpmapped,
                discard_all ? "did" : "could",
                count_discard_active, count_discard_inactive, count_discard_purgeable, count_discard_speculative, count_discard_cleaned);

    if (hibernate_stats.cd_skipped_xpmapped)
            HIBLOG("WARNING: hibernate_page_list_setall skipped %d xpmapped pages\n", hibernate_stats.cd_skipped_xpmapped);

    *pagesOut = pages - count_discard_active - count_discard_inactive - count_discard_purgeable - count_discard_speculative - count_discard_cleaned;

    if (preflight && will_discard) *pagesOut -= count_compressor + count_throttled + count_anonymous + count_inactive + count_cleaned + count_speculative + count_active;

#if MACH_ASSERT || DEBUG
    if (!preflight)
    {
        if (vm_page_local_q) {
            for (i = 0; i < vm_page_local_q_count; i++) {
                struct vpl      *lq;
                lq = &vm_page_local_q[i].vpl_un.vpl;
                VPL_UNLOCK(&lq->vpl_lock);
            }
        }
        vm_page_unlock_queues();
    }
#endif  /* MACH_ASSERT || DEBUG */

    if (preflight) {
        lck_mtx_unlock(&vm_page_queue_free_lock);
        vm_page_unlock_queues();
        vm_object_unlock(compressor_object);
    }

    KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 8) | DBG_FUNC_END, count_wire, *pagesOut, 0, 0, 0);
}

void
hibernate_page_list_discard(hibernate_page_list_t * page_list)
{
    uint64_t  start, end, nsec;
    vm_page_t m;
    vm_page_t next;
    uint32_t  i;
    uint32_t  count_discard_active    = 0;
    uint32_t  count_discard_inactive  = 0;
    uint32_t  count_discard_purgeable = 0;
    uint32_t  count_discard_cleaned   = 0;
    uint32_t  count_discard_speculative = 0;


#if MACH_ASSERT || DEBUG
        vm_page_lock_queues();
        if (vm_page_local_q) {
            for (i = 0; i < vm_page_local_q_count; i++) {
                struct vpl      *lq;
                lq = &vm_page_local_q[i].vpl_un.vpl;
                VPL_LOCK(&lq->vpl_lock);
            }
        }
#endif  /* MACH_ASSERT || DEBUG */

    clock_get_uptime(&start);

    m = (vm_page_t) queue_first(&vm_page_queue_anonymous);
    while (m && !queue_end(&vm_page_queue_anonymous, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        if (hibernate_page_bittst(page_list, m->phys_page))
        {
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_inactive++;
            hibernate_discard_page(m);
        }
        m = next;
    }

    for( i = 0; i <= VM_PAGE_MAX_SPECULATIVE_AGE_Q; i++ )
    {
       m = (vm_page_t) queue_first(&vm_page_queue_speculative[i].age_q);
       while (m && !queue_end(&vm_page_queue_speculative[i].age_q, (queue_entry_t)m))
       {
           next = (vm_page_t) m->pageq.next;
           if (hibernate_page_bittst(page_list, m->phys_page))
           {
               count_discard_speculative++;
               hibernate_discard_page(m);
           }
           m = next;
       }
    }

    m = (vm_page_t) queue_first(&vm_page_queue_inactive);
    while (m && !queue_end(&vm_page_queue_inactive, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        if (hibernate_page_bittst(page_list, m->phys_page))
        {
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_inactive++;
            hibernate_discard_page(m);
        }
        m = next;
    }

    m = (vm_page_t) queue_first(&vm_page_queue_active);
    while (m && !queue_end(&vm_page_queue_active, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        if (hibernate_page_bittst(page_list, m->phys_page))
        {
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_active++;
            hibernate_discard_page(m);
        }
        m = next;
    }

    m = (vm_page_t) queue_first(&vm_page_queue_cleaned);
    while (m && !queue_end(&vm_page_queue_cleaned, (queue_entry_t)m))
    {
        next = (vm_page_t) m->pageq.next;
        if (hibernate_page_bittst(page_list, m->phys_page))
        {
            if (m->dirty)
                count_discard_purgeable++;
            else
                count_discard_cleaned++;
            hibernate_discard_page(m);
        }
        m = next;
    }

#if MACH_ASSERT || DEBUG
        if (vm_page_local_q) {
            for (i = 0; i < vm_page_local_q_count; i++) {
                struct vpl      *lq;
                lq = &vm_page_local_q[i].vpl_un.vpl;
                VPL_UNLOCK(&lq->vpl_lock);
            }
        }
        vm_page_unlock_queues();
#endif  /* MACH_ASSERT || DEBUG */

    clock_get_uptime(&end);
    absolutetime_to_nanoseconds(end - start, &nsec);
    HIBLOG("hibernate_page_list_discard time: %qd ms, discarded act %d inact %d purgeable %d spec %d cleaned %d\n",
                nsec / 1000000ULL,
                count_discard_active, count_discard_inactive, count_discard_purgeable, count_discard_speculative, count_discard_cleaned);
}

boolean_t       hibernate_paddr_map_inited = FALSE;
boolean_t       hibernate_rebuild_needed = FALSE;
unsigned int    hibernate_teardown_last_valid_compact_indx = -1;
vm_page_t       hibernate_rebuild_hash_list = NULL;

unsigned int    hibernate_teardown_found_tabled_pages = 0;
unsigned int    hibernate_teardown_found_created_pages = 0;
unsigned int    hibernate_teardown_found_free_pages = 0;
unsigned int    hibernate_teardown_vm_page_free_count;


struct ppnum_mapping {
        struct ppnum_mapping    *ppnm_next;
        ppnum_t                 ppnm_base_paddr;
        unsigned int            ppnm_sindx;
        unsigned int            ppnm_eindx;
};

struct ppnum_mapping    *ppnm_head;
struct ppnum_mapping    *ppnm_last_found = NULL;


void
hibernate_create_paddr_map() 
{
        unsigned int    i;
        ppnum_t         next_ppnum_in_run = 0;
        struct ppnum_mapping *ppnm = NULL;

        if (hibernate_paddr_map_inited == FALSE) {

                for (i = 0; i < vm_pages_count; i++) {

                        if (ppnm)
                                ppnm->ppnm_eindx = i;

                        if (ppnm == NULL || vm_pages[i].phys_page != next_ppnum_in_run) {

                                ppnm = kalloc(sizeof(struct ppnum_mapping));

                                ppnm->ppnm_next = ppnm_head;
                                ppnm_head = ppnm;

                                ppnm->ppnm_sindx = i;
                                ppnm->ppnm_base_paddr = vm_pages[i].phys_page;
                        }
                        next_ppnum_in_run = vm_pages[i].phys_page + 1;
                }
                ppnm->ppnm_eindx++;

                hibernate_paddr_map_inited = TRUE;
        }
}

ppnum_t
hibernate_lookup_paddr(unsigned int indx)
{
        struct ppnum_mapping *ppnm = NULL;
        
        ppnm = ppnm_last_found;

        if (ppnm) {
                if (indx >= ppnm->ppnm_sindx && indx < ppnm->ppnm_eindx)
                        goto done;
        }
        for (ppnm = ppnm_head; ppnm; ppnm = ppnm->ppnm_next) {

                if (indx >= ppnm->ppnm_sindx && indx < ppnm->ppnm_eindx) {
                        ppnm_last_found = ppnm;
                        break;
                }
        }
        if (ppnm == NULL)
                panic("hibernate_lookup_paddr of %d failed\n", indx);
done:
        return (ppnm->ppnm_base_paddr + (indx - ppnm->ppnm_sindx));
}


uint32_t
hibernate_mark_as_unneeded(addr64_t saddr, addr64_t eaddr, hibernate_page_list_t *page_list, hibernate_page_list_t *page_list_wired)
{
        addr64_t        saddr_aligned;
        addr64_t        eaddr_aligned;
        addr64_t        addr;
        ppnum_t         paddr;
        unsigned int    mark_as_unneeded_pages = 0;

        saddr_aligned = (saddr + PAGE_MASK_64) & ~PAGE_MASK_64;
        eaddr_aligned = eaddr & ~PAGE_MASK_64;

        for (addr = saddr_aligned; addr < eaddr_aligned; addr += PAGE_SIZE_64) {

                paddr = pmap_find_phys(kernel_pmap, addr);

                assert(paddr);

                hibernate_page_bitset(page_list,       TRUE, paddr);
                hibernate_page_bitset(page_list_wired, TRUE, paddr);

                mark_as_unneeded_pages++;
        }
        return (mark_as_unneeded_pages);
}


void
hibernate_hash_insert_page(vm_page_t mem)
{
        vm_page_bucket_t *bucket;
        int             hash_id;

        assert(mem->hashed);
        assert(mem->object);
        assert(mem->offset != (vm_object_offset_t) -1);

        /*
         *      Insert it into the object_object/offset hash table
         */
        hash_id = vm_page_hash(mem->object, mem->offset);
        bucket = &vm_page_buckets[hash_id];

        mem->next_m = bucket->page_list;
        bucket->page_list = VM_PAGE_PACK_PTR(mem);
}


void
hibernate_free_range(int sindx, int eindx)
{
        vm_page_t       mem;
        unsigned int    color;

        while (sindx < eindx) {
                mem = &vm_pages[sindx];

                vm_page_init(mem, hibernate_lookup_paddr(sindx), FALSE);

                mem->lopage = FALSE;
                mem->free = TRUE;

                color = mem->phys_page & vm_color_mask;
                queue_enter_first(&vm_page_queue_free[color],
                                  mem,
                                  vm_page_t,
                                  pageq);
                vm_page_free_count++;

                sindx++;
        }
}


extern void hibernate_rebuild_pmap_structs(void);

void
hibernate_rebuild_vm_structs(void)
{
        int             cindx, sindx, eindx;
        vm_page_t       mem, tmem, mem_next;
        AbsoluteTime    startTime, endTime;
        uint64_t        nsec;

        if (hibernate_rebuild_needed == FALSE)
                return;

        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 13) | DBG_FUNC_START, 0, 0, 0, 0, 0);
        HIBLOG("hibernate_rebuild started\n");

        clock_get_uptime(&startTime);

        hibernate_rebuild_pmap_structs();

        bzero(&vm_page_buckets[0], vm_page_bucket_count * sizeof(vm_page_bucket_t));
        eindx = vm_pages_count;

        for (cindx = hibernate_teardown_last_valid_compact_indx; cindx >= 0; cindx--) {
                
                mem = &vm_pages[cindx];
                /*
                 * hibernate_teardown_vm_structs leaves the location where
                 * this vm_page_t must be located in "next".
                 */
                tmem = VM_PAGE_UNPACK_PTR(mem->next_m);
                mem->next_m = VM_PAGE_PACK_PTR(NULL);

                sindx = (int)(tmem - &vm_pages[0]);

                if (mem != tmem) {
                        /*
                         * this vm_page_t was moved by hibernate_teardown_vm_structs,
                         * so move it back to its real location
                         */
                        *tmem = *mem;
                        mem = tmem;
                }
                if (mem->hashed)
                        hibernate_hash_insert_page(mem);
                /*
                 * the 'hole' between this vm_page_t and the previous
                 * vm_page_t we moved needs to be initialized as 
                 * a range of free vm_page_t's
                 */
                hibernate_free_range(sindx + 1, eindx);

                eindx = sindx;
        }
        if (sindx)
                hibernate_free_range(0, sindx);

        assert(vm_page_free_count == hibernate_teardown_vm_page_free_count);

        /*
         * process the list of vm_page_t's that were entered in the hash,
         * but were not located in the vm_pages arrary... these are 
         * vm_page_t's that were created on the fly (i.e. fictitious)
         */
        for (mem = hibernate_rebuild_hash_list; mem; mem = mem_next) {
                mem_next = VM_PAGE_UNPACK_PTR(mem->next_m);

                mem->next_m = VM_PAGE_PACK_PTR(NULL);
                hibernate_hash_insert_page(mem);
        }
        hibernate_rebuild_hash_list = NULL;

        clock_get_uptime(&endTime);
        SUB_ABSOLUTETIME(&endTime, &startTime);
        absolutetime_to_nanoseconds(endTime, &nsec);

        HIBLOG("hibernate_rebuild completed - took %qd msecs\n", nsec / 1000000ULL);

        hibernate_rebuild_needed = FALSE;

        KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 13) | DBG_FUNC_END, 0, 0, 0, 0, 0);
}


extern void hibernate_teardown_pmap_structs(addr64_t *, addr64_t *);

uint32_t
hibernate_teardown_vm_structs(hibernate_page_list_t *page_list, hibernate_page_list_t *page_list_wired)
{
        unsigned int    i;
        unsigned int    compact_target_indx;
        vm_page_t       mem, mem_next;
        vm_page_bucket_t *bucket;
        unsigned int    mark_as_unneeded_pages = 0;
        unsigned int    unneeded_vm_page_bucket_pages = 0;
        unsigned int    unneeded_vm_pages_pages = 0;
        unsigned int    unneeded_pmap_pages = 0;
        addr64_t        start_of_unneeded = 0;
        addr64_t        end_of_unneeded = 0;

        
        if (hibernate_should_abort())
                return (0);

        HIBLOG("hibernate_teardown: wired_pages %d, free_pages %d, active_pages %d, inactive_pages %d, speculative_pages %d, cleaned_pages %d, compressor_pages %d\n",
               vm_page_wire_count, vm_page_free_count, vm_page_active_count, vm_page_inactive_count, vm_page_speculative_count,
               vm_page_cleaned_count, compressor_object->resident_page_count);

        for (i = 0; i < vm_page_bucket_count; i++) {

                bucket = &vm_page_buckets[i];

                for (mem = VM_PAGE_UNPACK_PTR(bucket->page_list); mem != VM_PAGE_NULL; mem = mem_next) {
                        assert(mem->hashed);

                        mem_next = VM_PAGE_UNPACK_PTR(mem->next_m);

                        if (mem < &vm_pages[0] || mem >= &vm_pages[vm_pages_count]) {
                                mem->next_m = VM_PAGE_PACK_PTR(hibernate_rebuild_hash_list);
                                hibernate_rebuild_hash_list = mem;
                        }
                }
        }
        unneeded_vm_page_bucket_pages = hibernate_mark_as_unneeded((addr64_t)&vm_page_buckets[0], (addr64_t)&vm_page_buckets[vm_page_bucket_count], page_list, page_list_wired);
        mark_as_unneeded_pages += unneeded_vm_page_bucket_pages;

        hibernate_teardown_vm_page_free_count = vm_page_free_count;

        compact_target_indx = 0;

        for (i = 0; i < vm_pages_count; i++) {

                mem = &vm_pages[i];

                if (mem->free) {
                        unsigned int color;

                        assert(mem->busy);
                        assert(!mem->lopage);

                        color = mem->phys_page & vm_color_mask;

                        queue_remove(&vm_page_queue_free[color],
                                     mem,
                                     vm_page_t,
                                     pageq);
                        mem->pageq.next = NULL;
                        mem->pageq.prev = NULL;

                        vm_page_free_count--;

                        hibernate_teardown_found_free_pages++;

                        if ( !vm_pages[compact_target_indx].free)
                                compact_target_indx = i;
                } else {
                        /*
                         * record this vm_page_t's original location
                         * we need this even if it doesn't get moved
                         * as an indicator to the rebuild function that
                         * we don't have to move it
                         */
                        mem->next_m = VM_PAGE_PACK_PTR(mem);

                        if (vm_pages[compact_target_indx].free) {
                                /*
                                 * we've got a hole to fill, so
                                 * move this vm_page_t to it's new home
                                 */
                                vm_pages[compact_target_indx] = *mem;
                                mem->free = TRUE;

                                hibernate_teardown_last_valid_compact_indx = compact_target_indx;
                                compact_target_indx++;
                        } else
                                hibernate_teardown_last_valid_compact_indx = i;
                }
        }
        unneeded_vm_pages_pages = hibernate_mark_as_unneeded((addr64_t)&vm_pages[hibernate_teardown_last_valid_compact_indx+1],
                                                             (addr64_t)&vm_pages[vm_pages_count-1], page_list, page_list_wired);
        mark_as_unneeded_pages += unneeded_vm_pages_pages;

        hibernate_teardown_pmap_structs(&start_of_unneeded, &end_of_unneeded);

        if (start_of_unneeded) {
                unneeded_pmap_pages = hibernate_mark_as_unneeded(start_of_unneeded, end_of_unneeded, page_list, page_list_wired);
                mark_as_unneeded_pages += unneeded_pmap_pages;
        }
        HIBLOG("hibernate_teardown: mark_as_unneeded_pages %d, %d, %d\n", unneeded_vm_page_bucket_pages, unneeded_vm_pages_pages, unneeded_pmap_pages);

        hibernate_rebuild_needed = TRUE;

        return (mark_as_unneeded_pages);
}


#endif /* HIBERNATION */

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include <mach_vm_debug.h>
#if     MACH_VM_DEBUG

#include <mach_debug/hash_info.h>
#include <vm/vm_debug.h>

/*
 *      Routine:        vm_page_info
 *      Purpose:
 *              Return information about the global VP table.
 *              Fills the buffer with as much information as possible
 *              and returns the desired size of the buffer.
 *      Conditions:
 *              Nothing locked.  The caller should provide
 *              possibly-pageable memory.
 */

unsigned int
vm_page_info(
        hash_info_bucket_t *info,
        unsigned int count)
{
        unsigned int i;
        lck_spin_t      *bucket_lock;

        if (vm_page_bucket_count < count)
                count = vm_page_bucket_count;

        for (i = 0; i < count; i++) {
                vm_page_bucket_t *bucket = &vm_page_buckets[i];
                unsigned int bucket_count = 0;
                vm_page_t m;

                bucket_lock = &vm_page_bucket_locks[i / BUCKETS_PER_LOCK];
                lck_spin_lock(bucket_lock);

                for (m = VM_PAGE_UNPACK_PTR(bucket->page_list); m != VM_PAGE_NULL; m = VM_PAGE_UNPACK_PTR(m->next_m))
                        bucket_count++;

                lck_spin_unlock(bucket_lock);

                /* don't touch pageable memory while holding locks */
                info[i].hib_count = bucket_count;
        }

        return vm_page_bucket_count;
}
#endif  /* MACH_VM_DEBUG */

#if VM_PAGE_BUCKETS_CHECK
void
vm_page_buckets_check(void)
{
        unsigned int i;
        vm_page_t p;
        unsigned int p_hash;
        vm_page_bucket_t *bucket;
        lck_spin_t      *bucket_lock;

        if (!vm_page_buckets_check_ready) {
                return;
        }

#if HIBERNATION
        if (hibernate_rebuild_needed ||
            hibernate_rebuild_hash_list) {
                panic("BUCKET_CHECK: hibernation in progress: "
                      "rebuild_needed=%d rebuild_hash_list=%p\n",
                      hibernate_rebuild_needed,
                      hibernate_rebuild_hash_list);
        }
#endif /* HIBERNATION */

#if VM_PAGE_FAKE_BUCKETS
        char *cp;
        for (cp = (char *) vm_page_fake_buckets_start;
             cp < (char *) vm_page_fake_buckets_end;
             cp++) {
                if (*cp != 0x5a) {
                        panic("BUCKET_CHECK: corruption at %p in fake buckets "
                              "[0x%llx:0x%llx]\n",
                              cp,
                              (uint64_t) vm_page_fake_buckets_start,
                              (uint64_t) vm_page_fake_buckets_end);
                }
        }
#endif /* VM_PAGE_FAKE_BUCKETS */

        for (i = 0; i < vm_page_bucket_count; i++) {
                bucket = &vm_page_buckets[i];
                if (!bucket->page_list) {
                        continue;
                }

                bucket_lock = &vm_page_bucket_locks[i / BUCKETS_PER_LOCK];
                lck_spin_lock(bucket_lock);
                p = VM_PAGE_UNPACK_PTR(bucket->page_list);
                while (p != VM_PAGE_NULL) {
                        if (!p->hashed) {
                                panic("BUCKET_CHECK: page %p (%p,0x%llx) "
                                      "hash %d in bucket %d at %p "
                                      "is not hashed\n",
                                      p, p->object, p->offset,
                                      p_hash, i, bucket);
                        }
                        p_hash = vm_page_hash(p->object, p->offset);
                        if (p_hash != i) {
                                panic("BUCKET_CHECK: corruption in bucket %d "
                                      "at %p: page %p object %p offset 0x%llx "
                                      "hash %d\n",
                                      i, bucket, p, p->object, p->offset,
                                      p_hash);
                        }
                        p = VM_PAGE_UNPACK_PTR(p->next_m);
                }
                lck_spin_unlock(bucket_lock);
        }

//      printf("BUCKET_CHECK: checked buckets\n");
}
#endif /* VM_PAGE_BUCKETS_CHECK */

/*
 * 'vm_fault_enter' will place newly created pages (zero-fill and COW) onto the
 * local queues if they exist... its the only spot in the system where we add pages
 * to those queues...  once on those queues, those pages can only move to one of the
 * global page queues or the free queues... they NEVER move from local q to local q.
 * the 'local' state is stable when vm_page_queues_remove is called since we're behind
 * the global vm_page_queue_lock at this point...  we still need to take the local lock
 * in case this operation is being run on a different CPU then the local queue's identity,
 * but we don't have to worry about the page moving to a global queue or becoming wired
 * while we're grabbing the local lock since those operations would require the global
 * vm_page_queue_lock to be held, and we already own it.
 *
 * this is why its safe to utilze the wire_count field in the vm_page_t as the local_id...
 * 'wired' and local are ALWAYS mutually exclusive conditions.
 */
void
vm_page_queues_remove(vm_page_t mem)
{
        boolean_t       was_pageable;

        VM_PAGE_QUEUES_ASSERT(mem, 1);
        assert(!mem->pageout_queue);
        /*
         *      if (mem->pageout_queue)
         *              NOTE: vm_page_queues_remove does not deal with removing pages from the pageout queue...
         *              the caller is responsible for determing if the page is on that queue, and if so, must
         *              either first remove it (it needs both the page queues lock and the object lock to do
         *              this via vm_pageout_steal_laundry), or avoid the call to vm_page_queues_remove
         */
        if (mem->local) {
                struct vpl      *lq;
                assert(mem->object != kernel_object);
                assert(mem->object != compressor_object);
                assert(!mem->inactive && !mem->speculative);
                assert(!mem->active && !mem->throttled);
                assert(!mem->clean_queue);
                assert(!mem->fictitious);
                lq = &vm_page_local_q[mem->local_id].vpl_un.vpl;
                VPL_LOCK(&lq->vpl_lock);
                queue_remove(&lq->vpl_queue,
                             mem, vm_page_t, pageq);
                mem->local = FALSE;
                mem->local_id = 0;
                lq->vpl_count--;
                if (mem->object->internal) {
                        lq->vpl_internal_count--;
                } else {
                        lq->vpl_external_count--;
                }
                VPL_UNLOCK(&lq->vpl_lock);
                was_pageable = FALSE;
        }

        else if (mem->active) {
                assert(mem->object != kernel_object);
                assert(mem->object != compressor_object);
                assert(!mem->inactive && !mem->speculative);
                assert(!mem->clean_queue);
                assert(!mem->throttled);
                assert(!mem->fictitious);
                queue_remove(&vm_page_queue_active,
                        mem, vm_page_t, pageq);
                mem->active = FALSE;
                vm_page_active_count--;
                was_pageable = TRUE;
        }

        else if (mem->inactive) {
                assert(mem->object != kernel_object);
                assert(mem->object != compressor_object);
                assert(!mem->active && !mem->speculative);
                assert(!mem->throttled);
                assert(!mem->fictitious);
                vm_page_inactive_count--;
                if (mem->clean_queue) {
                        queue_remove(&vm_page_queue_cleaned,
                        mem, vm_page_t, pageq);
                        mem->clean_queue = FALSE;
                        vm_page_cleaned_count--;
                } else {
                        if (mem->object->internal) {
                                queue_remove(&vm_page_queue_anonymous,
                                mem, vm_page_t, pageq);
                                vm_page_anonymous_count--;
                        } else {
                                queue_remove(&vm_page_queue_inactive,
                                mem, vm_page_t, pageq);
                        }
                        vm_purgeable_q_advance_all();
                }
                mem->inactive = FALSE;
                was_pageable = TRUE;
        }

        else if (mem->throttled) {
                assert(mem->object != compressor_object);
                assert(!mem->active && !mem->inactive);
                assert(!mem->speculative);
                assert(!mem->fictitious);
                queue_remove(&vm_page_queue_throttled,
                             mem, vm_page_t, pageq);
                mem->throttled = FALSE;
                vm_page_throttled_count--;
                was_pageable = FALSE;
        }

        else if (mem->speculative) {
                assert(mem->object != compressor_object);
                assert(!mem->active && !mem->inactive);
                assert(!mem->throttled);
                assert(!mem->fictitious);
                remque(&mem->pageq);
                mem->speculative = FALSE;
                vm_page_speculative_count--;
                was_pageable = TRUE;
        }

        else if (mem->pageq.next || mem->pageq.prev) {
                was_pageable = FALSE;
                panic("vm_page_queues_remove: unmarked page on Q");
        } else {
                was_pageable = FALSE;
        }

        mem->pageq.next = NULL;
        mem->pageq.prev = NULL;
        VM_PAGE_QUEUES_ASSERT(mem, 0);
        if (was_pageable) {
                if (mem->object->internal) {
                        vm_page_pageable_internal_count--;
                } else {
                        vm_page_pageable_external_count--;
                }
        }
}

void
vm_page_remove_internal(vm_page_t page)
{
        vm_object_t __object = page->object;
        if (page == __object->memq_hint) {
                vm_page_t       __new_hint;
                queue_entry_t   __qe;
                __qe = queue_next(&page->listq);
                if (queue_end(&__object->memq, __qe)) {
                        __qe = queue_prev(&page->listq);
                        if (queue_end(&__object->memq, __qe)) {
                                __qe = NULL;
                        }
                }
                __new_hint = (vm_page_t) __qe;
                __object->memq_hint = __new_hint;
        }
        queue_remove(&__object->memq, page, vm_page_t, listq);
}

void
vm_page_enqueue_inactive(vm_page_t mem, boolean_t first)
{
        VM_PAGE_QUEUES_ASSERT(mem, 0);
        assert(!mem->fictitious);
        assert(!mem->laundry);
        assert(!mem->pageout_queue);
        vm_page_check_pageable_safe(mem);
        if (mem->object->internal) {
                if (first == TRUE)
                        queue_enter_first(&vm_page_queue_anonymous, mem, vm_page_t, pageq);
                else
                        queue_enter(&vm_page_queue_anonymous, mem, vm_page_t, pageq);
                vm_page_anonymous_count++;
                vm_page_pageable_internal_count++;
        } else {
                if (first == TRUE)
                        queue_enter_first(&vm_page_queue_inactive, mem, vm_page_t, pageq);
                else
                        queue_enter(&vm_page_queue_inactive, mem, vm_page_t, pageq);
                vm_page_pageable_external_count++;
        }
        mem->inactive = TRUE;
        vm_page_inactive_count++;
        token_new_pagecount++;
}

/*
 * Pages from special kernel objects shouldn't
 * be placed on pageable queues.
 */
void
vm_page_check_pageable_safe(vm_page_t page)
{
        if (page->object == kernel_object) {
                panic("vm_page_check_pageable_safe: trying to add page" \
                         "from kernel object (%p) to pageable queue", kernel_object);
        }

        if (page->object == compressor_object) {
                panic("vm_page_check_pageable_safe: trying to add page" \
                         "from compressor object (%p) to pageable queue", compressor_object);
        }

        if (page->object == vm_submap_object) {
                panic("vm_page_check_pageable_safe: trying to add page" \
                        "from submap object (%p) to pageable queue", vm_submap_object);
        }
}

/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * wired page diagnose
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

#include <libkern/OSKextLibPrivate.h>

vm_allocation_site_t * 
vm_allocation_sites[VM_KERN_MEMORY_COUNT];

vm_tag_t 
vm_tag_bt(void)
{
    uintptr_t* frameptr;
    uintptr_t* frameptr_next;
    uintptr_t retaddr;
    uintptr_t kstackb, kstackt;
    const vm_allocation_site_t * site;
    thread_t cthread;
    
    cthread = current_thread();
    if (__improbable(cthread == NULL)) return VM_KERN_MEMORY_OSFMK;

    kstackb = cthread->kernel_stack;
    kstackt = kstackb + kernel_stack_size;

    /* Load stack frame pointer (EBP on x86) into frameptr */
    frameptr = __builtin_frame_address(0);
    site = NULL;
    while (frameptr != NULL) 
    {
        /* Verify thread stack bounds */
        if (((uintptr_t)(frameptr + 2) > kstackt) || ((uintptr_t)frameptr < kstackb)) break;

        /* Next frame pointer is pointed to by the previous one */
        frameptr_next = (uintptr_t*) *frameptr;

        /* Pull return address from one spot above the frame pointer */
        retaddr = *(frameptr + 1);

        if ((retaddr < vm_kernel_stext) || (retaddr > vm_kernel_top))
        {
            site = OSKextGetAllocationSiteForCaller(retaddr);
            break;
        }

        frameptr = frameptr_next;
    }
    return (site ? site->tag : VM_KERN_MEMORY_NONE);
}

static uint64_t free_tag_bits[256/64];

void
vm_tag_alloc_locked(vm_allocation_site_t * site)
{
    vm_tag_t tag;
    uint64_t avail;
    uint64_t idx;

    if (site->tag) return;

    idx = 0;
    while (TRUE)
    {
        avail = free_tag_bits[idx];
        if (avail)
        {
            tag = __builtin_clzll(avail);
            avail &= ~(1ULL << (63 - tag));
            free_tag_bits[idx] = avail;
            tag += (idx << 6);
            break;
        }
        idx++;
        if (idx >= (sizeof(free_tag_bits) / sizeof(free_tag_bits[0])))
        {
             tag = VM_KERN_MEMORY_ANY;
             break;
        }
    }
    site->tag = tag;
    if (VM_KERN_MEMORY_ANY != tag)
    {
        assert(!vm_allocation_sites[tag]);
        vm_allocation_sites[tag] = site;
    }
}

static void
vm_tag_free_locked(vm_tag_t tag)
{
    uint64_t avail;
    uint32_t idx;
    uint64_t bit;

    if (VM_KERN_MEMORY_ANY == tag) return;

    idx = (tag >> 6);
    avail = free_tag_bits[idx];
    tag &= 63;
    bit = (1ULL << (63 - tag));
    assert(!(avail & bit));
    free_tag_bits[idx] = (avail | bit);
}

static void
vm_tag_init(void)
{
    vm_tag_t tag;
    for (tag = VM_KERN_MEMORY_FIRST_DYNAMIC; tag < VM_KERN_MEMORY_ANY; tag++)
    {
        vm_tag_free_locked(tag);
    }
}

vm_tag_t
vm_tag_alloc(vm_allocation_site_t * site)
{
    vm_tag_t tag;

    if (VM_TAG_BT & site->flags)
    {
        tag = vm_tag_bt();
        if (VM_KERN_MEMORY_NONE != tag) return (tag);
    }

    if (!site->tag) 
    {
        lck_spin_lock(&vm_allocation_sites_lock);
        vm_tag_alloc_locked(site);
        lck_spin_unlock(&vm_allocation_sites_lock);
    }

    return (site->tag);
}

static void 
vm_page_count_object(mach_memory_info_t * sites, unsigned int __unused num_sites, vm_object_t object)
{
    if (!object->wired_page_count) return;
    if (object != kernel_object)
    {
        assert(object->wire_tag < num_sites);
        sites[object->wire_tag].size += ptoa_64(object->wired_page_count);
    }
}

typedef void (*vm_page_iterate_proc)(mach_memory_info_t * sites, 
                                     unsigned int num_sites, vm_object_t object);

static void 
vm_page_iterate_purgeable_objects(mach_memory_info_t * sites, unsigned int num_sites,
                                  vm_page_iterate_proc proc, purgeable_q_t queue, 
                                  int group)
{
    vm_object_t object;

    for (object = (vm_object_t) queue_first(&queue->objq[group]);
        !queue_end(&queue->objq[group], (queue_entry_t) object);
        object = (vm_object_t) queue_next(&object->objq))
    {
        proc(sites, num_sites, object);
    }
}

static void 
vm_page_iterate_objects(mach_memory_info_t * sites, unsigned int num_sites,
                        vm_page_iterate_proc proc)
{
    purgeable_q_t   volatile_q;
    queue_head_t  * nonvolatile_q;
    vm_object_t     object;
    int             group;

    lck_spin_lock(&vm_objects_wired_lock);
    queue_iterate(&vm_objects_wired,
                  object,
                  vm_object_t,
                  objq)
    {
        proc(sites, num_sites, object);
    }
    lck_spin_unlock(&vm_objects_wired_lock);

    lck_mtx_lock(&vm_purgeable_queue_lock);
    nonvolatile_q = &purgeable_nonvolatile_queue;
    for (object = (vm_object_t) queue_first(nonvolatile_q);
         !queue_end(nonvolatile_q, (queue_entry_t) object);
         object = (vm_object_t) queue_next(&object->objq))
    {
        proc(sites, num_sites, object);
    }

    volatile_q = &purgeable_queues[PURGEABLE_Q_TYPE_OBSOLETE];
    vm_page_iterate_purgeable_objects(sites, num_sites, proc, volatile_q, 0);

    volatile_q = &purgeable_queues[PURGEABLE_Q_TYPE_FIFO];
    for (group = 0; group < NUM_VOLATILE_GROUPS; group++)
    {
        vm_page_iterate_purgeable_objects(sites, num_sites, proc, volatile_q, group);
    }

    volatile_q = &purgeable_queues[PURGEABLE_Q_TYPE_LIFO];
    for (group = 0; group < NUM_VOLATILE_GROUPS; group++)
    {
        vm_page_iterate_purgeable_objects(sites, num_sites, proc, volatile_q, group);
    }
    lck_mtx_unlock(&vm_purgeable_queue_lock);
}

static uint64_t
process_account(mach_memory_info_t * sites, unsigned int __unused num_sites)
{
    uint64_t found;
    unsigned int idx;
    vm_allocation_site_t * site;

    assert(num_sites >= VM_KERN_MEMORY_COUNT);
    found = 0;
    for (idx = 0; idx < VM_KERN_MEMORY_COUNT; idx++) 
    {
        found += sites[idx].size;
        if (idx < VM_KERN_MEMORY_FIRST_DYNAMIC)
        {
            sites[idx].site   = idx;
            sites[idx].flags |= VM_KERN_SITE_TAG;
            if (VM_KERN_MEMORY_ZONE == idx) sites[idx].flags |= VM_KERN_SITE_HIDE;
            else                            sites[idx].flags |= VM_KERN_SITE_WIRED;
            continue;
        }
        lck_spin_lock(&vm_allocation_sites_lock);
        if ((site = vm_allocation_sites[idx]))
        {
            if (sites[idx].size)
            {
                sites[idx].flags |= VM_KERN_SITE_WIRED;
                if (VM_TAG_KMOD == (VM_KERN_SITE_TYPE & site->flags))
                {
                    sites[idx].site   = OSKextGetKmodIDForSite(site);
                    sites[idx].flags |= VM_KERN_SITE_KMOD;
                }
                else
                {
                    sites[idx].site   = VM_KERNEL_UNSLIDE(site);
                    sites[idx].flags |= VM_KERN_SITE_KERNEL;
                }
                site = NULL;
            }
            else
            {
#if 1
                site = NULL;
#else
                /* this code would free a site with no allocations but can race a new
                 * allocation being made */
                vm_tag_free_locked(site->tag);
                site->tag = VM_KERN_MEMORY_NONE;
                vm_allocation_sites[idx] = NULL;
                if (!(VM_TAG_UNLOAD & site->flags)) site = NULL;
#endif
            }
        }
        lck_spin_unlock(&vm_allocation_sites_lock);
        if (site) OSKextFreeSite(site);
    }
    return (found);
}

kern_return_t 
vm_page_diagnose(mach_memory_info_t * sites, unsigned int num_sites)
{
    enum                   { kMaxKernelDepth = 1 };
    vm_map_t                 maps   [kMaxKernelDepth];
    vm_map_entry_t           entries[kMaxKernelDepth];
    vm_map_t                 map;
    vm_map_entry_t           entry;
    vm_object_offset_t       offset;
    vm_page_t                page;
    int                      stackIdx, count;
    uint64_t                 wired_size;
    uint64_t                 wired_managed_size;
    uint64_t                 wired_reserved_size;
    mach_memory_info_t     * counts;

    bzero(sites, num_sites * sizeof(mach_memory_info_t));

    vm_page_iterate_objects(sites, num_sites, &vm_page_count_object);

    wired_size          = ptoa_64(vm_page_wire_count + vm_lopage_free_count + vm_page_throttled_count);
    wired_reserved_size = ptoa_64(vm_page_wire_count_initial - vm_page_stolen_count + vm_page_throttled_count);
    wired_managed_size  = ptoa_64(vm_page_wire_count - vm_page_wire_count_initial);

    assert(num_sites >= (VM_KERN_MEMORY_COUNT + VM_KERN_COUNTER_COUNT));
    counts = &sites[VM_KERN_MEMORY_COUNT];

#define SET_COUNT(xcount, xsize, xflags)                        \
    counts[xcount].site  = (xcount);                    \
    counts[xcount].size  = (xsize);                     \
    counts[xcount].flags = VM_KERN_SITE_COUNTER | xflags;

    SET_COUNT(VM_KERN_COUNT_MANAGED,              ptoa_64(vm_page_pages),        0);
    SET_COUNT(VM_KERN_COUNT_WIRED,                wired_size,                    0);
    SET_COUNT(VM_KERN_COUNT_WIRED_MANAGED,        wired_managed_size,            0);
    SET_COUNT(VM_KERN_COUNT_RESERVED,             wired_reserved_size,           VM_KERN_SITE_WIRED);
    SET_COUNT(VM_KERN_COUNT_STOLEN,               ptoa_64(vm_page_stolen_count), VM_KERN_SITE_WIRED);
    SET_COUNT(VM_KERN_COUNT_LOPAGE,               ptoa_64(vm_lopage_free_count), VM_KERN_SITE_WIRED);

#define SET_MAP(xcount, xsize, xfree, xlargest)         \
    counts[xcount].site    = (xcount);                  \
    counts[xcount].size    = (xsize);                   \
    counts[xcount].free    = (xfree);                   \
    counts[xcount].largest = (xlargest);                \
    counts[xcount].flags   = VM_KERN_SITE_COUNTER;

    vm_map_size_t map_size, map_free, map_largest;

    vm_map_sizes(kernel_map, &map_size, &map_free, &map_largest);
    SET_MAP(VM_KERN_COUNT_MAP_KERNEL, map_size, map_free, map_largest);

    vm_map_sizes(zone_map, &map_size, &map_free, &map_largest);
    SET_MAP(VM_KERN_COUNT_MAP_ZONE, map_size, map_free, map_largest);

    vm_map_sizes(kalloc_map, &map_size, &map_free, &map_largest);
    SET_MAP(VM_KERN_COUNT_MAP_KALLOC, map_size, map_free, map_largest);

    map = kernel_map;
    stackIdx = 0;
    while (map)
    {
        vm_map_lock(map);
        for (entry = map->hdr.links.next; map; entry = entry->links.next)
        {
            if (entry->is_sub_map)
            {
                assert(stackIdx < kMaxKernelDepth);
                maps[stackIdx] = map;
                entries[stackIdx] = entry;
                stackIdx++;
                map = VME_SUBMAP(entry);
                entry = NULL;
                break;
            }
            if (VME_OBJECT(entry) == kernel_object)
            {
                count = 0;
                vm_object_lock(VME_OBJECT(entry));
                for (offset = entry->links.start; offset < entry->links.end; offset += page_size)
                {
                        page = vm_page_lookup(VME_OBJECT(entry), offset);
                        if (page && VM_PAGE_WIRED(page)) count++;
                }
                vm_object_unlock(VME_OBJECT(entry));

                if (count)
                {
                    assert(VME_ALIAS(entry) < num_sites);
                    sites[VME_ALIAS(entry)].size += ptoa_64(count);
                }
            }
            if (entry == vm_map_last_entry(map))
            {
                vm_map_unlock(map);
                if (!stackIdx) map = NULL;
                else
                {
                    --stackIdx;
                    map = maps[stackIdx];
                    entry = entries[stackIdx];
                }
            }
        }
    }

    process_account(sites, num_sites);
    
    return (KERN_SUCCESS);
}