]> git.saurik.com Git - apple/xnu.git/blobdiff - osfmk/vm/vm_compressor.c
xnu-4570.71.2.tar.gz
[apple/xnu.git] / osfmk / vm / vm_compressor.c
index bc565e3f1c05ad8585bb822289aa6fcbd690e625..f474385b7d7da5f7b91905e1f339d8ae475ee692 100644 (file)
  */
 
 #include <vm/vm_compressor.h>
+
+#if CONFIG_PHANTOM_CACHE
+#include <vm/vm_phantom_cache.h>
+#endif
+
 #include <vm/vm_map.h>
 #include <vm/vm_pageout.h>
 #include <vm/memory_object.h>
+#include <vm/vm_compressor_algorithms.h>
+#include <vm/vm_fault.h>
+#include <vm/vm_protos.h>
 #include <mach/mach_host.h>            /* for host_info() */
 #include <kern/ledger.h>
+#include <kern/policy_internal.h>
+#include <kern/thread_group.h>
+#include <san/kasan.h>
 
-#include <default_pager/default_pager_alerts.h>
-#include <default_pager/default_pager_object_server.h>
+#if !CONFIG_EMBEDDED
+#include <i386/misc_protos.h>
+#endif
 
 #include <IOKit/IOHibernatePrivate.h>
 
+#if POPCOUNT_THE_COMPRESSED_DATA
+boolean_t popcount_c_segs = TRUE;
+
+static inline uint32_t vmc_pop(uintptr_t ins, int sz) {
+       uint32_t rv = 0;
+
+       if (__probable(popcount_c_segs == FALSE)) {
+               return 0xDEAD707C;
+       }
+
+       while (sz >= 16) {
+               uint32_t rv1, rv2;
+               uint64_t *ins64 = (uint64_t *) ins;
+               uint64_t *ins642 = (uint64_t *) (ins + 8);
+               rv1 = __builtin_popcountll(*ins64);
+               rv2 = __builtin_popcountll(*ins642);
+               rv += rv1 + rv2;
+               sz -= 16;
+               ins += 16;
+       }
+
+       while (sz >= 4) {
+               uint32_t *ins32 = (uint32_t *) ins;
+               rv += __builtin_popcount(*ins32);
+               sz -= 4;
+               ins += 4;
+       }
+
+       while (sz > 0) {
+               char *ins8 = (char *)ins;
+               rv += __builtin_popcount(*ins8);
+               sz--;
+               ins++;
+       }
+       return rv;
+}
+#endif
+
 /*
  * vm_compressor_mode has a heirarchy of control to set its value.
  * boot-args are checked first, then device-tree, and finally
  * the boot-arg & device-tree code.
  */
 
-extern ipc_port_t min_pages_trigger_port;
-extern lck_mtx_t paging_segments_lock;
-#define PSL_LOCK()             lck_mtx_lock(&paging_segments_lock)
-#define PSL_UNLOCK()   lck_mtx_unlock(&paging_segments_lock)
+#if CONFIG_EMBEDDED
 
+#if CONFIG_FREEZE
+int            vm_compressor_mode = VM_PAGER_FREEZER_DEFAULT;
+
+void           *freezer_chead; /* The chead used to track c_segs allocated for the exclusive use of holding just one task's compressed memory.*/
+char           *freezer_compressor_scratch_buf = NULL;
+
+#define                VM_MAX_FREEZER_CSEG_SWAP_COUNT  64 /* The maximum number of c_segs holding just one task's compressed memory that can be swapped out to disk.*/
+extern int     c_freezer_swapout_count;           /* This count keeps track of the # of c_segs holding just one task's compressed memory on the swapout queue. This count is used during each freeze i.e. on a per-task basis.*/
+
+#else /* CONFIG_FREEZE */
+int            vm_compressor_mode = VM_PAGER_NOT_CONFIGURED;
+#endif /* CONFIG_FREEZE */
+
+int            vm_scale = 1;
 
+#else /* CONFIG_EMBEDDED */
 int            vm_compressor_mode = VM_PAGER_COMPRESSOR_WITH_SWAP;
 int            vm_scale = 16;
 
+#endif /* CONFIG_EMBEDDED */
 
+int            vm_compressor_is_active = 0;
 int            vm_compression_limit = 0;
+int            vm_compressor_available = 0;
 
-extern boolean_t vm_swap_up;
 extern void    vm_pageout_io_throttle(void);
 
 #if CHECKSUM_THE_DATA || CHECKSUM_THE_SWAP || CHECKSUM_THE_COMPRESSED_DATA
 extern unsigned int hash_string(char *cp, int len);
-#endif
+static unsigned int vmc_hash(char *, int);
+boolean_t checksum_c_segs = TRUE;
 
-struct c_slot {
-       uint64_t        c_offset:C_SEG_OFFSET_BITS,
-                       c_size:12,
-                       c_packed_ptr:36;
-#if CHECKSUM_THE_DATA
-       unsigned int    c_hash_data;
-#endif
-#if CHECKSUM_THE_COMPRESSED_DATA
-       unsigned int    c_hash_compressed_data;
+unsigned int vmc_hash(char *cp, int len) {
+       if (__probable(checksum_c_segs == FALSE)) {
+               return 0xDEAD7A37;
+       }
+       return hash_string(cp, len);
+}
 #endif
 
-};
-
-#define UNPACK_C_SIZE(cs)      ((cs->c_size == (PAGE_SIZE-1)) ? 4096 : cs->c_size)
+#define UNPACK_C_SIZE(cs)      ((cs->c_size == (PAGE_SIZE-1)) ? PAGE_SIZE : cs->c_size)
 #define PACK_C_SIZE(cs, size)  (cs->c_size = ((size == PAGE_SIZE) ? PAGE_SIZE - 1 : size))
 
 
-struct  c_slot_mapping {
-        uint32_t        s_cseg:22,     /* segment number + 1 */
-                       s_cindx:10;     /* index in the segment */
+struct c_sv_hash_entry {
+       union {
+               struct  {
+                       uint32_t        c_sv_he_ref;
+                       uint32_t        c_sv_he_data;
+               } c_sv_he;
+               uint64_t        c_sv_he_record;
+
+       } c_sv_he_un;   
 };
 
-typedef struct c_slot_mapping *c_slot_mapping_t;
+#define        he_ref  c_sv_he_un.c_sv_he.c_sv_he_ref
+#define        he_data c_sv_he_un.c_sv_he.c_sv_he_data
+#define        he_record c_sv_he_un.c_sv_he_record
+
+#define C_SV_HASH_MAX_MISS     32
+#define C_SV_HASH_SIZE         ((1 << 10))
+#define C_SV_HASH_MASK         ((1 << 10) - 1)
+#define C_SV_CSEG_ID           ((1 << 22) - 1)
 
 
 union c_segu {
        c_segment_t     c_seg;
-       uint32_t        c_segno;
+       uintptr_t       c_segno;
 };
 
 
 
-#define C_SLOT_PACK_PTR(ptr)           (((uintptr_t)ptr - (uintptr_t) VM_MIN_KERNEL_AND_KEXT_ADDRESS) >> 2)
-#define C_SLOT_UNPACK_PTR(cslot)       ((uintptr_t)(cslot->c_packed_ptr << 2) + (uintptr_t) VM_MIN_KERNEL_AND_KEXT_ADDRESS)
+#define C_SLOT_PACK_PTR(ptr)           (((uintptr_t)ptr - (uintptr_t) KERNEL_PMAP_HEAP_RANGE_START) >> 2)
+#define C_SLOT_UNPACK_PTR(cslot)       ((uintptr_t)(cslot->c_packed_ptr << 2) + (uintptr_t) KERNEL_PMAP_HEAP_RANGE_START)
 
 
 uint32_t       c_segment_count = 0;
+uint32_t       c_segment_count_max = 0;
 
 uint64_t       c_generation_id = 0;
 uint64_t       c_generation_id_flush_barrier;
@@ -112,33 +186,62 @@ boolean_t hibernate_no_swapspace = FALSE;
 clock_sec_t    hibernate_flushing_deadline = 0;
 
 
-#if TRACK_BAD_C_SEGMENTS
-queue_head_t   c_bad_list_head;
-uint32_t       c_bad_count = 0;
+#if RECORD_THE_COMPRESSED_DATA
+char   *c_compressed_record_sbuf;
+char   *c_compressed_record_ebuf;
+char   *c_compressed_record_cptr;
 #endif
 
+
 queue_head_t   c_age_list_head;
 queue_head_t   c_swapout_list_head;
 queue_head_t   c_swappedin_list_head;
 queue_head_t   c_swappedout_list_head;
 queue_head_t   c_swappedout_sparse_list_head;
+queue_head_t   c_major_list_head;
+queue_head_t   c_filling_list_head;
+queue_head_t   c_bad_list_head;
 
 uint32_t       c_age_count = 0;
 uint32_t       c_swapout_count = 0;
 uint32_t       c_swappedin_count = 0;
 uint32_t       c_swappedout_count = 0;
 uint32_t       c_swappedout_sparse_count = 0;
+uint32_t       c_major_count = 0;
+uint32_t       c_filling_count = 0;
+uint32_t       c_empty_count = 0;
+uint32_t       c_bad_count = 0;
+
 
 queue_head_t   c_minor_list_head;
 uint32_t       c_minor_count = 0;
 
+int            c_overage_swapped_count = 0;
+int            c_overage_swapped_limit = 0;
+
+int            c_seg_fixed_array_len;
 union  c_segu  *c_segments;
+vm_offset_t    c_buffers;
+vm_size_t       c_buffers_size;
 caddr_t                c_segments_next_page;
 boolean_t      c_segments_busy;
 uint32_t       c_segments_available;
 uint32_t       c_segments_limit;
+uint32_t       c_segments_nearing_limit;
+
+uint32_t       c_segment_svp_in_hash;
+uint32_t       c_segment_svp_hash_succeeded;
+uint32_t       c_segment_svp_hash_failed;
+uint32_t       c_segment_svp_zero_compressions;
+uint32_t       c_segment_svp_nonzero_compressions;
+uint32_t       c_segment_svp_zero_decompressions;
+uint32_t       c_segment_svp_nonzero_decompressions;
+
+uint32_t       c_segment_noncompressible_pages;
+
 uint32_t       c_segment_pages_compressed;
 uint32_t       c_segment_pages_compressed_limit;
+uint32_t       c_segment_pages_compressed_nearing_limit;
 uint32_t       c_free_segno_head = (uint32_t)-1;
 
 uint32_t       vm_compressor_minorcompact_threshold_divisor = 10;
@@ -152,23 +255,19 @@ uint32_t  vm_compressor_catchup_threshold_divisor = 10;
 lck_grp_attr_t vm_compressor_lck_grp_attr;
 lck_attr_t     vm_compressor_lck_attr;
 lck_grp_t      vm_compressor_lck_grp;
-
-
-#if __i386__ || __x86_64__
 lck_mtx_t      *c_list_lock;
-#else /* __i386__ || __x86_64__ */
-lck_spin_t     *c_list_lock;
-#endif /* __i386__ || __x86_64__ */
-
 lck_rw_t       c_master_lock;
-lck_rw_t       c_decompressor_lock;
+boolean_t      decompressions_blocked = FALSE;
 
 zone_t         compressor_segment_zone;
 int            c_compressor_swap_trigger = 0;
 
 uint32_t       compressor_cpus;
 char           *compressor_scratch_bufs;
-
+char           *kdp_compressor_scratch_buf;
+char           *kdp_compressor_decompressed_page;
+addr64_t       kdp_compressor_decompressed_page_paddr;
+ppnum_t                kdp_compressor_decompressed_page_ppnum;
 
 clock_sec_t    start_of_sample_period_sec = 0;
 clock_nsec_t   start_of_sample_period_nsec = 0;
@@ -181,11 +280,16 @@ uint32_t  last_eval_compression_count = 0;
 
 #define                DECOMPRESSION_SAMPLE_MAX_AGE            (60 * 30)
 
+boolean_t      vm_swapout_ripe_segments = FALSE;
+uint32_t       vm_ripe_target_age = (60 * 60 * 48);
+
 uint32_t       swapout_target_age = 0;
 uint32_t       age_of_decompressions_during_sample_period[DECOMPRESSION_SAMPLE_MAX_AGE];
 uint32_t       overage_decompressions_during_sample_period = 0;
+uint32_t       vm_compressor_pages_grabbed = 0;
+
 
-void           do_fastwake_warmup(void);
+void           do_fastwake_warmup(queue_head_t *, boolean_t);
 boolean_t      fastwake_warmup = FALSE;
 boolean_t      fastwake_recording_in_progress = FALSE;
 clock_sec_t    dont_trim_until_ts = 0;
@@ -195,18 +299,22 @@ uint64_t  first_c_segment_to_warm_generation_id = 0;
 uint64_t       last_c_segment_to_warm_generation_id = 0;
 boolean_t      hibernate_flushing = FALSE;
 
-int64_t                c_segment_input_bytes = 0;
-int64_t                c_segment_compressed_bytes = 0;
-int64_t                compressor_bytes_used = 0;
+int64_t                c_segment_input_bytes __attribute__((aligned(8))) = 0;
+int64_t                c_segment_compressed_bytes __attribute__((aligned(8))) = 0;
+int64_t                compressor_bytes_used __attribute__((aligned(8))) = 0;
+
+
+struct c_sv_hash_entry c_segment_sv_hash_table[C_SV_HASH_SIZE]  __attribute__ ((aligned (8)));
 
 static boolean_t compressor_needs_to_swap(void);
 static void vm_compressor_swap_trigger_thread(void);
 static void vm_compressor_do_delayed_compactions(boolean_t);
 static void vm_compressor_compact_and_swap(boolean_t);
 static void vm_compressor_age_swapped_in_segments(boolean_t);
-static uint64_t compute_elapsed_msecs(clock_sec_t, clock_nsec_t, clock_sec_t, clock_nsec_t);
 
-boolean_t vm_compressor_low_on_space(void);
+#if !CONFIG_EMBEDDED
+static void vm_compressor_take_paging_space_action(void);
+#endif
 
 void compute_swapout_target_age(void);
 
@@ -216,19 +324,33 @@ boolean_t c_seg_major_compact_ok(c_segment_t, c_segment_t);
 int  c_seg_minor_compaction_and_unlock(c_segment_t, boolean_t);
 int  c_seg_do_minor_compaction_and_unlock(c_segment_t, boolean_t, boolean_t, boolean_t);
 void c_seg_try_minor_compaction_and_unlock(c_segment_t c_seg);
-void c_seg_need_delayed_compaction(c_segment_t);
 
 void c_seg_move_to_sparse_list(c_segment_t);
 void c_seg_insert_into_q(queue_head_t *, c_segment_t);
 
-boolean_t c_seg_try_free(c_segment_t);
-void     c_seg_free(c_segment_t);
-void     c_seg_free_locked(c_segment_t);
+uint64_t vm_available_memory(void);
+uint64_t vm_compressor_pages_compressed(void);
+
+/*
+ * indicate the need to do a major compaction if
+ * the overall set of in-use compression segments
+ * becomes sparse... on systems that support pressure
+ * driven swapping, this will also cause swapouts to
+ * be initiated.
+ */
+static inline boolean_t        vm_compressor_needs_to_major_compact()
+{
+       uint32_t        incore_seg_count;
 
+       incore_seg_count = c_segment_count - c_swappedout_count - c_swappedout_sparse_count;
 
-uint64_t vm_available_memory(void);
+       if ((c_segment_count >= (c_segments_nearing_limit / 8)) &&
+           ((incore_seg_count * C_SEG_MAX_PAGES) - VM_PAGE_COMPRESSOR_COUNT) >
+           ((incore_seg_count / 8) * C_SEG_MAX_PAGES))
+               return (1);
+       return (0);
+}
 
-extern unsigned int dp_pages_free, dp_pages_reserve;
 
 uint64_t
 vm_available_memory(void)
@@ -237,24 +359,29 @@ vm_available_memory(void)
 }
 
 
-boolean_t
-vm_compression_available(void)
+uint64_t
+vm_compressor_pages_compressed(void)
 {
-       if ( !(COMPRESSED_PAGER_IS_ACTIVE || DEFAULT_FREEZER_COMPRESSED_PAGER_IS_ACTIVE))
-               return (FALSE);
+       return (c_segment_pages_compressed * PAGE_SIZE_64);
+}
 
-       if (c_segments_available >= c_segments_limit || c_segment_pages_compressed >= c_segment_pages_compressed_limit)
-               return (FALSE);
 
-       return (TRUE);
+boolean_t
+vm_compressor_low_on_space(void)
+{
+       if ((c_segment_pages_compressed > c_segment_pages_compressed_nearing_limit) ||
+           (c_segment_count > c_segments_nearing_limit))
+               return (TRUE);
+
+       return (FALSE);
 }
 
 
 boolean_t
-vm_compressor_low_on_space(void)
+vm_compressor_out_of_space(void)
 {
-       if ((c_segment_pages_compressed > (c_segment_pages_compressed_limit - 20000)) ||
-           (c_segment_count > (c_segments_limit - 250)))
+       if ((c_segment_pages_compressed >= c_segment_pages_compressed_limit) ||
+           (c_segment_count >= c_segments_limit))
                return (TRUE);
 
        return (FALSE);
@@ -262,19 +389,59 @@ vm_compressor_low_on_space(void)
            
 
 int
-vm_low_on_space(void)
+vm_wants_task_throttled(task_t task)
 {
-       if (vm_compressor_mode == COMPRESSED_PAGER_IS_ACTIVE || vm_compressor_mode == DEFAULT_FREEZER_COMPRESSED_PAGER_IS_ACTIVE) {
-               if (vm_compressor_low_on_space() || HARD_THROTTLE_LIMIT_REACHED())
-                       return (1);
-       } else {
-               if (((dp_pages_free + dp_pages_reserve < 2000) && VM_DYNAMIC_PAGING_ENABLED(memory_manager_default)))
+       if (task == kernel_task)
+               return (0);
+
+       if (VM_CONFIG_SWAP_IS_ACTIVE) {
+               if ((vm_compressor_low_on_space() || HARD_THROTTLE_LIMIT_REACHED()) &&
+                   (unsigned int)pmap_compressed(task->map->pmap) > (c_segment_pages_compressed / 4))
                        return (1);
        }
        return (0);
 }
 
 
+#if DEVELOPMENT || DEBUG
+boolean_t kill_on_no_paging_space = FALSE; /* On compressor/swap exhaustion, kill the largest process regardless of
+                                           * its chosen process policy. Controlled by a boot-arg of the same name. */
+#endif /* DEVELOPMENT || DEBUG */
+
+#if !CONFIG_EMBEDDED
+
+static uint32_t        no_paging_space_action_in_progress = 0;
+extern void memorystatus_send_low_swap_note(void);
+
+static void
+vm_compressor_take_paging_space_action(void)
+{
+       if (no_paging_space_action_in_progress == 0) {
+
+               if (OSCompareAndSwap(0, 1, (UInt32 *)&no_paging_space_action_in_progress)) {
+
+                       if (no_paging_space_action()) {
+#if DEVELOPMENT || DEBUG
+                               if (kill_on_no_paging_space == TRUE) {
+                                       /*
+                                        * Since we are choosing to always kill a process, we don't need the
+                                        * "out of application memory" dialog box in this mode. And, hence we won't
+                                        * send the knote.
+                                        */
+                                       no_paging_space_action_in_progress = 0;
+                                       return;
+                               }
+#endif /* DEVELOPMENT || DEBUG */
+                               memorystatus_send_low_swap_note();
+                       }
+
+                       no_paging_space_action_in_progress = 0;
+               }
+       }
+}
+#endif /* !CONFIG_EMBEDDED */
+
+
 void
 vm_compressor_init_locks(void)
 {
@@ -283,34 +450,132 @@ vm_compressor_init_locks(void)
        lck_attr_setdefault(&vm_compressor_lck_attr);
 
        lck_rw_init(&c_master_lock, &vm_compressor_lck_grp, &vm_compressor_lck_attr);
-       lck_rw_init(&c_decompressor_lock, &vm_compressor_lck_grp, &vm_compressor_lck_attr);
 }
 
 
 void
 vm_decompressor_lock(void)
 {
-       lck_rw_lock_exclusive(&c_decompressor_lock);
+       PAGE_REPLACEMENT_ALLOWED(TRUE);
+
+       decompressions_blocked = TRUE;
+       
+       PAGE_REPLACEMENT_ALLOWED(FALSE);
 }
 
 void
 vm_decompressor_unlock(void)
 {
-       lck_rw_done(&c_decompressor_lock);
+       PAGE_REPLACEMENT_ALLOWED(TRUE);
+
+       decompressions_blocked = FALSE;
+
+       PAGE_REPLACEMENT_ALLOWED(FALSE);
 
+       thread_wakeup((event_t)&decompressions_blocked);
 }
 
+static inline void cslot_copy(c_slot_t cdst, c_slot_t csrc) {
+#if CHECKSUM_THE_DATA
+               cdst->c_hash_data = csrc->c_hash_data;
+#endif
+#if CHECKSUM_THE_COMPRESSED_DATA
+               cdst->c_hash_compressed_data = csrc->c_hash_compressed_data;
+#endif
+#if POPCOUNT_THE_COMPRESSED_DATA
+               cdst->c_pop_cdata = csrc->c_pop_cdata;
+#endif
+               cdst->c_size = csrc->c_size;
+               cdst->c_packed_ptr = csrc->c_packed_ptr;
+#if defined(__arm__) || defined(__arm64__)
+               cdst->c_codec = csrc->c_codec;
+#endif
+}
+
+vm_map_t compressor_map;
+uint64_t compressor_pool_max_size;
+uint64_t compressor_pool_size;
+uint32_t compressor_pool_multiplier;
 
+#if DEVELOPMENT || DEBUG
+/*
+ * Compressor segments are write-protected in development/debug
+ * kernels to help debug memory corruption.
+ * In cases where performance is a concern, this can be disabled
+ * via the boot-arg "-disable_cseg_write_protection".
+ */
+boolean_t write_protect_c_segs = TRUE;
+int vm_compressor_test_seg_wp;
+uint32_t vm_ktrace_enabled;
+#endif /* DEVELOPMENT || DEBUG */
 
 void
 vm_compressor_init(void)
 {
        thread_t        thread;
+       struct c_slot   cs_dummy;
+       c_slot_t cs  = &cs_dummy;
+       int             c_segment_min_size;
+       int             c_segment_padded_size;
+       int             attempts = 1;
+       kern_return_t   retval = KERN_SUCCESS;
+       vm_offset_t     start_addr = 0;
+       vm_size_t       c_segments_arr_size = 0, compressor_submap_size = 0;
+       vm_map_kernel_flags_t vmk_flags;
+#if RECORD_THE_COMPRESSED_DATA
+       vm_size_t       c_compressed_record_sbuf_size = 0;
+#endif /* RECORD_THE_COMPRESSED_DATA */
+
+#if DEVELOPMENT || DEBUG
+       char bootarg_name[32];
+       if (PE_parse_boot_argn("-kill_on_no_paging_space", bootarg_name, sizeof (bootarg_name))) {
+               kill_on_no_paging_space = TRUE;
+       }
+       if (PE_parse_boot_argn("-disable_cseg_write_protection", bootarg_name, sizeof (bootarg_name))) {
+               write_protect_c_segs = FALSE;
+       }
+       int vmcval = 1;
+       PE_parse_boot_argn("vm_compressor_validation", &vmcval, sizeof(vmcval));
+
+       if (kern_feature_override(KF_COMPRSV_OVRD)) {
+               vmcval = 0;
+       }
+       if (vmcval == 0) {
+#if POPCOUNT_THE_COMPRESSED_DATA
+               popcount_c_segs = FALSE;
+#endif
+#if CHECKSUM_THE_DATA || CHECKSUM_THE_COMPRESSED_DATA
+               checksum_c_segs = FALSE;
+#endif
+               write_protect_c_segs = FALSE;
+       }
+#endif /* DEVELOPMENT || DEBUG */
+
+       /*
+        * ensure that any pointer that gets created from
+        * the vm_page zone can be packed properly
+        */
+       cs->c_packed_ptr = C_SLOT_PACK_PTR(zone_map_min_address);
+
+       if (C_SLOT_UNPACK_PTR(cs) != (uintptr_t)zone_map_min_address)
+               panic("C_SLOT_UNPACK_PTR failed on zone_map_min_address - %p", (void *)zone_map_min_address);
+
+       cs->c_packed_ptr = C_SLOT_PACK_PTR(zone_map_max_address);
+
+       if (C_SLOT_UNPACK_PTR(cs) != (uintptr_t)zone_map_max_address)
+               panic("C_SLOT_UNPACK_PTR failed on zone_map_max_address - %p", (void *)zone_map_max_address);
+
 
        assert((C_SEGMENTS_PER_PAGE * sizeof(union c_segu)) == PAGE_SIZE);
 
        PE_parse_boot_argn("vm_compression_limit", &vm_compression_limit, sizeof (vm_compression_limit));
 
+#ifdef CONFIG_EMBEDDED
+       vm_compressor_minorcompact_threshold_divisor = 20;
+       vm_compressor_majorcompact_threshold_divisor = 30;
+       vm_compressor_unthrottle_threshold_divisor = 40;
+       vm_compressor_catchup_threshold_divisor = 60;
+#else
        if (max_mem <= (3ULL * 1024ULL * 1024ULL * 1024ULL)) {
                vm_compressor_minorcompact_threshold_divisor = 11;
                vm_compressor_majorcompact_threshold_divisor = 13;
@@ -322,64 +587,138 @@ vm_compressor_init(void)
                vm_compressor_unthrottle_threshold_divisor = 35;
                vm_compressor_catchup_threshold_divisor = 50;
        }
+#endif
        /*
         * vm_page_init_lck_grp is now responsible for calling vm_compressor_init_locks
         * c_master_lock needs to be available early so that "vm_page_find_contiguous" can
         * use PAGE_REPLACEMENT_ALLOWED to coordinate with the compressor.
         */
 
-#if __i386__ || __x86_64__
        c_list_lock = lck_mtx_alloc_init(&vm_compressor_lck_grp, &vm_compressor_lck_attr);
-#else /* __i386__ || __x86_64__ */
-       c_list_lock = lck_spin_alloc_init(&vm_compressor_lck_grp, &vm_compressor_lck_attr);
-#endif /* __i386__ || __x86_64__ */
 
-#if TRACK_BAD_C_SEGMENTS
        queue_init(&c_bad_list_head);
-#endif
        queue_init(&c_age_list_head);
        queue_init(&c_minor_list_head);
+       queue_init(&c_major_list_head);
+       queue_init(&c_filling_list_head);
        queue_init(&c_swapout_list_head);
        queue_init(&c_swappedin_list_head);
        queue_init(&c_swappedout_list_head);
        queue_init(&c_swappedout_sparse_list_head);
 
-       compressor_segment_zone = zinit(sizeof (struct c_segment),
-                                     128000 * sizeof (struct c_segment),
-                                     8192, "compressor_segment");
-       zone_change(compressor_segment_zone, Z_CALLERACCT, FALSE);
-       zone_change(compressor_segment_zone, Z_NOENCRYPT, TRUE);
-
-       
        c_free_segno_head = -1;
        c_segments_available = 0;
 
+       if (vm_compression_limit)
+               compressor_pool_size = (uint64_t)vm_compression_limit * PAGE_SIZE_64;
+
+       compressor_pool_max_size = C_SEG_MAX_LIMIT;
+       compressor_pool_max_size *= C_SEG_BUFSIZE;
+
+#if defined(__x86_64__)
+
        if (vm_compression_limit == 0) {
-               c_segment_pages_compressed_limit = (uint32_t)((max_mem / PAGE_SIZE)) * vm_scale;
 
-#define        OLD_SWAP_LIMIT  (1024 * 1024 * 16)
-#define MAX_SWAP_LIMIT (1024 * 1024 * 128)
+               if (max_mem <= (4ULL * 1024ULL * 1024ULL * 1024ULL))
+                         compressor_pool_size = 16ULL * max_mem;
+               else if (max_mem <= (8ULL * 1024ULL * 1024ULL * 1024ULL))
+                         compressor_pool_size = 8ULL * max_mem;
+               else if (max_mem <= (32ULL * 1024ULL * 1024ULL * 1024ULL))
+                         compressor_pool_size = 4ULL * max_mem;
+               else
+                         compressor_pool_size = 2ULL * max_mem;
+       }
+       if (max_mem <= (8ULL * 1024ULL * 1024ULL * 1024ULL))
+                compressor_pool_multiplier = 1;
+       else if (max_mem <= (32ULL * 1024ULL * 1024ULL * 1024ULL))
+               compressor_pool_multiplier = 2;
+       else
+               compressor_pool_multiplier = 4;
+
+#elif defined(__arm__)
+
+#define        VM_RESERVE_SIZE                 (1024 * 1024 * 256)
+#define MAX_COMPRESSOR_POOL_SIZE       (1024 * 1024 * 450)
+
+       if (compressor_pool_max_size > MAX_COMPRESSOR_POOL_SIZE)
+               compressor_pool_max_size = MAX_COMPRESSOR_POOL_SIZE;
        
-               if (c_segment_pages_compressed_limit > (OLD_SWAP_LIMIT))
-                       c_segment_pages_compressed_limit = OLD_SWAP_LIMIT;
+       if (vm_compression_limit == 0)
+               compressor_pool_size = ((kernel_map->max_offset - kernel_map->min_offset) - kernel_map->size) - VM_RESERVE_SIZE;
+       compressor_pool_multiplier = 1;
+#else
+       if (compressor_pool_max_size > max_mem)
+               compressor_pool_max_size = max_mem;
 
-               if (c_segment_pages_compressed_limit < (uint32_t)(max_mem / PAGE_SIZE_64))
-                       c_segment_pages_compressed_limit = (uint32_t)(max_mem / PAGE_SIZE_64);
-       } else {
-               if (vm_compression_limit < MAX_SWAP_LIMIT)
-                       c_segment_pages_compressed_limit = vm_compression_limit;
-               else
-                       c_segment_pages_compressed_limit = MAX_SWAP_LIMIT;
+       if (vm_compression_limit == 0)
+               compressor_pool_size = max_mem;
+       compressor_pool_multiplier = 1;
+#endif
+       if (compressor_pool_size > compressor_pool_max_size)
+               compressor_pool_size = compressor_pool_max_size;
+
+try_again:
+       c_segments_limit = (uint32_t)(compressor_pool_size / (vm_size_t)(C_SEG_ALLOCSIZE));
+       c_segments_nearing_limit = (uint32_t)(((uint64_t)c_segments_limit * 98ULL) / 100ULL);
+
+       c_segment_pages_compressed_limit = (c_segments_limit * (C_SEG_BUFSIZE / PAGE_SIZE) * compressor_pool_multiplier);
+
+       if (c_segment_pages_compressed_limit < (uint32_t)(max_mem / PAGE_SIZE))
+               c_segment_pages_compressed_limit = (uint32_t)(max_mem / PAGE_SIZE);
+
+       c_segment_pages_compressed_nearing_limit = (uint32_t)(((uint64_t)c_segment_pages_compressed_limit * 98ULL) / 100ULL);
+
+       /*
+        * Submap needs space for:
+        * - c_segments
+        * - c_buffers
+        * - swap reclaimations -- C_SEG_BUFSIZE
+        */
+       c_segments_arr_size = vm_map_round_page((sizeof(union c_segu) * c_segments_limit), VM_MAP_PAGE_MASK(kernel_map));
+       c_buffers_size = vm_map_round_page(((vm_size_t)C_SEG_ALLOCSIZE * (vm_size_t)c_segments_limit), VM_MAP_PAGE_MASK(kernel_map));
+
+       compressor_submap_size = c_segments_arr_size + c_buffers_size + C_SEG_BUFSIZE;
+
+#if RECORD_THE_COMPRESSED_DATA
+       c_compressed_record_sbuf_size = (vm_size_t)C_SEG_ALLOCSIZE + (PAGE_SIZE * 2);
+       compressor_submap_size += c_compressed_record_sbuf_size;
+#endif /* RECORD_THE_COMPRESSED_DATA */
+
+       vmk_flags = VM_MAP_KERNEL_FLAGS_NONE;
+       vmk_flags.vmkf_permanent = TRUE;
+       retval = kmem_suballoc(kernel_map, &start_addr, compressor_submap_size,
+                              FALSE, VM_FLAGS_ANYWHERE, vmk_flags, VM_KERN_MEMORY_COMPRESSOR,
+                              &compressor_map);
+
+       if (retval != KERN_SUCCESS) {
+               if (++attempts > 3)
+                       panic("vm_compressor_init: kmem_suballoc failed - 0x%llx", (uint64_t)compressor_submap_size);
+
+               compressor_pool_size = compressor_pool_size / 2;
+
+               kprintf("retrying creation of the compressor submap at 0x%llx bytes\n", compressor_pool_size);
+               goto try_again;
        }
-       if ((c_segments_limit = c_segment_pages_compressed_limit / (C_SEG_BUFSIZE / PAGE_SIZE)) > C_SEG_MAX_LIMIT)
-               c_segments_limit = C_SEG_MAX_LIMIT;
+       if (kernel_memory_allocate(compressor_map, (vm_offset_t *)(&c_segments), (sizeof(union c_segu) * c_segments_limit), 0, KMA_KOBJECT | KMA_VAONLY | KMA_PERMANENT, VM_KERN_MEMORY_COMPRESSOR) != KERN_SUCCESS)
+               panic("vm_compressor_init: kernel_memory_allocate failed - c_segments\n");
+       if (kernel_memory_allocate(compressor_map, &c_buffers, c_buffers_size, 0, KMA_COMPRESSOR | KMA_VAONLY | KMA_PERMANENT, VM_KERN_MEMORY_COMPRESSOR) != KERN_SUCCESS)
+               panic("vm_compressor_init: kernel_memory_allocate failed - c_buffers\n");
 
-       c_segments_busy = FALSE;
 
-       if (kernel_memory_allocate(kernel_map, (vm_offset_t *)(&c_segments), (sizeof(union c_segu) * c_segments_limit), 0, KMA_KOBJECT | KMA_VAONLY) != KERN_SUCCESS)
-               panic("vm_compressor_init: kernel_memory_allocate failed\n");
+       c_segment_min_size = sizeof(struct c_segment) + (C_SEG_SLOT_VAR_ARRAY_MIN_LEN * sizeof(struct c_slot));
+       
+       for (c_segment_padded_size = 128; c_segment_padded_size < c_segment_min_size; c_segment_padded_size = c_segment_padded_size << 1);
+
+       compressor_segment_zone = zinit(c_segment_padded_size, c_segments_limit * c_segment_padded_size, PAGE_SIZE, "compressor_segment");
+       zone_change(compressor_segment_zone, Z_CALLERACCT, FALSE);
+       zone_change(compressor_segment_zone, Z_NOENCRYPT, TRUE);
+
+       c_seg_fixed_array_len = (c_segment_padded_size - sizeof(struct c_segment)) / sizeof(struct c_slot);
+       
+       c_segments_busy = FALSE;
 
        c_segments_next_page = (caddr_t)c_segments;
+       vm_compressor_algorithm_init();
 
        {
                host_basic_info_data_t hinfo;
@@ -389,29 +728,45 @@ vm_compressor_init(void)
                host_info((host_t)BSD_HOST, HOST_BASIC_INFO, (host_info_t)&hinfo, &count);
 
                compressor_cpus = hinfo.max_cpus;
+               compressor_scratch_bufs = kalloc_tag(compressor_cpus * vm_compressor_get_decode_scratch_size(), VM_KERN_MEMORY_COMPRESSOR);
 
-               compressor_scratch_bufs = kalloc(compressor_cpus * WKdm_SCRATCH_BUF_SIZE);
+               kdp_compressor_scratch_buf = kalloc_tag(vm_compressor_get_decode_scratch_size(), VM_KERN_MEMORY_COMPRESSOR);
+               kdp_compressor_decompressed_page = kalloc_tag(PAGE_SIZE, VM_KERN_MEMORY_COMPRESSOR);
+               kdp_compressor_decompressed_page_paddr = kvtophys((vm_offset_t)kdp_compressor_decompressed_page);
+               kdp_compressor_decompressed_page_ppnum = (ppnum_t) atop(kdp_compressor_decompressed_page_paddr);
        }
+#if CONFIG_FREEZE
+       freezer_compressor_scratch_buf = kalloc_tag(vm_compressor_get_encode_scratch_size(), VM_KERN_MEMORY_COMPRESSOR);
+#endif
+
+#if RECORD_THE_COMPRESSED_DATA
+       if (kernel_memory_allocate(compressor_map, (vm_offset_t *)&c_compressed_record_sbuf, c_compressed_record_sbuf_size, 0, KMA_KOBJECT, VM_KERN_MEMORY_COMPRESSOR) != KERN_SUCCESS)
+               panic("vm_compressor_init: kernel_memory_allocate failed - c_compressed_record_sbuf\n");
+
+       c_compressed_record_cptr = c_compressed_record_sbuf;
+       c_compressed_record_ebuf = c_compressed_record_sbuf + c_compressed_record_sbuf_size;
+#endif
 
        if (kernel_thread_start_priority((thread_continue_t)vm_compressor_swap_trigger_thread, NULL,
-                                        BASEPRI_PREEMPT - 1, &thread) != KERN_SUCCESS) {
+                                        BASEPRI_VM, &thread) != KERN_SUCCESS) {
                panic("vm_compressor_swap_trigger_thread: create failed");
        }
-       thread->options |= TH_OPT_VMPRIV;
-
        thread_deallocate(thread);
 
-       assert(default_pager_init_flag == 0);
-               
        if (vm_pageout_internal_start() != KERN_SUCCESS) {
                panic("vm_compressor_init: Failed to start the internal pageout thread.\n");
        }
+       if (VM_CONFIG_SWAP_IS_PRESENT)
+               vm_compressor_swap_init();
+
+       if (VM_CONFIG_COMPRESSOR_IS_ACTIVE)
+               vm_compressor_is_active = 1;
 
 #if CONFIG_FREEZE
        memorystatus_freeze_enabled = TRUE;
 #endif /* CONFIG_FREEZE */
 
-       default_pager_init_flag = 1;
+       vm_compressor_available = 1;
 
        vm_page_reactivate_all_throttled();
 }
@@ -424,7 +779,6 @@ c_seg_validate(c_segment_t c_seg, boolean_t must_be_compact)
 {
        int             c_indx;
        int32_t         bytes_used;
-       int32_t         bytes_unused;
        uint32_t        c_rounded_size;
        uint32_t        c_size;
        c_slot_t        cs;
@@ -440,7 +794,6 @@ c_seg_validate(c_segment_t c_seg, boolean_t must_be_compact)
                        panic("c_seg_validate:  c_firstemptyslot has non-zero size (%d)\n", cs->c_size);
        }
        bytes_used = 0;
-       bytes_unused = 0;
 
        for (c_indx = 0; c_indx < c_seg->c_nextslot; c_indx++) {
                
@@ -453,8 +806,11 @@ c_seg_validate(c_segment_t c_seg, boolean_t must_be_compact)
                bytes_used += c_rounded_size;
 
 #if CHECKSUM_THE_COMPRESSED_DATA
-               if (c_size && cs->c_hash_compressed_data != hash_string((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size))
-                       panic("compressed data doesn't match original");
+               unsigned csvhash;
+               if (c_size && cs->c_hash_compressed_data != (csvhash = vmc_hash((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size))) {
+                       addr64_t csvphys = kvtophys((vm_offset_t)&c_seg->c_store.c_buffer[cs->c_offset]);
+                       panic("Compressed data doesn't match original %p phys: 0x%llx %d %p %d %d 0x%x 0x%x", c_seg, csvphys, cs->c_offset, cs, c_indx, c_size, cs->c_hash_compressed_data, csvhash);
+               }
 #endif
        }
 
@@ -476,25 +832,30 @@ c_seg_validate(c_segment_t c_seg, boolean_t must_be_compact)
 
 
 void
-c_seg_need_delayed_compaction(c_segment_t c_seg)
+c_seg_need_delayed_compaction(c_segment_t c_seg, boolean_t c_list_lock_held)
 {
        boolean_t       clear_busy = FALSE;
 
-       if ( !lck_mtx_try_lock_spin_always(c_list_lock)) {
-               c_seg->c_busy = 1;
+       if (c_list_lock_held == FALSE) {
+               if ( !lck_mtx_try_lock_spin_always(c_list_lock)) {
+                       C_SEG_BUSY(c_seg);
                
-               lck_mtx_unlock_always(&c_seg->c_lock);
-               lck_mtx_lock_spin_always(c_list_lock);
-               lck_mtx_lock_spin_always(&c_seg->c_lock);
+                       lck_mtx_unlock_always(&c_seg->c_lock);
+                       lck_mtx_lock_spin_always(c_list_lock);
+                       lck_mtx_lock_spin_always(&c_seg->c_lock);
 
-               clear_busy = TRUE;
+                       clear_busy = TRUE;
+               }
        }
-       if (!c_seg->c_on_minorcompact_q && !c_seg->c_ondisk && !c_seg->c_on_swapout_q) {
+       assert(c_seg->c_state != C_IS_FILLING);
+
+       if (!c_seg->c_on_minorcompact_q && !(C_SEG_IS_ON_DISK_OR_SOQ(c_seg))) {
                queue_enter(&c_minor_list_head, c_seg, c_segment_t, c_list);
                c_seg->c_on_minorcompact_q = 1;
                c_minor_count++;
        }
-       lck_mtx_unlock_always(c_list_lock);
+       if (c_list_lock_held == FALSE)
+               lck_mtx_unlock_always(c_list_lock);
        
        if (clear_busy == TRUE)
                C_SEG_WAKEUP_DONE(c_seg);
@@ -509,7 +870,7 @@ c_seg_move_to_sparse_list(c_segment_t c_seg)
        boolean_t       clear_busy = FALSE;
 
        if ( !lck_mtx_try_lock_spin_always(c_list_lock)) {
-               c_seg->c_busy = 1;
+               C_SEG_BUSY(c_seg);
 
                lck_mtx_unlock_always(&c_seg->c_lock);
                lck_mtx_lock_spin_always(c_list_lock);
@@ -517,17 +878,7 @@ c_seg_move_to_sparse_list(c_segment_t c_seg)
                
                clear_busy = TRUE;
        }
-       assert(c_seg->c_ondisk);
-       assert(c_seg->c_on_swappedout_q);
-       assert(!c_seg->c_on_swappedout_sparse_q);
-
-       queue_remove(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
-       c_seg->c_on_swappedout_q = 0;
-       c_swappedout_count--;
-
-       c_seg_insert_into_q(&c_swappedout_sparse_list_head, c_seg);
-       c_seg->c_on_swappedout_sparse_q = 1;
-       c_swappedout_sparse_count++;
+       c_seg_switch_state(c_seg, C_ON_SWAPPEDOUTSPARSE_Q, FALSE);
 
        c_seg_moved_to_sparse_list++;
 
@@ -590,7 +941,7 @@ c_seg_try_minor_compaction_and_unlock(c_segment_t c_seg)
        } else {
                try_minor_compaction_succeeded++;
 
-               c_seg->c_busy = 1;
+               C_SEG_BUSY(c_seg);
                c_seg_do_minor_compaction_and_unlock(c_seg, TRUE, FALSE, FALSE);
        }
 }
@@ -602,7 +953,21 @@ c_seg_do_minor_compaction_and_unlock(c_segment_t c_seg, boolean_t clear_busy, bo
        int     c_seg_freed;
 
        assert(c_seg->c_busy);
+       assert(!C_SEG_IS_ON_DISK_OR_SOQ(c_seg));
 
+       /*
+        * check for the case that can occur when we are not swapping
+        * and this segment has been major compacted in the past
+        * and moved to the majorcompact q to remove it from further
+        * consideration... if the occupancy falls too low we need
+        * to put it back on the age_q so that it will be considered
+        * in the next major compaction sweep... if we don't do this
+        * we will eventually run into the c_segments_limit
+        */
+       if (c_seg->c_state == C_ON_MAJORCOMPACT_Q && C_SEG_SHOULD_MAJORCOMPACT_NOW(c_seg)) {
+               
+               c_seg_switch_state(c_seg, C_ON_AGE_Q, FALSE);
+       }
        if (!c_seg->c_on_minorcompact_q) {
                if (clear_busy == TRUE)
                        C_SEG_WAKEUP_DONE(c_seg);
@@ -647,159 +1012,288 @@ c_seg_wait_on_busy(c_segment_t c_seg)
 }
 
 
+void
+c_seg_switch_state(c_segment_t c_seg, int new_state, boolean_t insert_head)
+{
+       int     old_state = c_seg->c_state;
+
+#if __i386__ || __x86_64__
+       if (new_state != C_IS_FILLING)
+               LCK_MTX_ASSERT(&c_seg->c_lock, LCK_MTX_ASSERT_OWNED);
+       LCK_MTX_ASSERT(c_list_lock, LCK_MTX_ASSERT_OWNED);
+#endif
+       switch (old_state) {
+
+               case C_IS_EMPTY:
+                       assert(new_state == C_IS_FILLING || new_state == C_IS_FREE);
 
-int    try_free_succeeded = 0;
-int    try_free_failed = 0;
+                       c_empty_count--;
+                       break;
 
-boolean_t
-c_seg_try_free(c_segment_t c_seg)
-{
-       /*
-        * c_seg is currently on the delayed minor compaction
-        * or the spapped out sparse queue and we have c_seg locked...
-        * if we can get the c_list_lock w/o blocking (if we blocked we
-        * could deadlock because the lock order is c_list_lock then c_seg's lock)
-        * we'll pull it from the appropriate queue and free it
-        */
-       if ( !lck_mtx_try_lock_spin_always(c_list_lock)) {
-               /*
-                * c_list_lock is held, we need to bail
-                */
-               try_free_failed++;
-               return (FALSE);
-       }
-       if (c_seg->c_on_minorcompact_q) {
-               queue_remove(&c_minor_list_head, c_seg, c_segment_t, c_list);
-               c_seg->c_on_minorcompact_q = 0;
-               c_minor_count--;
-       } else {
-               assert(c_seg->c_on_swappedout_sparse_q);
+               case C_IS_FILLING:
+                       assert(new_state == C_ON_AGE_Q || new_state == C_ON_SWAPOUT_Q);
 
-               /*
-                * c_seg_free_locked will remove it from the swappedout sparse list
-                */
-       }
-       if (!c_seg->c_busy_swapping)
-               c_seg->c_busy = 1;
+                       queue_remove(&c_filling_list_head, c_seg, c_segment_t, c_age_list);
+                       c_filling_count--;
+                       break;
 
-       c_seg_free_locked(c_seg);
+               case C_ON_AGE_Q:
+                       assert(new_state == C_ON_SWAPOUT_Q || new_state == C_ON_MAJORCOMPACT_Q ||
+                              new_state == C_IS_FREE);
 
-       try_free_succeeded++;
+                       queue_remove(&c_age_list_head, c_seg, c_segment_t, c_age_list);
+                       c_age_count--;
+                       break;
+               
+               case C_ON_SWAPPEDIN_Q:
+                       assert(new_state == C_ON_AGE_Q || new_state == C_IS_FREE);
 
-       return (TRUE);
-}
+                       queue_remove(&c_swappedin_list_head, c_seg, c_segment_t, c_age_list);
+                       c_swappedin_count--;
+                       break;
 
+               case C_ON_SWAPOUT_Q:
+                       assert(new_state == C_ON_SWAPPEDOUT_Q || new_state == C_ON_SWAPPEDOUTSPARSE_Q ||
+                              new_state == C_ON_AGE_Q || new_state == C_IS_FREE || new_state == C_IS_EMPTY);
 
-void
-c_seg_free(c_segment_t c_seg)
-{
-       if (!c_seg->c_busy_swapping)
-               c_seg->c_busy = 1;
+                       queue_remove(&c_swapout_list_head, c_seg, c_segment_t, c_age_list);
+                       thread_wakeup((event_t)&compaction_swapper_running);
+                       c_swapout_count--;
+                       break;
 
-       lck_mtx_unlock_always(&c_seg->c_lock);
-       lck_mtx_lock_spin_always(c_list_lock);
-       lck_mtx_lock_spin_always(&c_seg->c_lock);
+               case C_ON_SWAPPEDOUT_Q:
+                       assert(new_state == C_ON_SWAPPEDIN_Q || new_state == C_ON_AGE_Q ||
+                              new_state == C_ON_SWAPPEDOUTSPARSE_Q ||
+                              new_state == C_ON_BAD_Q || new_state == C_IS_EMPTY || new_state == C_IS_FREE);
 
-       c_seg_free_locked(c_seg);
-}
+                       queue_remove(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
+                       c_swappedout_count--;
+                       break;
 
+               case C_ON_SWAPPEDOUTSPARSE_Q:
+                       assert(new_state == C_ON_SWAPPEDIN_Q || new_state == C_ON_AGE_Q ||
+                              new_state == C_ON_BAD_Q || new_state == C_IS_EMPTY || new_state == C_IS_FREE);
 
-void
-c_seg_free_locked(c_segment_t c_seg)
-{
-       int             segno, i;
-       int             pages_populated;
-       int32_t         *c_buffer = NULL;
-       uint64_t        c_swap_handle;
+                       queue_remove(&c_swappedout_sparse_list_head, c_seg, c_segment_t, c_age_list);
+                       c_swappedout_sparse_count--;
+                       break;
 
-       assert(!c_seg->c_on_minorcompact_q);
+               case C_ON_MAJORCOMPACT_Q:
+                       assert(new_state == C_ON_AGE_Q || new_state == C_IS_FREE);
 
-       if (c_seg->c_on_age_q) {
-               queue_remove(&c_age_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_age_q = 0;
-               c_age_count--;
-       } else if (c_seg->c_on_swappedin_q) {
-               queue_remove(&c_swappedin_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedin_q = 0;
-               c_swappedin_count--;
-       } else if (c_seg->c_on_swapout_q) {
-               queue_remove(&c_swapout_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swapout_q = 0;
-               c_swapout_count--;
-               thread_wakeup((event_t)&compaction_swapper_running);
-       } else if (c_seg->c_on_swappedout_q) {
-               queue_remove(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedout_q = 0;
-               c_swappedout_count--;
-       } else if (c_seg->c_on_swappedout_sparse_q) {
-               queue_remove(&c_swappedout_sparse_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedout_sparse_q = 0;
-               c_swappedout_sparse_count--;
-       }
-#if TRACK_BAD_C_SEGMENTS
-       else if (c_seg->c_on_bad_q) {
-               queue_remove(&c_bad_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_bad_q = 0;
-               c_bad_count--;
-       }
-#endif
-       segno = c_seg->c_mysegno;
-       c_segments[segno].c_segno = c_free_segno_head;
-       c_free_segno_head = segno;
-       c_segment_count--;
+                       queue_remove(&c_major_list_head, c_seg, c_segment_t, c_age_list);
+                       c_major_count--;
+                       break;
 
-       lck_mtx_unlock_always(c_list_lock);
+               case C_ON_BAD_Q:
+                       assert(new_state == C_IS_FREE);
 
-       if (c_seg->c_wanted) {
-               thread_wakeup((event_t) (c_seg));
-               c_seg->c_wanted = 0;
-       }
-       if (c_seg->c_busy_swapping) {
-               c_seg->c_must_free = 1;
+                       queue_remove(&c_bad_list_head, c_seg, c_segment_t, c_age_list);
+                       c_bad_count--;
+                       break;
 
-               lck_mtx_unlock_always(&c_seg->c_lock);
-               return;
+               default:
+                       panic("c_seg %p has bad c_state = %d\n", c_seg, old_state);
        }
-       if (c_seg->c_ondisk == 0) {
-               pages_populated = (round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset))) / PAGE_SIZE;
 
-               c_buffer = c_seg->c_store.c_buffer;
-               c_seg->c_store.c_buffer = NULL;
-       } else {
-                /*
-                 * Free swap space on disk.
-                */
-               c_swap_handle = c_seg->c_store.c_swap_handle;
-               c_seg->c_store.c_swap_handle = (uint64_t)-1;
+       switch(new_state) {
+               case C_IS_FREE:
+                       assert(old_state != C_IS_FILLING);
+
+                       break;
+
+               case C_IS_EMPTY:
+                       assert(old_state == C_ON_SWAPOUT_Q || old_state == C_ON_SWAPPEDOUT_Q || old_state == C_ON_SWAPPEDOUTSPARSE_Q);
+
+                       c_empty_count++;
+                       break;
+
+               case C_IS_FILLING:
+                       assert(old_state == C_IS_EMPTY);
+
+                       queue_enter(&c_filling_list_head, c_seg, c_segment_t, c_age_list);
+                       c_filling_count++;
+                       break;
+
+               case C_ON_AGE_Q:
+                       assert(old_state == C_IS_FILLING || old_state == C_ON_SWAPPEDIN_Q || old_state == C_ON_SWAPOUT_Q ||
+                              old_state == C_ON_MAJORCOMPACT_Q || old_state == C_ON_SWAPPEDOUT_Q || old_state == C_ON_SWAPPEDOUTSPARSE_Q);
+
+                       if (old_state == C_IS_FILLING)
+                               queue_enter(&c_age_list_head, c_seg, c_segment_t, c_age_list);
+                       else {
+                               if (!queue_empty(&c_age_list_head)) {
+                                       c_segment_t     c_first;
+                               
+                                       c_first = (c_segment_t)queue_first(&c_age_list_head);
+                                       c_seg->c_creation_ts = c_first->c_creation_ts;
+                               }
+                               queue_enter_first(&c_age_list_head, c_seg, c_segment_t, c_age_list);
+                       }
+                       c_age_count++;
+                       break;
+               
+               case C_ON_SWAPPEDIN_Q:
+                       assert(c_seg->c_state == C_ON_SWAPPEDOUT_Q || c_seg->c_state == C_ON_SWAPPEDOUTSPARSE_Q);
+
+                       if (insert_head == TRUE)
+                               queue_enter_first(&c_swappedin_list_head, c_seg, c_segment_t, c_age_list);
+                       else
+                               queue_enter(&c_swappedin_list_head, c_seg, c_segment_t, c_age_list);
+                       c_swappedin_count++;
+                       break;
+
+               case C_ON_SWAPOUT_Q:
+                       assert(old_state == C_ON_AGE_Q || old_state == C_IS_FILLING);
+
+                       if (insert_head == TRUE)
+                               queue_enter_first(&c_swapout_list_head, c_seg, c_segment_t, c_age_list);
+                       else
+                               queue_enter(&c_swapout_list_head, c_seg, c_segment_t, c_age_list);
+                       c_swapout_count++;
+                       break;
+
+               case C_ON_SWAPPEDOUT_Q:
+                       assert(c_seg->c_state == C_ON_SWAPOUT_Q);
+
+                       if (insert_head == TRUE)
+                               queue_enter_first(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
+                       else
+                               queue_enter(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
+                       c_swappedout_count++;
+                       break;
+
+               case C_ON_SWAPPEDOUTSPARSE_Q:
+                       assert(c_seg->c_state == C_ON_SWAPOUT_Q || c_seg->c_state == C_ON_SWAPPEDOUT_Q);
+                       
+                       if (insert_head == TRUE)
+                               queue_enter_first(&c_swappedout_sparse_list_head, c_seg, c_segment_t, c_age_list);
+                       else
+                               queue_enter(&c_swappedout_sparse_list_head, c_seg, c_segment_t, c_age_list);
+
+                       c_swappedout_sparse_count++;
+                       break;
+
+               case C_ON_MAJORCOMPACT_Q:
+                       assert(c_seg->c_state == C_ON_AGE_Q);
+
+                       if (insert_head == TRUE)
+                               queue_enter_first(&c_major_list_head, c_seg, c_segment_t, c_age_list);
+                       else
+                               queue_enter(&c_major_list_head, c_seg, c_segment_t, c_age_list);
+                       c_major_count++;
+                       break;
+
+               case C_ON_BAD_Q:
+                       assert(c_seg->c_state == C_ON_SWAPPEDOUT_Q || c_seg->c_state == C_ON_SWAPPEDOUTSPARSE_Q);
+
+                       if (insert_head == TRUE)
+                               queue_enter_first(&c_bad_list_head, c_seg, c_segment_t, c_age_list);
+                       else
+                               queue_enter(&c_bad_list_head, c_seg, c_segment_t, c_age_list);
+                       c_bad_count++;
+                       break;
+
+               default:
+                      panic("c_seg %p requesting bad c_state = %d\n", c_seg, new_state);
        }
+       c_seg->c_state = new_state;
+}
+
+
+
+void
+c_seg_free(c_segment_t c_seg)
+{
+       assert(c_seg->c_busy);
+
+       lck_mtx_unlock_always(&c_seg->c_lock);
+       lck_mtx_lock_spin_always(c_list_lock);
+       lck_mtx_lock_spin_always(&c_seg->c_lock);
+
+       c_seg_free_locked(c_seg);
+}
+
+
+void
+c_seg_free_locked(c_segment_t c_seg)
+{
+       int             segno;
+       int             pages_populated = 0;
+       int32_t         *c_buffer = NULL;
+       uint64_t        c_swap_handle = 0;
+
+       assert(c_seg->c_busy);
+       assert(c_seg->c_slots_used == 0);
+       assert(!c_seg->c_on_minorcompact_q);
+       assert(!c_seg->c_busy_swapping);
+
+       if (c_seg->c_overage_swap == TRUE) {
+               c_overage_swapped_count--;
+               c_seg->c_overage_swap = FALSE;
+       }       
+       if ( !(C_SEG_IS_ONDISK(c_seg)))
+               c_buffer = c_seg->c_store.c_buffer;
+       else
+               c_swap_handle = c_seg->c_store.c_swap_handle;
+
+       c_seg_switch_state(c_seg, C_IS_FREE, FALSE);
+
+       lck_mtx_unlock_always(c_list_lock);
+
+       if (c_buffer) {
+               pages_populated = (round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset))) / PAGE_SIZE;
+               c_seg->c_store.c_buffer = NULL;
+       } else
+               c_seg->c_store.c_swap_handle = (uint64_t)-1;
+
        lck_mtx_unlock_always(&c_seg->c_lock);
 
        if (c_buffer) {
                if (pages_populated)
-                       kernel_memory_depopulate(kernel_map, (vm_offset_t) c_buffer, pages_populated * PAGE_SIZE, KMA_COMPRESSOR);
+                       kernel_memory_depopulate(compressor_map, (vm_offset_t) c_buffer, pages_populated * PAGE_SIZE, KMA_COMPRESSOR);
 
-               kmem_free(kernel_map, (vm_offset_t) c_buffer, C_SEG_ALLOCSIZE);
-       } else if (c_swap_handle)
+       } else if (c_swap_handle) {
+                /*
+                 * Free swap space on disk.
+                */
                vm_swap_free(c_swap_handle);
+       }
+       lck_mtx_lock_spin_always(&c_seg->c_lock);
+       /*
+        * c_seg must remain busy until
+        * after the call to vm_swap_free
+        */
+       C_SEG_WAKEUP_DONE(c_seg);
+       lck_mtx_unlock_always(&c_seg->c_lock);
 
+       segno = c_seg->c_mysegno;
+
+       lck_mtx_lock_spin_always(c_list_lock);
+       /*
+        * because the c_buffer is now associated with the segno,
+        * we can't put the segno back on the free list until
+        * after we have depopulated the c_buffer range, or 
+        * we run the risk of depopulating a range that is 
+        * now being used in one of the compressor heads
+        */
+       c_segments[segno].c_segno = c_free_segno_head;
+       c_free_segno_head = segno;
+       c_segment_count--;
+
+       lck_mtx_unlock_always(c_list_lock);
 
-#if __i386__ || __x86_64__
        lck_mtx_destroy(&c_seg->c_lock, &vm_compressor_lck_grp);
-#else /* __i386__ || __x86_64__ */
-       lck_spin_destroy(&c_seg->c_lock, &vm_compressor_lck_grp);
-#endif /* __i386__ || __x86_64__ */
 
-       for (i = 0; i < C_SEG_SLOT_ARRAYS; i++) {
-               if (c_seg->c_slots[i] == 0)
-                       break;
+       if (c_seg->c_slot_var_array_len)
+               kfree(c_seg->c_slot_var_array, sizeof(struct c_slot) * c_seg->c_slot_var_array_len);
 
-               kfree((char *)c_seg->c_slots[i], sizeof(struct c_slot) * C_SEG_SLOT_ARRAY_SIZE);
-       }
        zfree(compressor_segment_zone, c_seg);
 }
 
-
+#if DEVELOPMENT || DEBUG
 int c_seg_trim_page_count = 0;
+#endif
 
 void
 c_seg_trim_tail(c_segment_t c_seg)
@@ -828,13 +1322,16 @@ c_seg_trim_tail(c_segment_t c_seg)
                                c_offset = cs->c_offset + C_SEG_BYTES_TO_OFFSET(c_rounded_size);
 
                                c_seg->c_nextoffset = c_offset;
-                               c_seg->c_populated_offset = (c_offset + (C_SEG_BYTES_TO_OFFSET(PAGE_SIZE) - 1)) & ~(C_SEG_BYTES_TO_OFFSET(PAGE_SIZE) - 1);
+                               c_seg->c_populated_offset = (c_offset + (C_SEG_BYTES_TO_OFFSET(PAGE_SIZE) - 1)) &
+                                                                      ~(C_SEG_BYTES_TO_OFFSET(PAGE_SIZE) - 1);
 
                                if (c_seg->c_firstemptyslot > c_seg->c_nextslot)
                                        c_seg->c_firstemptyslot = c_seg->c_nextslot;
-
+#if DEVELOPMENT || DEBUG
                                c_seg_trim_page_count += ((round_page_32(C_SEG_OFFSET_TO_BYTES(current_populated_offset)) -
-                                                          round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset))) / PAGE_SIZE);
+                                                          round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset))) /
+                                                         PAGE_SIZE);
+#endif
                        }
                        break;
                }               
@@ -856,7 +1353,6 @@ c_seg_minor_compaction_and_unlock(c_segment_t c_seg, boolean_t clear_busy)
        int             i;
        c_slot_t        c_dst;
        c_slot_t        c_src;
-       boolean_t       need_unlock = TRUE;
 
        assert(c_seg->c_busy);
 
@@ -867,9 +1363,17 @@ c_seg_minor_compaction_and_unlock(c_segment_t c_seg, boolean_t clear_busy)
                c_seg_free(c_seg);
                return (1);
        }
+       lck_mtx_unlock_always(&c_seg->c_lock);
+
        if (c_seg->c_firstemptyslot >= c_seg->c_nextslot || C_SEG_UNUSED_BYTES(c_seg) < PAGE_SIZE)
                goto done;
-               
+
+/* TODO: assert first emptyslot's c_size is actually 0 */
+
+#if DEVELOPMENT || DEBUG
+       C_SEG_MAKE_WRITEABLE(c_seg);
+#endif
+
 #if VALIDATE_C_SEGMENTS
        c_seg->c_was_minor_compacted++;
 #endif
@@ -888,23 +1392,16 @@ c_seg_minor_compaction_and_unlock(c_segment_t c_seg, boolean_t clear_busy)
                if (c_size == 0)
                        continue;
 
-               memcpy(&c_seg->c_store.c_buffer[c_offset], &c_seg->c_store.c_buffer[c_src->c_offset], c_size);
+               c_rounded_size = (c_size + C_SEG_OFFSET_ALIGNMENT_MASK) & ~C_SEG_OFFSET_ALIGNMENT_MASK;
+/* N.B.: This memcpy may be an overlapping copy */
+               memcpy(&c_seg->c_store.c_buffer[c_offset], &c_seg->c_store.c_buffer[c_src->c_offset], c_rounded_size);
 
-#if CHECKSUM_THE_DATA
-               c_dst->c_hash_data = c_src->c_hash_data;
-#endif
-#if CHECKSUM_THE_COMPRESSED_DATA
-               c_dst->c_hash_compressed_data = c_src->c_hash_compressed_data;
-#endif
-               c_dst->c_size = c_src->c_size;
-               c_dst->c_packed_ptr = c_src->c_packed_ptr;
+               cslot_copy(c_dst, c_src);
                c_dst->c_offset = c_offset;
 
                slot_ptr = (c_slot_mapping_t)C_SLOT_UNPACK_PTR(c_dst);
                slot_ptr->s_cindx = c_indx;
 
-               c_rounded_size = (c_size + C_SEG_OFFSET_ALIGNMENT_MASK) & ~C_SEG_OFFSET_ALIGNMENT_MASK;
-
                c_offset += C_SEG_BYTES_TO_OFFSET(c_rounded_size);
                PACK_C_SIZE(c_src, 0);
                c_indx++;
@@ -920,7 +1417,6 @@ c_seg_minor_compaction_and_unlock(c_segment_t c_seg, boolean_t clear_busy)
 #if VALIDATE_C_SEGMENTS
        c_seg_validate(c_seg, TRUE);
 #endif
-
        if (old_populated_offset > c_seg->c_populated_offset) {
                uint32_t        gc_size;
                int32_t         *gc_ptr;
@@ -928,23 +1424,59 @@ c_seg_minor_compaction_and_unlock(c_segment_t c_seg, boolean_t clear_busy)
                gc_size = C_SEG_OFFSET_TO_BYTES(old_populated_offset - c_seg->c_populated_offset);
                gc_ptr = &c_seg->c_store.c_buffer[c_seg->c_populated_offset];
 
+               kernel_memory_depopulate(compressor_map, (vm_offset_t)gc_ptr, gc_size, KMA_COMPRESSOR);
+       }
+
+#if DEVELOPMENT || DEBUG
+       C_SEG_WRITE_PROTECT(c_seg);
+#endif
+
+done:
+       if (clear_busy == TRUE) {
+               lck_mtx_lock_spin_always(&c_seg->c_lock);
+               C_SEG_WAKEUP_DONE(c_seg);
                lck_mtx_unlock_always(&c_seg->c_lock);
+       }
+       return (0);
+}
 
-               kernel_memory_depopulate(kernel_map, (vm_offset_t)gc_ptr, gc_size, KMA_COMPRESSOR);
 
-               if (clear_busy == TRUE)
-                       lck_mtx_lock_spin_always(&c_seg->c_lock);
+static void
+c_seg_alloc_nextslot(c_segment_t c_seg)
+{
+       struct c_slot   *old_slot_array = NULL;
+       struct c_slot   *new_slot_array = NULL;
+       int             newlen;
+       int             oldlen;
+
+       if (c_seg->c_nextslot < c_seg_fixed_array_len)
+               return;
+
+       if ((c_seg->c_nextslot - c_seg_fixed_array_len) >= c_seg->c_slot_var_array_len) {
+
+               oldlen = c_seg->c_slot_var_array_len;
+               old_slot_array = c_seg->c_slot_var_array;
+
+               if (oldlen == 0)
+                       newlen = C_SEG_SLOT_VAR_ARRAY_MIN_LEN;
                else
-                       need_unlock = FALSE;
-       }
-done:
-       if (need_unlock == TRUE) {
-               if (clear_busy == TRUE)
-                       C_SEG_WAKEUP_DONE(c_seg);
+                       newlen = oldlen * 2;
+
+               new_slot_array = (struct c_slot *)kalloc(sizeof(struct c_slot) * newlen);
+
+               lck_mtx_lock_spin_always(&c_seg->c_lock);
+
+               if (old_slot_array)
+                       memcpy((char *)new_slot_array, (char *)old_slot_array, sizeof(struct c_slot) * oldlen);
+
+               c_seg->c_slot_var_array_len = newlen;
+               c_seg->c_slot_var_array = new_slot_array;
 
                lck_mtx_unlock_always(&c_seg->c_lock);
+               
+               if (old_slot_array)
+                       kfree(old_slot_array, sizeof(struct c_slot) * oldlen);
        }
-       return (0);
 }
 
 
@@ -956,12 +1488,11 @@ struct {
        uint64_t moved_bytes;
        uint64_t wasted_space_in_swapouts;
        uint64_t count_of_swapouts;
+       uint64_t count_of_freed_segs;
 } c_seg_major_compact_stats;
 
 
-#define        C_MAJOR_COMPACTION_AGE_APPROPRIATE      30
-#define C_MAJOR_COMPACTION_OLD_ENOUGH          300
-#define C_MAJOR_COMPACTION_SIZE_APPROPRIATE    ((C_SEG_BUFSIZE * 80) / 100)
+#define C_MAJOR_COMPACTION_SIZE_APPROPRIATE    ((C_SEG_BUFSIZE * 90) / 100)
 
 
 boolean_t
@@ -972,17 +1503,11 @@ c_seg_major_compact_ok(
 
        c_seg_major_compact_stats.asked_permission++;
 
-       if (c_seg_src->c_filling) {
-               /*
-                * we're at or near the head... don't compact
-                */
-               return (FALSE);
-       }
        if (c_seg_src->c_bytes_used >= C_MAJOR_COMPACTION_SIZE_APPROPRIATE &&
            c_seg_dst->c_bytes_used >= C_MAJOR_COMPACTION_SIZE_APPROPRIATE)
                return (FALSE);
 
-       if (c_seg_dst->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg_dst->c_nextslot >= C_SLOT_MAX) {
+       if (c_seg_dst->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg_dst->c_nextslot >= C_SLOT_MAX_INDEX) {
                /*
                 * destination segment is full... can't compact
                 */
@@ -1005,7 +1530,6 @@ c_seg_major_compact(
        int             i;
        c_slot_t        c_dst;
        c_slot_t        c_src;
-       int             slotarray;
        boolean_t       keep_compacting = TRUE;
        
        /*
@@ -1015,6 +1539,9 @@ c_seg_major_compact(
         * from c_seg_src to c_seg_dst and update both c_segment's
         * state w/o holding the master lock
         */
+#if DEVELOPMENT || DEBUG
+       C_SEG_MAKE_WRITEABLE(c_seg_dst);
+#endif
 
 #if VALIDATE_C_SEGMENTS
        c_seg_dst->c_was_major_compacted++;
@@ -1036,30 +1563,30 @@ c_seg_major_compact(
                }
 
                if (C_SEG_OFFSET_TO_BYTES(c_seg_dst->c_populated_offset - c_seg_dst->c_nextoffset) < (unsigned) c_size) {
+                       int     size_to_populate;
+
                        /* doesn't fit */
-                       if ((C_SEG_OFFSET_TO_BYTES(c_seg_dst->c_populated_offset) == C_SEG_BUFSIZE)) {
+                       size_to_populate = C_SEG_BUFSIZE - C_SEG_OFFSET_TO_BYTES(c_seg_dst->c_populated_offset);
+
+                       if (size_to_populate == 0) {
                                /* can't fit */
                                keep_compacting = FALSE;
                                break;
                        }
-                       kernel_memory_populate(kernel_map,
+                       if (size_to_populate > C_SEG_MAX_POPULATE_SIZE)
+                               size_to_populate = C_SEG_MAX_POPULATE_SIZE;
+
+                       kernel_memory_populate(compressor_map,
                                               (vm_offset_t) &c_seg_dst->c_store.c_buffer[c_seg_dst->c_populated_offset],
-                                              PAGE_SIZE,
-                                              KMA_COMPRESSOR);
+                                              size_to_populate,
+                                              KMA_COMPRESSOR, 
+                                              VM_KERN_MEMORY_COMPRESSOR);
 
-                       c_seg_dst->c_populated_offset += C_SEG_BYTES_TO_OFFSET(PAGE_SIZE);
+                       c_seg_dst->c_populated_offset += C_SEG_BYTES_TO_OFFSET(size_to_populate);
                        assert(C_SEG_OFFSET_TO_BYTES(c_seg_dst->c_populated_offset) <= C_SEG_BUFSIZE);
                }
+               c_seg_alloc_nextslot(c_seg_dst);
 
-               slotarray = C_SEG_SLOTARRAY_FROM_INDEX(c_seg_dst, c_seg_dst->c_nextslot);
-
-               if (c_seg_dst->c_slots[slotarray] == 0) {
-                       KERNEL_DEBUG(0xe0400008 | DBG_FUNC_START, 0, 0, 0, 0, 0);
-                       c_seg_dst->c_slots[slotarray] = (struct c_slot *)
-                               kalloc(sizeof(struct c_slot) *
-                                      C_SEG_SLOT_ARRAY_SIZE);
-                       KERNEL_DEBUG(0xe0400008 | DBG_FUNC_END, 0, 0, 0, 0, 0);
-               }
                c_dst = C_SEG_SLOT_FROM_INDEX(c_seg_dst, c_seg_dst->c_nextslot);
 
                memcpy(&c_seg_dst->c_store.c_buffer[c_seg_dst->c_nextoffset], &c_seg_src->c_store.c_buffer[c_src->c_offset], c_size);
@@ -1069,18 +1596,12 @@ c_seg_major_compact(
                c_seg_major_compact_stats.moved_slots++;
                c_seg_major_compact_stats.moved_bytes += c_size;
 
-#if CHECKSUM_THE_DATA
-               c_dst->c_hash_data = c_src->c_hash_data;
-#endif
-#if CHECKSUM_THE_COMPRESSED_DATA
-               c_dst->c_hash_compressed_data = c_src->c_hash_compressed_data;
-#endif
-               c_dst->c_size = c_src->c_size;
-               c_dst->c_packed_ptr = c_src->c_packed_ptr;
+               cslot_copy(c_dst, c_src);
                c_dst->c_offset = c_seg_dst->c_nextoffset;
 
                if (c_seg_dst->c_firstemptyslot == c_seg_dst->c_nextslot)
                        c_seg_dst->c_firstemptyslot++;
+               c_seg_dst->c_slots_used++;
                c_seg_dst->c_nextslot++;
                c_seg_dst->c_bytes_used += c_rounded_size;
                c_seg_dst->c_nextoffset += C_SEG_BYTES_TO_OFFSET(c_rounded_size);
@@ -1091,12 +1612,18 @@ c_seg_major_compact(
                c_seg_src->c_bytes_unused += c_rounded_size;
                c_seg_src->c_firstemptyslot = 0;
 
-               if (c_seg_dst->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg_dst->c_nextslot >= C_SLOT_MAX) {
+               assert(c_seg_src->c_slots_used);
+               c_seg_src->c_slots_used--;
+
+               if (c_seg_dst->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg_dst->c_nextslot >= C_SLOT_MAX_INDEX) {
                        /* dest segment is now full */
                        keep_compacting = FALSE;
                        break;
                }
        }
+#if DEVELOPMENT || DEBUG
+       C_SEG_WRITE_PROTECT(c_seg_dst);
+#endif
        if (dst_slot < c_seg_dst->c_nextslot) {
 
                PAGE_REPLACEMENT_ALLOWED(TRUE);
@@ -1122,8 +1649,8 @@ c_seg_major_compact(
 }
 
 
-static uint64_t
-compute_elapsed_msecs(clock_sec_t end_sec, clock_nsec_t end_nsec, clock_sec_t start_sec, clock_nsec_t start_nsec)
+uint64_t
+vm_compressor_compute_elapsed_msecs(clock_sec_t end_sec, clock_nsec_t end_nsec, clock_sec_t start_sec, clock_nsec_t start_nsec)
 {
         uint64_t end_msecs;
         uint64_t start_msecs;
@@ -1142,6 +1669,9 @@ uint32_t compressor_sample_max_in_msecs = 10000;
 uint32_t compressor_thrashing_threshold_per_10msecs = 50;
 uint32_t compressor_thrashing_min_per_10msecs = 20;
 
+/* When true, reset sample data next chance we get. */
+static boolean_t       compressor_need_sample_reset = FALSE;
+
 extern uint32_t vm_page_filecache_min;
 
 
@@ -1153,19 +1683,19 @@ compute_swapout_target_age(void)
        uint32_t        min_operations_needed_in_this_sample;
        uint64_t        elapsed_msecs_in_eval;
        uint64_t        elapsed_msecs_in_sample;
-       boolean_t       need_sample_reset = FALSE;
        boolean_t       need_eval_reset = FALSE;
 
        clock_get_system_nanotime(&cur_ts_sec, &cur_ts_nsec);
 
-       elapsed_msecs_in_sample = compute_elapsed_msecs(cur_ts_sec, cur_ts_nsec, start_of_sample_period_sec, start_of_sample_period_nsec);
+       elapsed_msecs_in_sample = vm_compressor_compute_elapsed_msecs(cur_ts_sec, cur_ts_nsec, start_of_sample_period_sec, start_of_sample_period_nsec);
 
-       if (elapsed_msecs_in_sample >= compressor_sample_max_in_msecs) {
-               need_sample_reset = TRUE;
+       if (compressor_need_sample_reset ||
+           elapsed_msecs_in_sample >= compressor_sample_max_in_msecs) {
+               compressor_need_sample_reset = TRUE;
                need_eval_reset = TRUE;
                goto done;
        }
-       elapsed_msecs_in_eval = compute_elapsed_msecs(cur_ts_sec, cur_ts_nsec, start_of_eval_period_sec, start_of_eval_period_nsec);
+       elapsed_msecs_in_eval = vm_compressor_compute_elapsed_msecs(cur_ts_sec, cur_ts_nsec, start_of_eval_period_sec, start_of_eval_period_nsec);
        
        if (elapsed_msecs_in_eval < compressor_eval_period_in_msecs)
                goto done;
@@ -1183,7 +1713,7 @@ compute_swapout_target_age(void)
 
                swapout_target_age = 0;
 
-               need_sample_reset = TRUE;
+               compressor_need_sample_reset = TRUE;
                need_eval_reset = TRUE;
                goto done;
        }
@@ -1241,12 +1771,12 @@ compute_swapout_target_age(void)
                } else
                        KERNEL_DEBUG(0xe0400020 | DBG_FUNC_END, working_target, running_total, 0, 4, 0);
 
-               need_sample_reset = TRUE;
+               compressor_need_sample_reset = TRUE;
                need_eval_reset = TRUE;
        } else
                KERNEL_DEBUG(0xe0400020 | DBG_FUNC_END, sample_period_decompression_count, (compressor_thrashing_threshold_per_10msecs * elapsed_msecs_in_sample) / 10, 0, 6, 0);
 done:
-       if (need_sample_reset == TRUE) {
+       if (compressor_need_sample_reset == TRUE) {
                bzero(age_of_decompressions_during_sample_period, sizeof(age_of_decompressions_during_sample_period));
                overage_decompressions_during_sample_period = 0;
 
@@ -1256,6 +1786,7 @@ done:
                sample_period_compression_count = 0;
                last_eval_decompression_count = 0;
                last_eval_compression_count = 0;
+               compressor_need_sample_reset = FALSE;
        }
        if (need_eval_reset == TRUE) {
                start_of_eval_period_sec = cur_ts_sec;
@@ -1264,16 +1795,18 @@ done:
 }
 
 
-
-int            calls_since_last_considered = 0;
+int            compaction_swapper_init_now = 0;
 int            compaction_swapper_running = 0;
+int            compaction_swapper_awakened = 0;
 int            compaction_swapper_abort = 0;
 
 
 #if CONFIG_JETSAM
 boolean_t      memorystatus_kill_on_VM_thrashing(boolean_t);
+boolean_t      memorystatus_kill_on_FC_thrashing(boolean_t);
 int            compressor_thrashing_induced_jetsam = 0;
-boolean_t      vm_compressor_thrashing_detected = FALSE;
+int            filecache_thrashing_induced_jetsam = 0;
+static boolean_t       vm_compressor_thrashing_detected = FALSE;
 #endif /* CONFIG_JETSAM */
 
 static boolean_t
@@ -1281,14 +1814,35 @@ compressor_needs_to_swap(void)
 {
        boolean_t       should_swap = FALSE;
 
-       if (vm_swap_up == TRUE) {
+       if (vm_swapout_ripe_segments == TRUE && c_overage_swapped_count < c_overage_swapped_limit) {
+               c_segment_t     c_seg;
+               clock_sec_t     now;
+               clock_sec_t     age;
+               clock_nsec_t    nsec;
+               
+               clock_get_system_nanotime(&now,  &nsec);
+               age = 0;
+
+               lck_mtx_lock_spin_always(c_list_lock);
+
+               if ( !queue_empty(&c_age_list_head)) {
+                       c_seg = (c_segment_t) queue_first(&c_age_list_head);
+
+                       age = now - c_seg->c_creation_ts;
+               }
+               lck_mtx_unlock_always(c_list_lock);
+
+               if (age >= vm_ripe_target_age)
+                       return (TRUE);
+       }
+       if (VM_CONFIG_SWAP_IS_ACTIVE) {
                if (COMPRESSOR_NEEDS_TO_SWAP()) {
                        return (TRUE);
                }
                if (VM_PAGE_Q_THROTTLED(&vm_pageout_queue_external) && vm_page_anonymous_count < (vm_page_inactive_count / 20)) {
                        return (TRUE);
                }
-               if (vm_page_free_count < (vm_page_free_reserved - COMPRESSOR_FREE_RESERVED_LIMIT))
+               if (vm_page_free_count < (vm_page_free_reserved - (COMPRESSOR_FREE_RESERVED_LIMIT * 2)))
                        return (TRUE);
        }
        compute_swapout_target_age();
@@ -1302,115 +1856,263 @@ compressor_needs_to_swap(void)
 
                        c_seg = (c_segment_t) queue_first(&c_age_list_head);
 
-                       if (c_seg->c_creation_ts <= swapout_target_age)
-                               should_swap = TRUE;
-                       else
+                       if (c_seg->c_creation_ts > swapout_target_age)
                                swapout_target_age = 0;
                }
                lck_mtx_unlock_always(c_list_lock);
        }
+#if CONFIG_PHANTOM_CACHE
+       if (vm_phantom_cache_check_pressure())
+               should_swap = TRUE;
+#endif
+       if (swapout_target_age)
+               should_swap = TRUE;
 
-       if (vm_swap_up == FALSE) {
 #if CONFIG_JETSAM
-               if (should_swap) {
-                       if (vm_compressor_thrashing_detected == FALSE) {
-                               vm_compressor_thrashing_detected = TRUE;
+       if (should_swap || vm_compressor_low_on_space() == TRUE) {
+
+               if (vm_compressor_thrashing_detected == FALSE) {
+                       vm_compressor_thrashing_detected = TRUE;
+                               
+                       if (swapout_target_age || vm_compressor_low_on_space() == TRUE) {
                                memorystatus_kill_on_VM_thrashing(TRUE /* async */);
                                compressor_thrashing_induced_jetsam++;
-                               /*
-                                * let the jetsam take precedence over
-                                * any major compactions we might have
-                                * been able to do... otherwise we run
-                                * the risk of doing major compactions
-                                * on segments we're about to free up
-                                * due to the jetsam activity.
-                                */
-                               should_swap = FALSE;
+                       } else {
+                               memorystatus_kill_on_FC_thrashing(TRUE /* async */);
+                               filecache_thrashing_induced_jetsam++;
                        }
-               } else
+               }
+               /*
+                * let the jetsam take precedence over
+                * any major compactions we might have
+                * been able to do... otherwise we run
+                * the risk of doing major compactions
+                * on segments we're about to free up
+                * due to the jetsam activity.
+                */
+               should_swap = FALSE;
+       }
+
 #endif /* CONFIG_JETSAM */
-                       if (COMPRESSOR_NEEDS_TO_MAJOR_COMPACT())
-                               should_swap = TRUE;
+
+       if (should_swap == FALSE) {
+               /*
+                * vm_compressor_needs_to_major_compact returns true only if we're
+                * about to run out of available compressor segments... in this
+                * case, we absolutely need to run a major compaction even if
+                * we've just kicked off a jetsam or we don't otherwise need to
+                * swap... terminating objects releases
+                * pages back to the uncompressed cache, but does not guarantee
+                * that we will free up even a single compression segment
+                */
+               should_swap = vm_compressor_needs_to_major_compact();
        }
+
        /*
         * returning TRUE when swap_supported == FALSE
         * will cause the major compaction engine to
         * run, but will not trigger any swapping...
         * segments that have been major compacted
-        * will be moved to the swapped_out_q
-        * but will not have the c_ondisk flag set
+        * will be moved to the majorcompact queue
         */
        return (should_swap);
 }
 
-uint64_t
-vm_compressor_total_compressions(void)
+#if CONFIG_JETSAM
+/*
+ * This function is called from the jetsam thread after killing something to
+ * mitigate thrashing.
+ *
+ * We need to restart our thrashing detection heuristics since memory pressure
+ * has potentially changed significantly, and we don't want to detect on old
+ * data from before the jetsam.
+ */
+void
+vm_thrashing_jetsam_done(void)
 {
-       processor_t processor = processor_list;
-       vm_statistics64_t stat = &PROCESSOR_DATA(processor, vm_stat);
-
-       uint64_t compressions = stat->compressions;
-
-       if (processor_count > 1) {
-               simple_lock(&processor_list_lock);
-
-               while ((processor = processor->processor_list) != NULL) {
-                       stat = &PROCESSOR_DATA(processor, vm_stat);
-                       compressions += stat->compressions;
-               }
+       vm_compressor_thrashing_detected = FALSE;
 
-               simple_unlock(&processor_list_lock);
+       /* Were we compressor-thrashing or filecache-thrashing? */
+       if (swapout_target_age) {
+               swapout_target_age = 0;
+               compressor_need_sample_reset = TRUE;
        }
-
-       return compressions;
+#if CONFIG_PHANTOM_CACHE
+       else {
+               vm_phantom_cache_restart_sample();
+       }
+#endif
 }
+#endif /* CONFIG_JETSAM */
 
 uint32_t vm_wake_compactor_swapper_calls = 0;
+uint32_t vm_run_compactor_already_running = 0;
+uint32_t vm_run_compactor_empty_minor_q = 0;
+uint32_t vm_run_compactor_did_compact = 0;
+uint32_t vm_run_compactor_waited = 0;
 
 void
-vm_wake_compactor_swapper(void)
+vm_run_compactor(void)
 {
-       if (compaction_swapper_running)
+       if (c_segment_count == 0)
                return;
 
-       if (c_minor_count == 0)
+       lck_mtx_lock_spin_always(c_list_lock);
+
+       if (c_minor_count == 0) {
+               vm_run_compactor_empty_minor_q++;
+
+               lck_mtx_unlock_always(c_list_lock);
                return;
+       }
+       if (compaction_swapper_running) {
 
-       lck_mtx_lock_spin_always(c_list_lock);
+               if (vm_restricted_to_single_processor == FALSE) {
+                       vm_run_compactor_already_running++;
 
-       fastwake_warmup = FALSE;
+                       lck_mtx_unlock_always(c_list_lock);
+                       return;
+               }
+               vm_run_compactor_waited++;
 
-       if (compaction_swapper_running == 0) {
-               vm_wake_compactor_swapper_calls++;
+               assert_wait((event_t)&compaction_swapper_running, THREAD_UNINT);
 
-               thread_wakeup((event_t)&c_compressor_swap_trigger);
+               lck_mtx_unlock_always(c_list_lock);
                
-               compaction_swapper_running = 1;
+               thread_block(THREAD_CONTINUE_NULL);
+
+               return;
        }
+       vm_run_compactor_did_compact++;
+
+       fastwake_warmup = FALSE;
+       compaction_swapper_running = 1;
+
+       vm_compressor_do_delayed_compactions(FALSE);
+
+       compaction_swapper_running = 0;
+
        lck_mtx_unlock_always(c_list_lock);
+
+       thread_wakeup((event_t)&compaction_swapper_running);
 }
 
+
 void
-vm_consider_waking_compactor_swapper(void)
+vm_wake_compactor_swapper(void)
 {
-       boolean_t       need_wakeup = FALSE;
-
-       if (calls_since_last_considered++ < 1000 || compaction_swapper_running)
+       if (compaction_swapper_running || compaction_swapper_awakened || c_segment_count == 0)
                return;
-       calls_since_last_considered = 0;
 
-       if (c_minor_count && (COMPRESSOR_NEEDS_TO_MINOR_COMPACT())) {
+       if (c_minor_count || vm_compressor_needs_to_major_compact()) {
 
-               need_wakeup = TRUE;
+               lck_mtx_lock_spin_always(c_list_lock);
 
-       } else if (compressor_needs_to_swap()) {
+               fastwake_warmup = FALSE;
 
-               need_wakeup = TRUE;
+               if (compaction_swapper_running == 0 && compaction_swapper_awakened == 0) {
 
-       } else if (c_minor_count) {
-               uint64_t        total_bytes;
+                       vm_wake_compactor_swapper_calls++;
 
-               total_bytes = compressor_object->resident_page_count * PAGE_SIZE_64;
+                       compaction_swapper_awakened = 1;
+                       thread_wakeup((event_t)&c_compressor_swap_trigger);
+               }
+               lck_mtx_unlock_always(c_list_lock);
+       }
+}
+
+
+void
+vm_consider_swapping()
+{
+       c_segment_t     c_seg, c_seg_next;
+       clock_sec_t     now;
+       clock_nsec_t    nsec;
+
+       assert(VM_CONFIG_SWAP_IS_PRESENT);
+
+       lck_mtx_lock_spin_always(c_list_lock);
+
+       compaction_swapper_abort = 1;
+
+       while (compaction_swapper_running) {
+               assert_wait((event_t)&compaction_swapper_running, THREAD_UNINT);
+
+               lck_mtx_unlock_always(c_list_lock);
+               
+               thread_block(THREAD_CONTINUE_NULL);
+
+               lck_mtx_lock_spin_always(c_list_lock);
+       }
+       compaction_swapper_abort = 0;
+       compaction_swapper_running = 1;
+
+       vm_swapout_ripe_segments = TRUE;
+
+       if (!queue_empty(&c_major_list_head)) {
+               
+               clock_get_system_nanotime(&now, &nsec);
+                       
+               c_seg = (c_segment_t)queue_first(&c_major_list_head);
+
+               while (!queue_end(&c_major_list_head, (queue_entry_t)c_seg)) {
+
+                       if (c_overage_swapped_count >= c_overage_swapped_limit)
+                               break;
+
+                       c_seg_next = (c_segment_t) queue_next(&c_seg->c_age_list);
+
+                       if ((now - c_seg->c_creation_ts) >= vm_ripe_target_age) {
+                       
+                               lck_mtx_lock_spin_always(&c_seg->c_lock);
+                               
+                               c_seg_switch_state(c_seg, C_ON_AGE_Q, FALSE);
+
+                               lck_mtx_unlock_always(&c_seg->c_lock);
+                       }
+                       c_seg = c_seg_next;
+               }
+       }
+       vm_compressor_compact_and_swap(FALSE);
+
+       compaction_swapper_running = 0;
+
+       vm_swapout_ripe_segments = FALSE;
+       
+       lck_mtx_unlock_always(c_list_lock);
+
+       thread_wakeup((event_t)&compaction_swapper_running);
+}
+
+
+void
+vm_consider_waking_compactor_swapper(void)
+{
+       boolean_t       need_wakeup = FALSE;
+
+       if (c_segment_count == 0)
+               return;
+
+       if (compaction_swapper_running || compaction_swapper_awakened)
+               return;
+
+       if (!compaction_swapper_inited && !compaction_swapper_init_now) {
+               compaction_swapper_init_now = 1;
+               need_wakeup = TRUE;
+       }
+
+       if (c_minor_count && (COMPRESSOR_NEEDS_TO_MINOR_COMPACT())) {
+
+               need_wakeup = TRUE;
+
+       } else if (compressor_needs_to_swap()) {
+
+               need_wakeup = TRUE;
+
+       } else if (c_minor_count) {
+               uint64_t        total_bytes;
+
+               total_bytes = compressor_object->resident_page_count * PAGE_SIZE_64;
 
                if ((total_bytes - compressor_bytes_used) > total_bytes / 10)
                        need_wakeup = TRUE;
@@ -1421,12 +2123,11 @@ vm_consider_waking_compactor_swapper(void)
 
                fastwake_warmup = FALSE;
 
-               if (compaction_swapper_running == 0) {
+               if (compaction_swapper_running == 0 && compaction_swapper_awakened == 0) {
                        memoryshot(VM_WAKEUP_COMPACTOR_SWAPPER, DBG_FUNC_NONE);
 
+                       compaction_swapper_awakened = 1;
                        thread_wakeup((event_t)&c_compressor_swap_trigger);
-
-                       compaction_swapper_running = 1;
                }
                lck_mtx_unlock_always(c_list_lock);
        }
@@ -1444,7 +2145,9 @@ vm_compressor_do_delayed_compactions(boolean_t flush_all)
        boolean_t       needs_to_swap = FALSE;
 
 
-       lck_mtx_assert(c_list_lock, LCK_MTX_ASSERT_OWNED);
+#if !CONFIG_EMBEDDED
+       LCK_MTX_ASSERT(c_list_lock, LCK_MTX_ASSERT_OWNED);
+#endif /* !CONFIG_EMBEDDED */
 
        while (!queue_empty(&c_minor_list_head) && needs_to_swap == FALSE) {
                
@@ -1452,19 +2155,19 @@ vm_compressor_do_delayed_compactions(boolean_t flush_all)
                
                lck_mtx_lock_spin_always(&c_seg->c_lock);
 
-                if (c_seg->c_busy) {
+               if (c_seg->c_busy) {
 
-                        lck_mtx_unlock_always(c_list_lock);
-                        c_seg_wait_on_busy(c_seg);
-                        lck_mtx_lock_spin_always(c_list_lock);
+                       lck_mtx_unlock_always(c_list_lock);
+                       c_seg_wait_on_busy(c_seg);
+                       lck_mtx_lock_spin_always(c_list_lock);
 
-                        continue;
-                }
-               c_seg->c_busy = 1;
+                       continue;
+               }
+               C_SEG_BUSY(c_seg);
 
                c_seg_do_minor_compaction_and_unlock(c_seg, TRUE, FALSE, TRUE);
 
-               if (vm_swap_up == TRUE && (number_compacted++ > DELAYED_COMPACTIONS_PER_PASS)) {
+               if (VM_CONFIG_SWAP_IS_ACTIVE && (number_compacted++ > DELAYED_COMPACTIONS_PER_PASS)) {
                        
                        if ((flush_all == TRUE || compressor_needs_to_swap() == TRUE) && c_swapout_count < C_SWAPOUT_LIMIT)
                                needs_to_swap = TRUE;
@@ -1496,19 +2199,21 @@ vm_compressor_age_swapped_in_segments(boolean_t flush_all)
                        
                lck_mtx_lock_spin_always(&c_seg->c_lock);
 
-               queue_remove(&c_swappedin_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedin_q = 0;
-               c_swappedin_count--;
-
-               c_seg_insert_into_q(&c_age_list_head, c_seg);
-               c_seg->c_on_age_q = 1;
-               c_age_count++;
+               c_seg_switch_state(c_seg, C_ON_AGE_Q, FALSE);
 
                lck_mtx_unlock_always(&c_seg->c_lock);
        }
 }
 
 
+extern int     vm_num_swap_files;
+extern int     vm_num_pinned_swap_files;
+extern int     vm_swappin_enabled;
+
+extern unsigned int    vm_swapfile_total_segs_used;
+extern unsigned int    vm_swapfile_total_segs_alloced;
+
+
 void
 vm_compressor_flush(void)
 {
@@ -1573,31 +2278,59 @@ vm_compressor_flush(void)
        
        lck_mtx_unlock_always(c_list_lock);
 
+       thread_wakeup((event_t)&compaction_swapper_running);
+
         clock_get_uptime(&endTime);
         SUB_ABSOLUTETIME(&endTime, &startTime);
         absolutetime_to_nanoseconds(endTime, &nsec);
 
-       HIBLOG("vm_compressor_flush completed - took %qd msecs\n", nsec / 1000000ULL);
+       HIBLOG("vm_compressor_flush completed - took %qd msecs - vm_num_swap_files = %d, vm_num_pinned_swap_files = %d, vm_swappin_enabled = %d\n",
+              nsec / 1000000ULL, vm_num_swap_files, vm_num_pinned_swap_files, vm_swappin_enabled);
 }
 
 
-
 int            compaction_swap_trigger_thread_awakened = 0;
 
 static void
 vm_compressor_swap_trigger_thread(void)
 {
+       current_thread()->options |= TH_OPT_VMPRIV;
+
+       /*
+        * compaction_swapper_init_now is set when the first call to
+        * vm_consider_waking_compactor_swapper is made from 
+        * vm_pageout_scan... since this function is called upon 
+        * thread creation, we want to make sure to delay adjusting
+        * the tuneables until we are awakened via vm_pageout_scan
+        * so that we are at a point where the vm_swapfile_open will
+        * be operating on the correct directory (in case the default
+        * of /var/vm/  is overridden by the dymanic_pager 
+        */
+       if (compaction_swapper_init_now) {
+               vm_compaction_swapper_do_init();
 
+               if (vm_restricted_to_single_processor == TRUE)
+                       thread_vm_bind_group_add();
+               thread_set_thread_name(current_thread(), "VM_cswap_trigger");
+               compaction_swapper_init_now = 0;
+       }
        lck_mtx_lock_spin_always(c_list_lock);
 
        compaction_swap_trigger_thread_awakened++;
+       compaction_swapper_awakened = 0;
 
-       vm_compressor_compact_and_swap(FALSE);
+       if (compaction_swapper_running == 0) {
 
+               compaction_swapper_running = 1;
+
+               vm_compressor_compact_and_swap(FALSE);
+
+               compaction_swapper_running = 0;
+       }
        assert_wait((event_t)&c_compressor_swap_trigger, THREAD_UNINT);
 
-       compaction_swapper_running = 0;
-       thread_wakeup((event_t)&compaction_swapper_running);
+       if (compaction_swapper_running == 0)
+               thread_wakeup((event_t)&compaction_swapper_running);
 
        lck_mtx_unlock_always(c_list_lock);
                
@@ -1654,7 +2387,7 @@ vm_compressor_record_warmup_end(void)
 }
 
 
-#define DELAY_TRIM_ON_WAKE_SECS                4
+#define DELAY_TRIM_ON_WAKE_SECS                25
 
 void
 vm_compressor_delay_trim(void)
@@ -1679,20 +2412,43 @@ vm_compressor_do_warmup(void)
                return;
        }
 
-       if (compaction_swapper_running == 0) {
+       if (compaction_swapper_running == 0 && compaction_swapper_awakened == 0) {
 
                fastwake_warmup = TRUE;
-               compaction_swapper_running = 1;
+
+               compaction_swapper_awakened = 1;
                thread_wakeup((event_t)&c_compressor_swap_trigger);
        }
        lck_mtx_unlock_always(c_list_lock);
 }
 
+void
+do_fastwake_warmup_all(void)
+{
+
+       lck_mtx_lock_spin_always(c_list_lock);
+
+       if (queue_empty(&c_swappedout_list_head) && queue_empty(&c_swappedout_sparse_list_head)) {
+
+               lck_mtx_unlock_always(c_list_lock);
+               return;
+       }
+
+       fastwake_warmup = TRUE;
+
+       do_fastwake_warmup(&c_swappedout_list_head, TRUE);
+
+       do_fastwake_warmup(&c_swappedout_sparse_list_head, TRUE);
+
+       fastwake_warmup = FALSE;
+
+       lck_mtx_unlock_always(c_list_lock);
+
+}
 
 void
-do_fastwake_warmup(void)
+do_fastwake_warmup(queue_head_t *c_queue, boolean_t consider_all_cseg)
 {
-       uint64_t        my_thread_id;
        c_segment_t     c_seg = NULL;
        AbsoluteTime    startTime, endTime;
        uint64_t        nsec;
@@ -1704,21 +2460,25 @@ do_fastwake_warmup(void)
 
        lck_mtx_unlock_always(c_list_lock);
 
-       my_thread_id = current_thread()->thread_id;
-       proc_set_task_policy_thread(kernel_task, my_thread_id,
-                                   TASK_POLICY_INTERNAL, TASK_POLICY_IO, THROTTLE_LEVEL_COMPRESSOR_TIER2);
+       proc_set_thread_policy(current_thread(),
+                              TASK_POLICY_INTERNAL, TASK_POLICY_IO, THROTTLE_LEVEL_COMPRESSOR_TIER2);
 
        PAGE_REPLACEMENT_DISALLOWED(TRUE);
 
        lck_mtx_lock_spin_always(c_list_lock);
 
-       while (!queue_empty(&c_swappedout_list_head) && fastwake_warmup == TRUE) {
+       while (!queue_empty(c_queue) && fastwake_warmup == TRUE) {
 
-               c_seg = (c_segment_t) queue_first(&c_swappedout_list_head);
+               c_seg = (c_segment_t) queue_first(c_queue);
 
-               if (c_seg->c_generation_id < first_c_segment_to_warm_generation_id || 
-                   c_seg->c_generation_id > last_c_segment_to_warm_generation_id)
-                       break;
+               if (consider_all_cseg == FALSE) {
+                       if (c_seg->c_generation_id < first_c_segment_to_warm_generation_id ||
+                           c_seg->c_generation_id > last_c_segment_to_warm_generation_id)
+                               break;
+
+                       if (vm_page_free_count < (AVAILABLE_MEMORY / 4))
+                               break;
+               }
 
                lck_mtx_lock_spin_always(&c_seg->c_lock);
                lck_mtx_unlock_always(c_list_lock);
@@ -1728,9 +2488,8 @@ do_fastwake_warmup(void)
                        c_seg_wait_on_busy(c_seg);
                        PAGE_REPLACEMENT_DISALLOWED(TRUE);
                } else {
-                       c_seg_swapin(c_seg, TRUE);
-
-                       lck_mtx_unlock_always(&c_seg->c_lock);
+                       if (c_seg_swapin(c_seg, TRUE, FALSE) == 0)
+                               lck_mtx_unlock_always(&c_seg->c_lock);
                        c_segment_warmup_count++;
 
                        PAGE_REPLACEMENT_DISALLOWED(FALSE);
@@ -1743,8 +2502,8 @@ do_fastwake_warmup(void)
 
        PAGE_REPLACEMENT_DISALLOWED(FALSE);
 
-       proc_set_task_policy_thread(kernel_task, my_thread_id,
-                                   TASK_POLICY_INTERNAL, TASK_POLICY_IO, THROTTLE_LEVEL_COMPRESSOR_TIER0);
+       proc_set_thread_policy(current_thread(),
+                              TASK_POLICY_INTERNAL, TASK_POLICY_IO, THROTTLE_LEVEL_COMPRESSOR_TIER0);
 
         clock_get_uptime(&endTime);
         SUB_ABSOLUTETIME(&endTime, &startTime);
@@ -1754,7 +2513,9 @@ do_fastwake_warmup(void)
 
        lck_mtx_lock_spin_always(c_list_lock);
 
-       first_c_segment_to_warm_generation_id = last_c_segment_to_warm_generation_id = 0;
+       if (consider_all_cseg == FALSE) {
+               first_c_segment_to_warm_generation_id = last_c_segment_to_warm_generation_id = 0;
+       }
 }
 
 
@@ -1763,6 +2524,8 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 {
        c_segment_t     c_seg, c_seg_next;
        boolean_t       keep_compacting;
+       clock_sec_t     now;
+       clock_nsec_t    nsec;
 
 
        if (fastwake_warmup == TRUE) {
@@ -1772,7 +2535,7 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 
                KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 11) | DBG_FUNC_START, c_segment_warmup_count,
                                      first_c_segment_to_warm_generation_id, last_c_segment_to_warm_generation_id, 0, 0);
-               do_fastwake_warmup();
+               do_fastwake_warmup(&c_swappedout_list_head, FALSE);
                KERNEL_DEBUG_CONSTANT(IOKDBG_CODE(DBG_HIBERNATE, 11) | DBG_FUNC_END, c_segment_warmup_count, c_segment_warmup_count - starting_warmup_count, 0, 0, 0);
 
                fastwake_warmup = FALSE;
@@ -1789,12 +2552,18 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 
        vm_compressor_age_swapped_in_segments(flush_all);
 
+       /*
+        * we only need to grab the timestamp once per
+        * invocation of this function since the 
+        * timescale we're interested in is measured
+        * in days
+        */
+       clock_get_system_nanotime(&now,  &nsec);
 
        while (!queue_empty(&c_age_list_head) && compaction_swapper_abort == 0) {
 
                if (hibernate_flushing == TRUE) {
                        clock_sec_t     sec;
-                       clock_nsec_t    nsec;
 
                        if (hibernate_should_abort()) {
                                HIBLOG("vm_compressor_flush - hibernate_should_abort returned TRUE\n");
@@ -1804,6 +2573,15 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
                                HIBLOG("vm_compressor_flush - out of swap space\n");
                                break;
                        }
+                       if (vm_swap_files_pinned() == FALSE) {
+                               HIBLOG("vm_compressor_flush - unpinned swap files\n");
+                               break;
+                       }
+                       if (hibernate_in_progress_with_pinned_swap == TRUE &&
+                           (vm_swapfile_total_segs_alloced == vm_swapfile_total_segs_used)) {
+                               HIBLOG("vm_compressor_flush - out of pinned swap space\n");
+                               break;
+                       }
                        clock_get_system_nanotime(&sec, &nsec);
                
                        if (sec > hibernate_flushing_deadline) {
@@ -1849,6 +2627,11 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 
                        needs_to_swap = compressor_needs_to_swap();
 
+#if !CONFIG_EMBEDDED
+                       if (needs_to_swap == TRUE && vm_swap_low_on_space())
+                               vm_compressor_take_paging_space_action();
+#endif /* !CONFIG_EMBEDDED */
+
                        lck_mtx_lock_spin_always(c_list_lock);
                        
                        if (needs_to_swap == FALSE)
@@ -1858,15 +2641,11 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
                        break;
                c_seg = (c_segment_t) queue_first(&c_age_list_head);
 
-               if (flush_all == TRUE && c_seg->c_generation_id > c_generation_id_flush_barrier)
-                       break;
+               assert(c_seg->c_state == C_ON_AGE_Q);
 
-               if (c_seg->c_filling) {
-                       /*
-                        * we're at or near the head... no more work to do
-                        */
+               if (flush_all == TRUE && c_seg->c_generation_id > c_generation_id_flush_barrier)
                        break;
-               }
+               
                lck_mtx_lock_spin_always(&c_seg->c_lock);
 
                if (c_seg->c_busy) {
@@ -1877,13 +2656,14 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 
                        continue;
                }
-               c_seg->c_busy = 1;
+               C_SEG_BUSY(c_seg);
 
                if (c_seg_do_minor_compaction_and_unlock(c_seg, FALSE, TRUE, TRUE)) {
                        /*
                         * found an empty c_segment and freed it
                         * so go grab the next guy in the queue
                         */
+                       c_seg_major_compact_stats.count_of_freed_segs++;
                        continue;
                }
                /*
@@ -1902,6 +2682,8 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
                        if (queue_end(&c_age_list_head, (queue_entry_t)c_seg_next))
                                break;
 
+                       assert(c_seg_next->c_state == C_ON_AGE_Q);
+
                        if (c_seg_major_compact_ok(c_seg, c_seg_next) == FALSE)
                                break;
 
@@ -1916,13 +2698,14 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
                                continue;
                        }
                        /* grab that segment */
-                       c_seg_next->c_busy = 1;
+                       C_SEG_BUSY(c_seg_next);
 
                        if (c_seg_do_minor_compaction_and_unlock(c_seg_next, FALSE, TRUE, TRUE)) {
                                /*
                                 * found an empty c_segment and freed it
                                 * so we can't continue to use c_seg_next
                                 */
+                               c_seg_major_compact_stats.count_of_freed_segs++;
                                continue;
                        }
 
@@ -1946,7 +2729,8 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
                         * by passing TRUE, we ask for c_busy to be cleared
                         * and c_wanted to be taken care of
                         */
-                       c_seg_minor_compaction_and_unlock(c_seg_next, TRUE);
+                       if (c_seg_minor_compaction_and_unlock(c_seg_next, TRUE))
+                               c_seg_major_compact_stats.count_of_freed_segs++;
 
                        PAGE_REPLACEMENT_DISALLOWED(FALSE);
 
@@ -1955,27 +2739,44 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 
                } /* major compaction */
 
-               c_seg_major_compact_stats.wasted_space_in_swapouts += C_SEG_BUFSIZE - c_seg->c_bytes_used;
-               c_seg_major_compact_stats.count_of_swapouts++;
-
                lck_mtx_lock_spin_always(&c_seg->c_lock);
 
                assert(c_seg->c_busy);
-               assert(c_seg->c_on_age_q);
                assert(!c_seg->c_on_minorcompact_q);
 
-               queue_remove(&c_age_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_age_q = 0;
-               c_age_count--;
+               if (VM_CONFIG_SWAP_IS_ACTIVE) {
+                       /*
+                        * This mode of putting a generic c_seg on the swapout list is
+                        * only supported when we have general swapping enabled
+                        */
+                       c_seg_switch_state(c_seg, C_ON_SWAPOUT_Q, FALSE);
+               } else {
+                       if ((vm_swapout_ripe_segments == TRUE && c_overage_swapped_count < c_overage_swapped_limit)) {
 
-               if (vm_swap_up == TRUE) {
-                       queue_enter(&c_swapout_list_head, c_seg, c_segment_t, c_age_list);
-                       c_seg->c_on_swapout_q = 1;
-                       c_swapout_count++;
+                               assert(VM_CONFIG_SWAP_IS_PRESENT);
+                               /*
+                                * we are running compressor sweeps with swap-behind
+                                * make sure the c_seg has aged enough before swapping it
+                                * out...
+                                */
+                               if ((now - c_seg->c_creation_ts) >= vm_ripe_target_age) {
+                                       c_seg->c_overage_swap = TRUE;
+                                       c_overage_swapped_count++;
+                                       c_seg_switch_state(c_seg, C_ON_SWAPOUT_Q, FALSE);
+                               }
+                       }
+               }
+               if (c_seg->c_state == C_ON_AGE_Q) {
+                       /*
+                        * this c_seg didn't get moved to the swapout queue
+                        * so we need to move it out of the way...
+                        * we just did a major compaction on it so put it
+                        * on that queue
+                        */ 
+                       c_seg_switch_state(c_seg, C_ON_MAJORCOMPACT_Q, FALSE);
                } else {
-                       queue_enter(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
-                       c_seg->c_on_swappedout_q = 1;
-                       c_swappedout_count++;
+                       c_seg_major_compact_stats.wasted_space_in_swapouts += C_SEG_BUFSIZE - c_seg->c_bytes_used;
+                       c_seg_major_compact_stats.count_of_swapouts++;
                }
                C_SEG_WAKEUP_DONE(c_seg);
 
@@ -1995,16 +2796,18 @@ vm_compressor_compact_and_swap(boolean_t flush_all)
 static c_segment_t
 c_seg_allocate(c_segment_t *current_chead)
 {
-        clock_sec_t    sec;
-        clock_nsec_t   nsec;
        c_segment_t     c_seg;
-       int             slotarray;
+       int             min_needed;
+       int             size_to_populate;
+
+#if !CONFIG_EMBEDDED
+       if (vm_compressor_low_on_space())
+               vm_compressor_take_paging_space_action();
+#endif /* !CONFIG_EMBEDDED */
 
        if ( (c_seg = *current_chead) == NULL ) {
                uint32_t        c_segno;
 
-               KERNEL_DEBUG(0xe0400004 | DBG_FUNC_START, 0, 0, 0, 0, 0);
-
                lck_mtx_lock_spin_always(c_list_lock);
 
                while (c_segments_busy == TRUE) {
@@ -2017,116 +2820,133 @@ c_seg_allocate(c_segment_t *current_chead)
                        lck_mtx_lock_spin_always(c_list_lock);
                }
                if (c_free_segno_head == (uint32_t)-1) {
+                       uint32_t        c_segments_available_new;
 
                        if (c_segments_available >= c_segments_limit || c_segment_pages_compressed >= c_segment_pages_compressed_limit) {
                                lck_mtx_unlock_always(c_list_lock);
 
-                               KERNEL_DEBUG(0xe0400004 | DBG_FUNC_END, 0, 0, 0, 1, 0);
                                return (NULL);
                        }
                        c_segments_busy = TRUE;
                        lck_mtx_unlock_always(c_list_lock);
 
-                       kernel_memory_populate(kernel_map, (vm_offset_t)c_segments_next_page, PAGE_SIZE, KMA_KOBJECT);
+                       kernel_memory_populate(compressor_map, (vm_offset_t)c_segments_next_page, 
+                                               PAGE_SIZE, KMA_KOBJECT, VM_KERN_MEMORY_COMPRESSOR);
                        c_segments_next_page += PAGE_SIZE;
 
-                       for (c_segno = c_segments_available + 1; c_segno < (c_segments_available + C_SEGMENTS_PER_PAGE); c_segno++)
+                       c_segments_available_new = c_segments_available + C_SEGMENTS_PER_PAGE;
+
+                       if (c_segments_available_new > c_segments_limit)
+                               c_segments_available_new = c_segments_limit;
+
+                       for (c_segno = c_segments_available + 1; c_segno < c_segments_available_new; c_segno++)
                                c_segments[c_segno - 1].c_segno = c_segno;
 
                        lck_mtx_lock_spin_always(c_list_lock);
 
                        c_segments[c_segno - 1].c_segno = c_free_segno_head;
                        c_free_segno_head = c_segments_available;
-                       c_segments_available += C_SEGMENTS_PER_PAGE;
+                       c_segments_available = c_segments_available_new;
 
                        c_segments_busy = FALSE;
                        thread_wakeup((event_t) (&c_segments_busy));
                }
                c_segno = c_free_segno_head;
-               c_free_segno_head = c_segments[c_segno].c_segno;
+               assert(c_segno >= 0 && c_segno < c_segments_limit);
+
+               c_free_segno_head = (uint32_t)c_segments[c_segno].c_segno;
+
+               /*
+                * do the rest of the bookkeeping now while we're still behind
+                * the list lock and grab our generation id now into a local
+                * so that we can install it once we have the c_seg allocated
+                */
+               c_segment_count++;
+               if (c_segment_count > c_segment_count_max)
+                       c_segment_count_max = c_segment_count;
 
                lck_mtx_unlock_always(c_list_lock);
 
                c_seg = (c_segment_t)zalloc(compressor_segment_zone);
                bzero((char *)c_seg, sizeof(struct c_segment));
 
-               if (kernel_memory_allocate(kernel_map, (vm_offset_t *)(&c_seg->c_store.c_buffer), C_SEG_ALLOCSIZE, 0, KMA_COMPRESSOR | KMA_VAONLY) != KERN_SUCCESS) {
-                       zfree(compressor_segment_zone, c_seg);
-
-                       lck_mtx_lock_spin_always(c_list_lock);
-
-                       c_segments[c_segno].c_segno = c_free_segno_head;
-                       c_free_segno_head = c_segno;
-
-                       lck_mtx_unlock_always(c_list_lock);
-
-                       KERNEL_DEBUG(0xe0400004 | DBG_FUNC_END, 0, 0, 0, 2, 0);
+               c_seg->c_store.c_buffer = (int32_t *)C_SEG_BUFFER_ADDRESS(c_segno);
 
-                       return (NULL);
-               }
-
-#if __i386__ || __x86_64__
                lck_mtx_init(&c_seg->c_lock, &vm_compressor_lck_grp, &vm_compressor_lck_attr);
-#else /* __i386__ || __x86_64__ */
-               lck_spin_init(&c_seg->c_lock, &vm_compressor_lck_grp, &vm_compressor_lck_attr);
-#endif /* __i386__ || __x86_64__ */
        
-               kernel_memory_populate(kernel_map, (vm_offset_t)(c_seg->c_store.c_buffer), 3 * PAGE_SIZE, KMA_COMPRESSOR);
-
-               c_seg->c_populated_offset = C_SEG_BYTES_TO_OFFSET(3 * PAGE_SIZE);
-               c_seg->c_firstemptyslot = C_SLOT_MAX;
+               c_seg->c_state = C_IS_EMPTY;
+               c_seg->c_firstemptyslot = C_SLOT_MAX_INDEX;
                c_seg->c_mysegno = c_segno;
-               c_seg->c_filling = 1;
 
                lck_mtx_lock_spin_always(c_list_lock);
-
-               c_segment_count++;
+               c_empty_count++;
+               c_seg_switch_state(c_seg, C_IS_FILLING, FALSE);
                c_segments[c_segno].c_seg = c_seg;
-
-               c_seg->c_generation_id = c_generation_id++;
-               
-               queue_enter(&c_age_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_age_q = 1;
-               c_age_count++;
-
+               assert(c_segments[c_segno].c_segno > c_segments_available);
                lck_mtx_unlock_always(c_list_lock);
 
-               clock_get_system_nanotime(&sec, &nsec);
-               c_seg->c_creation_ts = (uint32_t)sec;
-
                *current_chead = c_seg;
 
-               KERNEL_DEBUG(0xe0400004 | DBG_FUNC_END, c_seg, 0, 0, 3, 0);
+#if DEVELOPMENT || DEBUG
+               C_SEG_MAKE_WRITEABLE(c_seg);
+#endif
+
        }
-       slotarray = C_SEG_SLOTARRAY_FROM_INDEX(c_seg, c_seg->c_nextslot);
+       c_seg_alloc_nextslot(c_seg);
 
-       if (c_seg->c_slots[slotarray] == 0) {
-               KERNEL_DEBUG(0xe0400008 | DBG_FUNC_START, 0, 0, 0, 0, 0);
+       size_to_populate = C_SEG_ALLOCSIZE - C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset);
+       
+       if (size_to_populate) {
+
+               min_needed = PAGE_SIZE + (C_SEG_ALLOCSIZE - C_SEG_BUFSIZE);
 
-               c_seg->c_slots[slotarray] = (struct c_slot *)kalloc(sizeof(struct c_slot) * C_SEG_SLOT_ARRAY_SIZE);
+               if (C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset - c_seg->c_nextoffset) < (unsigned) min_needed) {
 
-               KERNEL_DEBUG(0xe0400008 | DBG_FUNC_END, 0, 0, 0, 0, 0);
+                       if (size_to_populate > C_SEG_MAX_POPULATE_SIZE)
+                               size_to_populate = C_SEG_MAX_POPULATE_SIZE;
+                       vm_compressor_pages_grabbed += size_to_populate / PAGE_SIZE;
+
+                       kernel_memory_populate(compressor_map,
+                                              (vm_offset_t) &c_seg->c_store.c_buffer[c_seg->c_populated_offset],
+                                              size_to_populate,
+                                              KMA_COMPRESSOR,
+                                              VM_KERN_MEMORY_COMPRESSOR);
+               } else
+                       size_to_populate = 0;
        }
-               
        PAGE_REPLACEMENT_DISALLOWED(TRUE);
 
        lck_mtx_lock_spin_always(&c_seg->c_lock);
 
+       if (size_to_populate)
+               c_seg->c_populated_offset += C_SEG_BYTES_TO_OFFSET(size_to_populate);
+
        return (c_seg);
 }
 
 
-
 static void
 c_current_seg_filled(c_segment_t c_seg, c_segment_t *current_chead)
 {
        uint32_t        unused_bytes;
        uint32_t        offset_to_depopulate;
+       int             new_state = C_ON_AGE_Q;
+       clock_sec_t     sec;
+       clock_nsec_t    nsec;
 
        unused_bytes = trunc_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset - c_seg->c_nextoffset));
 
+#ifndef _OPEN_SOURCE
+       /* TODO: The HW codec can generate, lazily, a '2nd page not mapped'
+        * exception. So on such a platform, or platforms where we're confident
+        * the codec does not require a buffer page to absorb trailing writes,
+        * we can create an unmapped hole at the tail of the segment, rather
+        * than a populated mapping. This will also guarantee that the codec
+        * does not overwrite valid data past the edge of the segment and
+        * thus eliminate the depopulation overhead.
+        */
+#endif
        if (unused_bytes) {
-
                offset_to_depopulate = C_SEG_BYTES_TO_OFFSET(round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_nextoffset)));
 
                /*
@@ -2135,7 +2955,7 @@ c_current_seg_filled(c_segment_t c_seg, c_segment_t *current_chead)
                lck_mtx_unlock_always(&c_seg->c_lock);
 
                kernel_memory_depopulate(
-                       kernel_map,
+                       compressor_map,
                        (vm_offset_t) &c_seg->c_store.c_buffer[offset_to_depopulate],
                        unused_bytes,
                        KMA_COMPRESSOR);
@@ -2144,13 +2964,60 @@ c_current_seg_filled(c_segment_t c_seg, c_segment_t *current_chead)
 
                c_seg->c_populated_offset = offset_to_depopulate;
        }
-       c_seg->c_filling = 0;
+       assert(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset) <= C_SEG_BUFSIZE);
+
+#if DEVELOPMENT || DEBUG
+       {
+       boolean_t       c_seg_was_busy = FALSE;
 
-       if (C_SEG_UNUSED_BYTES(c_seg) >= PAGE_SIZE)
-               c_seg_need_delayed_compaction(c_seg);
+       if ( !c_seg->c_busy)
+               C_SEG_BUSY(c_seg);
+       else
+               c_seg_was_busy = TRUE;
 
        lck_mtx_unlock_always(&c_seg->c_lock);
 
+       C_SEG_WRITE_PROTECT(c_seg);
+
+       lck_mtx_lock_spin_always(&c_seg->c_lock);
+
+       if (c_seg_was_busy == FALSE)
+               C_SEG_WAKEUP_DONE(c_seg);
+       }
+#endif
+
+#if CONFIG_FREEZE
+       if (current_chead == (c_segment_t*)&freezer_chead &&
+           VM_CONFIG_SWAP_IS_PRESENT &&
+           VM_CONFIG_FREEZER_SWAP_IS_ACTIVE &&
+           c_freezer_swapout_count < VM_MAX_FREEZER_CSEG_SWAP_COUNT) {
+               new_state = C_ON_SWAPOUT_Q;
+       }
+#endif /* CONFIG_FREEZE */
+
+       clock_get_system_nanotime(&sec, &nsec);
+       c_seg->c_creation_ts = (uint32_t)sec;
+
+       lck_mtx_lock_spin_always(c_list_lock);
+
+       c_seg->c_generation_id = c_generation_id++;
+       c_seg_switch_state(c_seg, new_state, FALSE);
+
+#if CONFIG_FREEZE
+       if (c_seg->c_state == C_ON_SWAPOUT_Q)
+               c_freezer_swapout_count++;
+#endif /* CONFIG_FREEZE */
+
+       if (c_seg->c_state == C_ON_AGE_Q && C_SEG_UNUSED_BYTES(c_seg) >= PAGE_SIZE)
+               c_seg_need_delayed_compaction(c_seg, TRUE);
+
+       lck_mtx_unlock_always(c_list_lock);
+
+#if CONFIG_FREEZE
+       if (c_seg->c_state == C_ON_SWAPOUT_Q)
+               thread_wakeup((event_t)&c_swapout_list_head);
+#endif /* CONFIG_FREEZE */
+
        *current_chead = NULL;
 }
 
@@ -2159,7 +3026,7 @@ c_current_seg_filled(c_segment_t c_seg, c_segment_t *current_chead)
  * returns with c_seg locked
  */
 void
-c_seg_swapin_requeue(c_segment_t c_seg)
+c_seg_swapin_requeue(c_segment_t c_seg, boolean_t has_data, boolean_t minor_compact_ok, boolean_t age_on_swapin_q)
 {
         clock_sec_t    sec;
         clock_nsec_t   nsec;
@@ -2169,32 +3036,30 @@ c_seg_swapin_requeue(c_segment_t c_seg)
        lck_mtx_lock_spin_always(c_list_lock);
        lck_mtx_lock_spin_always(&c_seg->c_lock);
 
-       if (c_seg->c_on_swappedout_q) {
-               queue_remove(&c_swappedout_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedout_q = 0;
-               c_swappedout_count--;
+       assert(c_seg->c_busy_swapping);
+       assert(c_seg->c_busy);
+
+       c_seg->c_busy_swapping = 0;
+
+       if (c_seg->c_overage_swap == TRUE) {
+               c_overage_swapped_count--;
+               c_seg->c_overage_swap = FALSE;
+       }       
+       if (has_data == TRUE) {
+               if (age_on_swapin_q == TRUE)
+                       c_seg_switch_state(c_seg, C_ON_SWAPPEDIN_Q, FALSE);
+               else
+                       c_seg_switch_state(c_seg, C_ON_AGE_Q, FALSE);
+
+               if (minor_compact_ok == TRUE && !c_seg->c_on_minorcompact_q && C_SEG_UNUSED_BYTES(c_seg) >= PAGE_SIZE)
+                       c_seg_need_delayed_compaction(c_seg, TRUE);
        } else {
-               assert(c_seg->c_on_swappedout_sparse_q);
+               c_seg->c_store.c_buffer = (int32_t*) NULL;
+               c_seg->c_populated_offset = C_SEG_BYTES_TO_OFFSET(0);
 
-               queue_remove(&c_swappedout_sparse_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedout_sparse_q = 0;
-               c_swappedout_sparse_count--;
+               c_seg_switch_state(c_seg, C_ON_BAD_Q, FALSE);
        }
-       if (c_seg->c_store.c_buffer) {
-               queue_enter(&c_swappedin_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_swappedin_q = 1;
-               c_swappedin_count++;
-       }
-#if TRACK_BAD_C_SEGMENTS
-       else {
-               queue_enter(&c_bad_list_head, c_seg, c_segment_t, c_age_list);
-               c_seg->c_on_bad_q = 1;
-               c_bad_count++;
-       }
-#endif
        c_seg->c_swappedin_ts = (uint32_t)sec;
-       c_seg->c_ondisk = 0;
-       c_seg->c_was_swapped_in = 1;
 
        lck_mtx_unlock_always(c_list_lock);
 }
@@ -2202,94 +3067,211 @@ c_seg_swapin_requeue(c_segment_t c_seg)
 
 
 /*
- * c_seg has to be locked and is returned locked.
+ * c_seg has to be locked and is returned locked if the c_seg isn't freed
  * PAGE_REPLACMENT_DISALLOWED has to be TRUE on entry and is returned TRUE
+ * c_seg_swapin returns 1 if the c_seg was freed, 0 otherwise
  */
 
-void
-c_seg_swapin(c_segment_t c_seg, boolean_t force_minor_compaction)
+int
+c_seg_swapin(c_segment_t c_seg, boolean_t force_minor_compaction, boolean_t age_on_swapin_q)
 {
        vm_offset_t     addr = 0;
        uint32_t        io_size = 0;
        uint64_t        f_offset;
 
+       assert(C_SEG_IS_ONDISK(c_seg));
+       
 #if !CHECKSUM_THE_SWAP
-       if (c_seg->c_ondisk)
-               c_seg_trim_tail(c_seg);
+       c_seg_trim_tail(c_seg);
 #endif
        io_size = round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset));
        f_offset = c_seg->c_store.c_swap_handle;
-               
-       c_seg->c_busy = 1;
-       lck_mtx_unlock_always(&c_seg->c_lock);
-       
-       if (c_seg->c_ondisk) {
 
-               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+       C_SEG_BUSY(c_seg);
+       c_seg->c_busy_swapping = 1;
 
-               if (kernel_memory_allocate(kernel_map, &addr, C_SEG_ALLOCSIZE, 0, KMA_COMPRESSOR | KMA_VAONLY) != KERN_SUCCESS)
-                       panic("c_seg_swapin: kernel_memory_allocate failed\n");
+       /*
+        * This thread is likely going to block for I/O.
+        * Make sure it is ready to run when the I/O completes because
+        * it needs to clear the busy bit on the c_seg so that other
+        * waiting threads can make progress too. To do that, boost
+        * the rwlock_count so that the priority is boosted.
+        */
+       set_thread_rwlock_boost();
+       lck_mtx_unlock_always(&c_seg->c_lock);
 
-               kernel_memory_populate(kernel_map, addr, io_size, KMA_COMPRESSOR);
+       PAGE_REPLACEMENT_DISALLOWED(FALSE);
 
-               if (vm_swap_get(addr, f_offset, io_size) != KERN_SUCCESS) {
-                       PAGE_REPLACEMENT_DISALLOWED(TRUE);
+       addr = (vm_offset_t)C_SEG_BUFFER_ADDRESS(c_seg->c_mysegno);
+       c_seg->c_store.c_buffer = (int32_t*) addr;
 
-                       kernel_memory_depopulate(kernel_map, addr, io_size, KMA_COMPRESSOR);
-                       kmem_free(kernel_map, addr, C_SEG_ALLOCSIZE);
+       kernel_memory_populate(compressor_map, addr, io_size, KMA_COMPRESSOR, VM_KERN_MEMORY_COMPRESSOR);
 
-                       c_seg->c_store.c_buffer = (int32_t*) NULL;
-               } else {
-                       c_seg->c_store.c_buffer = (int32_t*) addr;
-#if CRYPTO
-                       vm_swap_decrypt(c_seg);
-#endif /* CRYPTO */
+       if (vm_swap_get(c_seg, f_offset, io_size) != KERN_SUCCESS) {
+               PAGE_REPLACEMENT_DISALLOWED(TRUE);
+
+               kernel_memory_depopulate(compressor_map, addr, io_size, KMA_COMPRESSOR);
+
+               c_seg_swapin_requeue(c_seg, FALSE, TRUE, age_on_swapin_q);
+       } else {
+#if ENCRYPTED_SWAP
+               vm_swap_decrypt(c_seg);
+#endif /* ENCRYPTED_SWAP */
 
 #if CHECKSUM_THE_SWAP
-                       if (c_seg->cseg_swap_size != io_size)
-                               panic("swapin size doesn't match swapout size");
+               if (c_seg->cseg_swap_size != io_size)
+                       panic("swapin size doesn't match swapout size");
 
-                       if (c_seg->cseg_hash != hash_string((char*) c_seg->c_store.c_buffer, (int)io_size)) {
-                               panic("c_seg_swapin - Swap hash mismatch\n");
-                       }
+               if (c_seg->cseg_hash != vmc_hash((char*) c_seg->c_store.c_buffer, (int)io_size)) {
+                       panic("c_seg_swapin - Swap hash mismatch\n");
+               }
 #endif /* CHECKSUM_THE_SWAP */
 
-                       PAGE_REPLACEMENT_DISALLOWED(TRUE);
+               PAGE_REPLACEMENT_DISALLOWED(TRUE);
 
-                       if (force_minor_compaction == TRUE) {
-                               lck_mtx_lock_spin_always(&c_seg->c_lock);
-                       
-                               c_seg_minor_compaction_and_unlock(c_seg, FALSE);
+               c_seg_swapin_requeue(c_seg, TRUE, force_minor_compaction == TRUE ? FALSE : TRUE, age_on_swapin_q);
+
+               OSAddAtomic64(c_seg->c_bytes_used, &compressor_bytes_used);
+
+               if (force_minor_compaction == TRUE) {
+                       if (c_seg_minor_compaction_and_unlock(c_seg, FALSE)) {
+                               /*
+                                * c_seg was completely empty so it was freed,
+                                * so be careful not to reference it again
+                                *
+                                * Drop the rwlock_count so that the thread priority
+                                * is returned back to where it is supposed to be.
+                                */
+                               clear_thread_rwlock_boost();
+                               return (1);
                        }
-                       OSAddAtomic64(c_seg->c_bytes_used, &compressor_bytes_used);
+
+                       lck_mtx_lock_spin_always(&c_seg->c_lock);
                }
        }
-       c_seg_swapin_requeue(c_seg);
-
        C_SEG_WAKEUP_DONE(c_seg);
+
+       /*
+        * Drop the rwlock_count so that the thread priority
+        * is returned back to where it is supposed to be.
+        */
+       clear_thread_rwlock_boost();
+
+       return (0);
+}
+
+
+static void
+c_segment_sv_hash_drop_ref(int hash_indx)
+{
+       struct c_sv_hash_entry o_sv_he, n_sv_he;
+
+       while (1) {
+
+               o_sv_he.he_record = c_segment_sv_hash_table[hash_indx].he_record;
+
+               n_sv_he.he_ref = o_sv_he.he_ref - 1;
+               n_sv_he.he_data = o_sv_he.he_data;
+
+               if (OSCompareAndSwap64((UInt64)o_sv_he.he_record, (UInt64)n_sv_he.he_record, (UInt64 *) &c_segment_sv_hash_table[hash_indx].he_record) == TRUE) {
+                       if (n_sv_he.he_ref == 0)
+                               OSAddAtomic(-1, &c_segment_svp_in_hash);
+                       break;
+               }
+       }
 }
 
 
+static int
+c_segment_sv_hash_insert(uint32_t data)
+{
+       int             hash_sindx;
+       int             misses;
+       struct c_sv_hash_entry o_sv_he, n_sv_he;
+       boolean_t       got_ref = FALSE;
+
+       if (data == 0)
+               OSAddAtomic(1, &c_segment_svp_zero_compressions);
+       else
+               OSAddAtomic(1, &c_segment_svp_nonzero_compressions);
+
+       hash_sindx = data & C_SV_HASH_MASK;
+       
+       for (misses = 0; misses < C_SV_HASH_MAX_MISS; misses++)
+       {
+               o_sv_he.he_record = c_segment_sv_hash_table[hash_sindx].he_record;
+
+               while (o_sv_he.he_data == data || o_sv_he.he_ref == 0) {
+                       n_sv_he.he_ref = o_sv_he.he_ref + 1;
+                       n_sv_he.he_data = data;
+
+                       if (OSCompareAndSwap64((UInt64)o_sv_he.he_record, (UInt64)n_sv_he.he_record, (UInt64 *) &c_segment_sv_hash_table[hash_sindx].he_record) == TRUE) {
+                               if (n_sv_he.he_ref == 1)
+                                       OSAddAtomic(1, &c_segment_svp_in_hash);
+                               got_ref = TRUE;
+                               break;
+                       }
+                       o_sv_he.he_record = c_segment_sv_hash_table[hash_sindx].he_record;
+               }
+               if (got_ref == TRUE)
+                       break;
+               hash_sindx++;
+
+               if (hash_sindx == C_SV_HASH_SIZE)
+                       hash_sindx = 0;
+       }
+       if (got_ref == FALSE)
+               return(-1);
+
+       return (hash_sindx);
+}
+
+
+#if RECORD_THE_COMPRESSED_DATA
+
+static void
+c_compressed_record_data(char *src, int c_size)
+{
+       if ((c_compressed_record_cptr + c_size + 4) >= c_compressed_record_ebuf)
+               panic("c_compressed_record_cptr >= c_compressed_record_ebuf");
+
+       *(int *)((void *)c_compressed_record_cptr) = c_size;
+
+       c_compressed_record_cptr += 4;
+
+       memcpy(c_compressed_record_cptr, src, c_size);
+       c_compressed_record_cptr += c_size;
+}
+#endif
+
+
 static int
 c_compress_page(char *src, c_slot_mapping_t slot_ptr, c_segment_t *current_chead, char *scratch_buf)
 {
        int             c_size;
-       int             c_rounded_size;
+       int             c_rounded_size = 0;
        int             max_csize;
        c_slot_t        cs;
        c_segment_t     c_seg;
 
        KERNEL_DEBUG(0xe0400000 | DBG_FUNC_START, *current_chead, 0, 0, 0, 0);
 retry:
-       if ((c_seg = c_seg_allocate(current_chead)) == NULL)
+       if ((c_seg = c_seg_allocate(current_chead)) == NULL) {
                return (1);
+       }
        /*
         * returns with c_seg lock held
-        * and PAGE_REPLACEMENT_DISALLOWED(TRUE)
+        * and PAGE_REPLACEMENT_DISALLOWED(TRUE)...
+        * c_nextslot has been allocated and
+        * c_store.c_buffer populated
         */
+       assert(c_seg->c_state == C_IS_FILLING);
+
        cs = C_SEG_SLOT_FROM_INDEX(c_seg, c_seg->c_nextslot);
 
        cs->c_packed_ptr = C_SLOT_PACK_PTR(slot_ptr);
+       assert(slot_ptr == (c_slot_mapping_t)C_SLOT_UNPACK_PTR(cs));
+
        cs->c_offset = c_seg->c_nextoffset;
 
        max_csize = C_SEG_BUFSIZE - C_SEG_OFFSET_TO_BYTES((int32_t)cs->c_offset);
@@ -2297,152 +3279,319 @@ retry:
        if (max_csize > PAGE_SIZE)
                max_csize = PAGE_SIZE;
 
-       if (C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset -
-                                 c_seg->c_nextoffset)
-           < (unsigned) max_csize + PAGE_SIZE &&
-           (C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset)
-            < C_SEG_ALLOCSIZE)) {
-               lck_mtx_unlock_always(&c_seg->c_lock);
-
-               kernel_memory_populate(kernel_map,
-                                      (vm_offset_t) &c_seg->c_store.c_buffer[c_seg->c_populated_offset],
-                                      PAGE_SIZE,
-                                      KMA_COMPRESSOR);
-
-               lck_mtx_lock_spin_always(&c_seg->c_lock);
-
-               c_seg->c_populated_offset += C_SEG_BYTES_TO_OFFSET(PAGE_SIZE);
-       }
-
 #if CHECKSUM_THE_DATA
-       cs->c_hash_data = hash_string(src, PAGE_SIZE);
+       cs->c_hash_data = vmc_hash(src, PAGE_SIZE);
 #endif
-       c_size = WKdm_compress_new((WK_word *)(uintptr_t)src, (WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
-                                  (WK_word *)(uintptr_t)scratch_buf, max_csize - 4);
-
-       assert(c_size <= (max_csize - 4) && c_size >= -1);
+       boolean_t incomp_copy = FALSE;
+       int max_csize_adj = (max_csize - 4);
+
+       if (vm_compressor_algorithm() != VM_COMPRESSOR_DEFAULT_CODEC) {
+#if defined(__arm__) || defined(__arm64__)
+               uint16_t ccodec = CINVALID;
+
+               if (max_csize >= C_SEG_OFFSET_ALIGNMENT_BOUNDARY) {
+                       c_size = metacompressor((const uint8_t *) src,
+                           (uint8_t *) &c_seg->c_store.c_buffer[cs->c_offset],
+                           max_csize_adj, &ccodec,
+                           scratch_buf, &incomp_copy);
+#if C_SEG_OFFSET_ALIGNMENT_BOUNDARY > 4
+                       if (c_size > max_csize_adj) {
+                               c_size = -1;
+                       }
+#endif
+               } else {
+                       c_size = -1;
+               }
+               assert(ccodec == CCWK || ccodec == CCLZ4);
+               cs->c_codec = ccodec;
+#endif
+       } else {
+#if defined(__arm__) || defined(__arm64__)
+       cs->c_codec = CCWK;
+#endif
+#if defined(__arm64__)
+       __unreachable_ok_push
+       if (PAGE_SIZE == 4096)
+               c_size = WKdm_compress_4k((WK_word *)(uintptr_t)src, (WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
+                                          (WK_word *)(uintptr_t)scratch_buf, max_csize_adj);
+       else {
+               c_size = WKdm_compress_16k((WK_word *)(uintptr_t)src, (WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
+                                          (WK_word *)(uintptr_t)scratch_buf, max_csize_adj);
+       }
+       __unreachable_ok_pop
+#else
+       c_size = WKdm_compress_new((const WK_word *)(uintptr_t)src, (WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
+                                 (WK_word *)(uintptr_t)scratch_buf, max_csize_adj);
+#endif
+       }
+       assertf(((c_size <= max_csize_adj) && (c_size >= -1)),
+           "c_size invalid (%d, %d), cur compressions: %d", c_size, max_csize_adj, c_segment_pages_compressed);
 
        if (c_size == -1) {
-
                if (max_csize < PAGE_SIZE) {
                        c_current_seg_filled(c_seg, current_chead);
+                       assert(*current_chead == NULL);
 
+                       lck_mtx_unlock_always(&c_seg->c_lock);
+                       /* TODO: it may be worth requiring codecs to distinguish
+                        * between incompressible inputs and failures due to
+                        * budget exhaustion.
+                        */
                        PAGE_REPLACEMENT_DISALLOWED(FALSE);
-
                        goto retry;
                }
                c_size = PAGE_SIZE;
 
+               if (incomp_copy == FALSE) {
+                       memcpy(&c_seg->c_store.c_buffer[cs->c_offset], src, c_size);
+               }
+
+               OSAddAtomic(1, &c_segment_noncompressible_pages);
+
+       } else if (c_size == 0) {
+               int             hash_index;
+
+               /*
+                * special case - this is a page completely full of a single 32 bit value
+                */
+               hash_index = c_segment_sv_hash_insert(*(uint32_t *)(uintptr_t)src);
+
+               if (hash_index != -1) {
+                       slot_ptr->s_cindx = hash_index;
+                       slot_ptr->s_cseg = C_SV_CSEG_ID;
+
+                       OSAddAtomic(1, &c_segment_svp_hash_succeeded);
+#if RECORD_THE_COMPRESSED_DATA
+                       c_compressed_record_data(src, 4);
+#endif
+                       goto sv_compression;
+               }
+               c_size = 4;
+               
                memcpy(&c_seg->c_store.c_buffer[cs->c_offset], src, c_size);
+
+               OSAddAtomic(1, &c_segment_svp_hash_failed);
        }
+
+#if RECORD_THE_COMPRESSED_DATA
+       c_compressed_record_data((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size);
+#endif
 #if CHECKSUM_THE_COMPRESSED_DATA
-       cs->c_hash_compressed_data = hash_string((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size);
+       cs->c_hash_compressed_data = vmc_hash((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size);
+#endif
+#if POPCOUNT_THE_COMPRESSED_DATA
+       cs->c_pop_cdata = vmc_pop((uintptr_t) &c_seg->c_store.c_buffer[cs->c_offset], c_size);
 #endif
        c_rounded_size = (c_size + C_SEG_OFFSET_ALIGNMENT_MASK) & ~C_SEG_OFFSET_ALIGNMENT_MASK;
 
        PACK_C_SIZE(cs, c_size);
        c_seg->c_bytes_used += c_rounded_size;
        c_seg->c_nextoffset += C_SEG_BYTES_TO_OFFSET(c_rounded_size);
+       c_seg->c_slots_used++;
 
        slot_ptr->s_cindx = c_seg->c_nextslot++;
        /* <csegno=0,indx=0> would mean "empty slot", so use csegno+1 */
        slot_ptr->s_cseg = c_seg->c_mysegno + 1; 
 
-       if (c_seg->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg->c_nextslot >= C_SLOT_MAX)
+sv_compression:
+       if (c_seg->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg->c_nextslot >= C_SLOT_MAX_INDEX) {
                c_current_seg_filled(c_seg, current_chead);
-       else
-               lck_mtx_unlock_always(&c_seg->c_lock);
+               assert(*current_chead == NULL);
+       }
+       lck_mtx_unlock_always(&c_seg->c_lock);
 
        PAGE_REPLACEMENT_DISALLOWED(FALSE);
 
-       OSAddAtomic64(c_rounded_size, &compressor_bytes_used);
+#if RECORD_THE_COMPRESSED_DATA
+       if ((c_compressed_record_cptr - c_compressed_record_sbuf) >= C_SEG_ALLOCSIZE) {
+               c_compressed_record_write(c_compressed_record_sbuf, (int)(c_compressed_record_cptr - c_compressed_record_sbuf));
+               c_compressed_record_cptr = c_compressed_record_sbuf;
+       }
+#endif
+       if (c_size) {
+               OSAddAtomic64(c_size, &c_segment_compressed_bytes);
+               OSAddAtomic64(c_rounded_size, &compressor_bytes_used);
+       }
        OSAddAtomic64(PAGE_SIZE, &c_segment_input_bytes);
-       OSAddAtomic64(c_size, &c_segment_compressed_bytes);
 
        OSAddAtomic(1, &c_segment_pages_compressed);
        OSAddAtomic(1, &sample_period_compression_count);
 
        KERNEL_DEBUG(0xe0400000 | DBG_FUNC_END, *current_chead, c_size, c_segment_input_bytes, c_segment_compressed_bytes, 0);
 
-       if (vm_compressor_low_on_space()) {
-               ipc_port_t      trigger = IP_NULL;
-
-               PSL_LOCK();
-               if (IP_VALID(min_pages_trigger_port)) {
-                       trigger = min_pages_trigger_port;
-                       min_pages_trigger_port = IP_NULL;
-               }
-               PSL_UNLOCK();
-
-               if (IP_VALID(trigger)) {
-                       no_paging_space_action();
-                       default_pager_space_alert(trigger, HI_WAT_ALERT);
-                       ipc_port_release_send(trigger);
-               }
-       }
        return (0);
 }
 
+static inline void sv_decompress(int32_t *ddst, int32_t pattern) {
+#if __x86_64__
+                       memset_word(ddst, pattern, PAGE_SIZE / sizeof(int32_t));
+#else
+                       size_t          i;
+
+                       /* Unroll the pattern fill loop 4x to encourage the
+                        * compiler to emit NEON stores, cf.
+                        * <rdar://problem/25839866> Loop autovectorization
+                        * anomalies.
+                        * We use separate loops for each PAGE_SIZE
+                        * to allow the autovectorizer to engage, as PAGE_SIZE
+                        * is currently not a constant.
+                        */
+
+                       __unreachable_ok_push
+                       if (PAGE_SIZE == 4096) {
+                               for (i = 0; i < (4096U / sizeof(int32_t)); i += 4) {
+                                       *ddst++ = pattern;
+                                       *ddst++ = pattern;
+                                       *ddst++ = pattern;
+                                       *ddst++ = pattern;
+                               }
+                       } else {
+                               assert(PAGE_SIZE == 16384);
+                               for (i = 0; i < (int)(16384U / sizeof(int32_t)); i += 4) {
+                                       *ddst++ = pattern;
+                                       *ddst++ = pattern;
+                                       *ddst++ = pattern;
+                                       *ddst++ = pattern;
+                               }
+                       }
+                       __unreachable_ok_pop
+#endif
+}
 
 static int
 c_decompress_page(char *dst, volatile c_slot_mapping_t slot_ptr, int flags, int *zeroslot)
 {
        c_slot_t        cs;
        c_segment_t     c_seg;
+       uint32_t        c_segno;
        int             c_indx;
        int             c_rounded_size;
        uint32_t        c_size;
        int             retval = 0;
-       boolean_t       c_seg_has_data = TRUE;
-       boolean_t       c_seg_swappedin = FALSE;
        boolean_t       need_unlock = TRUE;
        boolean_t       consider_defragmenting = FALSE;
+       boolean_t       kdp_mode = FALSE;
+
+       if (__improbable(flags & C_KDP)) {
+               if (not_in_kdp) {
+                       panic("C_KDP passed to decompress page from outside of debugger context");
+               }
+
+               assert((flags & C_KEEP) == C_KEEP);
+               assert((flags & C_DONT_BLOCK) == C_DONT_BLOCK);
+
+               if ((flags & (C_DONT_BLOCK | C_KEEP)) != (C_DONT_BLOCK | C_KEEP)) {
+                       return (-2);
+               }
+
+               kdp_mode = TRUE;
+               *zeroslot = 0;
+       }
 
 ReTry:
+       if (__probable(!kdp_mode)) {
+               PAGE_REPLACEMENT_DISALLOWED(TRUE);
+       } else {
+               if (kdp_lck_rw_lock_is_acquired_exclusive(&c_master_lock)) {
+                       return (-2);
+               }
+       }
+
 #if HIBERNATION
-       if (dst) {
-               if (lck_rw_try_lock_shared(&c_decompressor_lock) == 0) {
-                       if (flags & C_DONT_BLOCK) {
-                               *zeroslot = 0;
-                               return (-2);
+       /*
+        * if hibernation is enabled, it indicates (via a call
+        * to 'vm_decompressor_lock' that no further
+        * decompressions are allowed once it reaches
+        * the point of flushing all of the currently dirty
+        * anonymous memory through the compressor and out
+        * to disk... in this state we allow freeing of compressed
+        * pages and must honor the C_DONT_BLOCK case
+        */
+       if (__improbable(dst && decompressions_blocked == TRUE)) {
+               if (flags & C_DONT_BLOCK) {
+
+                       if (__probable(!kdp_mode)) {
+                               PAGE_REPLACEMENT_DISALLOWED(FALSE);
                        }
-                       lck_rw_lock_shared(&c_decompressor_lock);
+
+                       *zeroslot = 0;
+                       return (-2);
                }
+               /*
+                * it's safe to atomically assert and block behind the
+                * lock held in shared mode because "decompressions_blocked" is
+                * only set and cleared and the thread_wakeup done when the lock
+                * is held exclusively
+                */
+               assert_wait((event_t)&decompressions_blocked, THREAD_UNINT);
+
+               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+
+               thread_block(THREAD_CONTINUE_NULL);
+
+               goto ReTry;
        }
 #endif
-       PAGE_REPLACEMENT_DISALLOWED(TRUE);
-
        /* s_cseg is actually "segno+1" */
-       c_seg = c_segments[slot_ptr->s_cseg - 1].c_seg;
+       c_segno = slot_ptr->s_cseg - 1;
 
-       lck_mtx_lock_spin_always(&c_seg->c_lock);
+       if (__improbable(c_segno >= c_segments_available))
+               panic("c_decompress_page: c_segno %d >= c_segments_available %d, slot_ptr(%p), slot_data(%x)",
+                     c_segno, c_segments_available, slot_ptr, *(int *)((void *)slot_ptr));
 
-       if (flags & C_DONT_BLOCK) {
-               if (c_seg->c_busy || c_seg->c_ondisk) {
+       if (__improbable(c_segments[c_segno].c_segno < c_segments_available))
+               panic("c_decompress_page: c_segno %d is free, slot_ptr(%p), slot_data(%x)",
+                     c_segno, slot_ptr, *(int *)((void *)slot_ptr));
 
-                       retval = -2;
+       c_seg = c_segments[c_segno].c_seg;
+
+       if (__probable(!kdp_mode)) {
+               lck_mtx_lock_spin_always(&c_seg->c_lock);
+       } else {
+               if (kdp_lck_mtx_lock_spin_is_acquired(&c_seg->c_lock)) {
+                       return (-2);
+               }
+       }
+
+       assert(c_seg->c_state != C_IS_EMPTY && c_seg->c_state != C_IS_FREE);
+
+       if (dst == NULL && c_seg->c_busy_swapping) {
+               assert(c_seg->c_busy);
+
+               goto bypass_busy_check;
+       }
+       if (flags & C_DONT_BLOCK) {
+               if (c_seg->c_busy || (C_SEG_IS_ONDISK(c_seg) && dst)) {
                        *zeroslot = 0;
 
+                       retval = -2;
                        goto done;
                }
        }
        if (c_seg->c_busy) {
 
                PAGE_REPLACEMENT_DISALLOWED(FALSE);
-#if HIBERNATION
-               if (dst)
-                       lck_rw_done(&c_decompressor_lock);
-#endif
+
                c_seg_wait_on_busy(c_seg);
 
                goto ReTry;
        }
+bypass_busy_check:
+
        c_indx = slot_ptr->s_cindx;
 
+       if (__improbable(c_indx >= c_seg->c_nextslot))
+               panic("c_decompress_page: c_indx %d >= c_nextslot %d, c_seg(%p), slot_ptr(%p), slot_data(%x)",
+                     c_indx, c_seg->c_nextslot, c_seg, slot_ptr, *(int *)((void *)slot_ptr));
+
        cs = C_SEG_SLOT_FROM_INDEX(c_seg, c_indx);
 
        c_size = UNPACK_C_SIZE(cs);
 
+       if (__improbable(c_size == 0))
+               panic("c_decompress_page: c_size == 0, c_seg(%p), slot_ptr(%p), slot_data(%x)",
+                     c_seg, slot_ptr, *(int *)((void *)slot_ptr));
+
        c_rounded_size = (c_size + C_SEG_OFFSET_ALIGNMENT_MASK) & ~C_SEG_OFFSET_ALIGNMENT_MASK;
 
        if (dst) {
@@ -2450,53 +3599,111 @@ ReTry:
                clock_sec_t     cur_ts_sec;
                clock_nsec_t    cur_ts_nsec;
 
-               if (c_seg->c_on_swappedout_q || c_seg->c_on_swappedout_sparse_q) {
-                       if (c_seg->c_ondisk)
-                               c_seg_swappedin = TRUE;
-                       c_seg_swapin(c_seg, FALSE);
+               if (C_SEG_IS_ONDISK(c_seg)) {
+                       assert(kdp_mode == FALSE);
+                       retval = c_seg_swapin(c_seg, FALSE, TRUE);
+                       assert(retval == 0);
+
+                       retval = 1;
                }               
-               if (c_seg->c_store.c_buffer == NULL) {
-                       c_seg_has_data = FALSE;
-                       goto c_seg_invalid_data;
+               if (c_seg->c_state == C_ON_BAD_Q) {
+                       assert(c_seg->c_store.c_buffer == NULL);
+                       *zeroslot = 0;
+
+                       retval = -1;
+                       goto done;
                }
+
+#if POPCOUNT_THE_COMPRESSED_DATA
+               unsigned csvpop;
+               uintptr_t csvaddr = (uintptr_t) &c_seg->c_store.c_buffer[cs->c_offset];
+               if (cs->c_pop_cdata != (csvpop = vmc_pop(csvaddr, c_size))) {
+                       panic("Compressed data popcount doesn't match original, bit distance: %d %p (phys: %p) %p %p 0x%llx 0x%x 0x%x 0x%x", (csvpop - cs->c_pop_cdata), (void *)csvaddr, (void *) kvtophys(csvaddr), c_seg, cs, cs->c_offset, c_size, csvpop, cs->c_pop_cdata);
+               }
+#endif
+
 #if CHECKSUM_THE_COMPRESSED_DATA
-               if (cs->c_hash_compressed_data != hash_string((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size))
-                       panic("compressed data doesn't match original");
+               unsigned csvhash;
+               if (cs->c_hash_compressed_data != (csvhash = vmc_hash((char *)&c_seg->c_store.c_buffer[cs->c_offset], c_size))) {
+                       panic("Compressed data doesn't match original %p %p %u %u %u", c_seg, cs, c_size, cs->c_hash_compressed_data, csvhash);
+               }
 #endif
                if (c_rounded_size == PAGE_SIZE) {
                        /*
                         * page wasn't compressible... just copy it out
                         */
                        memcpy(dst, &c_seg->c_store.c_buffer[cs->c_offset], PAGE_SIZE);
+               } else if (c_size == 4) {
+                       int32_t         data;
+                       int32_t         *dptr;
+
+                       /*
+                        * page was populated with a single value
+                        * that didn't fit into our fast hash
+                        * so we packed it in as a single non-compressed value
+                        * that we need to populate the page with
+                        */
+                       dptr = (int32_t *)(uintptr_t)dst;
+                       data = *(int32_t *)(&c_seg->c_store.c_buffer[cs->c_offset]);
+                       sv_decompress(dptr, data);
                } else {
                        uint32_t        my_cpu_no;
                        char            *scratch_buf;
 
-                       /*
-                        * we're behind the c_seg lock held in spin mode
-                        * which means pre-emption is disabled... therefore
-                        * the following sequence is atomic and safe
-                        */
-                       my_cpu_no = cpu_number();
+                       if (__probable(!kdp_mode)) {
+                               /*
+                                * we're behind the c_seg lock held in spin mode
+                                * which means pre-emption is disabled... therefore
+                                * the following sequence is atomic and safe
+                                */
+                               my_cpu_no = cpu_number();
 
-                       assert(my_cpu_no < compressor_cpus);
+                               assert(my_cpu_no < compressor_cpus);
 
-                       scratch_buf = &compressor_scratch_bufs[my_cpu_no * WKdm_SCRATCH_BUF_SIZE];
+                               scratch_buf = &compressor_scratch_bufs[my_cpu_no * vm_compressor_get_decode_scratch_size()];
+                       } else {
+                               scratch_buf = kdp_compressor_scratch_buf;
+                       }
 
+                       if (vm_compressor_algorithm() != VM_COMPRESSOR_DEFAULT_CODEC) {
+#if defined(__arm__) || defined(__arm64__)
+                               uint16_t c_codec = cs->c_codec;
+                               metadecompressor((const uint8_t *) &c_seg->c_store.c_buffer[cs->c_offset],
+                                   (uint8_t *)dst, c_size, c_codec, (void *)scratch_buf);
+#endif
+                       } else {
+#if defined(__arm64__)
+                       __unreachable_ok_push
+                       if (PAGE_SIZE == 4096)
+                               WKdm_decompress_4k((WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
+                                                  (WK_word *)(uintptr_t)dst, (WK_word *)(uintptr_t)scratch_buf, c_size);
+                       else {
+                               WKdm_decompress_16k((WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
+                                                   (WK_word *)(uintptr_t)dst, (WK_word *)(uintptr_t)scratch_buf, c_size);
+                       }
+                       __unreachable_ok_pop
+#else
                        WKdm_decompress_new((WK_word *)(uintptr_t)&c_seg->c_store.c_buffer[cs->c_offset],
                                            (WK_word *)(uintptr_t)dst, (WK_word *)(uintptr_t)scratch_buf, c_size);
+#endif
+                       }
                }
 
 #if CHECKSUM_THE_DATA
-               if (cs->c_hash_data != hash_string(dst, PAGE_SIZE))
-                       panic("decompressed data doesn't match original");
+               if (cs->c_hash_data != vmc_hash(dst, PAGE_SIZE)) {
+#if    defined(__arm__) || defined(__arm64__)
+                       int32_t *dinput = &c_seg->c_store.c_buffer[cs->c_offset];
+                       panic("decompressed data doesn't match original cs: %p, hash: 0x%x, offset: %d, c_size: %d, c_rounded_size: %d, codec: %d, header: 0x%x 0x%x 0x%x", cs, cs->c_hash_data, cs->c_offset, c_size, c_rounded_size, cs->c_codec, *dinput, *(dinput + 1), *(dinput + 2));
+#else
+               panic("decompressed data doesn't match original cs: %p, hash: %d, offset: 0x%x, c_size: %d", cs, cs->c_hash_data, cs->c_offset, c_size);
 #endif
-               if (!c_seg->c_was_swapped_in) {
+               }
+#endif
+               if (c_seg->c_swappedin_ts == 0 && !kdp_mode) {
 
                        clock_get_system_nanotime(&cur_ts_sec, &cur_ts_nsec);
 
                        age_of_cseg = (uint32_t)cur_ts_sec - c_seg->c_creation_ts;
-
                        if (age_of_cseg < DECOMPRESSION_SAMPLE_MAX_AGE)
                                OSAddAtomic(1, &age_of_decompressions_during_sample_period[age_of_cseg]);
                        else
@@ -2504,26 +3711,19 @@ ReTry:
 
                        OSAddAtomic(1, &sample_period_decompression_count);
                }
-       } else {
-               if (c_seg->c_store.c_buffer == NULL)
-                       c_seg_has_data = FALSE;
        }
-c_seg_invalid_data:
-
-       if (c_seg_has_data == TRUE) {
-               if (c_seg_swappedin == TRUE)
-                       retval = 1;
-               else
-                       retval = 0;
-       } else
-               retval = -1;
-
        if (flags & C_KEEP) {
                *zeroslot = 0;
                goto done;
        }
+       assert(kdp_mode == FALSE);
+
        c_seg->c_bytes_unused += c_rounded_size;
        c_seg->c_bytes_used -= c_rounded_size;
+
+       assert(c_seg->c_slots_used);
+       c_seg->c_slots_used--;
+
        PACK_C_SIZE(cs, 0);
 
        if (c_indx < c_seg->c_firstemptyslot)
@@ -2531,55 +3731,79 @@ c_seg_invalid_data:
 
        OSAddAtomic(-1, &c_segment_pages_compressed);
 
-       if (c_seg_has_data == TRUE && !c_seg->c_ondisk) {
+       if (c_seg->c_state != C_ON_BAD_Q && !(C_SEG_IS_ONDISK(c_seg))) {
                /*
-                * c_ondisk == TRUE can occur when we're doing a
+                * C_SEG_IS_ONDISK == TRUE can occur when we're doing a
                 * free of a compressed page (i.e. dst == NULL)
                 */
                OSAddAtomic64(-c_rounded_size, &compressor_bytes_used);
        }
-       if (!c_seg->c_filling) {
+       if (c_seg->c_busy_swapping) {
+               /*
+                * bypass case for c_busy_swapping...
+                * let the swapin/swapout paths deal with putting
+                * the c_seg on the minor compaction queue if needed
+                */
+               assert(c_seg->c_busy);
+               goto done;
+       }
+       assert(!c_seg->c_busy);
+
+       if (c_seg->c_state != C_IS_FILLING) {
                if (c_seg->c_bytes_used == 0) {
-                       if (!c_seg->c_ondisk) {
+                       if ( !(C_SEG_IS_ONDISK(c_seg))) {
                                int     pages_populated;
 
                                pages_populated = (round_page_32(C_SEG_OFFSET_TO_BYTES(c_seg->c_populated_offset))) / PAGE_SIZE;
                                c_seg->c_populated_offset = C_SEG_BYTES_TO_OFFSET(0);
 
                                if (pages_populated) {
+
+                                       assert(c_seg->c_state != C_ON_BAD_Q);
                                        assert(c_seg->c_store.c_buffer != NULL);
 
-                                       c_seg->c_busy = 1;
+                                       C_SEG_BUSY(c_seg);
                                        lck_mtx_unlock_always(&c_seg->c_lock);
 
-                                       kernel_memory_depopulate(kernel_map, (vm_offset_t) c_seg->c_store.c_buffer, pages_populated * PAGE_SIZE, KMA_COMPRESSOR);
+                                       kernel_memory_depopulate(compressor_map, (vm_offset_t) c_seg->c_store.c_buffer, pages_populated * PAGE_SIZE, KMA_COMPRESSOR);
 
                                        lck_mtx_lock_spin_always(&c_seg->c_lock);
                                        C_SEG_WAKEUP_DONE(c_seg);
                                }
-                               if (!c_seg->c_on_minorcompact_q && !c_seg->c_on_swapout_q)
-                                       c_seg_need_delayed_compaction(c_seg);
-                       } else
-                               assert(c_seg->c_on_swappedout_sparse_q);
+                               if (!c_seg->c_on_minorcompact_q && c_seg->c_state != C_ON_SWAPOUT_Q)
+                                       c_seg_need_delayed_compaction(c_seg, FALSE);
+                       } else {
+                               if (c_seg->c_state != C_ON_SWAPPEDOUTSPARSE_Q) {
 
+                                       c_seg_move_to_sparse_list(c_seg);
+                                       consider_defragmenting = TRUE;
+                               }
+                       }
                } else if (c_seg->c_on_minorcompact_q) {
 
-                       if (C_SEG_INCORE_IS_SPARSE(c_seg)) {
+                       assert(c_seg->c_state != C_ON_BAD_Q);
+                       assert(!C_SEG_IS_ON_DISK_OR_SOQ(c_seg));
+
+                       if (C_SEG_SHOULD_MINORCOMPACT_NOW(c_seg)) {
                                c_seg_try_minor_compaction_and_unlock(c_seg);
                                need_unlock = FALSE;
                        }
-               } else if (!c_seg->c_ondisk) {
+               } else if ( !(C_SEG_IS_ONDISK(c_seg))) {
 
-                       if (c_seg_has_data == TRUE && !c_seg->c_on_swapout_q && C_SEG_UNUSED_BYTES(c_seg) >= PAGE_SIZE) {
-                               c_seg_need_delayed_compaction(c_seg);
+                       if (c_seg->c_state != C_ON_BAD_Q && c_seg->c_state != C_ON_SWAPOUT_Q && C_SEG_UNUSED_BYTES(c_seg) >= PAGE_SIZE) {
+                               c_seg_need_delayed_compaction(c_seg, FALSE);
                        }
-               } else if (!c_seg->c_on_swappedout_sparse_q && C_SEG_ONDISK_IS_SPARSE(c_seg)) {
+               } else if (c_seg->c_state != C_ON_SWAPPEDOUTSPARSE_Q && C_SEG_ONDISK_IS_SPARSE(c_seg)) {
 
                        c_seg_move_to_sparse_list(c_seg);
                        consider_defragmenting = TRUE;
                }
        }
 done:
+       if (__improbable(kdp_mode)) {
+               return retval;
+       }
+
        if (need_unlock == TRUE)
                lck_mtx_unlock_always(&c_seg->c_lock);
 
@@ -2587,10 +3811,12 @@ done:
 
        if (consider_defragmenting == TRUE)
                vm_swap_consider_defragmenting();
-#if HIBERNATION
-       if (dst)
-               lck_rw_done(&c_decompressor_lock);
+
+#if CONFIG_EMBEDDED
+       if ((c_minor_count && COMPRESSOR_NEEDS_TO_MINOR_COMPACT()) || vm_compressor_needs_to_major_compact())
+               vm_wake_compactor_swapper();
 #endif
+
        return (retval);
 }
 
@@ -2598,54 +3824,106 @@ done:
 int
 vm_compressor_get(ppnum_t pn, int *slot, int flags)
 {
+       c_slot_mapping_t  slot_ptr;
        char    *dst;
        int     zeroslot = 1;
        int     retval;
 
 #if __x86_64__
        dst = PHYSMAP_PTOV((uint64_t)pn << (uint64_t)PAGE_SHIFT);
+#elif __arm__ || __arm64__
+       dst = (char *) phystokv((pmap_paddr_t)pn << PAGE_SHIFT);
 #else
 #error "unsupported architecture"
 #endif
+       slot_ptr = (c_slot_mapping_t)slot;
+
+       if (slot_ptr->s_cseg == C_SV_CSEG_ID) {
+               int32_t         data;
+               int32_t         *dptr;
+
+               /*
+                * page was populated with a single value
+                * that found a home in our hash table
+                * grab that value from the hash and populate the page
+                * that we need to populate the page with
+                */
+               dptr = (int32_t *)(uintptr_t)dst;
+               data = c_segment_sv_hash_table[slot_ptr->s_cindx].he_data;
+#if __x86_64__
+               memset_word(dptr, data, PAGE_SIZE / sizeof(int32_t));
+#else
+               {
+               int             i;
+
+               for (i = 0; i < (int)(PAGE_SIZE / sizeof(int32_t)); i++)
+                       *dptr++ = data;
+               }
+#endif
+               if ( !(flags & C_KEEP)) {
+                       c_segment_sv_hash_drop_ref(slot_ptr->s_cindx);
+
+                       OSAddAtomic(-1, &c_segment_pages_compressed);
+                       *slot = 0;
+               }
+               if (data)
+                       OSAddAtomic(1, &c_segment_svp_nonzero_decompressions);
+               else
+                       OSAddAtomic(1, &c_segment_svp_zero_decompressions);
 
-       retval = c_decompress_page(dst, (c_slot_mapping_t)slot, flags, &zeroslot);
+               return (0);
+       }
+
+       retval = c_decompress_page(dst, slot_ptr, flags, &zeroslot);
 
        /*
         * zeroslot will be set to 0 by c_decompress_page if (flags & C_KEEP)
-        * or (flags & C_DONT_BLOCK) and we found 'c_busy' or 'c_ondisk' set
+        * or (flags & C_DONT_BLOCK) and we found 'c_busy' or 'C_SEG_IS_ONDISK' to be TRUE
         */
        if (zeroslot) {
-               /*
-                * We've just decompressed a page, and are about to hand that back to VM for
-                * re-entry into some pmap. This is a decompression operation which must have no
-                * impact on the pmap's physical footprint. However, when VM goes to re-enter
-                * this page into the pmap, it doesn't know that it came from the compressor,
-                * which means the pmap's physical footprint will be incremented. To compensate
-                * for that, we decrement the physical footprint here, so that the total net effect
-                * on the physical footprint statistic is zero.
-                */
-               pmap_ledger_debit(current_task()->map->pmap, task_ledgers.phys_footprint, PAGE_SIZE);
-
                *slot = 0;
        }
        /*
         * returns 0 if we successfully decompressed a page from a segment already in memory
         * returns 1 if we had to first swap in the segment, before successfully decompressing the page
         * returns -1 if we encountered an error swapping in the segment - decompression failed
-        * returns -2 if (flags & C_DONT_BLOCK) and we found 'c_busy' or 'c_ondisk' set
+        * returns -2 if (flags & C_DONT_BLOCK) and we found 'c_busy' or 'C_SEG_IS_ONDISK' to be true
         */
        return (retval);
 }
 
 
-void
-vm_compressor_free(int *slot)
+int
+vm_compressor_free(int *slot, int flags)
 {
+       c_slot_mapping_t  slot_ptr;
        int     zeroslot = 1;
+       int     retval;
+
+       assert(flags == 0 || flags == C_DONT_BLOCK);
+
+       slot_ptr = (c_slot_mapping_t)slot;
 
-       (void)c_decompress_page(NULL, (c_slot_mapping_t)slot, 0, &zeroslot);
+       if (slot_ptr->s_cseg == C_SV_CSEG_ID) {
 
-       *slot = 0;
+               c_segment_sv_hash_drop_ref(slot_ptr->s_cindx);
+               OSAddAtomic(-1, &c_segment_pages_compressed);
+
+               *slot = 0;
+               return (0);
+       }
+       retval = c_decompress_page(NULL, slot_ptr, flags, &zeroslot);
+       /*
+        * returns 0 if we successfully freed the specified compressed page
+        * returns -2 if (flags & C_DONT_BLOCK) and we found 'c_busy' set
+        */
+
+       if (retval == 0)
+               *slot = 0;
+       else
+               assert(retval == -2);
+
+       return (retval);
 }
 
 
@@ -2655,18 +3933,323 @@ vm_compressor_put(ppnum_t pn, int *slot, void  **current_chead, char *scratch_bu
        char    *src;
        int     retval;
 
-       if ((vm_offset_t)slot < VM_MIN_KERNEL_AND_KEXT_ADDRESS || (vm_offset_t)slot >= VM_MAX_KERNEL_ADDRESS)
-               panic("vm_compressor_put: slot 0x%llx address out of range [0x%llx:0x%llx]",
-                     (uint64_t)(vm_offset_t) slot,
-                     (uint64_t) VM_MIN_KERNEL_AND_KEXT_ADDRESS,
-                     (uint64_t) VM_MAX_KERNEL_ADDRESS);
-
 #if __x86_64__
        src = PHYSMAP_PTOV((uint64_t)pn << (uint64_t)PAGE_SHIFT);
+#elif __arm__ || __arm64__
+       src = (char *) phystokv((pmap_paddr_t)pn << PAGE_SHIFT);
 #else
 #error "unsupported architecture"
 #endif
+
        retval = c_compress_page(src, (c_slot_mapping_t)slot, (c_segment_t *)current_chead, scratch_buf);
 
        return (retval);
 }
+
+void
+vm_compressor_transfer(
+       int     *dst_slot_p,
+       int     *src_slot_p)
+{
+       c_slot_mapping_t        dst_slot, src_slot;
+       c_segment_t             c_seg;
+       int                     c_indx;
+       c_slot_t                cs;
+
+       src_slot = (c_slot_mapping_t) src_slot_p;
+
+       if (src_slot->s_cseg == C_SV_CSEG_ID) {
+               *dst_slot_p = *src_slot_p;
+               *src_slot_p = 0;
+               return;
+       }
+       dst_slot = (c_slot_mapping_t) dst_slot_p;
+Retry:
+       PAGE_REPLACEMENT_DISALLOWED(TRUE);
+       /* get segment for src_slot */
+       c_seg = c_segments[src_slot->s_cseg -1].c_seg;
+       /* lock segment */
+       lck_mtx_lock_spin_always(&c_seg->c_lock);
+       /* wait if it's busy */
+       if (c_seg->c_busy && !c_seg->c_busy_swapping) {
+               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+               c_seg_wait_on_busy(c_seg);
+               goto Retry;
+       }
+       /* find the c_slot */
+       c_indx = src_slot->s_cindx;
+       cs = C_SEG_SLOT_FROM_INDEX(c_seg, c_indx);
+       /* point the c_slot back to dst_slot instead of src_slot */
+       cs->c_packed_ptr = C_SLOT_PACK_PTR(dst_slot);
+       /* transfer */
+       *dst_slot_p = *src_slot_p;
+       *src_slot_p = 0;
+       lck_mtx_unlock_always(&c_seg->c_lock);
+       PAGE_REPLACEMENT_DISALLOWED(FALSE);
+}
+
+#if CONFIG_FREEZE
+
+int    freezer_finished_filling = 0;
+
+void
+vm_compressor_finished_filling(
+       void    **current_chead)
+{
+       c_segment_t     c_seg;
+
+       if ((c_seg = *(c_segment_t *)current_chead) == NULL)
+               return;
+
+       assert(c_seg->c_state == C_IS_FILLING);
+       
+       lck_mtx_lock_spin_always(&c_seg->c_lock);
+
+       c_current_seg_filled(c_seg, (c_segment_t *)current_chead);
+
+       lck_mtx_unlock_always(&c_seg->c_lock);
+
+       freezer_finished_filling++;
+}
+
+
+/*
+ * This routine is used to transfer the compressed chunks from
+ * the c_seg/cindx pointed to by slot_p into a new c_seg headed
+ * by the current_chead and a new cindx within that c_seg.
+ *
+ * Currently, this routine is only used by the "freezer backed by
+ * compressor with swap" mode to create a series of c_segs that
+ * only contain compressed data belonging to one task. So, we 
+ * move a task's previously compressed data into a set of new
+ * c_segs which will also hold the task's yet to be compressed data.
+ */
+
+kern_return_t
+vm_compressor_relocate(
+       void            **current_chead,
+       int             *slot_p)
+{
+       c_slot_mapping_t        slot_ptr;
+       c_slot_mapping_t        src_slot;
+       uint32_t                c_rounded_size;
+       uint32_t                c_size;
+       uint16_t                dst_slot;
+       c_slot_t                c_dst;
+       c_slot_t                c_src;
+       int                     c_indx;
+       c_segment_t             c_seg_dst = NULL;
+       c_segment_t             c_seg_src = NULL;
+       kern_return_t           kr = KERN_SUCCESS;
+
+
+       src_slot = (c_slot_mapping_t) slot_p;
+
+       if (src_slot->s_cseg == C_SV_CSEG_ID) {
+               /*
+                * no need to relocate... this is a page full of a single
+                * value which is hashed to a single entry not contained
+                * in a c_segment_t
+                */
+               return (kr);
+       }
+
+Relookup_dst:
+       c_seg_dst = c_seg_allocate((c_segment_t *)current_chead);
+       /*
+        * returns with c_seg lock held
+        * and PAGE_REPLACEMENT_DISALLOWED(TRUE)...
+        * c_nextslot has been allocated and
+        * c_store.c_buffer populated
+        */
+       if (c_seg_dst == NULL) {
+               /*
+                * Out of compression segments?
+                */
+               kr = KERN_RESOURCE_SHORTAGE;
+               goto out;
+       }
+
+       assert(c_seg_dst->c_busy == 0);
+
+       C_SEG_BUSY(c_seg_dst);
+
+       dst_slot = c_seg_dst->c_nextslot;
+       
+       lck_mtx_unlock_always(&c_seg_dst->c_lock);
+
+Relookup_src:
+       c_seg_src = c_segments[src_slot->s_cseg - 1].c_seg;
+
+       assert(c_seg_dst != c_seg_src);
+
+       lck_mtx_lock_spin_always(&c_seg_src->c_lock);
+
+       if (C_SEG_IS_ONDISK(c_seg_src)) {
+       
+               /*
+                * A "thaw" can mark a process as eligible for
+                * another freeze cycle without bringing any of
+                * its swapped out c_segs back from disk (because
+                * that is done on-demand).
+                *
+                * If the src c_seg we find for our pre-compressed
+                * data is already on-disk, then we are dealing
+                * with an app's data that is already packed and
+                * swapped out. Don't do anything.
+                */
+               
+               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+
+               lck_mtx_unlock_always(&c_seg_src->c_lock);
+
+               c_seg_src = NULL;
+
+               goto out;
+       }
+
+       if (c_seg_src->c_busy) {
+
+               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+               c_seg_wait_on_busy(c_seg_src);
+                       
+               c_seg_src = NULL;
+
+               PAGE_REPLACEMENT_DISALLOWED(TRUE);
+
+               goto Relookup_src;
+       }
+
+       C_SEG_BUSY(c_seg_src);
+
+       lck_mtx_unlock_always(&c_seg_src->c_lock);
+       
+       PAGE_REPLACEMENT_DISALLOWED(FALSE);
+
+       /* find the c_slot */
+       c_indx = src_slot->s_cindx;
+
+       c_src = C_SEG_SLOT_FROM_INDEX(c_seg_src, c_indx);
+
+       c_size = UNPACK_C_SIZE(c_src);
+
+       assert(c_size);
+
+       if (c_size > (uint32_t)(C_SEG_BUFSIZE - C_SEG_OFFSET_TO_BYTES((int32_t)c_seg_dst->c_nextoffset))) {
+               /*
+                * This segment is full. We need a new one.
+                */
+
+               PAGE_REPLACEMENT_DISALLOWED(TRUE);
+       
+               lck_mtx_lock_spin_always(&c_seg_src->c_lock);
+               C_SEG_WAKEUP_DONE(c_seg_src);
+               lck_mtx_unlock_always(&c_seg_src->c_lock);
+
+               c_seg_src = NULL;
+
+               lck_mtx_lock_spin_always(&c_seg_dst->c_lock);
+
+               assert(c_seg_dst->c_busy);
+               assert(c_seg_dst->c_state == C_IS_FILLING);
+               assert(!c_seg_dst->c_on_minorcompact_q);
+
+               c_current_seg_filled(c_seg_dst, (c_segment_t *)current_chead);
+               assert(*current_chead == NULL);
+       
+               C_SEG_WAKEUP_DONE(c_seg_dst);
+       
+               lck_mtx_unlock_always(&c_seg_dst->c_lock);
+
+               c_seg_dst = NULL;
+
+               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+
+               goto Relookup_dst;
+       }
+
+       c_dst = C_SEG_SLOT_FROM_INDEX(c_seg_dst, c_seg_dst->c_nextslot);
+
+       memcpy(&c_seg_dst->c_store.c_buffer[c_seg_dst->c_nextoffset], &c_seg_src->c_store.c_buffer[c_src->c_offset], c_size);
+//is platform alignment actually necessary since wkdm aligns its output?
+       c_rounded_size = (c_size + C_SEG_OFFSET_ALIGNMENT_MASK) & ~C_SEG_OFFSET_ALIGNMENT_MASK;
+
+       cslot_copy(c_dst, c_src);
+       c_dst->c_offset = c_seg_dst->c_nextoffset;
+
+       if (c_seg_dst->c_firstemptyslot == c_seg_dst->c_nextslot)
+               c_seg_dst->c_firstemptyslot++;
+
+       c_seg_dst->c_slots_used++;
+       c_seg_dst->c_nextslot++;
+       c_seg_dst->c_bytes_used += c_rounded_size;
+       c_seg_dst->c_nextoffset += C_SEG_BYTES_TO_OFFSET(c_rounded_size);
+               
+
+       PACK_C_SIZE(c_src, 0);
+
+       c_seg_src->c_bytes_used -= c_rounded_size;
+       c_seg_src->c_bytes_unused += c_rounded_size;
+
+       assert(c_seg_src->c_slots_used);
+       c_seg_src->c_slots_used--;
+       
+       if (c_indx < c_seg_src->c_firstemptyslot) {
+               c_seg_src->c_firstemptyslot = c_indx;
+       }
+
+       c_dst = C_SEG_SLOT_FROM_INDEX(c_seg_dst, dst_slot);
+               
+       PAGE_REPLACEMENT_ALLOWED(TRUE);
+       slot_ptr = (c_slot_mapping_t)C_SLOT_UNPACK_PTR(c_dst);
+       /* <csegno=0,indx=0> would mean "empty slot", so use csegno+1 */
+       slot_ptr->s_cseg = c_seg_dst->c_mysegno + 1;
+       slot_ptr->s_cindx = dst_slot;
+
+       PAGE_REPLACEMENT_ALLOWED(FALSE);
+
+out:
+       if (c_seg_src) {
+
+               lck_mtx_lock_spin_always(&c_seg_src->c_lock);
+
+               C_SEG_WAKEUP_DONE(c_seg_src);
+
+               if (c_seg_src->c_bytes_used == 0 && c_seg_src->c_state != C_IS_FILLING) {
+                       if (!c_seg_src->c_on_minorcompact_q)
+                               c_seg_need_delayed_compaction(c_seg_src, FALSE);
+               }
+
+               lck_mtx_unlock_always(&c_seg_src->c_lock);
+       }
+       
+       if (c_seg_dst) {
+
+               PAGE_REPLACEMENT_DISALLOWED(TRUE);
+
+               lck_mtx_lock_spin_always(&c_seg_dst->c_lock);
+
+               if (c_seg_dst->c_nextoffset >= C_SEG_OFF_LIMIT || c_seg_dst->c_nextslot >= C_SLOT_MAX_INDEX) {
+                       /*
+                        * Nearing or exceeded maximum slot and offset capacity.
+                        */
+                       assert(c_seg_dst->c_busy);
+                       assert(c_seg_dst->c_state == C_IS_FILLING);
+                       assert(!c_seg_dst->c_on_minorcompact_q);
+
+                       c_current_seg_filled(c_seg_dst, (c_segment_t *)current_chead);
+                       assert(*current_chead == NULL);
+               }  
+               
+               C_SEG_WAKEUP_DONE(c_seg_dst);
+
+               lck_mtx_unlock_always(&c_seg_dst->c_lock);
+
+               c_seg_dst = NULL;
+
+               PAGE_REPLACEMENT_DISALLOWED(FALSE);
+       }
+
+       return kr;
+}
+#endif /* CONFIG_FREEZE */