osfmk/vm/vm_purgeable_internal.h

   1 /*
   2  * Copyright (c) 2007 Apple Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  * Purgeable spelling rules
  26  * It is believed that the correct spelling is
  27  * { 'p', 'u', 'r', 'g', 'e', 'a', 'b', 'l', 'e' }.
  28  * However, there is one published API that likes to spell it without the
  29  * first 'e', vm_purgable_control(). Since we can't change that API,
  30  * here are the rules.
  31  * All qualifiers defined in vm_purgable.h are spelled without the e.
  32  * All other qualifiers are spelled with the e.
  33  * Right now, there are remains of the wrong spelling throughout the code,
  34  * vm_object_t.purgable for example. We expect to change these on occasion.
  35  */
  36
  37 #ifndef __VM_PURGEABLE_INTERNAL__
  38 #define __VM_PURGEABLE_INTERNAL__
  39
  40 #include <kern/queue.h>
  41
  42 enum purgeable_q_type {
  43         PURGEABLE_Q_TYPE_OBSOLETE,
  44         PURGEABLE_Q_TYPE_FIFO,
  45         PURGEABLE_Q_TYPE_LIFO,
  46         PURGEABLE_Q_TYPE_MAX
  47 };
  48
  49 #if (CONFIG_TOKEN_QUEUE_SMALL == 1)
  50 typedef uint16_t token_idx_t;
  51 typedef uint16_t token_cnt_t;
  52 #define TOKEN_COUNT_MAX UINT16_MAX
  53 #else
  54 typedef uint32_t token_idx_t;
  55 typedef uint32_t token_cnt_t;
  56 #define TOKEN_COUNT_MAX UINT32_MAX
  57 #endif
  58
  59 #define NUM_VOLATILE_GROUPS 8
  60 struct purgeable_q {
  61         token_idx_t token_q_head;    /* first token */
  62         token_idx_t token_q_tail;    /* last token  */
  63         token_idx_t token_q_unripe;  /* first token which is not ripe */
  64         int32_t new_pages;
  65         queue_head_t objq[NUM_VOLATILE_GROUPS];
  66         enum purgeable_q_type type;
  67 #if MACH_ASSERT
  68         int debug_count_tokens;
  69         int debug_count_objects;
  70 #endif
  71 };
  72
  73 typedef struct purgeable_q * purgeable_q_t;
  74
  75 extern struct purgeable_q purgeable_queues[PURGEABLE_Q_TYPE_MAX];
  76 extern int32_t token_new_pagecount;
  77 #define TOKEN_NEW_PAGECOUNT_MAX INT32_MAX
  78 extern int available_for_purge;
  79
  80
  81 /*
  82  * Locking:
  83  * the token counters are protected by the vm_page_queue_lock, since they're
  84  * mostly used in that context and we don't want to do a lot of extra locking
  85  * the purgeable page queues are protected by a separate lock since they're
  86  * mostly used on a user context and we don't want any contention with the
  87  * pageout daemon.
  88  */
  89 decl_lck_mtx_data(extern,vm_purgeable_queue_lock)
  90
  91 /* add a new token to queue. called by vm_object_purgeable_control */
  92 /* enter with page queue locked */
  93 kern_return_t vm_purgeable_token_add(purgeable_q_t queue);
  94
  95 /* enter with page queue locked */
  96 void vm_purgeable_token_delete_first(purgeable_q_t queue);
  97
  98 /*
  99  * decrement token counters.
 100  * enter with page queue locked
 101  */
 102 void vm_purgeable_q_advance_all(void);
 103
 104 /* the object purger. purges the next eligible object from memory. */
 105 /* returns TRUE if an object was purged, otherwise FALSE. */
 106 boolean_t vm_purgeable_object_purge_one(void);
 107
 108 /* purge all volatile objects now */
 109 void vm_purgeable_object_purge_all(void);
 110
 111 /* insert purgeable object into queue */
 112 void vm_purgeable_object_add(vm_object_t object, purgeable_q_t queue, int group);
 113
 114 /* look for object. If found, remove from purgeable queue. */
 115 purgeable_q_t vm_purgeable_object_remove(vm_object_t object);
 116
 117 #endif /* __VM_PURGEABLE_INTERNAL__ */