migration/page_cache.h

   1 /*
   2  * Page cache for QEMU
   3  * The cache is base on a hash of the page address
   4  *
   5  * Copyright 2012 Red Hat, Inc. and/or its affiliates
   6  *
   7  * Authors:
   8  *  Orit Wasserman  <owasserm@redhat.com>
   9  *
  10  * This work is licensed under the terms of the GNU GPL, version 2 or later.
  11  * See the COPYING file in the top-level directory.
  12  *
  13  */
  14
  15 #ifndef PAGE_CACHE_H
  16 #define PAGE_CACHE_H
  17
  18 /* Page cache for storing guest pages */
  19 typedef struct PageCache PageCache;
  20
  21 /**
  22  * cache_init: Initialize the page cache
  23  *
  24  *
  25  * Returns new allocated cache or NULL on error
  26  *
  27  * @cache_size: cache size in bytes
  28  * @page_size: cache page size
  29  * @errp: set *errp if the check failed, with reason
  30  */
  31 PageCache *cache_init(int64_t cache_size, size_t page_size, Error **errp);
  32 /**
  33  * cache_fini: free all cache resources
  34  * @cache pointer to the PageCache struct
  35  */
  36 void cache_fini(PageCache *cache);
  37
  38 /**
  39  * cache_is_cached: Checks to see if the page is cached
  40  *
  41  * Returns %true if page is cached
  42  *
  43  * @cache pointer to the PageCache struct
  44  * @addr: page addr
  45  * @current_age: current bitmap generation
  46  */
  47 bool cache_is_cached(const PageCache *cache, uint64_t addr,
  48                      uint64_t current_age);
  49
  50 /**
  51  * get_cached_data: Get the data cached for an addr
  52  *
  53  * Returns pointer to the data cached or NULL if not cached
  54  *
  55  * @cache pointer to the PageCache struct
  56  * @addr: page addr
  57  */
  58 uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
  59
  60 /**
  61  * cache_insert: insert the page into the cache. the page cache
  62  * will dup the data on insert. the previous value will be overwritten
  63  *
  64  * Returns -1 when the page isn't inserted into cache
  65  *
  66  * @cache pointer to the PageCache struct
  67  * @addr: page address
  68  * @pdata: pointer to the page
  69  * @current_age: current bitmap generation
  70  */
  71 int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
  72                  uint64_t current_age);
  73
  74 #endif