LXR qemu/include/migration/page

   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 */
  19typedef 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 pointer to the PageCache struct
  28 * @num_pages: cache maximal number of cached pages
  29 * @page_size: cache page size
  30 */
  31PageCache *cache_init(int64_t num_pages, unsigned int page_size);
  32
  33/**
  34 * cache_fini: free all cache resources
  35 * @cache pointer to the PageCache struct
  36 */
  37void cache_fini(PageCache *cache);
  38
  39/**
  40 * cache_is_cached: Checks to see if the page is cached
  41 *
  42 * Returns %true if page is cached
  43 *
  44 * @cache pointer to the PageCache struct
  45 * @addr: page addr
  46 * @current_age: current bitmap generation
  47 */
  48bool cache_is_cached(const PageCache *cache, uint64_t addr,
  49                     uint64_t current_age);
  50
  51/**
  52 * get_cached_data: Get the data cached for an addr
  53 *
  54 * Returns pointer to the data cached or NULL if not cached
  55 *
  56 * @cache pointer to the PageCache struct
  57 * @addr: page addr
  58 */
  59uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
  60
  61/**
  62 * cache_insert: insert the page into the cache. the page cache
  63 * will dup the data on insert. the previous value will be overwritten
  64 *
  65 * Returns -1 when the page isn't inserted into cache
  66 *
  67 * @cache pointer to the PageCache struct
  68 * @addr: page address
  69 * @pdata: pointer to the page
  70 * @current_age: current bitmap generation
  71 */
  72int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
  73                 uint64_t current_age);
  74
  75/**
  76 * cache_resize: resize the page cache. In case of size reduction the extra
  77 * pages will be freed
  78 *
  79 * Returns -1 on error new cache size on success
  80 *
  81 * @cache pointer to the PageCache struct
  82 * @num_pages: new page cache size (in pages)
  83 */
  84int64_t cache_resize(PageCache *cache, int64_t num_pages);
  85
  86#endif
  87