qemu-e2k/include/migration/page_cache.h

87 lines
2.2 KiB
C

/*
* Page cache for QEMU
* The cache is base on a hash of the page address
*
* Copyright 2012 Red Hat, Inc. and/or its affiliates
*
* Authors:
* Orit Wasserman <owasserm@redhat.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
*/
#ifndef PAGE_CACHE_H
#define PAGE_CACHE_H
/* Page cache for storing guest pages */
typedef struct PageCache PageCache;
/**
* cache_init: Initialize the page cache
*
*
* Returns new allocated cache or NULL on error
*
* @cache pointer to the PageCache struct
* @num_pages: cache maximal number of cached pages
* @page_size: cache page size
*/
PageCache *cache_init(int64_t num_pages, unsigned int page_size);
/**
* cache_fini: free all cache resources
* @cache pointer to the PageCache struct
*/
void cache_fini(PageCache *cache);
/**
* cache_is_cached: Checks to see if the page is cached
*
* Returns %true if page is cached
*
* @cache pointer to the PageCache struct
* @addr: page addr
* @current_age: current bitmap generation
*/
bool cache_is_cached(const PageCache *cache, uint64_t addr,
uint64_t current_age);
/**
* get_cached_data: Get the data cached for an addr
*
* Returns pointer to the data cached or NULL if not cached
*
* @cache pointer to the PageCache struct
* @addr: page addr
*/
uint8_t *get_cached_data(const PageCache *cache, uint64_t addr);
/**
* cache_insert: insert the page into the cache. the page cache
* will dup the data on insert. the previous value will be overwritten
*
* Returns -1 when the page isn't inserted into cache
*
* @cache pointer to the PageCache struct
* @addr: page address
* @pdata: pointer to the page
* @current_age: current bitmap generation
*/
int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
uint64_t current_age);
/**
* cache_resize: resize the page cache. In case of size reduction the extra
* pages will be freed
*
* Returns -1 on error new cache size on success
*
* @cache pointer to the PageCache struct
* @num_pages: new page cache size (in pages)
*/
int64_t cache_resize(PageCache *cache, int64_t num_pages);
#endif