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Diffstat (limited to 'qemu/include/migration/page_cache.h')
-rw-r--r-- | qemu/include/migration/page_cache.h | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/qemu/include/migration/page_cache.h b/qemu/include/migration/page_cache.h new file mode 100644 index 000000000..10ed53274 --- /dev/null +++ b/qemu/include/migration/page_cache.h @@ -0,0 +1,86 @@ +/* + * 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 |