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authorOrit Wasserman <owasserm@redhat.com>2012-08-06 21:42:50 +0300
committerJuan Quintela <quintela@redhat.com>2012-08-08 13:51:12 +0200
commit9fb26641ab497eda9138f9af75cbeb02ed59b5ae (patch)
treead4374600d582b27542fc8677048aa3f17f156ed /include
parent34c26412b76840e0cab9808047e29aebd429c139 (diff)
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Add cache handling functions
Add MRU page cache mechanism. The page are accessed by their address. Signed-off-by: Benoit Hudzia <benoit.hudzia@sap.com> Signed-off-by: Petter Svard <petters@cs.umu.se> Signed-off-by: Aidan Shribman <aidan.shribman@sap.com> Signed-off-by: Orit Wasserman <owasserm@redhat.com> Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com> Reviewed-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/qemu/page_cache.h79
1 files changed, 79 insertions, 0 deletions
diff --git a/include/qemu/page_cache.h b/include/qemu/page_cache.h
new file mode 100644
index 0000000..3839ac7
--- /dev/null
+++ b/include/qemu/page_cache.h
@@ -0,0 +1,79 @@
+/*
+ * 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
+ */
+bool cache_is_cached(const PageCache *cache, uint64_t addr);
+
+/**
+ * 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 previous value will be overwritten
+ *
+ * @cache pointer to the PageCache struct
+ * @addr: page address
+ * @pdata: pointer to the page
+ */
+void cache_insert(PageCache *cache, uint64_t addr, uint8_t *pdata);
+
+/**
+ * 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