sd.c: Handle NULL block backend in sd_get_inserted()

[qemu.git] / page_cache.c

diff --git a/page_cache.c b/page_cache.c
index 89bb1ec3a02183afb7eb011100b0c32ded55125f..cb8a69e964d74c8f847a94268e61dcb03511cec2 100644 (file)
--- a/page_cache.c
+++ b/page_cache.c
@@ -12,14 +12,7 @@
  *
  */
 
-#include <stdint.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <strings.h>
-#include <string.h>
-#include <sys/time.h>
-#include <sys/types.h>
-#include <stdbool.h>
+#include "qemu/osdep.h"
 #include <glib.h>
 
 #include "qemu-common.h"
@@ -33,6 +26,9 @@
     do { } while (0)
 #endif
 
+/* the page in cache will not be replaced in two cycles */
+#define CACHED_PAGE_LIFETIME 2
+
 typedef struct CacheItem CacheItem;
 
 struct CacheItem {
@@ -122,18 +118,6 @@ static size_t cache_get_cache_pos(const PageCache *cache,
     return pos;
 }
 
-bool cache_is_cached(const PageCache *cache, uint64_t addr)
-{
-    size_t pos;
-
-    g_assert(cache);
-    g_assert(cache->page_cache);
-
-    pos = cache_get_cache_pos(cache, addr);
-
-    return (cache->page_cache[pos].it_addr == addr);
-}
-
 static CacheItem *cache_get_by_addr(const PageCache *cache, uint64_t addr)
 {
     size_t pos;
@@ -151,17 +135,35 @@ uint8_t *get_cached_data(const PageCache *cache, uint64_t addr)
     return cache_get_by_addr(cache, addr)->it_data;
 }
 
-int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata)
+bool cache_is_cached(const PageCache *cache, uint64_t addr,
+                     uint64_t current_age)
 {
+    CacheItem *it;
 
-    CacheItem *it = NULL;
+    it = cache_get_by_addr(cache, addr);
 
-    g_assert(cache);
-    g_assert(cache->page_cache);
+    if (it->it_addr == addr) {
+        /* update the it_age when the cache hit */
+        it->it_age = current_age;
+        return true;
+    }
+    return false;
+}
+
+int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata,
+                 uint64_t current_age)
+{
+
+    CacheItem *it;
 
     /* actual update of entry */
     it = cache_get_by_addr(cache, addr);
 
+    if (it->it_data && it->it_addr != addr &&
+        it->it_age + CACHED_PAGE_LIFETIME > current_age) {
+        /* the cache page is fresh, don't replace it */
+        return -1;
+    }
     /* allocate page */
     if (!it->it_data) {
         it->it_data = g_try_malloc(cache->page_size);
@@ -174,7 +176,7 @@ int cache_insert(PageCache *cache, uint64_t addr, const uint8_t *pdata)
 
     memcpy(it->it_data, pdata, cache->page_size);
 
-    it->it_age = ++cache->max_item_age;
+    it->it_age = current_age;
     it->it_addr = addr;
 
     return 0;