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authorMax Reitz <mreitz@redhat.com>2014-08-18 22:07:31 +0200
committerKevin Wolf <kwolf@redhat.com>2014-08-20 11:51:28 +0200
commit440ba08aea3d841996efaf6a6b88426b0d59abf4 (patch)
tree43d6edcbbb02d93890e70c2ae3025ce320db7a99 /block/qcow2.h
parent18a7d0c56e1377f3d5fa1dc4d78a15dbab01cd83 (diff)
downloadqemu-440ba08aea3d841996efaf6a6b88426b0d59abf4.tar.gz
qcow2: Constant cache size in bytes
Specifying the metadata cache sizes in clusters results in less clusters (and much less bytes) covered for small cluster sizes and vice versa. Using a constant byte size reduces this difference, and makes it possible to manually specify the cache size in an easily comprehensible unit. Signed-off-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2.h')
-rw-r--r--block/qcow2.h10
1 files changed, 8 insertions, 2 deletions
diff --git a/block/qcow2.h b/block/qcow2.h
index b49424b85e..671783defe 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -64,10 +64,16 @@
#define MIN_CLUSTER_BITS 9
#define MAX_CLUSTER_BITS 21
-#define L2_CACHE_SIZE 16
+#define MIN_L2_CACHE_SIZE 1 /* cluster */
/* Must be at least 4 to cover all cases of refcount table growth */
-#define REFCOUNT_CACHE_SIZE 4
+#define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */
+
+#define DEFAULT_L2_CACHE_BYTE_SIZE 1048576 /* bytes */
+
+/* The refblock cache needs only a fourth of the L2 cache size to cover as many
+ * clusters */
+#define DEFAULT_L2_REFCOUNT_SIZE_RATIO 4
#define DEFAULT_CLUSTER_SIZE 65536