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authorAlberto Garcia <berto@igalia.com>2015-08-04 15:14:40 +0300
committerMax Reitz <mreitz@redhat.com>2015-09-04 21:00:32 +0200
commit279621c046ce57de0af9e3c00663b48d3a7835ae (patch)
treee14d8ab78e7bfcddf42b763a120cc8d116d38430 /block/qcow2.h
parent355ee2d0e8ca536a6278c9c763ddd2f136eace3f (diff)
qcow2: add option to clean unused cache entries after some time
This adds a new 'cache-clean-interval' option that cleans all qcow2 cache entries that haven't been used in a certain interval, given in seconds. This allows setting a large L2 cache size so it can handle scenarios with lots of I/O and at the same time use little memory during periods of inactivity. This feature currently relies on MADV_DONTNEED to free that memory, so it is not useful in systems that don't follow that behavior. Signed-off-by: Alberto Garcia <berto@igalia.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Message-id: a70d12da60433df9360ada648b3f34b8f6f354ce.1438690126.git.berto@igalia.com Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block/qcow2.h')
-rw-r--r--block/qcow2.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/block/qcow2.h b/block/qcow2.h
index 72e132838a..71dafd6dc9 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -96,6 +96,7 @@
#define QCOW2_OPT_CACHE_SIZE "cache-size"
#define QCOW2_OPT_L2_CACHE_SIZE "l2-cache-size"
#define QCOW2_OPT_REFCOUNT_CACHE_SIZE "refcount-cache-size"
+#define QCOW2_OPT_CACHE_CLEAN_INTERVAL "cache-clean-interval"
typedef struct QCowHeader {
uint32_t magic;
@@ -239,6 +240,8 @@ typedef struct BDRVQcowState {
Qcow2Cache* l2_table_cache;
Qcow2Cache* refcount_block_cache;
+ QEMUTimer *cache_clean_timer;
+ unsigned cache_clean_interval;
uint8_t *cluster_cache;
uint8_t *cluster_data;
@@ -581,6 +584,7 @@ int qcow2_cache_set_dependency(BlockDriverState *bs, Qcow2Cache *c,
Qcow2Cache *dependency);
void qcow2_cache_depends_on_flush(Qcow2Cache *c);
+void qcow2_cache_clean_unused(BlockDriverState *bs, Qcow2Cache *c);
int qcow2_cache_empty(BlockDriverState *bs, Qcow2Cache *c);
int qcow2_cache_get(BlockDriverState *bs, Qcow2Cache *c, uint64_t offset,