diff options
| author | Leonid Bloch <lbloch@janustech.com> | 2018-09-26 19:04:43 +0300 |
|---|---|---|
| committer | Kevin Wolf <kwolf@redhat.com> | 2018-10-01 12:51:12 +0200 |
| commit | b749562d9822d14ef69c9eaa5f85903010b86c30 (patch) | |
| tree | c1b104511519217d7134b190eb0f89ee498c6eab /block/qcow2.h | |
| parent | 657ada52abb85140e56949f522ecec527b256450 (diff) | |
qcow2: Assign the L2 cache relatively to the image size
Sufficient L2 cache can noticeably improve the performance when using
large images with frequent I/O.
Previously, unless 'cache-size' was specified and was large enough, the
L2 cache was set to a certain size without taking the virtual image size
into account.
Now, the L2 cache assignment is aware of the virtual size of the image,
and will cover the entire image, unless the cache size needed for that is
larger than a certain maximum. This maximum is set to 1 MB by default
(enough to cover an 8 GB image with the default cluster size) but can
be increased or decreased using the 'l2-cache-size' option. This option
was previously documented as the *maximum* L2 cache size, and this patch
makes it behave as such, instead of as a constant size. Also, the
existing option 'cache-size' can limit the sum of both L2 and refcount
caches, as previously.
Signed-off-by: Leonid Bloch <lbloch@janustech.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'block/qcow2.h')
| -rw-r--r-- | block/qcow2.h | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/block/qcow2.h b/block/qcow2.h index a8d6f757b1..2f8c1fd15c 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -74,9 +74,7 @@ /* Must be at least 4 to cover all cases of refcount table growth */ #define MIN_REFCOUNT_CACHE_SIZE 4 /* clusters */ -/* Whichever is more */ -#define DEFAULT_L2_CACHE_CLUSTERS 8 /* clusters */ -#define DEFAULT_L2_CACHE_SIZE S_1MiB +#define DEFAULT_L2_CACHE_MAX_SIZE S_1MiB #define DEFAULT_CLUSTER_SIZE S_64KiB |