diff options
| -rw-r--r-- | docs/qcow2-cache.txt | 20 | ||||
| -rw-r--r-- | qapi/block-core.json | 3 | ||||
| -rw-r--r-- | qemu-options.hx | 3 |
3 files changed, 14 insertions, 12 deletions
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt index 59358b816f..c459bf5dd3 100644 --- a/docs/qcow2-cache.txt +++ b/docs/qcow2-cache.txt @@ -202,18 +202,18 @@ Reducing the memory usage It is possible to clean unused cache entries in order to reduce the memory usage during periods of low I/O activity. -The parameter "cache-clean-interval" defines an interval (in seconds). -All cache entries that haven't been accessed during that interval are -removed from memory. +The parameter "cache-clean-interval" defines an interval (in seconds), +after which all the cache entries that haven't been accessed during the +interval are removed from memory. Setting this parameter to 0 disables this +feature. -This example removes all unused cache entries every 15 minutes: +The following example removes all unused cache entries every 15 minutes: -drive file=hd.qcow2,cache-clean-interval=900 -If unset, the default value for this parameter is 600. Setting it to 0 -disables this feature. +If unset, the default value for this parameter is 600 on platforms which +support this functionality, and is 0 (disabled) on other platforms. -Note that this functionality currently relies on the MADV_DONTNEED -argument for madvise() to actually free the memory. This is a -Linux-specific feature, so cache-clean-interval is not supported in -other systems. +This functionality currently relies on the MADV_DONTNEED argument for +madvise() to actually free the memory. This is a Linux-specific feature, +so cache-clean-interval is not supported on other systems. diff --git a/qapi/block-core.json b/qapi/block-core.json index 46dac23d2f..25b8a0e744 100644 --- a/qapi/block-core.json +++ b/qapi/block-core.json @@ -2895,7 +2895,8 @@ # # @cache-clean-interval: clean unused entries in the L2 and refcount # caches. The interval is in seconds. The default value -# is 600, and 0 disables this feature. (since 2.5) +# is 600 on supporting platforms, and 0 on other +# platforms. 0 disables this feature. (since 2.5) # # @encrypt: Image decryption options. Mandatory for # encrypted images, except when doing a metadata-only diff --git a/qemu-options.hx b/qemu-options.hx index 52d9d9f06d..f139459e80 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -747,7 +747,8 @@ it which is not used for the L2 cache) @item cache-clean-interval Clean unused entries in the L2 and refcount caches. The interval is in seconds. -The default value is 600. Setting it to 0 disables this feature. +The default value is 600 on supporting platforms, and 0 on other platforms. +Setting it to 0 disables this feature. @item pass-discard-request Whether discard requests to the qcow2 device should be forwarded to the data |