From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:57948) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1g71rE-0002YH-EG for qemu-devel@nongnu.org; Mon, 01 Oct 2018 13:19:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1g71rC-0007Ki-Ao for qemu-devel@nongnu.org; Mon, 01 Oct 2018 13:19:44 -0400 From: Kevin Wolf Date: Mon, 1 Oct 2018 19:18:59 +0200 Message-Id: <20181001171901.11004-22-kwolf@redhat.com> In-Reply-To: <20181001171901.11004-1-kwolf@redhat.com> References: <20181001171901.11004-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 21/23] qcow2: Fix cache-clean-interval documentation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org From: Leonid Bloch Fixing cache-clean-interval documentation following the recent change to a default of 600 seconds on supported plarforms (only Linux currently). Signed-off-by: Leonid Bloch Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- qapi/block-core.json | 3 ++- docs/qcow2-cache.txt | 20 ++++++++++---------- qemu-options.hx | 3 ++- 3 files changed, 14 insertions(+), 12 deletions(-) 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/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/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 -- 2.13.6