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[Qemu-block] [PATCH v11 8/9] qcow2: Set the default cache-clean-interval
From: |
Leonid Bloch |
Subject: |
[Qemu-block] [PATCH v11 8/9] qcow2: Set the default cache-clean-interval to 10 minutes |
Date: |
Tue, 25 Sep 2018 01:53:56 +0300 |
The default cache-clean-interval is set to 10 minutes, in order to lower
the overhead of the qcow2 caches (before the default was 0, i.e.
disabled).
* For non-Linux platforms the default is kept at 0, because
cache-clean-interval is not supported there yet.
Signed-off-by: Leonid Bloch <address@hidden>
Reviewed-by: Alberto Garcia <address@hidden>
---
block/qcow2.c | 2 +-
block/qcow2.h | 4 +++-
docs/qcow2-cache.txt | 4 ++--
qapi/block-core.json | 3 ++-
qemu-options.hx | 2 +-
5 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index c68f896c66..3c1859f9cc 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -944,7 +944,7 @@ static int qcow2_update_options_prepare(BlockDriverState
*bs,
/* New interval for cache cleanup timer */
r->cache_clean_interval =
qemu_opt_get_number(opts, QCOW2_OPT_CACHE_CLEAN_INTERVAL,
- s->cache_clean_interval);
+ DEFAULT_CACHE_CLEAN_INTERVAL);
#ifndef CONFIG_LINUX
if (r->cache_clean_interval != 0) {
error_setg(errp, QCOW2_OPT_CACHE_CLEAN_INTERVAL
diff --git a/block/qcow2.h b/block/qcow2.h
index 0f0e3534bf..ba430316b9 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -76,13 +76,15 @@
#ifdef CONFIG_LINUX
#define DEFAULT_L2_CACHE_MAX_SIZE S_32MiB
+#define DEFAULT_CACHE_CLEAN_INTERVAL 600 /* seconds */
#else
#define DEFAULT_L2_CACHE_MAX_SIZE S_8MiB
+/* Cache clean interval is currently available only on Linux, so must be 0 */
+#define DEFAULT_CACHE_CLEAN_INTERVAL 0
#endif
#define DEFAULT_CLUSTER_SIZE S_64KiB
-
#define QCOW2_OPT_LAZY_REFCOUNTS "lazy-refcounts"
#define QCOW2_OPT_DISCARD_REQUEST "pass-discard-request"
#define QCOW2_OPT_DISCARD_SNAPSHOT "pass-discard-snapshot"
diff --git a/docs/qcow2-cache.txt b/docs/qcow2-cache.txt
index 1fcc0658b2..59358b816f 100644
--- a/docs/qcow2-cache.txt
+++ b/docs/qcow2-cache.txt
@@ -210,8 +210,8 @@ This 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 0 and it disables
-this feature.
+If unset, the default value for this parameter is 600. Setting it to 0
+disables this feature.
Note that this functionality currently relies on the MADV_DONTNEED
argument for madvise() to actually free the memory. This is a
diff --git a/qapi/block-core.json b/qapi/block-core.json
index 4c7a37afdc..08c27b9af7 100644
--- a/qapi/block-core.json
+++ b/qapi/block-core.json
@@ -2827,7 +2827,8 @@
#
# @cache-clean-interval: clean unused entries in the L2 and refcount
# caches. The interval is in seconds. The default value
-# is 0 and it disables this feature (since 2.5)
+# is 600, and 0 disables this feature. (since 2.5)
+#
# @encrypt: Image decryption options. Mandatory for
# encrypted images, except when doing a metadata-only
# probe of the image. (since 2.10)
diff --git a/qemu-options.hx b/qemu-options.hx
index 14aee78c6c..52d9d9f06d 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -747,7 +747,7 @@ 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 0 and it disables this feature.
+The default value is 600. Setting it to 0 disables this feature.
@item pass-discard-request
Whether discard requests to the qcow2 device should be forwarded to the data
--
2.17.1
[Qemu-block] [PATCH v11 6/9] qcow2: Increase the default upper limit on the L2 cache size, Leonid Bloch, 2018/09/24
[Qemu-block] [PATCH v11 5/9] qcow2: Assign the L2 cache relatively to the image size, Leonid Bloch, 2018/09/24
[Qemu-block] [PATCH v11 4/9] qcow2: Avoid duplication in setting the refcount cache size, Leonid Bloch, 2018/09/24
[Qemu-block] [PATCH v11 2/9] include: Add a lookup table of sizes, Leonid Bloch, 2018/09/24