This is a note to let you know that I've just added the patch titled
smb3: lower default deferred close timeout to address perf regression
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
smb3-lower-default-deferred-close-timeout-to-address.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 51a9713180712fe92b9b0bbd465068ee0ae59747
Author: Steve French <stfrench@xxxxxxxxxxxxx>
Date: Thu Mar 23 15:10:26 2023 -0500
smb3: lower default deferred close timeout to address perf regression
[ Upstream commit 7e0e76d99079be13c9961dde7c93b2d1ee665af4 ]
Performance tests with large number of threads noted that the change
of the default closetimeo (deferred close timeout between when
close is done by application and when client has to send the close
to the server), to 5 seconds from 1 second, significantly degraded
perf in some cases like this (in the filebench example reported,
the stats show close requests on the wire taking twice as long,
and 50% regression in filebench perf). This is stil configurable
via mount parm closetimeo, but to be safe, decrease default back
to its previous value of 1 second.
Reported-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Reported-by: kernel test robot <yujie.liu@xxxxxxxxx>
Link: https://lore.kernel.org/lkml/997614df-10d4-af53-9571-edec36b0e2f3@xxxxxxxxx/
Fixes: 5efdd9122eff ("smb3: allow deferred close timeout to be configurable")
Cc: stable@xxxxxxxxxxxxxxx # 6.0+
Tested-by: Yin Fengwei <fengwei.yin@xxxxxxxxx>
Reviewed-by: Paulo Alcantara (SUSE) <pc@xxxxxxxxxxxxx>
Reviewed-by: Shyam Prasad N <sprasad@xxxxxxxxxxxxx>
Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
Stable-dep-of: d19342c6609b ("cifs: sanitize paths in cifs_update_super_prepath.")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index b5ae210bafe04..ad45256cf68e2 100644
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -282,5 +282,5 @@ extern void smb3_update_mnt_flags(struct cifs_sb_info *cifs_sb);
* max deferred close timeout (jiffies) - 2^30
*/
#define SMB3_MAX_DCLOSETIMEO (1 << 30)
-#define SMB3_DEF_DCLOSETIMEO (5 * HZ) /* Can increase later, other clients use larger */
+#define SMB3_DEF_DCLOSETIMEO (1 * HZ) /* even 1 sec enough to help eg open/write/close/open/read */
#endif
