[PATCH 2/3] smb3: lower default deferred close timeout to address perf regression

[Tim Gardner]

From: Steve French <stfrench at microsoft.com>

BugLink: https://bugs.launchpad.net/bugs/2013349

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 at intel.com>
Reported-by: kernel test robot <yujie.liu at intel.com>
Link: https://lore.kernel.org/lkml/997614df-10d4-af53-9571-edec36b0e2f3@intel.com/
Fixes: 5efdd9122eff ("smb3: allow deferred close timeout to be configurable")
Cc: stable at vger.kernel.org # 6.0+
Tested-by: Yin Fengwei <fengwei.yin at intel.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc at manguebit.com>
Reviewed-by: Shyam Prasad N <sprasad at microsoft.com>
Signed-off-by: Steve French <stfrench at microsoft.com>
(cherry picked from commit 7e0e76d99079be13c9961dde7c93b2d1ee665af4)
Signed-off-by: Tim Gardner <tim.gardner at canonical.com>
---
 fs/cifs/fs_context.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index bbaee4c2281f..a268896d05d5 100644
--- a/fs/cifs/fs_context.h
+++ b/fs/cifs/fs_context.h
@@ -286,5 +286,5 @@ 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
-- 
2.34.1