smb3: lower default deferred close timeout to address perf regression

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@intel.com>
Reported-by: kernel test robot <yujie.liu@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@vger.kernel.org # 6.0+
Tested-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Paulo Alcantara (SUSE) <pc@manguebit.com>
Reviewed-by: Shyam Prasad N <sprasad@microsoft.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

diff --git a/fs/cifs/fs_context.h b/fs/cifs/fs_context.h
index 1b8d4e27f831c1fc7fa9c2c14843d0eb9fc735a5..3de00e7127ec49624918aaff189544ebe99ecd87 100644 (file)
--- 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