From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from relay.sgi.com (relay3.corp.sgi.com [198.149.34.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p37LDSgC130752 for ; Thu, 7 Apr 2011 16:13:28 -0500 Subject: Re: [PATCH 3/9] xfs: convert ENOSPC inode flushing to use new syncd workqueue From: Alex Elder In-Reply-To: <1302141445-27457-4-git-send-email-david@fromorbit.com> References: <1302141445-27457-1-git-send-email-david@fromorbit.com> <1302141445-27457-4-git-send-email-david@fromorbit.com> Date: Thu, 07 Apr 2011 16:16:11 -0500 Message-ID: <1302210971.2576.599.camel@doink> Mime-Version: 1.0 Reply-To: aelder@sgi.com List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: Dave Chinner Cc: xfs@oss.sgi.com On Thu, 2011-04-07 at 11:57 +1000, Dave Chinner wrote: > From: Dave Chinner > > On of the problems with the current inode flush at ENOSPC is that we > queue a flush per ENOSPC event, regardless of how many are already > queued. Thi can result in hundreds of queued flushes, most of > which simply burn CPU scanned and do no real work. This simply slows > down allocation at ENOSPC. > > We really only need one active flush at a time, and we can easily > implement that via the new xfs_syncd_wq. All we need to do is queue > a flush if one is not already active, then block waiting for the > currently active flush to complete. The result is that we only ever > have a single ENOSPC inode flush active at a time and this greatly > reduces the overhead of ENOSPC processing. > > On my 2p test machine, this results in tests exercising ENOSPC > conditions running significantly faster - 042 halves execution time, > 083 drops from 60s to 5s, etc - while not introducing test > regressions. > > This allows us to remove the old xfssyncd threads and infrastructure > as they are no longer used. Looks good. You got rid of a useless log force as well. Reviewed-by: Alex Elder > Signed-off-by: Dave Chinner > Reviewed-by: Christoph Hellwig _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs