From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id pAKBkAMJ152944 for ; Sun, 20 Nov 2011 05:46:11 -0600 Received: from bombadil.infradead.org (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 324A01D1DB6F for ; Sun, 20 Nov 2011 03:46:09 -0800 (PST) Received: from bombadil.infradead.org (173-166-109-252-newengland.hfc.comcastbusiness.net [173.166.109.252]) by cuda.sgi.com with ESMTP id YdTyVaVHSlcAZNl1 for ; Sun, 20 Nov 2011 03:46:09 -0800 (PST) Date: Sun, 20 Nov 2011 06:46:09 -0500 From: Christoph Hellwig Subject: Re: [PATCH] xfs: force buffer writeback before blocking on the ilock in inode reclaim Message-ID: <20111120114609.GA14997@infradead.org> References: <20111120072334.GA27386@infradead.org> <20111120083345.GO7046@dastard> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20111120083345.GO7046@dastard> 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: Christoph Hellwig , xfs@oss.sgi.com On Sun, Nov 20, 2011 at 07:33:45PM +1100, Dave Chinner wrote: > On Sun, Nov 20, 2011 at 02:23:34AM -0500, Christoph Hellwig wrote: > > If we are doing synchronous inode reclaim we block the VM from making > > progress in memory reclaim. So if we encouter a flush locked inode > > make sure we force out all delayed buffers ASAP to speed up the wait > > for it to be unlocked. Without this we can get hangs of up to 30 > > seconds during workloads hitting synchronous inode reclaim. > > I don't think we need to push out all delayed buffers - that's an > awfully big sledge hammer to get a single buffer moving. Indeed, we > already have a mechanism for dealing with this problem - > xfs_buf_delwri_promote() - when we hit it during AIL flushing. > > IOWs, we only need to promote the buffer the inode sits in and kick > xfsbufd. that is, something like: > > bp = xfs_incore(ip->i_mount->m_ddev_targp, iip->ili_format.ilf_blkno, > iip->ili_format.ilf_len, XBF_TRYLOCK); > if (bp && XFS_BUF_ISDELAYWRITE(bp)) { > xfs_buf_delwri_promote(bp); > wake_up_process(mp->m_ddev_targp->bt_task); > } > if (bp) > xfs_buf_relse(bp); Yes, we could try a variant of that. Note that a buffer in synchronous reclaim isn't guaranteed to actually have a log item, but we can get the same information from ip->i_imap. _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs