From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id p820HrHO045540 for ; Thu, 1 Sep 2011 19:17:53 -0500 Received: from ipmail06.adl2.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id 47E6612E0F8 for ; Thu, 1 Sep 2011 17:17:51 -0700 (PDT) Received: from ipmail06.adl2.internode.on.net (ipmail06.adl2.internode.on.net [150.101.137.129]) by cuda.sgi.com with ESMTP id 0QGiQONe8axldGxZ for ; Thu, 01 Sep 2011 17:17:51 -0700 (PDT) Date: Fri, 2 Sep 2011 10:17:47 +1000 From: Dave Chinner Subject: Re: [PATCH 04/11] xfs: call xfs_buf_delwri_queue directly Message-ID: <20110902001747.GR32358@dastard> References: <20110823082802.335389799@bombadil.infradead.org> <20110823082912.512830398@bombadil.infradead.org> <1314904935.2903.62.camel@doink> <20110901214640.GB4579@infradead.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110901214640.GB4579@infradead.org> 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: Christoph Hellwig Cc: xfs@oss.sgi.com, Alex Elder On Thu, Sep 01, 2011 at 05:46:40PM -0400, Christoph Hellwig wrote: > On Thu, Sep 01, 2011 at 02:22:15PM -0500, Alex Elder wrote: > > that the buffer should be queued at unlock time, we now > > just put it in the queue right away. Seems reasonable. > > Do you know why enqueueing it was delayed before? > > I don't know why - it's a carryover from IRIX days, Right. On Irix a buffer could simply have the BUF_DELWRI flag set on it, and the buffer cache would take care of everything else. There wasn't a specific delayed write list in Irix, instead there was a fixed table of buffers (large!) that was scanned every 5 seconds (20% scanned once per second) and the delwri buffers were gathered by the scan. Hence there were places in XFS where it simply set the flag to mark a buffer delwri, and that's what this Linux code had to catch. > so long before my time. The XFS code long predates me, too, but I spend a couple of years in the trenches around the Irix buffer cache when I was at SGI so I at least know why it was like that. ;) Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs