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 (Postfix) with ESMTP id ED3A67FE2 for ; Wed, 3 Jun 2015 17:48:36 -0500 (CDT) Received: from cuda.sgi.com (cuda2.sgi.com [192.48.176.25]) by relay3.corp.sgi.com (Postfix) with ESMTP id 66F5CAC002 for ; Wed, 3 Jun 2015 15:48:36 -0700 (PDT) Received: from ipmail05.adl6.internode.on.net (ipmail05.adl6.internode.on.net [150.101.137.143]) by cuda.sgi.com with ESMTP id f2CyDbcdnoqkA81c for ; Wed, 03 Jun 2015 15:48:16 -0700 (PDT) Date: Thu, 4 Jun 2015 08:44:49 +1000 From: Dave Chinner Subject: Re: [PATCH] [RFC v2] xfs: byte range buffer dirty region tracking Message-ID: <20150603224449.GQ24666@dastard> References: <1432865777-14616-1-git-send-email-david@fromorbit.com> <556F0CE0.8080402@sgi.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <556F0CE0.8080402@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 Errors-To: xfs-bounces@oss.sgi.com Sender: xfs-bounces@oss.sgi.com To: Mark Tinguely Cc: xfs@oss.sgi.com On Wed, Jun 03, 2015 at 09:19:12AM -0500, Mark Tinguely wrote: > On 05/28/15 21:16, Dave Chinner wrote: > >Discussion: > > > >I think that we will eventually need to track multiple regions - 3 > >is probably sufficient - because the nature of directory operations > >are that just about every operation modifies a header in the buffer, > >a tail section in the buffer and then some number of bytes/regions > >in the middle of the buffer. > > Nod to the idea. > > What made you change from your original idea of using 4 regions to 3 > regions? 3 or 4 regions make little difference. header, body and tail is most common for random directory modifications, so whether we have 1 or 2 body regions won't make much difference once more than a couple of modifications are made to the same directory block. Indeed, I'm not sure that we even need multiple regions - the log bandwidth and log item memcpy overhead hasn't changed very much even on large directory buffers with a single region... Cheers, Dave. -- Dave Chinner david@fromorbit.com _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs