From: Chris Mason Subject: Re: buffered writeback torture program Date: Thu, 21 Apr 2011 14:00:29 -0400 Message-ID: <1303408265-sup-2454@think> References: <1303322378-sup-1722@think> <20110421083258.GA26784@infradead.org> <1303407205-sup-6141@think> <20110421174120.GA7267@infradead.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: linux-fsdevel , linux-ext4 , xfs , jack , axboe , dchinner To: Christoph Hellwig Return-path: Received: from rcsinet10.oracle.com ([148.87.113.121]:42029 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751561Ab1DUSCg (ORCPT ); Thu, 21 Apr 2011 14:02:36 -0400 In-reply-to: <20110421174120.GA7267@infradead.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: Excerpts from Christoph Hellwig's message of 2011-04-21 13:41:21 -0400: > On Thu, Apr 21, 2011 at 01:34:44PM -0400, Chris Mason wrote: > > Sorry, this doesn't do it. I think that given what a strange special > > case this is, we're best off waiting for the IO-less throttling, and > > maybe changing the code in xfs/ext4 to be a little more seek aware. Or > > maybe not, it has to get written eventually either way. > > I'm not sure what you mean with seek aware. XFS only clusters > additional pages that are in the same extent, and in fact only does > so for asynchrononous writeback. Not sure how this should be more > seek aware. > How big are extents? fiemap tells me the file has a single 8GB extent. There's a little room for seeking inside there. -chris