From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 9BAF56B005A for ; Thu, 30 Jul 2009 15:56:56 -0400 (EDT) Received: from spaceape7.eur.corp.google.com (spaceape7.eur.corp.google.com [172.28.16.141]) by smtp-out.google.com with ESMTP id n6UJtlwh026172 for ; Thu, 30 Jul 2009 20:55:48 +0100 Received: from pzk5 (pzk5.prod.google.com [10.243.19.133]) by spaceape7.eur.corp.google.com with ESMTP id n6UJtieo008577 for ; Thu, 30 Jul 2009 12:55:45 -0700 Received: by pzk5 with SMTP id 5so1150132pzk.23 for ; Thu, 30 Jul 2009 12:55:44 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20090730040803.GA20652@localhost> References: <1786ab030907281211x6e432ba6ha6afe9de73f24e0c@mail.gmail.com> <33307c790907281449k5e8d4f6cib2c93848f5ec2661@mail.gmail.com> <33307c790907290015m1e6b5666x9c0014cdaf5ed08@mail.gmail.com> <20090729114322.GA9335@localhost> <33307c790907290711s320607b0i79c939104d4c2d61@mail.gmail.com> <20090730010630.GA7326@localhost> <33307c790907291812j40146a96tc2e9c5e097a33615@mail.gmail.com> <20090730015754.GC7326@localhost> <33307c790907291959r47b1bd3ap7cfa06fd5154aaad@mail.gmail.com> <20090730040803.GA20652@localhost> Date: Thu, 30 Jul 2009 12:55:44 -0700 Message-ID: <33307c790907301255j136e003dtac0e4ba2032e890e@mail.gmail.com> Subject: Re: Bug in kernel 2.6.31, Slow wb_kupdate writeout From: Martin Bligh Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Michael Rubin , "sandeen@redhat.com" , Michael Davidson , Andrew Morton , Peter Zijlstra List-ID: > Note that this is a simple fix that may have suboptimal write performance= . > Here is an old reasoning: > > =A0 =A0 =A0 =A0http://lkml.org/lkml/2009/3/28/235 The other thing I've been experimenting with is to disable the per-page check in write_cache_pages, ie: if (wbc->nonblocking && bdi_write_congested(bdi)) { wb_stats_inc(WB_STATS_WCP_SECTION_CONG); wbc->encountered_congestion =3D 1; /* done =3D 1; */ This treats the congestion limits as soft, but encourages us to write back in larger, more efficient chunks. If that's not going to scare people unduly, I can submit that as well. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org