Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752634AbZG3Tz4 (ORCPT ); Thu, 30 Jul 2009 15:55:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752602AbZG3Tzw (ORCPT ); Thu, 30 Jul 2009 15:55:52 -0400 Received: from smtp-out.google.com ([216.239.33.17]:43219 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752561AbZG3Tzu convert rfc822-to-8bit (ORCPT ); Thu, 30 Jul 2009 15:55:50 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=mime-version:in-reply-to:references:date:message-id:subject:from:to: cc:content-type:content-transfer-encoding:x-system-of-record; b=VxSXyIFan6jsylWc3PYliEFGu1AihKzPBn1LB8B8lym0E21mJxmmSXkEpPdgx4V5F tg5artsGd05RelXQcdc6g== 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 To: Wu Fengguang Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , Michael Rubin , "sandeen@redhat.com" , Michael Davidson , Andrew Morton , Peter Zijlstra Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 945 Lines: 21 > Note that this is a simple fix that may have suboptimal write performance. > Here is an old reasoning: > > ? ? ? ?http://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 = 1; /* done = 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/