Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754019AbZIWC4h (ORCPT ); Tue, 22 Sep 2009 22:56:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753819AbZIWC4h (ORCPT ); Tue, 22 Sep 2009 22:56:37 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:46038 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753785AbZIWC4g (ORCPT ); Tue, 22 Sep 2009 22:56:36 -0400 Date: Tue, 22 Sep 2009 19:56:05 -0700 From: Andrew Morton To: Wu Fengguang Cc: Chris Mason , Peter Zijlstra , "Li, Shaohua" , "linux-kernel@vger.kernel.org" , "richard@rsk.demon.co.uk" , "jens.axboe@oracle.com" Subject: Re: regression in page writeback Message-Id: <20090922195605.a9a7aca8.akpm@linux-foundation.org> In-Reply-To: <20090923024958.GA13205@localhost> References: <1253608335.8439.283.camel@twins> <20090922155259.GL10825@think> <20090923002220.GA6382@localhost> <20090922175452.d66400dd.akpm@linux-foundation.org> <20090923011758.GC6382@localhost> <20090922182832.28e7f73a.akpm@linux-foundation.org> <20090923014500.GA11076@localhost> <20090922185941.1118e011.akpm@linux-foundation.org> <20090923022622.GB11918@localhost> <20090922193622.42c00012.akpm@linux-foundation.org> <20090923024958.GA13205@localhost> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 820 Lines: 19 On Wed, 23 Sep 2009 10:49:58 +0800 Wu Fengguang wrote: > > After the sleep we repoll all queues. > > I mean, it is not always necessary. Only when _all_ superblocks cannot > writeback their inodes (eg. all in congestion), we should wait. Well. The code will still submit MAX_WRITEBACK_PAGES pages to _some_ queue in that situation. But yup, maybe that's a bug! Sounds easy to fix. It doesn't justify rewriting the whole world and then saying "look, the new code is faster than the old code which had a bug which I knew about but didn't fix". -- 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/