From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267647AbUGWL1T (ORCPT ); Fri, 23 Jul 2004 07:27:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267649AbUGWL1T (ORCPT ); Fri, 23 Jul 2004 07:27:19 -0400 Received: from mx2.elte.hu ([157.181.151.9]:13709 "EHLO mx2.elte.hu") by vger.kernel.org with ESMTP id S267647AbUGWL1S (ORCPT ); Fri, 23 Jul 2004 07:27:18 -0400 Date: Fri, 23 Jul 2004 13:28:42 +0200 From: Ingo Molnar To: Paolo Ciarrocchi Cc: linux-kernel@vger.kernel.org, Rudo Thomas , Matt Heler Subject: [patch] voluntary-preempt-2.6.8-rc2-I4 Message-ID: <20040723112842.GA5133@elte.hu> References: <20040722160055.GA4837@ss1000.ms.mff.cuni.cz> <20040722161941.GA23972@elte.hu> <20040722172428.GA5632@ss1000.ms.mff.cuni.cz> <20040722175457.GA5855@ss1000.ms.mff.cuni.cz> <20040722180142.GC30059@elte.hu> <20040722180821.GA377@elte.hu> <20040722181426.GA892@elte.hu> <20040723104246.GA2752@elte.hu> <4d8e3fd30407230358141e0e58@mail.gmail.com> <20040723110430.GA3787@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040723110430.GA3787@elte.hu> User-Agent: Mutt/1.4.1i X-ELTE-SpamVersion: MailScanner 4.31.6-itk1 (ELTE 1.2) SpamAssassin 2.63 ClamAV 0.73 X-ELTE-VirusStatus: clean X-ELTE-SpamCheck: no X-ELTE-SpamCheck-Details: score=-4.9, required 5.9, autolearn=not spam, BAYES_00 -4.90 X-ELTE-SpamLevel: X-ELTE-SpamScore: -4 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8-rc2-I3 > > > > > > it mainly fixes an ext3 livelock that could result in long delays during > > > heavy commit traffic. > > > > Hello Ingo, do you have any measurement of the improvement available ? > > it's a bug in the patch, not really a latency fix. When this (rare) > condition under heavy write traffic occurs then kjournald would loop for > many seconds (or tens of seconds) in __journal_clean_checkpoint_list(), > effectively hanging the system. The system is still preemptible but the > user cannot do much with it. Note that this condition is not present in > the vanilla kernel, it got introduced by earlier versions of > voluntary-preempt. there's one more new version: http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8-rc2-I4 this fixes another rare bug: release_task() could trigger a 'Badness' atomicity message when the right conditions occur on a preemptible kernel. This bugfix also allowed the addition of might_sleep() checks (and hence voluntary-preemption points) to dput() and fput(), two common functions. Ingo