From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992787AbXDDKF0 (ORCPT ); Wed, 4 Apr 2007 06:05:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992821AbXDDKF0 (ORCPT ); Wed, 4 Apr 2007 06:05:26 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:48871 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992787AbXDDKFZ (ORCPT ); Wed, 4 Apr 2007 06:05:25 -0400 Date: Wed, 4 Apr 2007 12:04:31 +0200 From: Ingo Molnar To: Srivatsa Vaddagiri Cc: Gautham R Shenoy , akpm@linux-foundation.org, paulmck@us.ibm.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, Oleg Nesterov , "Rafael J. Wysocki" , dipankar@in.ibm.com, dino@in.ibm.com, masami.hiramatsu.pt@hitachi.com Subject: Re: [RFC] Cpu-hotplug: Using the Process Freezer (try2) Message-ID: <20070404100431.GB19120@elte.hu> References: <20070402053457.GA9076@in.ibm.com> <20070402061612.GA7072@elte.hu> <20070402092818.GE2456@in.ibm.com> <20070402111828.GA14771@elte.hu> <20070402124200.GA9566@in.ibm.com> <20070402185607.GA2081@elte.hu> <20070403125619.GA32444@in.ibm.com> <20070403141516.GB14900@in.ibm.com> <20070404031502.GA23591@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070404031502.GA23591@in.ibm.com> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Srivatsa Vaddagiri wrote: > > Rafael has already sent out the fix for that, but for some reason I > > don't see it in the -mm. > > > > With that fix, freezer and hence hotplug succeeds even when I am > > running a 'make -j' test. nice! > Good to know that! > > So Ingo/Rafael, should we ignore the problem of "TASK_UNINTERRUPTIBLE > sleepers can break freezer" for the timebeing? Mainly because its not > trivial to solve and we need to tackle it case by case basis as and > when users report specific problems. yeah, i think you are right - and the TASK_UNINTERRUPTIBLE thing is not only quite complex, it also breaks the symmetry of freezer use (sw-suspend obviously cannot freeze uninterruptible tasks). We should watch whether the current latency of freezing is good enough in practice. Ingo