Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762209AbXELBB0 (ORCPT ); Fri, 11 May 2007 21:01:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753932AbXELBBT (ORCPT ); Fri, 11 May 2007 21:01:19 -0400 Received: from mail.screens.ru ([213.234.233.54]:52925 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751821AbXELBBS (ORCPT ); Fri, 11 May 2007 21:01:18 -0400 Date: Sat, 12 May 2007 05:01:17 +0400 From: Oleg Nesterov To: Linus Torvalds Cc: "Rafael J. Wysocki" , Andrew Morton , Gautham R Shenoy , LKML , Pavel Machek , "Eric W. Biederman" Subject: Re: [PATCH 1/7] Freezer: Read PF_BORROWED_MM in a nonracy way Message-ID: <20070512010117.GB540@tv-sign.ru> References: <200705110035.32229.rjw@sisk.pl> <200705110036.26617.rjw@sisk.pl> <20070511123959.190adfaf.akpm@linux-foundation.org> <200705112240.54304.rjw@sisk.pl> <20070511232024.GA489@tv-sign.ru> <20070511234819.GA508@tv-sign.ru> <20070512004057.GA540@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070512004057.GA540@tv-sign.ru> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 894 Lines: 30 On 05/12, Oleg Nesterov wrote: > > Do we need freezer? Should we freeze kernel threads? I can't judge. I tried > to read a long thread about suspend, and failed to understand it. > > I personally think we can simplify things if CPU-hotplug use freezer, at least. Just a small example, debug_smp_processor_id: /* * Kernel threads bound to a single CPU can safely use * smp_processor_id(): */ this_mask = cpumask_of_cpu(this_cpu); if (cpus_equal(current->cpus_allowed, this_mask)) goto out; This is not true with CONFIG_HOTPLUG_CPU. This becomes true if we freeze the kernel threads from CPU_DOWN_PREPARE to CPU_DEAD. Oleg. - 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/