Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932221AbXAIQ53 (ORCPT ); Tue, 9 Jan 2007 11:57:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932233AbXAIQ53 (ORCPT ); Tue, 9 Jan 2007 11:57:29 -0500 Received: from mail.screens.ru ([213.234.233.54]:47052 "EHLO mail.screens.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932221AbXAIQ52 (ORCPT ); Tue, 9 Jan 2007 11:57:28 -0500 Date: Tue, 9 Jan 2007 19:56:55 +0300 From: Oleg Nesterov To: Srivatsa Vaddagiri Cc: Andrew Morton , David Howells , Christoph Hellwig , Ingo Molnar , Linus Torvalds , linux-kernel@vger.kernel.org, Gautham shenoy Subject: Re: [PATCH] flush_cpu_workqueue: don't flush an empty ->worklist Message-ID: <20070109165655.GA215@tv-sign.ru> References: <20070107110013.GD13579@in.ibm.com> <20070107115957.6080aa08.akpm@osdl.org> <20070107210139.GA2332@tv-sign.ru> <20070108155428.d76f3b73.akpm@osdl.org> <20070109050417.GC589@in.ibm.com> <20070108212656.ca77a3ba.akpm@osdl.org> <20070109150755.GB89@tv-sign.ru> <20070109155908.GD22080@in.ibm.com> <20070109163815.GA208@tv-sign.ru> <20070109164604.GA17915@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070109164604.GA17915@in.ibm.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1231 Lines: 32 On 01/09, Srivatsa Vaddagiri wrote: > > On Tue, Jan 09, 2007 at 07:38:15PM +0300, Oleg Nesterov wrote: > > We can't do this. We should thaw cwq->thread (which was bound to the > > dead CPU) to complete CPU_DEAD event. So we still need some changes. > > I noticed that, but I presumed kthread_stop() will post a wakeup which > will bring it out of frozen state. Looking at refrigerator(), I realize > that is not possible. > > So CPU_DEAD should do a thaw_process on the kthread before doing a > kthread_stop? Probably we can do this, or that. In any case we need changes, that was my point. And the best change I believe is to _remove_ CPU_DEAD handling from workqueue.c as I suggested before. This kthread_stop() is not a good idea per se, it calls wake_up_process(), but we should in fact use wake_up(&cwq->more_work). Yes, work->func() should be ready for the false wakeups, but still. But for now I hope the last "draft" patch is enough. I'll continue on next weekend. 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/