Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751427AbXAFQjG (ORCPT ); Sat, 6 Jan 2007 11:39:06 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751430AbXAFQjF (ORCPT ); Sat, 6 Jan 2007 11:39:05 -0500 Received: from e34.co.us.ibm.com ([32.97.110.152]:56694 "EHLO e34.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751427AbXAFQjD (ORCPT ); Sat, 6 Jan 2007 11:39:03 -0500 Date: Sat, 6 Jan 2007 22:08:51 +0530 From: Srivatsa Vaddagiri To: Oleg Nesterov Cc: Andrew Morton , David Howells , Christoph Hellwig , Ingo Molnar , Linus Torvalds , linux-kernel@vger.kernel.org, Gautham shenoy Subject: Re: [PATCH] fix-flush_workqueue-vs-cpu_dead-race-update Message-ID: <20070106163851.GA13579@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <20061217223416.GA6872@tv-sign.ru> <20061218162701.a3b5bfda.akpm@osdl.org> <20061219004319.GA821@tv-sign.ru> <20070104113214.GA30377@in.ibm.com> <20070104142936.GA179@tv-sign.ru> <20070104091850.c1feee76.akpm@osdl.org> <20070106151036.GA951@tv-sign.ru> <20070106154506.GC24274@in.ibm.com> <20070106163035.GA2948@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070106163035.GA2948@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: 1148 Lines: 32 On Sat, Jan 06, 2007 at 07:30:35PM +0300, Oleg Nesterov wrote: > Stupid me. Thanks. > > I'll try to do something else tomorrow. Do you see a simple soulution? Sigh ..I dont see a simple solution, unless we have something like lock_cpu_hotplug() .. Andrew, This workqueue problem has exposed a classic example of how tough/miserable it can be to write hotplug safe code w/o something like lock_cpu_hotplug() ..Are you still inclined towards banning it? :) FYI, the lock_cpu_hotplug() rewrite proposed by Gautham at http://lkml.org/lkml/2006/10/26/65 may still need refinement to avoid all the kind of deadlocks we have unearthed with workqueue example. I can review that design with Gautham if there is some interest to revive lock_cpu_hotplug() .. > The current usage of workqueue_mutex (I mean stable kernel) is broken > and deadlockable. We really need to change it. Yep .. -- Regards, vatsa - 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/