From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964986AbXBTPMn (ORCPT ); Tue, 20 Feb 2007 10:12:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965021AbXBTPMn (ORCPT ); Tue, 20 Feb 2007 10:12:43 -0500 Received: from e33.co.us.ibm.com ([32.97.110.151]:45551 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964986AbXBTPMm (ORCPT ); Tue, 20 Feb 2007 10:12:42 -0500 Date: Tue, 20 Feb 2007 20:42:20 +0530 From: Srivatsa Vaddagiri To: Oleg Nesterov Cc: Gautham R Shenoy , akpm@osdl.org, paulmck@us.ibm.com, mingo@elte.hu, dipankar@in.ibm.com, venkatesh.pallipadi@intel.com, linux-kernel@vger.kernel.org, rjw@sisk.pl Subject: Re: [RFC PATCH(Experimental) 2/4] Revert changes to workqueue.c Message-ID: <20070220151220.GB4960@in.ibm.com> Reply-To: vatsa@in.ibm.com References: <20070214144031.GA15257@in.ibm.com> <20070214144229.GA19789@in.ibm.com> <20070214144305.GB19789@in.ibm.com> <20070214200904.GB301@tv-sign.ru> <20070216052626.GB8373@in.ibm.com> <20070216153321.GB83@tv-sign.ru> <20070216164730.GD21457@in.ibm.com> <20070216235939.GB244@tv-sign.ru> <20070217022940.GB25924@in.ibm.com> <20070217215928.GA563@tv-sign.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070217215928.GA563@tv-sign.ru> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Feb 18, 2007 at 12:59:28AM +0300, Oleg Nesterov wrote: > Before you begin. You are doing CPU_DOWN_PREPARE after freeze_processes(). > Not good. This makes impossible to do flush_workueue() at CPU_DOWN_PREPARE > stage, we have callers. We have few solutions to deal with this: a. Mark such workqueues not freezable for hotplug b. If above is not possible, don't call flush_workqueue in DOWN_PREPARE c. If above is not possible, send DOWN_PREPARE before freeze_processes() I would prefer a solution in the above order listed. Which caller are you referring to here? Maybe we can decide on the option after we see the users of flush_workqueue() in DOWN_PREPARE. > I'm afraid it won't be so easy to solve all locking/racing problems. Will > wait for the patch :) I dont see problems for workqueue.c even if we follow option c. Do you see any? -- Regards, vatsa