Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759326AbXFZW0R (ORCPT ); Tue, 26 Jun 2007 18:26:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757581AbXFZW0I (ORCPT ); Tue, 26 Jun 2007 18:26:08 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:53719 "EHLO amd.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757372AbXFZW0G (ORCPT ); Tue, 26 Jun 2007 18:26:06 -0400 Date: Tue, 26 Jun 2007 10:48:54 +0200 From: Pavel Machek To: "Rafael J. Wysocki" Cc: Andrew Morton , Nigel Cunningham , Uli Luckas , Oleg Nesterov , linux-kernel@vger.kernel.org Subject: Re: [PATCH -mm] PM: Prevent frozen user mode helpers from failing the freezing of tasks (rev. 2) Message-ID: <20070626084854.GA4594@elf.ucw.cz> References: <200706252352.24137.rjw@sisk.pl> <20070625215527.GE2051@elf.ucw.cz> <200706260027.02396.rjw@sisk.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200706260027.02396.rjw@sisk.pl> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.11+cvs20060126 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1123 Lines: 38 Hi! > > > [I hope the ACKs still apply.] > > > > Uhuh, not 100% sure. > > > > > +static int usermodehelper_disabled; > > > + > > > > > > ... > > > > > case PM_HIBERNATION_PREPARE: > > > case PM_SUSPEND_PREPARE: > > > usermodehelper_disabled = 1; > > > - return NOTIFY_OK; > > > + smp_mb(); > > > > usermodehelper_disabled should be atomic variable, too, so we don't > > have to play these ugly tricks by hand? This should not be > > performance-critical, right? > > Well, I think we'd need to add the barriers anyway. > > The problem, as far as I understand it, is that the instructions can get > reordered if there are no barriers in there. Are you sure? I thought atomic variables have barrirers built-in. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/