Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756726AbZAJOxX (ORCPT ); Sat, 10 Jan 2009 09:53:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753701AbZAJOxP (ORCPT ); Sat, 10 Jan 2009 09:53:15 -0500 Received: from one.firstfloor.org ([213.235.205.2]:38641 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753461AbZAJOxO (ORCPT ); Sat, 10 Jan 2009 09:53:14 -0500 Date: Sat, 10 Jan 2009 16:07:29 +0100 From: Andi Kleen To: Pavel Machek Cc: Andi Kleen , Nick Piggin , Christoph Hellwig , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: 2.6.29 -mm merge plans Message-ID: <20090110150729.GE26290@one.firstfloor.org> References: <20090105004300.19ed52d1.akpm@linux-foundation.org> <20090106225744.GA10553@infradead.org> <20090106151131.b6c4ff0b.akpm@linux-foundation.org> <20090106232418.GB25103@infradead.org> <20090107011448.GB3390@wotan.suse.de> <87tz8b3nfe.fsf@basil.nowhere.org> <20090107014915.GE3390@wotan.suse.de> <20090107025725.GJ496@one.firstfloor.org> <20090108132455.GE2247@ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090108132455.GE2247@ucw.cz> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1175 Lines: 29 On Thu, Jan 08, 2009 at 02:24:55PM +0100, Pavel Machek wrote: > On Wed 2009-01-07 03:57:25, Andi Kleen wrote: > > > sys_sync B which is invoked *after* sys_sync caller A should not > > > return before A. If you didn't have a global lock, they'd tend to > > > block one another's pages anyway. I think it's OK. > > > > It means that you cannot reboot because reboot does sync. > > What happens when the sync gets stuck somewhere on a really > > slow device? > > And what do you propose? Silently corrupt data on the slow device? Yes not writing is better than being unable to reboot. There should be always a timeout at least for the reboot case. Consider it from a uptime perspective: if something is really screwed up (and that happens sometimes; classical example was the IO stack getting hung up forever in error handling loops) the only way to get running again is to reboot and try again. -Andi -- ak@linux.intel.com -- 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/