Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756957AbZJFKMJ (ORCPT ); Tue, 6 Oct 2009 06:12:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756915AbZJFKMI (ORCPT ); Tue, 6 Oct 2009 06:12:08 -0400 Received: from fgwmail5.fujitsu.co.jp ([192.51.44.35]:50708 "EHLO fgwmail5.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756889AbZJFKMH (ORCPT ); Tue, 6 Oct 2009 06:12:07 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 From: KOSAKI Motohiro To: Peter Zijlstra Subject: Re: [PATCH 2/2] mlock use lru_add_drain_all_async() Cc: kosaki.motohiro@jp.fujitsu.com, LKML , linux-mm , Andrew Morton , Oleg Nesterov , Christoph Lameter In-Reply-To: <1254820131.21044.126.camel@laptop> References: <20091006114052.5FAA.A69D9226@jp.fujitsu.com> <1254820131.21044.126.camel@laptop> Message-Id: <20091006190507.126C.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Mailer: Becky! ver. 2.50.07 [ja] Date: Tue, 6 Oct 2009 19:11:25 +0900 (JST) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1638 Lines: 41 > On Tue, 2009-10-06 at 11:41 +0900, KOSAKI Motohiro wrote: > > Recently, Peter Zijlstra reported RT-task can lead to prevent mlock > > very long time. > > > > Suppose you have 2 cpus, cpu1 is busy doing a SCHED_FIFO-99 while(1), > > cpu0 does mlock()->lru_add_drain_all(), which does > > schedule_on_each_cpu(), which then waits for all cpus to complete the > > work. Except that cpu1, which is busy with the RT task, will never run > > keventd until the RT load goes away. > > > > This is not so much an actual deadlock as a serious starvation case. > > > > Actually, mlock() doesn't need to wait to finish lru_add_drain_all(). > > Thus, this patch replace it with lru_add_drain_all_async(). > > > > Cc: Oleg Nesterov > > Reported-by: Peter Zijlstra > > Signed-off-by: KOSAKI Motohiro > > It was actually Mike Galbraith who brought it to my attention. > > Patch looks sane enough, altough I'm not sure I'd have split it in two > like you did (leaves the first without a real changelog too). Ah, yes. they shold be folded. thanks. In my local patch queue, this patch series have another two caller. - lumpy reclaim: currently, PCP often cause failure large order allocation. - page migration: in almost case, PCP doesn't hold the migration target page. but they are still testing. -- 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/