From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vc0-f182.google.com (mail-vc0-f182.google.com [209.85.220.182]) by kanga.kvack.org (Postfix) with ESMTP id 3249F6B0035 for ; Tue, 29 Jul 2014 11:26:26 -0400 (EDT) Received: by mail-vc0-f182.google.com with SMTP id hy4so13633568vcb.41 for ; Tue, 29 Jul 2014 08:26:25 -0700 (PDT) Received: from qmta04.emeryville.ca.mail.comcast.net (qmta04.emeryville.ca.mail.comcast.net. [2001:558:fe2d:43:76:96:30:40]) by mx.google.com with ESMTP id cj3si3700150qcb.26.2014.07.29.08.26.25 for ; Tue, 29 Jul 2014 08:26:25 -0700 (PDT) Date: Tue, 29 Jul 2014 10:26:08 -0500 (CDT) From: Christoph Lameter Subject: Re: vmstat: On demand vmstat workers V8 In-Reply-To: <20140729151415.GF4791@htj.dyndns.org> Message-ID: References: <53D31101.8000107@oracle.com> <20140729075637.GA19379@twins.programming.kicks-ass.net> <20140729120525.GA28366@mtj.dyndns.org> <20140729122303.GA3935@laptop> <20140729131226.GS7462@htj.dyndns.org> <20140729151415.GF4791@htj.dyndns.org> Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Tejun Heo Cc: Peter Zijlstra , Sasha Levin , akpm@linux-foundation.org, Gilad Ben-Yossef , Thomas Gleixner , John Stultz , Mike Frysinger , Minchan Kim , Hakan Akkan , Max Krasnyansky , Frederic Weisbecker , "Paul E. McKenney" , linux-kernel@vger.kernel.org, linux-mm@kvack.org, hughd@google.com, viresh.kumar@linaro.org, hpa@zytor.com, mingo@kernel.org, Lai Jiangshan On Tue, 29 Jul 2014, Tejun Heo wrote: > > mm/vmstat.c already has cpu down hooks. See vmstat_cpuup_callback(). > > Hmmm, well, then it's something else. Either a bug in workqueue or in > the caller. Given the track record, the latter is more likely. > e.g. it looks kinda suspicious that the work func is cleared after > cancel_delayed_work_sync() is called. What happens if somebody tries Ok we can clear it before then. Just looked at the current upstream code. It also does a __this_cpu_read() in refresh_cpu_stats() without triggering the preemption check. What changed in -next that made the test trigger now? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org