Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756491Ab2EHPWz (ORCPT ); Tue, 8 May 2012 11:22:55 -0400 Received: from mail-ey0-f174.google.com ([209.85.215.174]:65115 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755815Ab2EHPWy convert rfc822-to-8bit (ORCPT ); Tue, 8 May 2012 11:22:54 -0400 MIME-Version: 1.0 X-Originating-IP: [212.179.42.66] In-Reply-To: <4FA823A7.9000801@gmail.com> References: <1336056962-10465-1-git-send-email-gilad@benyossef.com> <1336056962-10465-6-git-send-email-gilad@benyossef.com> <4FA823A7.9000801@gmail.com> Date: Tue, 8 May 2012 18:22:45 +0300 Message-ID: Subject: Re: [PATCH v1 5/6] mm: make vmstat_update periodic run conditional From: Gilad Ben-Yossef To: KOSAKI Motohiro Cc: Christoph Lameter , linux-kernel@vger.kernel.org, Thomas Gleixner , Tejun Heo , John Stultz , Andrew Morton , KOSAKI Motohiro , Mel Gorman , Mike Frysinger , David Rientjes , Hugh Dickins , Minchan Kim , Konstantin Khlebnikov , Chris Metcalf , Hakan Akkan , Max Krasnyansky , Frederic Weisbecker , linux-mm@kvack.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2144 Lines: 63 On Mon, May 7, 2012 at 10:33 PM, KOSAKI Motohiro wrote: >>> @@ -1204,8 +1265,14 @@ static int __init setup_vmstat(void) >>> >>> ? ? ? ?register_cpu_notifier(&vmstat_notifier); >>> >>> + ? ? ? INIT_DELAYED_WORK_DEFERRABLE(&vmstat_monitor_work, >>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? vmstat_update_monitor); >>> + ? ? ? queue_delayed_work(system_unbound_wq, >>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? &vmstat_monitor_work, >>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? round_jiffies_relative(HZ)); >>> + >>> ? ? ? ?for_each_online_cpu(cpu) >>> - ? ? ? ? ? ? ? start_cpu_timer(cpu); >>> + ? ? ? ? ? ? ? setup_cpu_timer(cpu); >>> ?#endif >>> ?#ifdef CONFIG_PROC_FS >>> ? ? ? ?proc_create("buddyinfo", S_IRUGO, >>> NULL,&fragmentation_file_operations); >> >> >> So the monitoring thread just bounces around the system? Hope that the >> scheduler does the right thing to keep it on processors that do some other >> work. > > > Good point. Usually, all cpus have update items and monitor worker only > makes > new noise. I think this feature is only useful some hpc case. ?So I wonder > if > this vmstat improvemnt can integrate Frederic's Nohz cpusets activity. I.e. > vmstat-update integrate timer house keeping and automatically stop when > stopping > hz house keeping. I wrote this and the previous IPI patch set explicitly to use with Frederic's Nohz stuff for CPU isolation. It just seemed at the time to be wrong to tie them together - I mean people that do CPU isolation can enjoy this even if they don't want to kill the tick (that comes with its own overhead for doing system calls, for example). Thanks! Gilad -- Gilad Ben-Yossef Chief Coffee Drinker gilad@benyossef.com Israel Cell: +972-52-8260388 US Cell: +1-973-8260388 http://benyossef.com "If you take a class in large-scale robotics, can you end up in a situation where the homework eats your dog?" ?-- Jean-Baptiste Queru -- 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/