From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io0-f174.google.com (mail-io0-f174.google.com [209.85.223.174]) by kanga.kvack.org (Postfix) with ESMTP id 0284A6B0253 for ; Thu, 21 Jan 2016 10:41:31 -0500 (EST) Received: by mail-io0-f174.google.com with SMTP id g73so59305365ioe.3 for ; Thu, 21 Jan 2016 07:41:30 -0800 (PST) Received: from resqmta-ch2-08v.sys.comcast.net (resqmta-ch2-08v.sys.comcast.net. [2001:558:fe21:29:69:252:207:40]) by mx.google.com with ESMTPS id lp5si31681602igb.64.2016.01.21.07.41.30 for (version=TLS1_2 cipher=AES128-SHA bits=128/128); Thu, 21 Jan 2016 07:41:30 -0800 (PST) Date: Thu, 21 Jan 2016 09:41:28 -0600 (CST) From: Christoph Lameter Subject: Re: vmstat: make vmstat_updater deferrable again and shut down on idle In-Reply-To: Message-ID: References: Content-Type: text/plain; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: Shiraz Hashim Cc: Michal Hocko , akpm@linux-foundation.org, linux-mm@kvack.org, LKML , hannes@cmpxchg.org, penguin-kernel@i-love.sakura.ne.jp On Thu, 21 Jan 2016, Shiraz Hashim wrote: > > On idle we fold counters immediately. So there is no loss of accuracy. > > vmstat is scheduled by shepherd or by itself (conditionally). In case shepherd > is deferred and vmstat doesn't schedule itself, then vmstat needs to wait > for shepherd to be up and then schedule it. This may end up in delayed status > update for all live cpus. Isn't it ? The shepherd runs on a processor with an active tick and thus should do its duty every 2 seconds as scheduled. Small milisecond range deferrals do not matter much. -- 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