From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934487AbcATPM5 (ORCPT ); Wed, 20 Jan 2016 10:12:57 -0500 Received: from resqmta-ch2-03v.sys.comcast.net ([69.252.207.35]:53541 "EHLO resqmta-ch2-03v.sys.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934215AbcATPMz (ORCPT ); Wed, 20 Jan 2016 10:12:55 -0500 Date: Wed, 20 Jan 2016 09:12:52 -0600 (CST) From: Christoph Lameter X-X-Sender: cl@east.gentwo.org 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 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: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 20 Jan 2016, Shiraz Hashim wrote: > The patch makes vmstat_shepherd deferable which if is quiesed > would not schedule vmstat update on other cpus. Wouldn't this > aggravate the problem of vmstat for rest cpus not gettng updated. Its only "deferred" in order to make it at the next tick and not cause an extra event. This means that vmstat will run periodically from tick processing. It merely causes a synching so that we have one interruption that does both. On idle we fold counters immediately. So there is no loss of accuracy.