Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752989Ab3IWPKM (ORCPT ); Mon, 23 Sep 2013 11:10:12 -0400 Received: from a9-46.smtp-out.amazonses.com ([54.240.9.46]:36140 "EHLO a9-46.smtp-out.amazonses.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752655Ab3IWPKJ (ORCPT ); Mon, 23 Sep 2013 11:10:09 -0400 Date: Mon, 23 Sep 2013 15:10:07 +0000 From: Christoph Lameter X-X-Sender: cl@gentwo.org To: Thomas Gleixner cc: Frederic Weisbecker , Andrew Morton , Gilad Ben-Yossef , Tejun Heo , John Stultz , Mike Frysinger , Minchan Kim , Hakan Akkan , Max Krasnyansky , "linux-kernel@vger.kernel.org" , "Paul E. McKenney" , Linux-MM , Peter Zijlstra Subject: Re: RFC vmstat: On demand vmstat threads In-Reply-To: Message-ID: <000001414b5ebafe-a82f870f-283a-4210-a1d8-4035e2720c4f-000000@email.amazonses.com> References: <00000140e9dfd6bd-40db3d4f-c1be-434f-8132-7820f81bb586-000000@email.amazonses.com> <0000014109b8e5db-4b0f577e-c3b4-47fe-b7f2-0e5febbcc948-000000@email.amazonses.com> <20130918150659.5091a2c3ca94b99304427ec5@linux-foundation.org> <000001413796641f-017482d3-1194-499b-8f2a-d7686c1ae61f-000000@email.amazonses.com> <20130920164201.GB30381@localhost.localdomain> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-SES-Outgoing: 2013.09.23-54.240.9.46 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 887 Lines: 20 On Fri, 20 Sep 2013, Thomas Gleixner wrote: > Now when a cpu becomes isolated we stop the callback scheduling on > that cpu and assign it to the cpu with the smallest NUMA > distance. So that cpu will process the data for itself and for the > newly isolated cpu. That is not possible for many percpu threads since they rely on running on a specific cpu for optimization purposes. Running on a different processor makes these threads racy. What is needed is to be able to switch these things off and on. Something on a different cpu may monitor if processing on that specific cpu is needed or not but it cannot perform the vmstat updates. -- 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/