Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754034AbaATPAO (ORCPT ); Mon, 20 Jan 2014 10:00:14 -0500 Received: from mail-oa0-f46.google.com ([209.85.219.46]:64746 "EHLO mail-oa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751947AbaATPAL (ORCPT ); Mon, 20 Jan 2014 10:00:11 -0500 MIME-Version: 1.0 In-Reply-To: References: Date: Mon, 20 Jan 2014 20:30:10 +0530 Message-ID: Subject: Re: [QUERY]: Is using CPU hotplug right for isolating CPUs? From: Viresh Kumar To: Lei Wen Cc: =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= , Kevin Hilman , Lists linaro-kernel , Peter Zijlstra , Linux Kernel Mailing List , Steven Rostedt , Linaro Networking Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 20 January 2014 19:29, Lei Wen wrote: > Hi Viresh, Hi Lei, > I have one question regarding unbounded workqueue migration in your case. > You use hotplug to migrate the unbounded work to other cpus, but its cpu mask > would still be 0xf, since cannot be changed by cpuset. > > My question is how you could prevent this unbounded work migrate back > to your isolated cpu? > Seems to me there is no such mechanism in kernel, am I understand wrong? These workqueues are normally queued back from workqueue handler. And we normally queue them on the local cpu, that's the default behavior of workqueue subsystem. And so they land up on the same CPU again and again. -- 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/