Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752566AbdLSQcX (ORCPT ); Tue, 19 Dec 2017 11:32:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:53516 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752052AbdLSQcT (ORCPT ); Tue, 19 Dec 2017 11:32:19 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3388E21921 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=frederic@kernel.org X-Google-Smtp-Source: ACJfBovlRxO2Lzt1oS0evvKFuMXtUFhC/wwtv6WZeFDFXGS8FAILJ+oowALasVRWxaIYoqOs8LXuvaDCqQv9fN1JCDk= MIME-Version: 1.0 In-Reply-To: References: <1513653838-31314-1-git-send-email-frederic@kernel.org> <1513653838-31314-5-git-send-email-frederic@kernel.org> From: Frederic Weisbecker Date: Tue, 19 Dec 2017 17:32:17 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload To: Christopher Lameter Cc: LKML , Peter Zijlstra , Chris Metcalf , Thomas Gleixner , Luiz Capitulino , "Paul E . McKenney" , Ingo Molnar , Wanpeng Li , Mike Galbraith , Rik van Riel Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 562 Lines: 13 2017-12-19 17:03 UTC+01:00, Christopher Lameter : > On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > >> Adding the boot parameter "isolcpus=nohz_offload" will now outsource >> these scheduler ticks to the global workqueue so that a housekeeping CPU >> handles that tick remotely. > > The vmstat processing required per cpu area access. How does that work if > the code is running on a remote processor? It seems that current::sched_class::task_tick() is ok with this, as it uses per runqueues or per task datas. And both are passed as arguments.