From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10682C43603 for ; Wed, 11 Dec 2019 09:52:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D73922053B for ; Wed, 11 Dec 2019 09:52:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1576057957; bh=/Q8K9m7bLUS1Wl9b0/6U6Vy+QE8BOUQfzq7CUqu+0wQ=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=jUOSDesaK+6MZv2F2fkMcgTng/7XNqMMnJUzzmzg8Wl9MDwDDt1Edr0eVya+GobGR zQdvc4qe1LwydjGCAU8yhddSxgwzI7LXQHXkmHE8PNy3TvgsJzv1IFA5APWK+I3Btp 63yKJ8HpEht/xqjgs3TFaMsQLpaV9OBtCmQIoUaU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727829AbfLKJwh (ORCPT ); Wed, 11 Dec 2019 04:52:37 -0500 Received: from mail-ot1-f41.google.com ([209.85.210.41]:39649 "EHLO mail-ot1-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727493AbfLKJwh (ORCPT ); Wed, 11 Dec 2019 04:52:37 -0500 Received: by mail-ot1-f41.google.com with SMTP id 77so18254737oty.6 for ; Wed, 11 Dec 2019 01:52:36 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=0VYbMrpAPVUP++42+if6/sOAJ6aqp54klXfwh9b8UiI=; b=JhmXtbTosb5/lPM2cAaY9bbnCVnDdII1BtL2kVU+5D56v8XT/OpAdXAf77DBCufnfw qxqm4xCpYvJ+hJ+lZmiUE/LmC/9DKHRFPgIXMPudf66d/pZBPsSBCMjUXN1x0ZfYXj4f cVu7i9Zc/5hDizQShi9PbnFyiszBLsmGHnxq0qXqh1szPIVO5w4AalD4nT5z96KARzMH GATwm3kKsvRjMXTH/1JkzQdbnUQGGPUQw3fQrGSDrLA0Uesyag4D5p1UVSIMYOuTD/5e Ro/guvTj29uFZWSo5uRTpeSfQbvpD3XOGErA+oQ+4UvBVr5Rq1CuAUkcnzOufdk2tWBl YxfQ== X-Gm-Message-State: APjAAAWW1ukGjULeMljLDARKhKpzNkXAmEY2WHi552vQbI9mP+jEYCM3 4UOSGqG8Q3kZSqUXxQFveh6swlDB+Xf+MkKO9Cc= X-Google-Smtp-Source: APXvYqwbjdUhbVprV8OnOXcs2lz0eNVF/OUlpcMJfeS0wLIcQtsYz8p02cguUyXF8K0MAMlsL3Mzh1cJrsG4neMvnM4= X-Received: by 2002:a05:6830:4b9:: with SMTP id l25mr1688428otd.266.1576057956020; Wed, 11 Dec 2019 01:52:36 -0800 (PST) MIME-Version: 1.0 References: <5310126.hg2rr5Fjtk@kreacher> <7233060.oySJ2cjCuV@kreacher> In-Reply-To: From: "Rafael J. Wysocki" Date: Wed, 11 Dec 2019 10:52:24 +0100 Message-ID: Subject: Re: About CPU hot-plug stress test failed in cpufreq driver To: Peng Fan Cc: "Rafael J. Wysocki" , "Rafael J. Wysocki" , Anson Huang , Viresh Kumar , Jacky Bai , "linux-pm@vger.kernel.org" , Vincent Guittot , Peter Zijlstra , Paul McKenney Content-Type: text/plain; charset="UTF-8" Sender: linux-pm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Wed, Dec 11, 2019 at 10:43 AM Peng Fan wrote: > > > Subject: Re: About CPU hot-plug stress test failed in cpufreq driver > > > > On Wed, Dec 11, 2019 at 9:59 AM Peng Fan wrote: [cut] > > But preventing CPUs with NULL cpufreq_update_util_data pointers from > > running cpufreq utilization update code at all (like in the last > > patch) should be sufficient to address this problem entirely. At least I don't > > see why not. > > I just think the scheduler want to inject irq_work on the cpu even during the > cpu offlining process, but we not inject irq work with your patch. Is this right? Yes, but that means that we just avoid a cross-update which would be discarded due to the policy->cpus mask check without dvfs_possible_from_any_cpu. The target online CPU will run this update by itself eventually anyway.