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=-11.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL 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 CE72BC433E7 for ; Mon, 12 Oct 2020 13:10:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 79FF220878 for ; Mon, 12 Oct 2020 13:10:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="XGY9IxnK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726130AbgJLNKO (ORCPT ); Mon, 12 Oct 2020 09:10:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388696AbgJLNKK (ORCPT ); Mon, 12 Oct 2020 09:10:10 -0400 Received: from mail-wr1-x442.google.com (mail-wr1-x442.google.com [IPv6:2a00:1450:4864:20::442]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89624C0613D0 for ; Mon, 12 Oct 2020 06:10:09 -0700 (PDT) Received: by mail-wr1-x442.google.com with SMTP id n18so19132515wrs.5 for ; Mon, 12 Oct 2020 06:10:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=HDv79H0T0YMmpA6Cg6LXdiKcuj2DrLE+0Njp0Y0u8KM=; b=XGY9IxnK+Djfx5Zb8HC+CkSfHoX6LZfeU7EHgj0M7jE27eNiu/NTCS/8O2N4CTMsIr 5HqQk78SAe0OaeEucGW1pj0pUs0eJK0sgVXRExrJJ1zO7w1xG78/XBvpsOoi0BhY+Z1w jF7hYRNPIHRUxxFrSyeAToz+/9RQ+zjKRDJgcjSHa4Uap2u0tdqxNVZf7hqSh24Xi9sT f+HixQE9Y0oDRYUii64YVp8p/vFZjnBTnvXhhjUpoK82Up70SzvU6+iF4rws5ul5hPfy YRi+o3/CaD4VTZS0wfrcVj/HR330hT2wnk/fWjBuNSrCrx78+tJHm2Pf+4dKLNOcsWEp 9FQg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=HDv79H0T0YMmpA6Cg6LXdiKcuj2DrLE+0Njp0Y0u8KM=; b=s9joCbanxzwvQcCMRtWqEZfgWoCTNHXr+QbQC9skjSqjTEwhjqpw0i/v5nhqNKdVZf Sd2RzN5raMPFYDyNERSATASbHzZ4895BSQNPfGf2Y7EWT66SHnK9eLHPkFlYVpXlpTD3 E/OhjFf3hxL5x5HyVfL32eNz2aryQc3SwmT8ouB8xgBiAiAvi/Zl7Daf5HM+CJTMmDDW NaPyyyH4PkOs8aRLOLwkawa3iTPcmqnBUKsUXPJtGzzigxkJ3DFxp3/OM20QNsXKurQN hkH9agZeiKesUH0ucJBo5oaKXQGZJW++hpO0iy6ZhrrbVBlqg1bkEx0BCS9i1xlZai/C Yl9g== X-Gm-Message-State: AOAM533kyOk65x3MjUdrG+9BuWupjDCKuDff+1LzqfaT2h9ebU38/ucf FhyrMFNF+38OXOorSN8I08eGAg== X-Google-Smtp-Source: ABdhPJysslHpkfKa/rNifK/bUIFGSLBzE605Lmx/ZaVPZeJstlvv21gBu3jK5rmlIjoNhyVsWXs6gg== X-Received: by 2002:adf:97dd:: with SMTP id t29mr21818564wrb.322.1602508208105; Mon, 12 Oct 2020 06:10:08 -0700 (PDT) Received: from google.com ([2a00:79e0:d:110:f693:9fff:fef4:a7ef]) by smtp.gmail.com with ESMTPSA id u20sm15595626wmm.29.2020.10.12.06.10.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 12 Oct 2020 06:10:07 -0700 (PDT) Date: Mon, 12 Oct 2020 14:10:04 +0100 From: Quentin Perret To: zhuguangqing83@gmail.com Cc: lukasz.luba@arm.com, quentin.perret@arm.com, rjw@rjwysocki.net, pavel@ucw.cz, len.brown@intel.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, zhuguangqing Subject: Re: [PATCH] PM / EM: consult something about cpumask in em_dev_register_perf_domain Message-ID: <20201012131004.GB3366383@google.com> References: <20201012124136.4147-1-zhuguangqing83@gmail.com> <20201012130501.GA3366383@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201012130501.GA3366383@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-pm@vger.kernel.org On Monday 12 Oct 2020 at 14:05:01 (+0100), Quentin Perret wrote: > > 3, The third question is, how can we ensure cpu_dev as follows is not > > NULL? If we can't ensure that, maybe we should add a check before using > > it. > > /kernel/power/energy_model.c > > 174) static int em_create_pd(struct device *dev, int nr_states, > > 175) struct em_data_callback *cb, cpumask_t *cpus) > > 176) { > > 199) if (_is_cpu_device(dev)) > > 200) for_each_cpu(cpu, cpus) { > > 201) cpu_dev = get_cpu_device(cpu); > > 202) cpu_dev->em_pd = pd; > > 203) } > > And that should not be necessary as we check for the !dev case at the > top of em_dev_register_perf_domain(). Or were you thinking about > something else? Oh I think I read that one wrong, but the conclusion should be the same, at least on Arm64 -- all _possible_ CPUs should be registered early enough for that not to be an issue. Did you observe anything wrong there for your use-case? Thanks, Quentin