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=-2.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 83F8FC432C0 for ; Wed, 27 Nov 2019 12:08:27 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 515B92068E for ; Wed, 27 Nov 2019 12:08:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="opoido2A" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 515B92068E Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WFKWZEl7mGS9qkRh/ilucLhg6wSxs6SVHUvCvMiWHJw=; b=opoido2ABYAVGt KlP+i7uPxFmlBaDXetBqY707SLrjwtN6m1Z73c557S0DKsQfWrqMGcJ7hfgJZLN8qAWbLHDZVEnIs 1o3stcuwzt4vvMZ8KgKwc3BR+eo4JKVLWIb41M0eRkk08FtflON6dX9nXvFfqC9dDYs0dAHAeIZpQ 05e9ywSnWpIZzPEEB3Yazcsah5sbfsl1SkGUj1a6mAT0ZwNBbevvXGEnY1xqnJ1F5+bpytIyOdgFs xqaepjXOmngDtZsAtI7virD+23kWncwEJJqiKJWAIUFIMasDZ7xWeVt5zbVvLQlbtpkuxmtCfldrC h7tMZwgLbTYjzwQEBLOg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iZw7N-0000lk-Ug; Wed, 27 Nov 2019 12:08:25 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iZw7J-0000i4-3P for linux-arm-kernel@lists.infradead.org; Wed, 27 Nov 2019 12:08:23 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 2325530E; Wed, 27 Nov 2019 04:08:20 -0800 (PST) Received: from bogus (e107155-lin.cambridge.arm.com [10.1.196.42]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A73C73F6C4; Wed, 27 Nov 2019 04:08:18 -0800 (PST) Date: Wed, 27 Nov 2019 12:08:16 +0000 From: Sudeep Holla To: Dietmar Eggemann Subject: Re: [PATCH] cpufreq: vexpress-spc: Fix wrong alternation of policy->related_cpus during CPU hp Message-ID: <20191127120816.GC29301@bogus> References: <20191127114801.23837-1-dietmar.eggemann@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20191127114801.23837-1-dietmar.eggemann@arm.com> User-Agent: Mutt/1.9.4 (2018-02-28) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191127_040821_221573_3B5C76DC X-CRM114-Status: GOOD ( 14.80 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "Rafael J . Wysocki" , Lorenzo Pieralisi , linux-pm@vger.kernel.org, Viresh Kumar , Liviu Dudau , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sudeep Holla , Morten Rasmussen , Lukasz Luba Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Nov 27, 2019 at 12:48:01PM +0100, Dietmar Eggemann wrote: > Since commit ca74b316df96 ("arm: Use common cpu_topology structure and > functions.") the core cpumask has to be modified during cpu hotplug > operations. > > ("arm: Fix topology setup in case of CPU hotplug for CONFIG_SCHED_MC") > [1] fixed that but revealed another issue on TC2, i.e in its cpufreq > driver. > > During CPU hp stress operations on multiple CPUs, policy->related_cpus > can be altered. This is wrong since this cpumask should contain the > online and offline CPUs. > > The WARN_ON(!cpumask_test_cpu(cpu, policy->related_cpus)) in > cpufreq_online() triggers in this case. > > The core cpumask can't be used to set the policy->cpus in > ve_spc_cpufreq_init() anymore in case it is called via > cpuhp_cpufreq_online()->cpufreq_online()->cpufreq_driver->init(). > > An empty online() callback can be used to avoid that the init() > driver function is called during CPU hotplug in so that > policy->related_cpus will not be changed. > Unlike DT based drivers, it not easy to get the fixed cpumask unless we add some mechanism to extract it based on clks/OPP added. I prefer this simple solution instead. > Implementing an online() also requires an offline() callback. > > Tested on TC2 with CPU hp stress test (CPU hp from multiple CPUs at > the same time). > > [1] > https://lore.kernel.org/r/20191127103353.12417-1-dietmar.eggemann@arm.com > Reviewed-by: Sudeep Holla Tested-by: Sudeep Holla -- Regards, Sudeep _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel