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=-15.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 D033CC4361B for ; Mon, 14 Dec 2020 12:59:07 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 7365820728 for ; Mon, 14 Dec 2020 12:59:07 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7365820728 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+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=merlin.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=oq/RMzj6/d87EPXJCRzIMHJdxzuN6e403dXGLqC3awE=; b=squEwcMzujeH7ueHZS9bFbfXc mjKoJF9zMaQ5ihmIAxpg+y6xHS30haOOEuIW1kAsYtGl+m9yEMdgoWmkK91NnHmNKxn3dmKi8+Bx3 7nVDeQMVtGmY35AyV8J/lw34KBVmRiplCAwbr48Xx+fJpb+FxXC+WGCtmP2s5c+N7rNg2pALtgip1 4mGNmNv7NR4Tc1eBGdmlb07T8XuF3YyVuUsyYnzjEBoumEg5xEWCbWR1PyBcKz/xzhp+pAW27q4cd YvUZXSCLmQndXp1B6njVKSysJkoU+jefw2UijB5uiV9xzdYCJDaFjWI7E3xXRs89qtznLik6MJLPl 6Umrd5URA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1konQM-0000lQ-06; Mon, 14 Dec 2020 12:57:58 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1konQI-0000kJ-KI for linux-arm-kernel@lists.infradead.org; Mon, 14 Dec 2020 12:57:55 +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 B58091FB; Mon, 14 Dec 2020 04:57:52 -0800 (PST) Received: from localhost (unknown [10.1.198.32]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 4D7FE3F66B; Mon, 14 Dec 2020 04:57:52 -0800 (PST) Date: Mon, 14 Dec 2020 12:57:50 +0000 From: Ionela Voinescu To: Viresh Kumar Subject: Re: [PATCH V2 1/2] arm64: topology: Avoid the have_policy check Message-ID: <20201214125750.GA15405@arm.com> References: <5f85c2ddf7aa094d7d2ebebe8426f84fad0a99b7.1607617625.git.viresh.kumar@linaro.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5f85c2ddf7aa094d7d2ebebe8426f84fad0a99b7.1607617625.git.viresh.kumar@linaro.org> 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-20201214_075754_770783_AAE5927A X-CRM114-Status: GOOD ( 28.50 ) 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: Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Vincent Guittot Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thursday 10 Dec 2020 at 21:59:22 (+0530), Viresh Kumar wrote: > Every time I have stumbled upon this routine, I get confused with the > way 'have_policy' is used and I have to dig in to understand why is it > so. Here is an attempt to make it easier to understand, and hopefully it > is an improvement. > > The 'have_policy' check was just an optimization to avoid writing > to amu_fie_cpus in case we don't have to, but that optimization itself > is creating more confusion than the real work. Lets just do that if all > the CPUs support AMUs. It is much cleaner that way. > > Signed-off-by: Viresh Kumar > --- > V2: > - Skip the have_policy check altogether > - Updated subject and log > > arch/arm64/kernel/topology.c | 20 ++++++-------------- > 1 file changed, 6 insertions(+), 14 deletions(-) > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index f6faa697e83e..ebadc73449f9 100644 > --- a/arch/arm64/kernel/topology.c > +++ b/arch/arm64/kernel/topology.c > @@ -199,14 +199,14 @@ static int freq_inv_set_max_ratio(int cpu, u64 max_rate, u64 ref_rate) > return 0; > } > > -static inline bool > +static inline void > enable_policy_freq_counters(int cpu, cpumask_var_t valid_cpus) > { > struct cpufreq_policy *policy = cpufreq_cpu_get(cpu); > > if (!policy) { > pr_debug("CPU%d: No cpufreq policy found.\n", cpu); > - return false; > + return; > } > > if (cpumask_subset(policy->related_cpus, valid_cpus)) > @@ -214,8 +214,6 @@ enable_policy_freq_counters(int cpu, cpumask_var_t valid_cpus) > amu_fie_cpus); > > cpufreq_cpu_put(policy); > - > - return true; > } > > static DEFINE_STATIC_KEY_FALSE(amu_fie_key); > @@ -225,7 +223,6 @@ static int __init init_amu_fie(void) > { > bool invariance_status = topology_scale_freq_invariant(); > cpumask_var_t valid_cpus; > - bool have_policy = false; > int ret = 0; > int cpu; > > @@ -245,17 +242,12 @@ static int __init init_amu_fie(void) > continue; > > cpumask_set_cpu(cpu, valid_cpus); > - have_policy |= enable_policy_freq_counters(cpu, valid_cpus); > + enable_policy_freq_counters(cpu, valid_cpus); > } > > - /* > - * If we are not restricted by cpufreq policies, we only enable > - * the use of the AMU feature for FIE if all CPUs support AMU. > - * Otherwise, enable_policy_freq_counters has already enabled > - * policy cpus. > - */ > - if (!have_policy && cpumask_equal(valid_cpus, cpu_present_mask)) > - cpumask_or(amu_fie_cpus, amu_fie_cpus, valid_cpus); > + /* Overwrite amu_fie_cpus if all CPUs support AMU */ > + if (cpumask_equal(valid_cpus, cpu_present_mask)) > + cpumask_copy(amu_fie_cpus, cpu_present_mask); > > if (!cpumask_empty(amu_fie_cpus)) { > pr_info("CPUs[%*pbl]: counters will be used for FIE.", > -- > 2.25.0.rc1.19.g042ed3e048af > Reviewed-by: Ionela Voinescu Thanks, Ionela. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel