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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 00FD3C433EF for ; Fri, 11 Feb 2022 17:28:10 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1352153AbiBKR2K (ORCPT ); Fri, 11 Feb 2022 12:28:10 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:46560 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352122AbiBKR2I (ORCPT ); Fri, 11 Feb 2022 12:28:08 -0500 Received: from smtp.smtpout.orange.fr (smtp02.smtpout.orange.fr [80.12.242.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 72E1B2BF for ; Fri, 11 Feb 2022 09:28:07 -0800 (PST) Received: from [192.168.1.18] ([90.126.236.122]) by smtp.orange.fr with ESMTPA id IZi8niEgMeHnVIZi8nZeqD; Fri, 11 Feb 2022 18:28:05 +0100 X-ME-Helo: [192.168.1.18] X-ME-Auth: YWZlNiIxYWMyZDliZWIzOTcwYTEyYzlhMmU3ZiQ1M2U2MzfzZDfyZTMxZTBkMTYyNDBjNDJlZmQ3ZQ== X-ME-Date: Fri, 11 Feb 2022 18:28:05 +0100 X-ME-IP: 90.126.236.122 Message-ID: <2b67edce-c45e-c602-6e79-d1e148d57eca@wanadoo.fr> Date: Fri, 11 Feb 2022 18:27:56 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Subject: Re: [PATCH 12/49] perf: replace bitmap_weight with bitmap_empty where appropriate Content-Language: en-US To: Yury Norov , Andy Shevchenko , Rasmus Villemoes , Andrew Morton , =?UTF-8?B?TWljaGHFgiBNaXJvc8WCYXc=?= , Greg Kroah-Hartman , Peter Zijlstra , David Laight , Joe Perches , Dennis Zhou , Emil Renner Berthing , Nicholas Piggin , Matti Vaittinen , Alexey Klimov , linux-kernel@vger.kernel.org, Will Deacon , Mark Rutland , Shaokun Zhang , Qi Liu , Khuong Dinh , linux-arm-kernel@lists.infradead.org References: <20220210224933.379149-1-yury.norov@gmail.com> <20220210224933.379149-13-yury.norov@gmail.com> From: Christophe JAILLET In-Reply-To: <20220210224933.379149-13-yury.norov@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 10/02/2022 à 23:48, Yury Norov a écrit : > In some places, drivers/perf code calls bitmap_weight() to check if any > bit of a given bitmap is set. It's better to use bitmap_empty() in that > case because bitmap_empty() stops traversing the bitmap as soon as it > finds first set bit, while bitmap_weight() counts all bits unconditionally. > > Signed-off-by: Yury Norov > --- > drivers/perf/arm-cci.c | 2 +- > drivers/perf/arm_pmu.c | 4 ++-- > drivers/perf/hisilicon/hisi_uncore_pmu.c | 2 +- > drivers/perf/xgene_pmu.c | 2 +- > 4 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/drivers/perf/arm-cci.c b/drivers/perf/arm-cci.c > index 54aca3a62814..96e09fa40909 100644 > --- a/drivers/perf/arm-cci.c > +++ b/drivers/perf/arm-cci.c > @@ -1096,7 +1096,7 @@ static void cci_pmu_enable(struct pmu *pmu) > { > struct cci_pmu *cci_pmu = to_cci_pmu(pmu); > struct cci_pmu_hw_events *hw_events = &cci_pmu->hw_events; > - int enabled = bitmap_weight(hw_events->used_mask, cci_pmu->num_cntrs); > + bool enabled = !bitmap_empty(hw_events->used_mask, cci_pmu->num_cntrs); > unsigned long flags; > > if (!enabled) > diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c > index 295cc7952d0e..a31b302b0ade 100644 > --- a/drivers/perf/arm_pmu.c > +++ b/drivers/perf/arm_pmu.c > @@ -524,7 +524,7 @@ static void armpmu_enable(struct pmu *pmu) > { > struct arm_pmu *armpmu = to_arm_pmu(pmu); > struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); > - int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events); > + bool enabled = !bitmap_empty(hw_events->used_mask, armpmu->num_events); > > /* For task-bound events we may be called on other CPUs */ > if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) > @@ -785,7 +785,7 @@ static int cpu_pm_pmu_notify(struct notifier_block *b, unsigned long cmd, > { > struct arm_pmu *armpmu = container_of(b, struct arm_pmu, cpu_pm_nb); > struct pmu_hw_events *hw_events = this_cpu_ptr(armpmu->hw_events); > - int enabled = bitmap_weight(hw_events->used_mask, armpmu->num_events); > + bool enabled = !bitmap_empty(hw_events->used_mask, armpmu->num_events); > > if (!cpumask_test_cpu(smp_processor_id(), &armpmu->supported_cpus)) > return NOTIFY_DONE; > diff --git a/drivers/perf/hisilicon/hisi_uncore_pmu.c b/drivers/perf/hisilicon/hisi_uncore_pmu.c > index a738aeab5c04..358e4e284a62 100644 > --- a/drivers/perf/hisilicon/hisi_uncore_pmu.c > +++ b/drivers/perf/hisilicon/hisi_uncore_pmu.c > @@ -393,7 +393,7 @@ EXPORT_SYMBOL_GPL(hisi_uncore_pmu_read); > void hisi_uncore_pmu_enable(struct pmu *pmu) > { > struct hisi_pmu *hisi_pmu = to_hisi_pmu(pmu); > - int enabled = bitmap_weight(hisi_pmu->pmu_events.used_mask, > + bool enabled = !bitmap_empty(hisi_pmu->pmu_events.used_mask, > hisi_pmu->num_counters); > > if (!enabled) > diff --git a/drivers/perf/xgene_pmu.c b/drivers/perf/xgene_pmu.c > index 5283608dc055..0c32dffc7ede 100644 > --- a/drivers/perf/xgene_pmu.c > +++ b/drivers/perf/xgene_pmu.c > @@ -867,7 +867,7 @@ static void xgene_perf_pmu_enable(struct pmu *pmu) > { > struct xgene_pmu_dev *pmu_dev = to_pmu_dev(pmu); > struct xgene_pmu *xgene_pmu = pmu_dev->parent; > - int enabled = bitmap_weight(pmu_dev->cntr_assign_mask, > + bool enabled = !bitmap_empty(pmu_dev->cntr_assign_mask, > pmu_dev->max_counters); Would it make sense to call it 'disabled', remove the "!"... > > if (!enabled) ... and 'if (disabled)' here? Just my 2c, CJ