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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0C845C4332F for ; Fri, 11 Feb 2022 10:40:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 769316B0078; Fri, 11 Feb 2022 05:40:01 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 719A36B007B; Fri, 11 Feb 2022 05:40:01 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 5E08C6B007D; Fri, 11 Feb 2022 05:40:01 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id 4C2FC6B0078 for ; Fri, 11 Feb 2022 05:40:01 -0500 (EST) Received: from smtpin02.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 1BB2360D8B for ; Fri, 11 Feb 2022 10:40:01 +0000 (UTC) X-FDA: 79130153802.02.0C03974 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by imf24.hostedemail.com (Postfix) with ESMTP id 86C60180008 for ; Fri, 11 Feb 2022 10:40:00 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 1250AB8286B; Fri, 11 Feb 2022 10:39:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 691E5C340E9; Fri, 11 Feb 2022 10:39:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1644575997; bh=epNf5a++0MNgic0Ddcu/sWPTzxUU2JKWCnmcuxoxMf8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=T+KwGIaahMH2W44YXM1ZixMDEUJhV/OA0A8G7KY/XfL25XNoO3eKDus9SOUQ1B/t7 crRIGCn6FcuE65Aje7whQbuaV8+DSDf29hbNQ0reHb8t44EVkwcrxJVDJUdCqpl29f z+oIOHQVcS1n8BLoiOzD7/2q/JAyrdQR7oNO12BzYbmVsrILmZabtajLmesKci4bbJ wNGQ6ddv2E7bn//wLkPs4nddZEWCK1+t991DOay9gJgwaSGgApmb/mHYT4WsZgmlS9 2KzDFW+0W+SXmJZpoQbdso+TEkaT8rJXlyD8linQbvq1xoIbWWpneIHWqlFw7d9k3N OYuBUQbic/CBw== Date: Fri, 11 Feb 2022 12:39:47 +0200 From: Mike Rapoport To: Yury Norov Cc: 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, linux-mm@kvack.org Subject: Re: [PATCH 24/49] mm/vmstat: replace cpumask_weight with cpumask_empty where appropriate Message-ID: References: <20220210224933.379149-1-yury.norov@gmail.com> <20220210224933.379149-25-yury.norov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220210224933.379149-25-yury.norov@gmail.com> X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 86C60180008 X-Stat-Signature: tp5niu36uo76typoexhds5webae11qfw Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=T+KwGIaa; dmarc=pass (policy=none) header.from=kernel.org; spf=pass (imf24.hostedemail.com: domain of rppt@kernel.org designates 145.40.68.75 as permitted sender) smtp.mailfrom=rppt@kernel.org X-HE-Tag: 1644576000-567132 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Feb 10, 2022 at 02:49:08PM -0800, Yury Norov wrote: > mm/vmstat.c code calls cpumask_weight() to check if any bit of a given > cpumask is set. We can do it more efficiently with cpumask_empty() because > cpumask_empty() stops traversing the cpumask as soon as it finds first set > bit, while cpumask_weight() counts all bits unconditionally. > > Signed-off-by: Yury Norov Acked-by: Mike Rapoport > --- > mm/vmstat.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/vmstat.c b/mm/vmstat.c > index d5cc8d739fac..27a94afd4ee5 100644 > --- a/mm/vmstat.c > +++ b/mm/vmstat.c > @@ -2041,7 +2041,7 @@ static void __init init_cpu_node_state(void) > int node; > > for_each_online_node(node) { > - if (cpumask_weight(cpumask_of_node(node)) > 0) > + if (!cpumask_empty(cpumask_of_node(node))) > node_set_state(node, N_CPU); > } > } > @@ -2068,7 +2068,7 @@ static int vmstat_cpu_dead(unsigned int cpu) > > refresh_zone_stat_thresholds(); > node_cpus = cpumask_of_node(node); > - if (cpumask_weight(node_cpus) > 0) > + if (!cpumask_empty(node_cpus)) > return 0; > > node_clear_state(node, N_CPU); > -- > 2.32.0 > > -- Sincerely yours, Mike.