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 5FC34C00140 for ; Mon, 8 Aug 2022 16:41:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC91B6B0071; Mon, 8 Aug 2022 12:41:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E51898E0001; Mon, 8 Aug 2022 12:41:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CA5146B0073; Mon, 8 Aug 2022 12:41:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id B592E6B0071 for ; Mon, 8 Aug 2022 12:41:06 -0400 (EDT) Received: from smtpin24.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 96822C0C82 for ; Mon, 8 Aug 2022 16:41:06 +0000 (UTC) X-FDA: 79776990132.24.BF51C6B Received: from mail-oi1-f182.google.com (mail-oi1-f182.google.com [209.85.167.182]) by imf03.hostedemail.com (Postfix) with ESMTP id 09CA320160 for ; Mon, 8 Aug 2022 16:41:05 +0000 (UTC) Received: by mail-oi1-f182.google.com with SMTP id j5so5263981oih.6 for ; Mon, 08 Aug 2022 09:41:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc; bh=fLnheameMTeEL0CE77MMCkg1If0aNMzopn0WMXOJTKk=; b=qOJKou/ClLwTQLP4NNnUxSQa6KbdAPdN0mUjvDRIOhKCgcX0DCi4Fc3l3cTaGTeanB 6X1xlputAEYCKUowsG8f6hACY+bgsiVHi8U65759+pnIgp3hIaB3Hsl3OZm3riTrsENz tB0pm4ezHPBKQEq1/Ftb4Z8FTByzZbJmmdO4gXh1nS1+gI5AO9lCCfBSjbUJTGpDpLjk e5wD7Dm7U0+UT4d+ZPHKj6eXmPQUrRmMulH1EjVa2Ia9jGbokP+GEpJNi9CBU5LWscIN Ndd9QcERICcThuNytvwSoXhb/7qHWB9xF2KIffs9vIQtAqz77DoiNLA4puVFdNbqLGbj j+GA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc; bh=fLnheameMTeEL0CE77MMCkg1If0aNMzopn0WMXOJTKk=; b=wEeejwPCul+FfhCbFNAF8lhZlamwvasb0CLtiQo/ri9G7xuV4nWGLwzqHBUsjLHs/5 x8RLow5FI8pk8ZsmfLHs3UxyGwwI4pO6IkTZGAK57EdcareAxLj+M7m37a//A/jVBv6z mubNUZ31qcy7W9A0iRkEVbD4LIO4sCdzs0ooLu0Sfuv1h3yBwetbWrf0E/4bchk0qyIo u0asUT+b7a1W3pfbzizrSM6AperF146a+2AHOpthUPaAyqD4PQDUDHL2SQ4b34t6FxIS l91m1z/LWNV862SpdiCRGz8NhcGvLdf6Jiy5a5i1g537kc3VNq1THXsCg3/Q//0GyNfv 8FMQ== X-Gm-Message-State: ACgBeo0DxIm0E2yKPrd7bmXAJxgIuhyQov3QFs0ABd/4dzrkqdikultk bIj2jsKGZu0aa/8spQJ7IIE= X-Google-Smtp-Source: AA6agR7luNFvpCWE/t9/r8m8eopNqkdTdHSdd4rwc3gBkgtq2Df4OJnYf9DNr1arbqvv7Lck6GCiKA== X-Received: by 2002:a05:6808:138f:b0:33a:9bb6:80b5 with SMTP id c15-20020a056808138f00b0033a9bb680b5mr11130215oiw.243.1659976865158; Mon, 08 Aug 2022 09:41:05 -0700 (PDT) Received: from localhost ([12.97.180.36]) by smtp.gmail.com with ESMTPSA id a32-20020a056870a1a000b0010d997ffe7asm2444787oaf.37.2022.08.08.09.41.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Aug 2022 09:41:04 -0700 (PDT) Date: Mon, 8 Aug 2022 09:38:52 -0700 From: Yury Norov To: Thomas Gleixner Cc: linux-kernel@vger.kernel.org, Alexander Lobakin , Alexei Starovoitov , Alexey Klimov , Andrew Morton , Andrii Nakryiko , Andy Shevchenko , Ben Segall , Christoph Lameter , Dan Williams , Daniel Borkmann , Daniel Bristot de Oliveira , Dennis Zhou , Dietmar Eggemann , Eric Dumazet , Frederic Weisbecker , Guenter Roeck , Ingo Molnar , Isabella Basso , John Fastabend , Josh Poimboeuf , Juergen Gross , Juri Lelli , KP Singh , Kees Cook , Martin KaFai Lau , Mel Gorman , Miroslav Benes , Nathan Chancellor , "Paul E . McKenney" , Peter Zijlstra , Randy Dunlap , Rasmus Villemoes , Sebastian Andrzej Siewior , Song Liu , Steven Rostedt , Tejun Heo , Valentin Schneider , Vincent Guittot , Vlastimil Babka , Yonghong Song , linux-mm@kvack.org, netdev@vger.kernel.org, bpf@vger.kernel.org Subject: Re: [PATCH 11/16] time: optimize tick_check_preferred() Message-ID: References: <20220718192844.1805158-1-yury.norov@gmail.com> <20220718192844.1805158-12-yury.norov@gmail.com> <87fsi9rcxu.ffs@tglx> <87czdbq7up.ffs@tglx> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87czdbq7up.ffs@tglx> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1659976866; a=rsa-sha256; cv=none; b=DP4L4llvFKGxpkebamMi7cQcF1D0yF136Z2dSN8vRem2LdGKKxD1LGeU2VhZlSuArm5q7G Pogdmi+3zYNx/lmX+WVOF+kTDr8q1JH/qzdv8LENrbdZlKQltzyvC/ckBohRKWlL/z3PV/ 54Ov5HlsK1BweJVdup9L8SwOte8/8OY= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="qOJKou/C"; spf=pass (imf03.hostedemail.com: domain of yury.norov@gmail.com designates 209.85.167.182 as permitted sender) smtp.mailfrom=yury.norov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1659976866; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fLnheameMTeEL0CE77MMCkg1If0aNMzopn0WMXOJTKk=; b=Znjnq7dInPdqM/dmbEa3F44IWjoEb7GOCzy44ed6aZnnwkn3UAsa0P+Uu2ld3Y/0Kt7dWh sQ18lEorxsAWh++Ay/lDE2WWpAg/HsJsMtmx2NauuCEPNiuq1WwXjrsue+PK/UxrKCqSjS yOOTc4c/58HYqS0dSzpDv1J+kYaDSnE= X-Rspamd-Queue-Id: 09CA320160 X-Rspam-User: X-Rspamd-Server: rspam11 Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b="qOJKou/C"; spf=pass (imf03.hostedemail.com: domain of yury.norov@gmail.com designates 209.85.167.182 as permitted sender) smtp.mailfrom=yury.norov@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: 4gt18n8go4kfa1ztqyuuo7ixut4gzria X-HE-Tag: 1659976865-941859 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 Mon, Aug 08, 2022 at 01:42:54PM +0200, Thomas Gleixner wrote: > On Sat, Aug 06 2022 at 10:30, Thomas Gleixner wrote: > > On Mon, Jul 18 2022 at 12:28, Yury Norov wrote: > > > >> tick_check_preferred() calls cpumask_equal() even if > >> curdev->cpumask == newdev->cpumask. Fix it. > > > > What's to fix here? It's a pointless operation in a slow path and all > > your "fix' is doing is to make the code larger. Pointless operation in a slow path is still pointless. > In fact cpumask_equal() should have the ptr1 == ptr2 check, so you don't > have to add it all over the place. This adds to the image size: add/remove: 1/1 grow/shrink: 24/3 up/down: 507/-46 (461) The more important, cpumask shouldn't check parameters because this is an internal function. This whole series point is about adding such checks under DEBUG_BITMAP config, and not affecting general case. What about adding cpumask_equal__addr? (Any better name is welcome.) Thanks, Yury