From patchwork Sat Aug 14 21:17:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yury Norov X-Patchwork-Id: 12436855 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BB725C4338F for ; Sat, 14 Aug 2021 21:20:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 989B360F51 for ; Sat, 14 Aug 2021 21:20:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234528AbhHNVUh (ORCPT ); Sat, 14 Aug 2021 17:20:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54186 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235683AbhHNVT4 (ORCPT ); Sat, 14 Aug 2021 17:19:56 -0400 Received: from mail-pl1-x631.google.com (mail-pl1-x631.google.com [IPv6:2607:f8b0:4864:20::631]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0176C061292; Sat, 14 Aug 2021 14:19:05 -0700 (PDT) Received: by mail-pl1-x631.google.com with SMTP id e19so16290165pla.10; Sat, 14 Aug 2021 14:19:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:subject:date:message-id:in-reply-to:references:mime-version :content-transfer-encoding; bh=Cln644oA5BtyIgpgaZQiZNhvZEjmPyvVC+lofWod4OE=; b=WMJpwYfq3UWrnHQf3XZGnUwN7halllE4Zh6nVwPNP+xHqyTu1DBiwM63+thW+pB61w H0lrWah0eBUT5yAxpyUwU0zZt/dibfzOvgTPZaPZH53pRJ2GGERqb95nsamfAPaeHuY8 sqzjFzro/0HBMvkXu9jCm/lV4KF7sNZeh6a8baeBCXFHzS7iHNCyJW5i/qX3uzmFo54B g7tPy2mU45RHZkA0i9xNhHwqc8dvVplUiR58RGDbEQKqJF+gzV8X17g7K3uBUUdxPdYx Vw78pu3ui78jXj1e0LRtun92xYYb/T9VWLdB9qFhAf4MkYEHUC8S9wnbW0gnkulz4xF6 BjkQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Cln644oA5BtyIgpgaZQiZNhvZEjmPyvVC+lofWod4OE=; b=lfUos1MCGSa3NlQjUgBBLrEAo2ksuqJlhTG0wKmQignLE8+LAO5wVENE2jWjxGKd2K SOl4tSjEfFFYpl+jyhPHKiFDBjNOtpRIC5fZCmJ78laaAO1kQdsm1TO9DfyDdObuC70Z ezuXtQcybl+RAOSO4lr3Jkz7gUL8Mco7d5hNmo4am6qc+LOAtrlt9IAHzZXQU6OU4NtL 471OUkA6EhCgjN9IYSMZGL2RrEtnac0nt0DisHx8kwwJ4bJiwPDzThWNTbnAAoyAgYsS E4w1u2o41i2l+T/YV6RauokOnK/Hef2HIEvRKolaFhx7JYI8EPhaVKkYAPcqTclgsQf5 3M0w== X-Gm-Message-State: AOAM532KlkoWpNAfRrE2W9aO+cAXcdIDHUP15g5joPm0K30qMrzwSNvz 0OLFsAFxM87x5aKehP/Fw4c= X-Google-Smtp-Source: ABdhPJzpRyMzX46v+gpIRpFuXuj44bZVB/U1vao07RTfvftK/oxJua8CT59/WjdrrOo4bVCIWqTwCA== X-Received: by 2002:aa7:9050:0:b029:3af:7e99:f48f with SMTP id n16-20020aa790500000b02903af7e99f48fmr8626836pfo.2.1628975945341; Sat, 14 Aug 2021 14:19:05 -0700 (PDT) Received: from localhost ([12.28.44.171]) by smtp.gmail.com with ESMTPSA id 26sm7830159pgx.72.2021.08.14.14.19.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Aug 2021 14:19:05 -0700 (PDT) From: Yury Norov To: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mmc@vger.kernel.org, linux-perf-users@vger.kernel.org, kvm@vger.kernel.org, "James E.J. Bottomley" , Alexander Lobakin , Alexander Shishkin , Alexey Klimov , Andrea Merello , Andy Shevchenko , Arnaldo Carvalho de Melo , Arnd Bergmann , Ben Gardon , Benjamin Herrenschmidt , Brian Cain , Catalin Marinas , Christoph Lameter , Daniel Bristot de Oliveira , David Hildenbrand , Dennis Zhou , Geert Uytterhoeven , Heiko Carstens , Ian Rogers , Ingo Molnar , Jaegeuk Kim , Jakub Kicinski , Jiri Olsa , Joe Perches , Jonas Bonn , Leo Yan , Mark Rutland , Namhyung Kim , Palmer Dabbelt , Paolo Bonzini , Peter Xu , Peter Zijlstra , Petr Mladek , Rasmus Villemoes , Rich Felker , Samuel Mendoza-Jonas , Sean Christopherson , Sergey Senozhatsky , Shuah Khan , Stefan Kristiansson , Steven Rostedt , Tejun Heo , Thomas Bogendoerfer , Ulf Hansson , Will Deacon , Wolfram Sang , Yoshinori Sato , Yury Norov Subject: [PATCH 14/17] mm/percpu: micro-optimize pcpu_is_populated() Date: Sat, 14 Aug 2021 14:17:10 -0700 Message-Id: <20210814211713.180533-15-yury.norov@gmail.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210814211713.180533-1-yury.norov@gmail.com> References: <20210814211713.180533-1-yury.norov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org bitmap_next_clear_region() calls find_next_zero_bit() and find_next_bit() sequentially to find a range of clear bits. In case of pcpu_is_populated() there's a chance to return earlier if bitmap has all bits set. Signed-off-by: Yury Norov Tested-by: Wolfram Sang Acked-by: Dennis Zhou --- mm/percpu.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/mm/percpu.c b/mm/percpu.c index a43039629aa4..8bf8b88446d7 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -1070,17 +1070,18 @@ static void pcpu_block_update_hint_free(struct pcpu_chunk *chunk, int bit_off, static bool pcpu_is_populated(struct pcpu_chunk *chunk, int bit_off, int bits, int *next_off) { - unsigned int page_start, page_end, rs, re; + unsigned int start, end; - page_start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); - page_end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); + start = PFN_DOWN(bit_off * PCPU_MIN_ALLOC_SIZE); + end = PFN_UP((bit_off + bits) * PCPU_MIN_ALLOC_SIZE); - rs = page_start; - bitmap_next_clear_region(chunk->populated, &rs, &re, page_end); - if (rs >= page_end) + start = find_next_zero_bit(chunk->populated, end, start); + if (start >= end) return true; - *next_off = re * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; + end = find_next_bit(chunk->populated, end, start + 1); + + *next_off = end * PAGE_SIZE / PCPU_MIN_ALLOC_SIZE; return false; }