From nobody Thu Jun 18 18:46:46 2026 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 636A1C433F5 for ; Sat, 16 Apr 2022 06:11:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229606AbiDPGNr (ORCPT ); Sat, 16 Apr 2022 02:13:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229379AbiDPGNo (ORCPT ); Sat, 16 Apr 2022 02:13:44 -0400 Received: from mail-pj1-x1032.google.com (mail-pj1-x1032.google.com [IPv6:2607:f8b0:4864:20::1032]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22BDC3B285 for ; Fri, 15 Apr 2022 23:11:14 -0700 (PDT) Received: by mail-pj1-x1032.google.com with SMTP id g12-20020a17090a640c00b001cb59d7a57cso8735350pjj.1 for ; Fri, 15 Apr 2022 23:11:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bcOfBPL4OuuAG640SlARJZ6hb/FVaA7pZLG+NuBAIqI=; b=Nr9bl2Lz08LmMiCuXk2WBYjQ3ZmKPTXuZQS2+uFJ1CoadNQabr40ys3p22cNkg5BVK 1YThbJeevQDiujyTY5YVNqtAHT3QCkw8t8GqlDOPZncNJOwVv6YZASYqUOgZKLdCZrBk 9uPzDp1xjIrM3BjF1GsOjQjEOBi9oVUyqDErGdsYMM1O7hcf4dQWeuAQXk9IJHMBI0Sc V5cM2SGK1bWWxG67Si3NMEFkZDJTU9PFGhrRMJkRVqgHwCtkOKJSIdo1PvQgJuPoVTJH m0cTAELczTDhfJZKRRlon7bckFWhPdp0Qg9syoOVaLdTXxEHxyp/4D2B8Pg/okgVQhCV gFPw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bcOfBPL4OuuAG640SlARJZ6hb/FVaA7pZLG+NuBAIqI=; b=dvvgcJWdEBWTTVzCZ7sh2VreseDzNUt2nMJo8UFewxsVnyLMRbSfM+24zcCP80obVz VMKy+AHfmPFe0icA0ZYidQkvW5VbFVuR+yLk1dNKf7JCa8rex6QSu0UKv3dyGgj0I+8/ okQRhaPRgu/fMWHydllfmx7Wh9X39Ifk7tk583JUH21HJmcsonOZCrQfLsYhJKRD5Fil vU7FT9AFmdOjs16Wy+l5fpwQhNvyPrfxjFcxjRSOA4qKEQh3TypActbmpD0gcC9ZXGCo 73Sr2bhgR8IWr/UaRDPZGORit+HUO/z347Rtg4JaDkKKRYgVzhX7TSkStuS0knNWKpX7 wGJg== X-Gm-Message-State: AOAM533HWLb+fZQlqABn1o9jJ38ea0sy2qr9HAPk7fqRY0twwW8MSvzX C5kHe+wGbZTx+TOW/y1C2JM= X-Google-Smtp-Source: ABdhPJwepZdppnnzYaQcm1cA/smdaAO5t6Oc4XxNF8dETGCwvJW/qEmZficFIgsPqhVBdyUuKHNRHA== X-Received: by 2002:a17:90b:1642:b0:1c6:c6d0:fbfa with SMTP id il2-20020a17090b164200b001c6c6d0fbfamr2466474pjb.218.1650089473414; Fri, 15 Apr 2022 23:11:13 -0700 (PDT) Received: from localhost.localdomain ([125.131.156.123]) by smtp.gmail.com with ESMTPSA id n12-20020a17090a670c00b001cbb7fdb9e4sm10428029pjj.53.2022.04.15.23.11.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 15 Apr 2022 23:11:12 -0700 (PDT) From: Wonhyuk Yang To: vvghjk1234@gmail.com, Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/slub: Remove repeated action in calculate_order() Date: Sat, 16 Apr 2022 15:11:04 +0900 Message-Id: <20220416061104.481674-1-vvghjk1234@gmail.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" To calculate order, calc_slab_order() is called repeatly changing the fract_leftover. Thus, the branch which is not dependent on fract_leftover is executed repeatly. So make it run only once. Plus, when min_object reached to 0, we set fract_leftover to 1. In this case, we can calculate order by max(slub_min_order, get_order(size) instead of calling calc_slab_order(). No functional impact expectd. Signed-off-by: Wonhyuk Yang --- mm/slub.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index ed5c2c03a47a..e7a394d7b75a 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3795,9 +3795,6 @@ static inline unsigned int calc_slab_order(unsigned i= nt size, unsigned int min_order =3D slub_min_order; unsigned int order; =20 - if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE) - return get_order(size * MAX_OBJS_PER_PAGE) - 1; - for (order =3D max(min_order, (unsigned int)get_order(min_objects * size)= ); order <=3D max_order; order++) { =20 @@ -3820,6 +3817,11 @@ static inline int calculate_order(unsigned int size) unsigned int max_objects; unsigned int nr_cpus; =20 + if (unlikely(order_objects(slub_min_order, size) > MAX_OBJS_PER_PAGE)) { + order =3D get_order(size * MAX_OBJS_PER_PAGE) - 1; + goto out; + } + /* * Attempt to find best configuration for a slab. This * works by first attempting to generate a layout with @@ -3865,14 +3867,8 @@ static inline int calculate_order(unsigned int size) * We were unable to place multiple objects in a slab. Now * lets see if we can place a single object there. */ - order =3D calc_slab_order(size, 1, slub_max_order, 1); - if (order <=3D slub_max_order) - return order; - - /* - * Doh this slab cannot be placed using slub_max_order. - */ - order =3D calc_slab_order(size, 1, MAX_ORDER, 1); + order =3D max_t(unsigned int, slub_min_order, (unsigned int)get_order(siz= e)); +out: if (order < MAX_ORDER) return order; return -ENOSYS; --=20 2.30.2