From nobody Thu Jun 18 18:47:17 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 98A4DC433F5 for ; Sat, 16 Apr 2022 07:41:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230077AbiDPHoK (ORCPT ); Sat, 16 Apr 2022 03:44:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50414 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230059AbiDPHoH (ORCPT ); Sat, 16 Apr 2022 03:44:07 -0400 Received: from mail-pg1-x535.google.com (mail-pg1-x535.google.com [IPv6:2607:f8b0:4864:20::535]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 49F71F8EEC for ; Sat, 16 Apr 2022 00:41:36 -0700 (PDT) Received: by mail-pg1-x535.google.com with SMTP id t4so10083194pgc.1 for ; Sat, 16 Apr 2022 00:41:36 -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=YTmNGfrC+3pxkSIDNGI4Pu99E1WgWPC8IWfV/O/1jPo=; b=BuaJUevtcqJmCeqT9gjYj5JDfFjXqxpdLmSEYY3wyml2Ixmo/t7AumlMXEtfwsYnLz QT5QXdDnuywbvgo0TwQN9kjAZOnElhfXKh1CfYKSZpk2/hkTsJSJJyK2aS/mVm6T+dyP srFde8KDdu3+trIBgOq2ZPMXjYjG2aPkbEpDLe+tEQw1+ZnaU0NYCDEkPLvNn+qrN/vn DD3sp6tYHmSfb8HeauRdIoX3NYLHU5WCp65UVnrSxrf/p8clRN61C/5yg7Avdkobte1R Erf8GEEmFjF7N9IO+vB7BeHMAQ4mwTQqghPKnANEa5Nn3zaVbbGa15QqQ86t5Wz7yRxp Ob1g== 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=YTmNGfrC+3pxkSIDNGI4Pu99E1WgWPC8IWfV/O/1jPo=; b=Vadt6R3uZe7fZbT01R+7Y2RlPFSITUs8BuoMfcGQRWRzWwWNNM/qvccgwQd4vc9DUo 979chF+NwbV2wJViA43HEtAM4Sv/d6fhwgV+bmzX71G2vIIyd/WJIWe9EaVSnM3g9NTR AKbs2Ox9VGa6AkF30iRMk5n3x49FppU/Ezn9bSHP0xLWXBjquZykHkdAFtwaqgcGQ5yy fpG7SdNFli4fqckexRwINzn4O/Wbs2QJCExzaE2Aev6LiFBIinY0VGP3kP70cjum/a7v KTX6KG3Sxx1/DJrIqlsthctdIxtbBd/7aqSsivDKIgGLIt+t+LLk4KAAXxVYewehdS97 Uphw== X-Gm-Message-State: AOAM533AM8hAIBc+yiBGhhjPcylDDXCOuUUn4musk5aX72ERVmAdO8sl w9N6qZmvcmPVS6fJRtcG6iw= X-Google-Smtp-Source: ABdhPJx2jNKo3m5uktJcIeP3hTP5PFlKUvfSL5GX+AWVcLyenjLIBkBQzJADzIwtVmRfGoLRG8RyOg== X-Received: by 2002:a63:ad0c:0:b0:374:50b4:c955 with SMTP id g12-20020a63ad0c000000b0037450b4c955mr2037578pgf.530.1650094895773; Sat, 16 Apr 2022 00:41:35 -0700 (PDT) Received: from localhost.localdomain ([125.131.156.123]) by smtp.gmail.com with ESMTPSA id e6-20020a056a001a8600b004fac74c8382sm5078720pfv.47.2022.04.16.00.41.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 16 Apr 2022 00:41:35 -0700 (PDT) From: Wonhyuk Yang To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin Cc: Ohhoon Kwon , JaeSang Yoo , Wonhyuk Yang , Jiyoup Kim , Donghyeok Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v2] mm/slub: Remove repeated action in calculate_order() Date: Sat, 16 Apr 2022 16:40:59 +0900 Message-Id: <20220416074059.526970-1-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 expected. Signed-off-by: Wonhyuk Yang Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> --- V1 -> V2: Fix typo miss in a commit message 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