From nobody Mon Jun 15 10:14:28 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 57607C43217 for ; Sat, 30 Apr 2022 00:30:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1359771AbiD3A31 (ORCPT ); Fri, 29 Apr 2022 20:29:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50772 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235155AbiD3A3Y (ORCPT ); Fri, 29 Apr 2022 20:29:24 -0400 Received: from mail-pj1-x102e.google.com (mail-pj1-x102e.google.com [IPv6:2607:f8b0:4864:20::102e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 259D99681A for ; Fri, 29 Apr 2022 17:26:04 -0700 (PDT) Received: by mail-pj1-x102e.google.com with SMTP id o69so7017505pjo.3 for ; Fri, 29 Apr 2022 17:26:04 -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=wj0GCAwyvudPRmGRRgsX12+MeUaxxTPPMDMQ7+QSvNg=; b=l+jK1iji/9TzBj7wkgUFu/NItPRwk6FZVFT2XJAwgjLa7CgwjRFyTekvMZlCecijWr Rt+D6gKOqH/P69hDamtFwIfI6eu1sOM319CwQF0hbH+l5aYNTatIGAsZJXxJ+xT0DdHr eHvzW17qMHRMQSmyfKli/H+Wh/zCToKvFPDZNiHmG6FkZH6gE7Rp+JIY/zAAFsrRJvdq 5OKUiZDl62LVYIEs3Z0zCu+f/XqJ77zb1EWE6jj2Z5/Iz+yFG0O9EhK72C8Dbe8uln+B L/XaS/44KYb+2TvpdnAvY3wrU9/4t/BoYR9bYSKw5yz2JnLTIVPmuVnEnGfqd5BrqZ1E S4Ag== 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=wj0GCAwyvudPRmGRRgsX12+MeUaxxTPPMDMQ7+QSvNg=; b=OGx3TXZKsyK7bd01P9BBzwnqNgVKVsmLHgwlbdKY1STZ+VC55GTQ99EdTtSVCX0aoV Yo6LpUj3J4xb5u/ocVmdClulWjy2Apx1u+sg/Ljr48bQxjA+Il6mZVPcD+C7PSVcsVLv iwrSux4dWaGij2D6Ksq47524LBiA7OCCBjQhzKqj/bSmLjFKXByR8dzRpf8c8MyRE3hh pijzBJwZZBb8RHi5a+inUA497iiz6/uW6zq2BD8yrBKkOxX4pCT9F5fqX4E9qguNdBJw Zijv5Q+c0TDnKG4JQQhhhTVCjvFQtqZmaT+QNAMYOigVMYdyQNDLM3pdpDfULbgI+Ms1 HG2w== X-Gm-Message-State: AOAM531EcojkkpSvURBj8fffCzkSzILPpJ731wXUYBsNQ9gNk1dQ/f2k XGXejT5FOhW5RbPEnFQjX/4= X-Google-Smtp-Source: ABdhPJwbC29ym+34xajMXMcVDFqWB0hl6bj7vlrp2zq9ZwucXZYdNW6X1oLcnNgIex9U5/T1FF2XEw== X-Received: by 2002:a17:902:82c9:b0:15d:3a76:936f with SMTP id u9-20020a17090282c900b0015d3a76936fmr1733796plz.139.1651278363471; Fri, 29 Apr 2022 17:26:03 -0700 (PDT) Received: from localhost.localdomain ([125.131.156.123]) by smtp.gmail.com with ESMTPSA id u12-20020a170902e80c00b0015e8d4eb25fsm181271plg.169.2022.04.29.17.26.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 29 Apr 2022 17:26:02 -0700 (PDT) From: Wonhyuk Yang To: Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , Andrew Morton , Vlastimil Babka , Roman Gushchin Cc: Wonhyuk Yang , Hyeonggon Yoo <42.hyeyoo@gmail.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [Patch v3] mm/slub: Remove repeated action in calculate_order() Date: Sat, 30 Apr 2022 09:25:55 +0900 Message-Id: <20220430002555.3881-1-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 1, 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> --- mm/slub.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/mm/slub.c b/mm/slub.c index ed5c2c03a47a..1fe4d62b72b8 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, get_order(size)); +out: if (order < MAX_ORDER) return order; return -ENOSYS; --=20 2.30.2