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 X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 6C4B5C4361A for ; Fri, 4 Dec 2020 15:52:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3CAD922C97 for ; Fri, 4 Dec 2020 15:52:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730575AbgLDPwA (ORCPT ); Fri, 4 Dec 2020 10:52:00 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725987AbgLDPv7 (ORCPT ); Fri, 4 Dec 2020 10:51:59 -0500 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9DB7FC0613D1 for ; Fri, 4 Dec 2020 07:51:19 -0800 (PST) Received: by mail-pj1-x1042.google.com with SMTP id m5so3374687pjv.5 for ; Fri, 04 Dec 2020 07:51:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=n5W6880DKqAIq9417CXiZaILeavNMzWEyfMm3u4YBRE=; b=09RJ7j13Vuz2H2XyZMov0ihLgHO7ayJoLXI8ilqaksMNwAhdRcn43F2QXpQ3A2gd0+ 07ks051irH922qS/kso+dQmpyR4jv4VOem3NsaHrBR5NyntmE7VU6EdPVDrct+CJZrR9 ORTuNz256TD8L4mhU5tFqK/zVVV3MDpQJLVHrM0Id3l/naW1571tc6tkWZcS6y1jtOs1 CMKpMKE74A/kEYdJDeUqMx61yTIjlTdiyuyencXRJ5AKleLzpSx0Rgx8fJICdbjzf1Ft ORe52RyMXqtU3Lt6x2T+PAPE6+W/B6ioQtJsPcSEN/ZyENEus3JIBybaNxNFDs7hmoH3 wixQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=n5W6880DKqAIq9417CXiZaILeavNMzWEyfMm3u4YBRE=; b=uBvh9FZOj7utDiDaIEDRT6Kb6amSSAlXdC4AQwab/FWn7OjG4+3sxm7HioABZy2SO1 1C/OEEY2bE6bnPY/DkEDCmyAtoyzBnGBorw8gqCneFkeu2jidkLLBDwBGz3ls07JZDva 7gRVwoxiSTGxGGL44eLOSQFhIGfJSNZ/jA63vnoLyFvZO4+QF2Z2BV4edsmYZpdo1qF3 LBkgV59Ncs6blbFNDgi/2cCoKASTmD6ozkqkrcgdZvRWWpJen5zWw3uy5ArplPv42Z8t /cvBGUkeyV7dmLaeqYSgOeU6XQc2fH2APpSGzHs03SWfTHtQ6dS63G6yyqrC3NVUIKW/ aQtA== X-Gm-Message-State: AOAM530obUw3Ilfd9u4mf/TD66w3n1XcDWEN7HRJ+O/Pkm7LK6XrKcNw Jq6Qo/MLG0gNRPMBwLBKrNKNVQ== X-Google-Smtp-Source: ABdhPJwCc0IIsjbR0gYu1dcq7gxf9VoEsp2MROjWpOwTMgKpWPZ+lXyQsgYg/lRkxsgL+7tC4KQuzw== X-Received: by 2002:a17:90a:940c:: with SMTP id r12mr4592347pjo.201.1607097079193; Fri, 04 Dec 2020 07:51:19 -0800 (PST) Received: from localhost.bytedance.net ([103.136.220.120]) by smtp.gmail.com with ESMTPSA id m7sm5626617pfh.72.2020.12.04.07.51.16 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Fri, 04 Dec 2020 07:51:18 -0800 (PST) From: Muchun Song To: akpm@linux-foundation.org, vbabka@suse.cz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Muchun Song Subject: [PATCH v3] mm/page_alloc: speeding up the iteration of max_order Date: Fri, 4 Dec 2020 23:51:09 +0800 Message-Id: <20201204155109.55451-1-songmuchun@bytedance.com> X-Mailer: git-send-email 2.21.0 (Apple Git-122) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When we free a page whose order is very close to MAX_ORDER and greater than pageblock_order, it wastes some CPU cycles to increase max_order to MAX_ORDER one by one and check the pageblock migratetype of that page repeatedly especially when MAX_ORDER is much larger than pageblock_order. We also should not be checking migratetype of buddy when "order == MAX_ORDER - 1" as the buddy pfn may be invalid, so adjust the condition. With the new check, we don't need the max_order check anymore, so we replace it. Also adjust max_order initialization so that it's lower by one than previously, which makes the code hopefully more clear. Fixes: d9dddbf55667 ("mm/page_alloc: prevent merging between isolated and other pageblocks") Signed-off-by: Muchun Song Acked-by: Vlastimil Babka --- Changes in v3: - Update commit log. Changes in v2: - Rework the code suggested by Vlastimil. Thanks. mm/page_alloc.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f91df593bf71..56e603eea1dd 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1002,7 +1002,7 @@ static inline void __free_one_page(struct page *page, struct page *buddy; bool to_tail; - max_order = min_t(unsigned int, MAX_ORDER, pageblock_order + 1); + max_order = min_t(unsigned int, MAX_ORDER - 1, pageblock_order); VM_BUG_ON(!zone_is_initialized(zone)); VM_BUG_ON_PAGE(page->flags & PAGE_FLAGS_CHECK_AT_PREP, page); @@ -1015,7 +1015,7 @@ static inline void __free_one_page(struct page *page, VM_BUG_ON_PAGE(bad_range(zone, page), page); continue_merging: - while (order < max_order - 1) { + while (order < max_order) { if (compaction_capture(capc, page, order, migratetype)) { __mod_zone_freepage_state(zone, -(1 << order), migratetype); @@ -1041,7 +1041,7 @@ static inline void __free_one_page(struct page *page, pfn = combined_pfn; order++; } - if (max_order < MAX_ORDER) { + if (order < MAX_ORDER - 1) { /* If we are here, it means order is >= pageblock_order. * We want to prevent merge between freepages on isolate * pageblock and normal pageblock. Without this, pageblock @@ -1062,7 +1062,7 @@ static inline void __free_one_page(struct page *page, is_migrate_isolate(buddy_mt))) goto done_merging; } - max_order++; + max_order = order + 1; goto continue_merging; } -- 2.11.0