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[2620:137:e000::1:20]) by mx.google.com with ESMTP id s5-20020a63b405000000b0047856c2a3dbsi1729722pgf.257.2023.02.09.02.23.09; Thu, 09 Feb 2023 02:23:21 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.dev header.s=key1 header.b=bCrZpQ6G; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.dev Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229863AbjBIKMP (ORCPT + 99 others); Thu, 9 Feb 2023 05:12:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229984AbjBIKML (ORCPT ); Thu, 9 Feb 2023 05:12:11 -0500 Received: from out-99.mta1.migadu.com (out-99.mta1.migadu.com [95.215.58.99]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1FD9FCDCB for ; Thu, 9 Feb 2023 02:12:04 -0800 (PST) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1675937521; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=acc/K+18agrKkErMDlxGWmadF0URH1WEryhRG2AiOO0=; b=bCrZpQ6GGjG0vYTus6GLvux5o0qoWwOLfzRuP9WjEQEbWFy2yTDQn52GHf7tn+h7PsM7yC dFHuQKkjLbFgUYl5pEekrFspst31lhqSSKUStdC/LzDt9AN43tyFKDQ8AI3OdQVetbj89B dZVV0wvShWg9mU8EMKnr/qzBEjeRxHw= From: Yajun Deng To: akpm@linux-foundation.org Cc: ziy@nvidia.com, mgorman@techsingularity.net, david@redhat.com, vbabka@suse.cz, rppt@linux.ibm.com, osalvador@suse.de, rppt@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Yajun Deng Subject: [PATCH v2] mm/page_alloc: optimize find_suitable_fallback() and fallbacks array Date: Thu, 9 Feb 2023 18:11:44 +0800 Message-Id: <20230209101144.496144-1-yajun.deng@linux.dev> MIME-Version: 1.0 X-Migadu-Flow: FLOW_OUT X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1757348575739843200?= X-GMAIL-MSGID: =?utf-8?q?1757348575739843200?= There is no need to execute the next loop if it not return in the first loop. So add a break at the end of the loop. At the same time, add !migratetype_is_mergeable() before the loop and reduce the first index size from MIGRATE_TYPES to MIGRATE_PCPTYPES in fallbacks array. Signed-off-by: Yajun Deng Acked-by: Vlastimil Babka --- include/linux/mmzone.h | 2 +- mm/page_alloc.c | 11 +++++------ 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index ab94985ee7d9..0a817b8c7fb2 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -85,7 +85,7 @@ static inline bool is_migrate_movable(int mt) * Check whether a migratetype can be merged with another migratetype. * * It is only mergeable when it can fall back to other migratetypes for - * allocation. See fallbacks[MIGRATE_TYPES][3] in page_alloc.c. + * allocation. See fallbacks[][] array in page_alloc.c. */ static inline bool migratetype_is_mergeable(int mt) { diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 1113483fa6c5..536e8d838fb5 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2603,7 +2603,7 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order, * * The other migratetypes do not have fallbacks. */ -static int fallbacks[MIGRATE_TYPES][MIGRATE_PCPTYPES - 1] = { +static int fallbacks[MIGRATE_PCPTYPES][MIGRATE_PCPTYPES - 1] = { [MIGRATE_UNMOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE }, [MIGRATE_MOVABLE] = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE }, [MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE, MIGRATE_MOVABLE }, @@ -2861,7 +2861,7 @@ int find_suitable_fallback(struct free_area *area, unsigned int order, int i; int fallback_mt; - if (area->nr_free == 0) + if (area->nr_free == 0 || !migratetype_is_mergeable(migratetype)) return -1; *can_steal = false; @@ -2873,11 +2873,10 @@ int find_suitable_fallback(struct free_area *area, unsigned int order, if (can_steal_fallback(order, migratetype)) *can_steal = true; - if (!only_stealable) - return fallback_mt; - - if (*can_steal) + if (!only_stealable || *can_steal) return fallback_mt; + else + break; } return -1;