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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-Stat-Signature: jygq9k7pz7ptwecry11rf7cbrrnqacmj X-Rspam-User: X-Rspamd-Queue-Id: A7D15C0014 X-Rspamd-Server: rspam06 X-HE-Tag: 1675937523-686288 X-HE-Meta: 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 mjK3ZgBf dRGT/0xSW8/M2aMo63SS/sndkAaLzMDxVOaAWaxXGzVa6iuHq4eVoiVzaNnFGnLVhl6MC4W2zBPvhClZjQEt09l6dZhUC1nqG1m2VGjCWVKXyFEY8VqLB4sDj2VNkNoZjFzW+ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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;