From patchwork Sat Jan 23 07:38:25 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 12041175 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, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 AC06CC433DB for ; Sat, 23 Jan 2021 07:38:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F2CF823437 for ; Sat, 23 Jan 2021 07:38:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2CF823437 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 65DB86B000E; Sat, 23 Jan 2021 02:38:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 60D576B0010; Sat, 23 Jan 2021 02:38:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 522E76B0012; Sat, 23 Jan 2021 02:38:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0183.hostedemail.com [216.40.44.183]) by kanga.kvack.org (Postfix) with ESMTP id 3C9906B000E for ; Sat, 23 Jan 2021 02:38:51 -0500 (EST) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E95C11EE6 for ; Sat, 23 Jan 2021 07:38:50 +0000 (UTC) X-FDA: 77736238020.05.man95_6205c5a27572 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin05.hostedemail.com (Postfix) with ESMTP id C98ED180177F9 for ; Sat, 23 Jan 2021 07:38:50 +0000 (UTC) X-HE-Tag: man95_6205c5a27572 X-Filterd-Recvd-Size: 2097 Received: from szxga04-in.huawei.com (szxga04-in.huawei.com [45.249.212.190]) by imf49.hostedemail.com (Postfix) with ESMTP for ; Sat, 23 Jan 2021 07:38:50 +0000 (UTC) Received: from DGGEMS406-HUB.china.huawei.com (unknown [172.30.72.58]) by szxga04-in.huawei.com (SkyGuard) with ESMTP id 4DN7J76lzQz15rwr; Sat, 23 Jan 2021 15:37:27 +0800 (CST) Received: from huawei.com (10.175.104.175) by DGGEMS406-HUB.china.huawei.com (10.3.19.206) with Microsoft SMTP Server id 14.3.498.0; Sat, 23 Jan 2021 15:38:31 +0800 From: Miaohe Lin To: CC: , , Subject: [PATCH] mm/workingset.c: avoid unnecessary max_nodes estimation in count_shadow_nodes() Date: Sat, 23 Jan 2021 02:38:25 -0500 Message-ID: <20210123073825.46709-1-linmiaohe@huawei.com> X-Mailer: git-send-email 2.19.1 MIME-Version: 1.0 X-Originating-IP: [10.175.104.175] X-CFilter-Loop: Reflected 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: If list_lru_shrink_count is 0, we always return SHRINK_EMPTY regardless of the value of max_nodes. So we can return early if nodes == 0 to save some cpu cycles of approximating a reasonable limit for the nodes. Signed-off-by: Miaohe Lin Acked-by: Vlastimil Babka --- mm/workingset.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/mm/workingset.c b/mm/workingset.c index 10e96de945b3..7db8f3dad13c 100644 --- a/mm/workingset.c +++ b/mm/workingset.c @@ -461,6 +461,8 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, unsigned long pages; nodes = list_lru_shrink_count(&shadow_nodes, sc); + if (!nodes) + return SHRINK_EMPTY; /* * Approximate a reasonable limit for the nodes @@ -503,9 +505,6 @@ static unsigned long count_shadow_nodes(struct shrinker *shrinker, max_nodes = pages >> (XA_CHUNK_SHIFT - 3); - if (!nodes) - return SHRINK_EMPTY; - if (nodes <= max_nodes) return 0; return nodes - max_nodes;