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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT autolearn=unavailable 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 99BFCC433E1 for ; Mon, 20 Jul 2020 05:24:13 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 0F594207EA for ; Mon, 20 Jul 2020 05:24:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F594207EA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7FED66B0003; Mon, 20 Jul 2020 01:24:12 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 788366B0005; Mon, 20 Jul 2020 01:24:12 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6292F6B0006; Mon, 20 Jul 2020 01:24:12 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0104.hostedemail.com [216.40.44.104]) by kanga.kvack.org (Postfix) with ESMTP id 48F1F6B0003 for ; Mon, 20 Jul 2020 01:24:12 -0400 (EDT) Received: from smtpin25.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B27768248047 for ; Mon, 20 Jul 2020 05:24:11 +0000 (UTC) X-FDA: 77057313102.25.quilt38_240db9726f22 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin25.hostedemail.com (Postfix) with ESMTP id 7D8DF184138F1 for ; Mon, 20 Jul 2020 05:24:11 +0000 (UTC) X-HE-Tag: quilt38_240db9726f22 X-Filterd-Recvd-Size: 3509 Received: from out30-130.freemail.mail.aliyun.com (out30-130.freemail.mail.aliyun.com [115.124.30.130]) by imf43.hostedemail.com (Postfix) with ESMTP for ; Mon, 20 Jul 2020 05:24:04 +0000 (UTC) X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R601e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01355;MF=alex.shi@linux.alibaba.com;NM=1;PH=DS;RN=4;SR=0;TI=SMTPD_---0U3BbK4T_1595222637; Received: from localhost.localdomain(mailfrom:alex.shi@linux.alibaba.com fp:SMTPD_---0U3BbK4T_1595222637) by smtp.aliyun-inc.com(127.0.0.1); Mon, 20 Jul 2020 13:23:57 +0800 From: Alex Shi To: Cc: Alex Shi , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/vmstat: don't do count if no needs Date: Mon, 20 Jul 2020 13:23:48 +0800 Message-Id: <20200720052348.428564-1-alex.shi@linux.alibaba.com> X-Mailer: git-send-email 2.18.4 X-Rspamd-Queue-Id: 7D8DF184138F1 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam05 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000093, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: For couple of vmstat account funcs, the caller usually doesn't check the delta value, if delta == 0, irq or atomic operator is a waste. That's better to be skipped. Signed-off-by: Alex Shi Cc: Andrew Morton Cc: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org --- mm/vmstat.c | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/mm/vmstat.c b/mm/vmstat.c index 3fb23a21f6dd..91f28146daa7 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -321,6 +321,9 @@ void __mod_zone_page_state(struct zone *zone, enum zone_stat_item item, long x; long t; + if (!delta) + return; + x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); @@ -341,6 +344,9 @@ void __mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, long x; long t; + if (!delta) + return; + x = delta + __this_cpu_read(*p); t = __this_cpu_read(pcp->stat_threshold); @@ -484,6 +490,9 @@ static inline void mod_zone_state(struct zone *zone, s8 __percpu *p = pcp->vm_stat_diff + item; long o, n, t, z; + if (!delta) + return; + do { z = 0; /* overflow to zone counters */ @@ -518,6 +527,9 @@ static inline void mod_zone_state(struct zone *zone, void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, long delta) { + if (!delta) + return; + mod_zone_state(zone, item, delta, 0); } EXPORT_SYMBOL(mod_zone_page_state); @@ -541,6 +553,9 @@ static inline void mod_node_state(struct pglist_data *pgdat, s8 __percpu *p = pcp->vm_node_stat_diff + item; long o, n, t, z; + if (!delta) + return; + do { z = 0; /* overflow to node counters */ @@ -581,6 +596,9 @@ EXPORT_SYMBOL(mod_node_page_state); void inc_node_state(struct pglist_data *pgdat, enum node_stat_item item) { + if (!delta) + return; + mod_node_state(pgdat, item, 1, 1); } @@ -604,6 +622,9 @@ void mod_zone_page_state(struct zone *zone, enum zone_stat_item item, { unsigned long flags; + if (!delta) + return; + local_irq_save(flags); __mod_zone_page_state(zone, item, delta); local_irq_restore(flags); @@ -647,6 +668,9 @@ void mod_node_page_state(struct pglist_data *pgdat, enum node_stat_item item, { unsigned long flags; + if (!delta) + return; + local_irq_save(flags); __mod_node_page_state(pgdat, item, delta); local_irq_restore(flags); -- 2.18.4