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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 482DAC433ED for ; Fri, 30 Apr 2021 05:56:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2D08E61463 for ; Fri, 30 Apr 2021 05:56:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230119AbhD3F5h (ORCPT ); Fri, 30 Apr 2021 01:57:37 -0400 Received: from mail.kernel.org ([198.145.29.99]:50394 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbhD3F5g (ORCPT ); Fri, 30 Apr 2021 01:57:36 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 01B6A610FC; Fri, 30 Apr 2021 05:56:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762209; bh=Q8iz24SQ94LfbpU1yuLz06i5ZuI42EXgtfivq5NSTgo=; h=Date:From:To:Subject:In-Reply-To:From; b=kDhZZfmcFjikvqYVRsWE8K7/4lkJCfXdnN+VQO4flv6Ew1Nyf7DlBTC0C+tDfJr3m tT8gfLMNpaQlcqSyNfnAOj0IfnXq21QbF7nz9Z5e+O6mUeDhPR8f07eQWAf4StJL/J AKKd0huEhWgB1cbIzIkvS1NCiGVWOswcDj7Slogw= Date: Thu, 29 Apr 2021 22:56:48 -0700 From: Andrew Morton To: akpm@linux-foundation.org, duanxiongchun@bytedance.com, guro@fb.com, hannes@cmpxchg.org, linux-mm@kvack.org, mhocko@kernel.org, mm-commits@vger.kernel.org, shakeelb@google.com, songmuchun@bytedance.com, torvalds@linux-foundation.org, vdavydov.dev@gmail.com Subject: [patch 071/178] mm: memcontrol: change ug->dummy_page only if memcg changed Message-ID: <20210430055648.dvlfgXvVh%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Muchun Song Subject: mm: memcontrol: change ug->dummy_page only if memcg changed Just like assignment to ug->memcg, we only need to update ug->dummy_page if memcg changed. So move it to there. This is a very small optimization. Link: https://lkml.kernel.org/r/20210319163821.20704-5-songmuchun@bytedance.com Signed-off-by: Muchun Song Acked-by: Johannes Weiner Reviewed-by: Shakeel Butt Cc: Michal Hocko Cc: Roman Gushchin Cc: Vladimir Davydov Cc: Xiongchun Duan Signed-off-by: Andrew Morton --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/memcontrol.c~mm-memcontrol-change-ug-dummy_page-only-if-memcg-changed +++ a/mm/memcontrol.c @@ -6843,6 +6843,7 @@ static void uncharge_page(struct page *p uncharge_gather_clear(ug); } ug->memcg = page_memcg(page); + ug->dummy_page = page; /* pairs with css_put in uncharge_batch */ css_get(&ug->memcg->css); @@ -6856,7 +6857,6 @@ static void uncharge_page(struct page *p else ug->pgpgout++; - ug->dummy_page = page; page->memcg_data = 0; css_put(&ug->memcg->css); } _