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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 36176C43603 for ; Tue, 17 Dec 2019 11:31:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0A0F7207FF for ; Tue, 17 Dec 2019 11:31:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ay5w39y6" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727519AbfLQLbY (ORCPT ); Tue, 17 Dec 2019 06:31:24 -0500 Received: from mail-pl1-f193.google.com ([209.85.214.193]:37099 "EHLO mail-pl1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726756AbfLQLbY (ORCPT ); Tue, 17 Dec 2019 06:31:24 -0500 Received: by mail-pl1-f193.google.com with SMTP id c23so5982289plz.4 for ; Tue, 17 Dec 2019 03:31:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=fFfoleXjv3JSEmvkK0O9oMZGbyG7YMfuDochkkrQvOQ=; b=Ay5w39y6OP8b3+PSyWbNiB80MxHJVJSkjW+k+erc0+AmU1eBRpUnMfmFdSpTt3lBiL WXKb1e+X82cm+QC6jSydUQ6aqBNsbSp40uxC77iTvEE/hBw1nGeZiGyQrZek3edQH7Gl ifi8kZqgJUVhbSMYNppmKS5VPIFpQoxn8FW8OZfVzMArfXENhsNhFjv7OoOs906svNnk UyazUX4Lne2F3b0VB4++90jelJF4NorPxOROqwdwtNfnKoAq9gzFSoiF/IYMstPeSHeg 3O7TOCPm2IasOAdlxc7HFvCLj70+9f37uu7qlYmhyeS8aHA9bjFxLAUttL9nUe8+YMnG okPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=fFfoleXjv3JSEmvkK0O9oMZGbyG7YMfuDochkkrQvOQ=; b=NQ+0mBO8XPuTaFqTNuXzn7n1UALlGH/CPeNg1c2EjwlYY0gldSBEuwD+q6Br8NYn8r jOGV+ShyhVT75ZFj3lYfmKHnwDvIlD1tnXtDAb1XaOg9Nt0zI7LPHRYTgfb8hica46oD t5iPKzFXffNRnXSfhllCJ2Tc2FLSvDBbdBQcYOe20ahCHEiHrIvi9QWc9otBi9URaOPW 42WpCLvkKyfCO7KquBOQLxWXThqtU3pgcR5l45RUxhQvGO+hg332nOD1fvcNp4EKlx5J vtPlI2mkzbNSfpDwC725inR3//Jm/3ncaLGKkgJ/omqQJxEKPLC+YGPP5tKO0kKQ69Lu DW2Q== X-Gm-Message-State: APjAAAXvwHIpyu6CAcczMC30dCC0o7DP4M15MH3freJVhl670sVUNQ92 m0KrBu0oA+5/4UHUe5TxRCg= X-Google-Smtp-Source: APXvYqwgOIO9DkR9d5dmrB5DvMfBD6fXB5FS6maFa7bVNVo9BDd0ix+SDlXBo+0I1chqAKdB25eFeg== X-Received: by 2002:a17:902:9b86:: with SMTP id y6mr20608166plp.253.1576582283572; Tue, 17 Dec 2019 03:31:23 -0800 (PST) Received: from dev.localdomain ([203.100.54.194]) by smtp.gmail.com with ESMTPSA id q21sm26246460pff.105.2019.12.17.03.31.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 17 Dec 2019 03:31:23 -0800 (PST) From: Yafang Shao To: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com, akpm@linux-foundation.org, viro@zeniv.linux.org.uk Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Yafang Shao , Roman Gushchin Subject: [PATCH 2/4] mm, memcg: introduce MEMCG_PROT_SKIP for memcg zero usage case Date: Tue, 17 Dec 2019 06:29:17 -0500 Message-Id: <1576582159-5198-3-git-send-email-laoar.shao@gmail.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1576582159-5198-1-git-send-email-laoar.shao@gmail.com> References: <1576582159-5198-1-git-send-email-laoar.shao@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org If the usage of a memcg is zero, we don't need to do useless work to scan it. That is a minor optimization. Cc: Roman Gushchin Signed-off-by: Yafang Shao --- include/linux/memcontrol.h | 1 + mm/memcontrol.c | 2 +- mm/vmscan.c | 6 ++++++ 3 files changed, 8 insertions(+), 1 deletion(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 612a457..1a315c7 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -54,6 +54,7 @@ enum mem_cgroup_protection { MEMCG_PROT_NONE, MEMCG_PROT_LOW, MEMCG_PROT_MIN, + MEMCG_PROT_SKIP, /* For zero usage case */ }; struct mem_cgroup_reclaim_cookie { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c5b5f74..f35fcca 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6292,7 +6292,7 @@ enum mem_cgroup_protection mem_cgroup_protected(struct mem_cgroup *root, usage = page_counter_read(&memcg->memory); if (!usage) - return MEMCG_PROT_NONE; + return MEMCG_PROT_SKIP; emin = memcg->memory.min; elow = memcg->memory.low; diff --git a/mm/vmscan.c b/mm/vmscan.c index 5a6445e..3c4c2da 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2677,6 +2677,12 @@ static void shrink_node_memcgs(pg_data_t *pgdat, struct scan_control *sc) * thresholds (see get_scan_count). */ break; + case MEMCG_PROT_SKIP: + /* + * Skip scanning this memcg if the usage of it is + * zero. + */ + continue; } reclaimed = sc->nr_reclaimed; -- 1.8.3.1