Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2E239C7EE31 for ; Sun, 26 Feb 2023 14:56:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230511AbjBZO4r (ORCPT ); Sun, 26 Feb 2023 09:56:47 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230151AbjBZOyE (ORCPT ); Sun, 26 Feb 2023 09:54:04 -0500 Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 292599763 for ; Sun, 26 Feb 2023 06:50:04 -0800 (PST) Received: by mail-pl1-x62f.google.com with SMTP id n6so2822311plf.5 for ; Sun, 26 Feb 2023 06:50:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1677422925; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=c6cuoJEo92PScDqgnKjc0MgPFLiMUUPUvBDJj7SgxHo=; b=lIKiq8ErtDRmfz+i/ano83moR805w7pQEVFBs5DWz8iogOWtMgCKlWMtTjjG4CUYGf qZUEa/ayLAYcSmEePRMBNnD4UMS+HxFoUzmlroe0ZVHuqZ3z2bv2HGbh7Yq0wKCvHk4k QE8yyj88IWGiNyUTVZhSPdvEoYldgr4C6pMLd3y42cOtg65TmytTMhFeDnjLzWUSuqD4 9aNiX3gjRzbrv4MYxQIZGaPfntfaShxVFiNdV3/73U+gNlaqjtHmoW98ZiAC2kGLB21U 7G4hnPw+a24oAWIJ7kfT7KLIQYmuet0PscCXlnmSZhQ2rIyHh9ik/cyvUbqhLd+kEnv8 Uwjg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1677422925; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=c6cuoJEo92PScDqgnKjc0MgPFLiMUUPUvBDJj7SgxHo=; b=NnSkB4euJawKue+gYwn7w1aVgBcrOOIx/1LFZJAunt6QHlVTAT0NtzZk0MFa7TeSS1 3rpDbrWfSSpMLjz9LrxAoST4Yi7jUqBdYKJFuRIc0evIMxX1yfcxSun60ChsPNlH+2bH HYWyfCgbHTPZDaoO4HEK3n2sh8vX4usCIUyoB2YeJG/anMyAHo85h1ITLR+Q9tLrGyBv Ta79JOyTic+v61QNC3lpILuELVYQYQmEJ2xuSpJvJHSTD96O2BTs8KI11sTGxT9kJbxz mvUFAl+GefHyWwDWNUu1k+5yzrYqbnNkApy4c8+IRMWZhtz+Civ+d1QH6GiKG8qUufpt psNw== X-Gm-Message-State: AO0yUKV3yP3Sxn1qxSxtx/cm6t09wfVUG3NfhZTUypGer4ylaePsl1KX Q95oTmmGkKbVeLt9FQhH+m7XwQ== X-Google-Smtp-Source: AK7set+XvuciT55+1IMf9hAHsturuZDzsZyl61PmuY/3HoeWXaqHrVSGXMTK34S3WOCoi78lnQD8RA== X-Received: by 2002:a17:902:bb0f:b0:197:8e8e:f15 with SMTP id im15-20020a170902bb0f00b001978e8e0f15mr23385229plb.6.1677422925086; Sun, 26 Feb 2023 06:48:45 -0800 (PST) Received: from localhost.localdomain ([139.177.225.248]) by smtp.gmail.com with ESMTPSA id y20-20020a170902ed5400b0019c2cf12d15sm2755589plb.116.2023.02.26.06.48.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 26 Feb 2023 06:48:44 -0800 (PST) From: Qi Zheng To: akpm@linux-foundation.org, tkhai@ya.ru, hannes@cmpxchg.org, shakeelb@google.com, mhocko@kernel.org, roman.gushchin@linux.dev, muchun.song@linux.dev, david@redhat.com, shy828301@gmail.com Cc: sultan@kerneltoast.com, dave@stgolabs.net, penguin-kernel@I-love.SAKURA.ne.jp, paulmck@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: [PATCH v3 6/8] mm: vmscan: hold write lock to reparent shrinker nr_deferred Date: Sun, 26 Feb 2023 22:46:53 +0800 Message-Id: <20230226144655.79778-7-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230226144655.79778-1-zhengqi.arch@bytedance.com> References: <20230226144655.79778-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org For now, reparent_shrinker_deferred() is the only holder of read lock of shrinker_rwsem. And it already holds the global cgroup_mutex, so it will not be called in parallel. Therefore, in order to convert shrinker_rwsem to shrinker_mutex later, here we change to hold the write lock of shrinker_rwsem to reparent. Signed-off-by: Qi Zheng --- mm/vmscan.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index 99e852c0ab9e..16ff64813175 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -451,7 +451,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) parent = root_mem_cgroup; /* Prevent from concurrent shrinker_info expand */ - down_read(&shrinker_rwsem); + down_write(&shrinker_rwsem); for_each_node(nid) { child_info = shrinker_info_protected(memcg, nid); parent_info = shrinker_info_protected(parent, nid); @@ -460,7 +460,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) atomic_long_add(nr, &parent_info->nr_deferred[i]); } } - up_read(&shrinker_rwsem); + up_write(&shrinker_rwsem); } static bool cgroup_reclaim(struct scan_control *sc) -- 2.20.1