From patchwork Thu Jun 22 08:53:33 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13288779 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 63594C0015E for ; Thu, 22 Jun 2023 09:06:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232027AbjFVJGN (ORCPT ); Thu, 22 Jun 2023 05:06:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49972 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232171AbjFVJFM (ORCPT ); Thu, 22 Jun 2023 05:05:12 -0400 Received: from mail-pl1-x630.google.com (mail-pl1-x630.google.com [IPv6:2607:f8b0:4864:20::630]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21EBF4C04 for ; Thu, 22 Jun 2023 01:58:20 -0700 (PDT) Received: by mail-pl1-x630.google.com with SMTP id d9443c01a7336-1b515ec39feso12624195ad.0 for ; Thu, 22 Jun 2023 01:58:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1687424260; x=1690016260; 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=aRQUwtIbFrjRbKaWDWITc6Upds+hXxxlwcQqvFPvJow=; b=Kv6dWh2IIchnBu9RbCVLsx8HZLugRgYdolMOnFdVv/Mze68pcgFvadMFaompRsV/Ii Vr4ahAwXirWdfwADAjPFAtSTivwacduawKzyeKPVnp7cESQMTGYfaqAI7425tQvAdQ85 8rLDDpZCwcAbH67+6k+hMmW8Fi1etqH6LYFHkuQfbD+ESFiwPmeSocm5kXqI50kDiSjf PCd9vDumWTECSSKSpOEWhL8aCyPGbcSxO0SaB85LOV7uPD9a5LVIfvAATYV0qgfKCSQQ J+7inf8lDO5dvyUSQTFKKOcNdRaAbUMX2WbzVCHQayCH8tZA09PfVWiof+vKchWmVnWN 0e0g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687424260; x=1690016260; 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=aRQUwtIbFrjRbKaWDWITc6Upds+hXxxlwcQqvFPvJow=; b=EQpCRmIPgTY3K9uTMCBlcoZVP5qZkCo0o+zyYeSWw6Yhtyj/GbEMbXjIS/dLyeRoFA oAInvVYA4V7BdFrTMXuKUKpTRukU2MZROcUXiussxbeqbW3+ipkWbaH+9+Tq6FpRsDLM obEANBdYk14NCHUw1ldHZihwkcLzLj7nUZJ9a+hDg6LPlwCmFyJP4eGPlC2Iaguth2mp W2c8D7CxFPi3OcsAhXJTXi+19yu4fn9SnduSDbbl4JLnc1g/RRA0SSmGplVOU18rctIB CGeOvJORo4+c7xAqjegpqjxRJZW3OM5PJOXhrbjuDb+qFhx5Pe//uHorgdsve1ozx8WG oQMg== X-Gm-Message-State: AC+VfDyARWiVY9lYznbT9b9Z5YccAmV/UBNkXL4RrfdfuSWpMYA20vu6 wj+c1OIRiZDj8Ku/CIp5R14QeQ== X-Google-Smtp-Source: ACHHUZ4KKZ8AXrupsFYw18EsJWvGfL6qm7cyYV/rSPTKOdYWRQ8IhOkLOim7I9s7W96jDohmbJS9Lg== X-Received: by 2002:a17:903:41d2:b0:1a6:cf4b:4d7d with SMTP id u18-20020a17090341d200b001a6cf4b4d7dmr21650808ple.2.1687424260203; Thu, 22 Jun 2023 01:57:40 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([139.177.225.254]) by smtp.gmail.com with ESMTPSA id h2-20020a170902f7c200b001b549fce345sm4806971plw.230.2023.06.22.01.57.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Jun 2023 01:57:39 -0700 (PDT) From: Qi Zheng To: akpm@linux-foundation.org, david@fromorbit.com, tkhai@ya.ru, vbabka@suse.cz, roman.gushchin@linux.dev, djwong@kernel.org, brauner@kernel.org, paulmck@kernel.org, tytso@mit.edu Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-bcache@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Qi Zheng Subject: [PATCH 27/29] mm: vmscan: hold write lock to reparent shrinker nr_deferred Date: Thu, 22 Jun 2023 16:53:33 +0800 Message-Id: <20230622085335.77010-28-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230622085335.77010-1-zhengqi.arch@bytedance.com> References: <20230622085335.77010-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@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 357a1f2ad690..0711b63e68d9 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -433,7 +433,7 @@ 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); @@ -442,7 +442,7 @@ 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)