From patchwork Mon Aug 7 11:09:35 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13343812 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 3CA86C07E8C for ; Mon, 7 Aug 2023 11:23:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232513AbjHGLX5 (ORCPT ); Mon, 7 Aug 2023 07:23:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233006AbjHGLXr (ORCPT ); Mon, 7 Aug 2023 07:23:47 -0400 Received: from mail-pj1-x102a.google.com (mail-pj1-x102a.google.com [IPv6:2607:f8b0:4864:20::102a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5233B35B5 for ; Mon, 7 Aug 2023 04:20:58 -0700 (PDT) Received: by mail-pj1-x102a.google.com with SMTP id 98e67ed59e1d1-26890669c8eso933003a91.1 for ; Mon, 07 Aug 2023 04:20:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1691407200; x=1692012000; 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=X5ij/O+E/bk/tTzX9mgxwiCynzBHcXx4EKtI9EsHayo=; b=i3OLYIqgHrVEAaoeqhN7xu/7U1C+reDkv4O93uYT3wVXPD8PclsjVNwGlC6uACGJON 5G7yHqhhbIuKFoghA6ZSicHcXMJKMfCogQ8szn+vWtZn4EOKB8vbAdIc7rpijTp0cbxa Z/AamO41rUovV3Rd5mToLS3fdUn/gIbndWW5fXdkD//uV9WpRp/5E2yE1kJcYdxc2q43 2kKg85HGCsKzT23sBdglbe/LKtHC4WUeFtaNvdRNowxvHAXGs/cRyz4+kFuB/ka63yH8 5vv+ldmlZuknYjC0UrMsohE+IjtZuT+2tIf1cSRO1giyAMKM5zLXRshImNoV+3DwaEWW qy8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691407200; x=1692012000; 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=X5ij/O+E/bk/tTzX9mgxwiCynzBHcXx4EKtI9EsHayo=; b=dOUxHIY5RRRpz6mzG0xJxYzMqmX2ridXOVjnBFGk1JPlCym/1WyFpplBld78IT1PlW tnGN50zPnDuXkisShotYSVG7PTs6pQLY7RQ9b021zfFFJbpliffABPxqnETYRx2PGOZU gjbnnBBAwqPYQjhoPCsYQyW2S8+pXlPHkM+l3GJeZ9hnYW6dEmorCAIsL/awewRoZPwF /6s2cs6o3/bnBWCDDZc9zwpt8pkbQ7Okhw0xTLYGkY14Boo/zP7CyVpi75H9enMP6UYC b+7HX2aRcHzXbn5tZWfGItC1Isi9DeMgkX1fRwgzIgAUUgBlSB+LXAXm8KCBlAdMy48n c70g== X-Gm-Message-State: AOJu0YztvonpnLnqf3tG9gXWm3CCEmDXLJdQ4aI1m70wIzXcb9T/+Qxb /m9Qg+oT0ByEifVS+7mxLpoVPw== X-Google-Smtp-Source: AGHT+IH1iUQIXRu8fJbzxUHSh+kWmc44BJdJFh0ZxZy41KSEiq7lusFAb/6JfkXEPdg45Q03TKbByg== X-Received: by 2002:a17:90a:9c3:b0:269:41cf:7212 with SMTP id 61-20020a17090a09c300b0026941cf7212mr4973775pjo.4.1691407200010; Mon, 07 Aug 2023 04:20:00 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.146]) by smtp.gmail.com with ESMTPSA id y13-20020a17090aca8d00b0025be7b69d73sm5861191pjt.12.2023.08.07.04.19.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 07 Aug 2023 04:19:59 -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, steven.price@arm.com, cel@kernel.org, senozhatsky@chromium.org, yujie.liu@intel.com, gregkh@linuxfoundation.org, muchun.song@linux.dev, simon.horman@corigine.com, dlemoal@kernel.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, kvm@vger.kernel.org, xen-devel@lists.xenproject.org, linux-erofs@lists.ozlabs.org, linux-f2fs-devel@lists.sourceforge.net, cluster-devel@redhat.com, linux-nfs@vger.kernel.org, linux-mtd@lists.infradead.org, rcu@vger.kernel.org, netdev@vger.kernel.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-xfs@vger.kernel.org, linux-btrfs@vger.kernel.org, Qi Zheng Subject: [PATCH v4 47/48] mm: shrinker: hold write lock to reparent shrinker nr_deferred Date: Mon, 7 Aug 2023 19:09:35 +0800 Message-Id: <20230807110936.21819-48-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230807110936.21819-1-zhengqi.arch@bytedance.com> References: <20230807110936.21819-1-zhengqi.arch@bytedance.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@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/shrinker.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/shrinker.c b/mm/shrinker.c index fee6f62904fb..a12dede5d21f 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -299,7 +299,7 @@ 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); @@ -312,7 +312,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) } } } - up_read(&shrinker_rwsem); + up_write(&shrinker_rwsem); } #else static int shrinker_memcg_alloc(struct shrinker *shrinker)