From patchwork Thu Jul 27 08:05:01 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13329753 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 8A187C00528 for ; Thu, 27 Jul 2023 08:31:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234360AbjG0Ibe (ORCPT ); Thu, 27 Jul 2023 04:31:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38038 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235077AbjG0I3f (ORCPT ); Thu, 27 Jul 2023 04:29:35 -0400 Received: from mail-pf1-x433.google.com (mail-pf1-x433.google.com [IPv6:2607:f8b0:4864:20::433]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F690A5CF for ; Thu, 27 Jul 2023 01:16:23 -0700 (PDT) Received: by mail-pf1-x433.google.com with SMTP id d2e1a72fcca58-686f74a8992so78690b3a.1 for ; Thu, 27 Jul 2023 01:16:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1690445734; x=1691050534; 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=j4pDVeMcXcw7i7IAx1DNlz6iKEYUEIabVz59nN5q7bAhCS1y2gOKuzdzTgG4j/dBwO H4HIbZq+pOLjZVM5UGP2bbBpIOa2ebzQlUp84F0j/JFisMPJqEmZ2hJuFivDCiuZb9qk P5NgTQLX0gtg3X+vGmP6/3oCCgeQ9FljDUkAtb6pQhQ/VT+3lIzONbNoOLFITLjS+g+5 Vjj6M2H3z3FRG2iT9u3T7VH/LPW2zOuTNtSoF+jLae0SEMd2/P/I3VxNY7Hl9q3RH2MH NSqRY7EFleJMoWuU3X7ly6d0/rJ15DhvMCCJQ4sCCtoszhR0yDF7rbG/n/mEuDtWN3AJ wtVg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690445734; x=1691050534; 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=b4CM/dgL0piWsAb2CUA1Gl9csitQFy6k72/QdaJq7F5x0skrRmSHoVi5QkA9PT4uhp quA2/OQ7kU3llrJbKn8iQayfEujk+CEONpt9scB1M8mSoNuMysYDY4PeHgdYYsKhzYvA arbxZYJarJbJza8ZLa/8VHLKUlLGUAxiwSmny3HDk7wYPrqfb/QM5X1uGzuo88dkkS9C H2E6vZHnfqiG2PMw0+sGy2hr4y+LcPfjEuhkANXTGsdztvoC/s9//QNLkO0uNlZ1StvA URaqW4fLKRth/XR2ASRGc7dx97fSHb/+yKwR1t7FvJskl0mfxrzb1jqNeZIrSRGe0R+E 6elQ== X-Gm-Message-State: ABy/qLb29ud7GZoHAUTk9xFactszW4VphoKbqNPWJ7ejNgQJrw1mhN+V ZqsyeaUMhAXtfg/0F59tPcuZZQ== X-Google-Smtp-Source: APBJJlGCk2Vrs4jG84R1mGLjwsvlQmrr2Zz0KCmUr/tZ9etimLEYhkynVpF/d5AFiEeYea7/v2C0Wg== X-Received: by 2002:a05:6a20:7d87:b0:12e:f6e6:882b with SMTP id v7-20020a056a207d8700b0012ef6e6882bmr6451328pzj.1.1690445734330; Thu, 27 Jul 2023 01:15:34 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id j8-20020aa78d08000000b006828e49c04csm885872pfe.75.2023.07.27.01.15.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 27 Jul 2023 01:15:33 -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 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 v3 48/49] mm: shrinker: hold write lock to reparent shrinker nr_deferred Date: Thu, 27 Jul 2023 16:05:01 +0800 Message-Id: <20230727080502.77895-49-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230727080502.77895-1-zhengqi.arch@bytedance.com> References: <20230727080502.77895-1-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/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)