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[23.128.96.35]) by mx.google.com with ESMTPS id l9-20020a170902f68900b001bf88e777f9si8991155plg.33.2023.09.18.11.10.10 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 Sep 2023 11:10:11 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35; Authentication-Results: mx.google.com; dkim=pass header.i=@linux.dev header.s=key1 header.b=xDx23adU; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linux.dev Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by groat.vger.email (Postfix) with ESMTP id 814B980D6AED; Mon, 18 Sep 2023 00:19:43 -0700 (PDT) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.10 at groat.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236377AbjIRHSz (ORCPT + 99 others); Mon, 18 Sep 2023 03:18:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38428 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240163AbjIRHSk (ORCPT ); Mon, 18 Sep 2023 03:18:40 -0400 Received: from out-223.mta1.migadu.com (out-223.mta1.migadu.com [IPv6:2001:41d0:203:375::df]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7CF7EEA for ; Mon, 18 Sep 2023 00:18:13 -0700 (PDT) Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1695021491; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UfSW8jEm1VNQCD8pQwx0JLLdK+5bGgzdvIUujZD6iqI=; b=xDx23adUJq5H0ND0LkfTuGurXvDHBHI9PV6YTxEa06Kb/6sHlZwz4m5BsD3c4tuG6sM570 9GThhUfP+ZzNSF0u16ob3x2ewc+WNyoSAvPezwqg2vBX12Z20FOSqLxL1MGhrmKuQEjten OdYGLFAeEXGjk1pQgP8j79Nabvccp2Y= Mime-Version: 1.0 Subject: Re: [PATCH v6 44/45] mm: shrinker: hold write lock to reparent shrinker nr_deferred X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: <20230911094444.68966-45-zhengqi.arch@bytedance.com> Date: Mon, 18 Sep 2023 15:17:38 +0800 Cc: Andrew Morton , david@fromorbit.com, tkhai@ya.ru, Vlastimil Babka , Roman Gushchin , 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, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org Content-Transfer-Encoding: 7bit Message-Id: <807B2489-9F74-4B35-925D-B379E47E75AD@linux.dev> References: <20230911094444.68966-1-zhengqi.arch@bytedance.com> <20230911094444.68966-45-zhengqi.arch@bytedance.com> To: Qi Zheng X-Migadu-Flow: FLOW_OUT X-Spam-Status: No, score=-0.9 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on groat.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (groat.vger.email [0.0.0.0]); Mon, 18 Sep 2023 00:19:43 -0700 (PDT) > On Sep 11, 2023, at 17:44, Qi Zheng wrote: > > 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 Reviewed-by: Muchun Song Thanks.