From patchwork Mon Jul 24 09:43:53 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13324174 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 1C6B7C001B0 for ; Mon, 24 Jul 2023 10:04:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233135AbjGXKEt (ORCPT ); Mon, 24 Jul 2023 06:04:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35822 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233748AbjGXKEP (ORCPT ); Mon, 24 Jul 2023 06:04:15 -0400 Received: from mail-pl1-f171.google.com (mail-pl1-f171.google.com [209.85.214.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7FD057AA7 for ; Mon, 24 Jul 2023 02:56:32 -0700 (PDT) Received: by mail-pl1-f171.google.com with SMTP id d9443c01a7336-1b7dfb95761so5887695ad.1 for ; Mon, 24 Jul 2023 02:56:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1690192457; x=1690797257; 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=CMESg6KcZ1f/x8j8WNeV/0Ezds9kYbd4Innm/bU0Ooo=; b=dwKlx1oQ8gC3FGBisAur+bDXIIsIsnjGtPcpy7zH7OHDzky5UKxSTJ05GXNV3ifxFh uFNY+8ub7jUvRzU2N0mzwWkyUcySnlCtwLD3JQfZApULo5o50SUYvFf7wmqQeUGg+K3w AqzVxAjjzV5PNtSqJauuHxoQULcgDnOjWhlM27zpLCCDDjhxzzb13/oecO1ube7S7m7P 1safwLAq/c10jFTLUU1Xqd0TB13zkKzwSGxlgMOCVqCgGIAn0g9Om1mA4z6ti880Mese Evcqc6hGgzGiGoOdWdO80KWYfeQwXeXM+h1Vq8tuq+SebTbp5eEFtPf8XLS7hjdlVp+9 zxcw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690192457; x=1690797257; 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=CMESg6KcZ1f/x8j8WNeV/0Ezds9kYbd4Innm/bU0Ooo=; b=UsK0RrNrY++E+cP6QRfPSfaw2t20EPIQNkZJtBVK07K78DvZN9LbAy9vdMH4w0LRZl II/OXTonXEZNY24xoNCH8abZ5l/7jX9QDaULmccRaAoWyM61a2sZb4a9uqiSvWhgWZhF 5cX0BYjKh0XVdKDUMhlrcdz+A/lTF/EvmBtJw9XCTVNW1g8lxTccQpUlD5ME0Wt0/kAO XlwNWwxb5Q72dJhY1usbHPmBDpPCqkthlj08j+03N8AYGxGWDSkznIzrgzAc0rxG7yFL XXYNr01v5CX/A1ky2MZyo+TaBnGTijpmPvMDm/NRlLfqldULz72rZkd1JinRADYOh9pm B0SA== X-Gm-Message-State: ABy/qLaqvguhj1nMHpFwHIIflkjcjP/zas3ki5i1gDNj4eEKCnuHwGU6 pJ2tkVOD/ANhTh3HjMTnQk5Gsw== X-Google-Smtp-Source: APBJJlGXXWR+7sUNZwfELUHGku1GBmb2Z0Up/m3d12N15W4mEcGvzf3zzmR3Y2DB2osG2hV81y8tMw== X-Received: by 2002:a17:902:dacf:b0:1b8:9215:9163 with SMTP id q15-20020a170902dacf00b001b892159163mr12209813plx.6.1690192456927; Mon, 24 Jul 2023 02:54:16 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id d5-20020a170902c18500b001bb20380bf2sm8467233pld.13.2023.07.24.02.54.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Jul 2023 02:54:16 -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 v2 46/47] mm: shrinker: hold write lock to reparent shrinker nr_deferred Date: Mon, 24 Jul 2023 17:43:53 +0800 Message-Id: <20230724094354.90817-47-zhengqi.arch@bytedance.com> X-Mailer: git-send-email 2.24.3 (Apple Git-128) In-Reply-To: <20230724094354.90817-1-zhengqi.arch@bytedance.com> References: <20230724094354.90817-1-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 744361afd520..90c045620fe3 100644 --- a/mm/shrinker.c +++ b/mm/shrinker.c @@ -303,7 +303,7 @@ 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); @@ -316,7 +316,7 @@ 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)