From patchwork Mon Jul 24 09:43:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Qi Zheng X-Patchwork-Id: 13323707 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 76FACC04A94 for ; Mon, 24 Jul 2023 09:46:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232359AbjGXJqh (ORCPT ); Mon, 24 Jul 2023 05:46:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46212 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231876AbjGXJqD (ORCPT ); Mon, 24 Jul 2023 05:46:03 -0400 Received: from mail-pf1-x435.google.com (mail-pf1-x435.google.com [IPv6:2607:f8b0:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 828FE10E3 for ; Mon, 24 Jul 2023 02:45:32 -0700 (PDT) Received: by mail-pf1-x435.google.com with SMTP id d2e1a72fcca58-682eef7d752so1027582b3a.0 for ; Mon, 24 Jul 2023 02:45:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1690191931; x=1690796731; 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=ewD/GNBDsb9emQZc+crYJJhL9Ok7DRtPygkZmojk224=; b=DyvUb16iFXGbECeKR4Jj5b9Aqu7GqNXEePNkHat23I7b1VL4ke9XL7AFF21PJI8D03 dadzrjq6WC5mtymsIwcgysKxt2IeQhVQYSg0yzEciG/3J3jMvvonWrabgIjT5cyrH4U0 K1NmdQ2LZEMZR3X0ctjhZi8pkjfdY6FiANez7gH72dxDBt7t+C7AalBczQoExmv/leVd sjx5yitsqqA/ZPm80lkfCIhjuAfvEuRwNIJ4RlVw9F2GYFjyskW1Ygf/DVx+iz0W5Dlm 41zeCUlShQCZl1UPIlyRzbY5fG4LbR2jBKDZp6zvisQp1bayYn113SLSSif4m+cEaf+t mhLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690191931; x=1690796731; 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=ewD/GNBDsb9emQZc+crYJJhL9Ok7DRtPygkZmojk224=; b=bZ1v0RQeCyqHW1cFWVtNENkKwGPbAtc/STmLf4QsEpbYCL1ckNBup8BWf+biCTw/1M zEKbu4/VWSDlYtqmJsXRKQV50/KATYbneAsvuEJaips0bi1+WD02XJpSbRB2xM+X8L3C +4gnIWxaDT6IyWXXwgyoTxTEtoJdge4ggwxPQdJd96b0LzcoOoJoFW+Ee6KfWwwzal2l 3P6+k2VzflxyoPyBEskslOBmQvdmFFChjdVgNliicY1+vQLpF5MvjhZIBuZpBVmRNRoe rE6xwdUCHpfDDkCyTjVD9uoH14ZWrIXJTv3p7Hu5g8ujEn/8MsEx9hBpmNGXCT5w4Pz9 JB1w== X-Gm-Message-State: ABy/qLbm23K/kfAJAPSl6of/uLC6lQUVx9SyHVIvB11ZnTgJJJNMKHS1 ugSAp7lQ9z7n3v3JVmMLOa290Q== X-Google-Smtp-Source: APBJJlF4hVHTEAcnrryQeIsWufK3e63a7rX2g1OMpnBMufUIHv2BcOagu97Dc7evIwstimu7xBX17w== X-Received: by 2002:a17:902:e849:b0:1b8:35fa:cdcc with SMTP id t9-20020a170902e84900b001b835facdccmr12688015plg.5.1690191930816; Mon, 24 Jul 2023 02:45:30 -0700 (PDT) Received: from C02DW0BEMD6R.bytedance.net ([203.208.167.147]) by smtp.gmail.com with ESMTPSA id d5-20020a170902c18500b001bb20380bf2sm8467233pld.13.2023.07.24.02.45.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Jul 2023 02:45:30 -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 02/47] mm: shrinker: remove redundant shrinker_rwsem in debugfs operations Date: Mon, 24 Jul 2023 17:43:09 +0800 Message-Id: <20230724094354.90817-3-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 The debugfs_remove_recursive() will wait for debugfs_file_put() to return, so the shrinker will not be freed when doing debugfs operations (such as shrinker_debugfs_count_show() and shrinker_debugfs_scan_write()), so there is no need to hold shrinker_rwsem during debugfs operations. Signed-off-by: Qi Zheng Reviewed-by: Muchun Song --- mm/shrinker_debug.c | 14 -------------- 1 file changed, 14 deletions(-) diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index 3ab53fad8876..f1becfd45853 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -55,11 +55,6 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v) if (!count_per_node) return -ENOMEM; - ret = down_read_killable(&shrinker_rwsem); - if (ret) { - kfree(count_per_node); - return ret; - } rcu_read_lock(); memcg_aware = shrinker->flags & SHRINKER_MEMCG_AWARE; @@ -92,7 +87,6 @@ static int shrinker_debugfs_count_show(struct seq_file *m, void *v) } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL); rcu_read_unlock(); - up_read(&shrinker_rwsem); kfree(count_per_node); return ret; @@ -117,7 +111,6 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file, struct mem_cgroup *memcg = NULL; int nid; char kbuf[72]; - ssize_t ret; read_len = size < (sizeof(kbuf) - 1) ? size : (sizeof(kbuf) - 1); if (copy_from_user(kbuf, buf, read_len)) @@ -146,12 +139,6 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file, return -EINVAL; } - ret = down_read_killable(&shrinker_rwsem); - if (ret) { - mem_cgroup_put(memcg); - return ret; - } - sc.nid = nid; sc.memcg = memcg; sc.nr_to_scan = nr_to_scan; @@ -159,7 +146,6 @@ static ssize_t shrinker_debugfs_scan_write(struct file *file, shrinker->scan_objects(shrinker, &sc); - up_read(&shrinker_rwsem); mem_cgroup_put(memcg); return size;