From nobody Sat Feb 7 08:02:29 2026 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 2F913C77B73 for ; Wed, 31 May 2023 09:59:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235795AbjEaJ71 (ORCPT ); Wed, 31 May 2023 05:59:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54730 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235740AbjEaJ7Q (ORCPT ); Wed, 31 May 2023 05:59:16 -0400 Received: from out-54.mta0.migadu.com (out-54.mta0.migadu.com [IPv6:2001:41d0:1004:224b::36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8568E10E for ; Wed, 31 May 2023 02:58:53 -0700 (PDT) X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1685527129; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=mjcsinqX7KwTJ40/JcL+JgGM2W0swatrtd18npIFtVk=; b=baMB2GLVbbUmgLTp+CUXyhhVv/9x56bQV3iqZ8MjrGpSa7p5jatJsXPULpCV9EV8+jBrYl PchelLFH6ZF8vYpgvhoNebbx99TRM79XB4NftLwSZ90r/JoVrRMdf+o3xlQ1brouvtCBtm EjXCENjNIePsNVRgiPye7pdqlsEyPGs= From: Qi Zheng To: akpm@linux-foundation.org, tkhai@ya.ru, roman.gushchin@linux.dev, vbabka@suse.cz, viro@zeniv.linux.org.uk, brauner@kernel.org, djwong@kernel.org, hughd@google.com, paulmck@kernel.org, muchun.song@linux.dev Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org, Qi Zheng Subject: [PATCH 8/8] fs: use unregister_shrinker_delayed_{initiate, finalize} for super_block shrinker Date: Wed, 31 May 2023 09:57:42 +0000 Message-Id: <20230531095742.2480623-9-qi.zheng@linux.dev> In-Reply-To: <20230531095742.2480623-1-qi.zheng@linux.dev> References: <20230531095742.2480623-1-qi.zheng@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Migadu-Flow: FLOW_OUT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Kirill Tkhai Previous patches made all the data, which is touched from super_cache_count(), destroyed from destroy_super_work(): s_dentry_lru, s_inode_lru and super_block::s_fs_info. super_cache_scan() can't be called after SB_ACTIVE is cleared in generic_shutdown_super(). So, it safe to move heavy unregister_shrinker_delayed_finalize() part to delayed work, i.e. it's safe for parallel do_shrink_slab() to be executed between unregister_shrinker_delayed_initiate() and destroy_super_work()->unregister_shrinker_delayed_finalize(). This makes the heavy synchronize_srcu() to do not affect on user-visible unregistration speed (since now it's executed from workqueue). All further time-critical for unregistration places may be written in the same conception. Signed-off-by: Kirill Tkhai Signed-off-by: Qi Zheng --- fs/super.c | 4 +++- include/linux/fs.h | 5 +++++ 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/fs/super.c b/fs/super.c index 4e9d08224f86..c61efb74fa7f 100644 --- a/fs/super.c +++ b/fs/super.c @@ -165,6 +165,8 @@ static void destroy_super_work(struct work_struct *work) destroy_work); int i; =20 + unregister_shrinker_delayed_finalize(&s->s_shrink); + WARN_ON(list_lru_count(&s->s_dentry_lru)); WARN_ON(list_lru_count(&s->s_inode_lru)); list_lru_destroy(&s->s_dentry_lru); @@ -337,7 +339,7 @@ void deactivate_locked_super(struct super_block *s) { struct file_system_type *fs =3D s->s_type; if (atomic_dec_and_test(&s->s_active)) { - unregister_shrinker(&s->s_shrink); + unregister_shrinker_delayed_initiate(&s->s_shrink); fs->kill_sb(s); =20 put_filesystem(fs); diff --git a/include/linux/fs.h b/include/linux/fs.h index 30b46d0facfc..869dd8de91a5 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1929,6 +1929,11 @@ struct super_operations { ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, l= off_t); struct dquot **(*get_dquots)(struct inode *); #endif + /* + * Shrinker may call these two function on destructing super_block + * till unregister_shrinker_delayed_finalize() has completed + * in destroy_super_work(), and they must care about that. + */ long (*nr_cached_objects)(struct super_block *, struct shrink_control *); long (*free_cached_objects)(struct super_block *, --=20 2.30.2