From nobody Sat Feb 7 08:02:25 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 AB242C7EE24 for ; Wed, 31 May 2023 09:59:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235718AbjEaJ66 (ORCPT ); Wed, 31 May 2023 05:58:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232459AbjEaJ6x (ORCPT ); Wed, 31 May 2023 05:58:53 -0400 Received: from out-21.mta0.migadu.com (out-21.mta0.migadu.com [IPv6:2001:41d0:1004:224b::15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DDF9CE50 for ; Wed, 31 May 2023 02:58:28 -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=1685527104; 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=ZzyzkXd70pYEdWJhGutN+U1hmZmD/p5d/wpcM6Ajy+8=; b=ZihWgnR2scrQOnB2k5nDPiR/oFSAGcE5oxTl8DJZlC6c35SkDHP860/TT0nEoqYq/lrcq1 d6CKRaCpb2dkgODgBX/qkpML3eCN0n5h1kziLNHv4ErGYZOVxBG6L8XG40g2Y8QxSO+u0s Pr9f8hmxkoCyCfWi4RAZ5pmhxQ/yWCA= 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 2/8] mm: vmscan: split unregister_shrinker() Date: Wed, 31 May 2023 09:57:36 +0000 Message-Id: <20230531095742.2480623-3-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 This and the next patches in this series aim to make time effect of synchronize_srcu() invisible for user. The patch splits unregister_shrinker() in two functions: unregister_shrinker_delayed_initiate() unregister_shrinker_delayed_finalize() and shrinker users may make the second of them to be called asynchronous (e.g., from workqueue). Next patches make superblock shrinker to follow this way, so user-visible umount() time won't contain delays from synchronize_srcu(). Signed-off-by: Kirill Tkhai Signed-off-by: Qi Zheng --- include/linux/shrinker.h | 2 ++ mm/vmscan.c | 22 ++++++++++++++++++---- 2 files changed, 20 insertions(+), 4 deletions(-) diff --git a/include/linux/shrinker.h b/include/linux/shrinker.h index 224293b2dd06..e9d5a19d83fe 100644 --- a/include/linux/shrinker.h +++ b/include/linux/shrinker.h @@ -102,6 +102,8 @@ extern void register_shrinker_prepared(struct shrinker = *shrinker); extern int __printf(2, 3) register_shrinker(struct shrinker *shrinker, const char *fmt, ...); extern void unregister_shrinker(struct shrinker *shrinker); +extern void unregister_shrinker_delayed_initiate(struct shrinker *shrinker= ); +extern void unregister_shrinker_delayed_finalize(struct shrinker *shrinker= ); extern void free_prealloced_shrinker(struct shrinker *shrinker); extern void synchronize_shrinkers(void); =20 diff --git a/mm/vmscan.c b/mm/vmscan.c index a773e97e152e..baf8d2327d70 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -799,10 +799,7 @@ int register_shrinker(struct shrinker *shrinker, const= char *fmt, ...) #endif EXPORT_SYMBOL(register_shrinker); =20 -/* - * Remove one - */ -void unregister_shrinker(struct shrinker *shrinker) +void unregister_shrinker_delayed_initiate(struct shrinker *shrinker) { struct dentry *debugfs_entry; int debugfs_id; @@ -819,6 +816,13 @@ void unregister_shrinker(struct shrinker *shrinker) mutex_unlock(&shrinker_mutex); =20 shrinker_debugfs_remove(debugfs_entry, debugfs_id); +} +EXPORT_SYMBOL(unregister_shrinker_delayed_initiate); + +void unregister_shrinker_delayed_finalize(struct shrinker *shrinker) +{ + if (!shrinker->nr_deferred) + return; =20 atomic_inc(&shrinker_srcu_generation); synchronize_srcu(&shrinker_srcu); @@ -826,6 +830,16 @@ void unregister_shrinker(struct shrinker *shrinker) kfree(shrinker->nr_deferred); shrinker->nr_deferred =3D NULL; } +EXPORT_SYMBOL(unregister_shrinker_delayed_finalize); + +/* + * Remove one + */ +void unregister_shrinker(struct shrinker *shrinker) +{ + unregister_shrinker_delayed_initiate(shrinker); + unregister_shrinker_delayed_finalize(shrinker); +} EXPORT_SYMBOL(unregister_shrinker); =20 /** --=20 2.30.2