From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-f198.google.com (mail-qt0-f198.google.com [209.85.216.198]) by kanga.kvack.org (Postfix) with ESMTP id E2DAC6B0279 for ; Tue, 7 Aug 2018 11:38:37 -0400 (EDT) Received: by mail-qt0-f198.google.com with SMTP id b7-v6so13775280qtp.14 for ; Tue, 07 Aug 2018 08:38:37 -0700 (PDT) Received: from EUR03-DB5-obe.outbound.protection.outlook.com (mail-eopbgr40096.outbound.protection.outlook.com. [40.107.4.96]) by mx.google.com with ESMTPS id u27-v6si1642637qte.81.2018.08.07.08.38.36 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 07 Aug 2018 08:38:37 -0700 (PDT) Subject: [PATCH RFC 05/10] fs: Move list_lru_destroy() to destroy_super_work() From: Kirill Tkhai Date: Tue, 07 Aug 2018 18:38:23 +0300 Message-ID: <153365630328.19074.5326096793225967868.stgit@localhost.localdomain> In-Reply-To: <153365347929.19074.12509495712735843805.stgit@localhost.localdomain> References: <153365347929.19074.12509495712735843805.stgit@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org, gregkh@linuxfoundation.org, rafael@kernel.org, viro@zeniv.linux.org.uk, darrick.wong@oracle.com, paulmck@linux.vnet.ibm.com, josh@joshtriplett.org, rostedt@goodmis.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, hughd@google.com, shuah@kernel.org, robh@kernel.org, ulf.hansson@linaro.org, aspriel@gmail.com, vivek.gautam@codeaurora.org, robin.murphy@arm.com, joe@perches.com, heikki.krogerus@linux.intel.com, ktkhai@virtuozzo.com, sfr@canb.auug.org.au, vdavydov.dev@gmail.com, mhocko@suse.com, chris@chris-wilson.co.uk, penguin-kernel@I-love.SAKURA.ne.jp, aryabinin@virtuozzo.com, willy@infradead.org, ying.huang@intel.com, shakeelb@google.com, jbacik@fb.com, mingo@kernel.org, mhiramat@kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org The patch makes s_dentry_lru and s_inode_lru be destroyed later from the workqueue. This is preparation to split unregister_shrinker(super_block::s_shrink) in two stages, and to call finalize stage from destroy_super_work(). Note, that generic filesystem shrinker unregistration is safe to be splitted in two stages right after this patch, since super_cache_count() and super_cache_scan() have a deal with s_dentry_lru and s_inode_lru only. But there are two exceptions: XFS and SHMEM, which define .nr_cached_objects() and .free_cached_objects() callbacks. These two do not allow us to do the splitting right after this patch. They touch fs-specific data, which is destroyed earlier, than destroy_super_work(). So, we can't call unregister_shrinker_delayed_finalize() from destroy_super_work() because of them, and next patches make preparations to make this possible. Signed-off-by: Kirill Tkhai --- fs/super.c | 17 +++++------------ 1 file changed, 5 insertions(+), 12 deletions(-) diff --git a/fs/super.c b/fs/super.c index 426161360af3..457834278e37 100644 --- a/fs/super.c +++ b/fs/super.c @@ -159,6 +159,11 @@ static void destroy_super_work(struct work_struct *work) destroy_work); int i; + 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); + list_lru_destroy(&s->s_inode_lru); + for (i = 0; i < SB_FREEZE_LEVELS; i++) percpu_free_rwsem(&s->s_writers.rw_sem[i]); kfree(s); @@ -177,8 +182,6 @@ static void destroy_unused_super(struct super_block *s) if (!s) return; up_write(&s->s_umount); - list_lru_destroy(&s->s_dentry_lru); - list_lru_destroy(&s->s_inode_lru); security_sb_free(s); put_user_ns(s->s_user_ns); kfree(s->s_subtype); @@ -283,8 +286,6 @@ static void __put_super(struct super_block *s) { if (!--s->s_count) { list_del_init(&s->s_list); - WARN_ON(s->s_dentry_lru.node); - WARN_ON(s->s_inode_lru.node); WARN_ON(!list_empty(&s->s_mounts)); security_sb_free(s); put_user_ns(s->s_user_ns); @@ -327,14 +328,6 @@ void deactivate_locked_super(struct super_block *s) unregister_shrinker(&s->s_shrink); fs->kill_sb(s); - /* - * Since list_lru_destroy() may sleep, we cannot call it from - * put_super(), where we hold the sb_lock. Therefore we destroy - * the lru lists right now. - */ - list_lru_destroy(&s->s_dentry_lru); - list_lru_destroy(&s->s_inode_lru); - put_filesystem(fs); put_super(s); } else {