From: "Paul E. McKenney" <paulmck@kernel.org>
To: clm@fb.com
Cc: riel@surriel.com, viro@zeniv.linux.org.uk,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
kernel-team@fb.com
Subject: [PATCH RFC fs/namespace] Make kern_unmount() use synchronize_rcu_expedited()
Date: Mon, 14 Feb 2022 11:05:49 -0800 [thread overview]
Message-ID: <20220214190549.GA2815154@paulmck-ThinkPad-P17-Gen-1> (raw)
Experimental. Not for inclusion. Yet, anyway.
Freeing large numbers of namespaces in quick succession can result in
a bottleneck on the synchronize_rcu() invoked from kern_unmount().
This patch applies the synchronize_rcu_expedited() hammer to allow
further testing and fault isolation.
Hey, at least there was no need to change the comment! ;-)
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Not-yet-signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/namespace.c b/fs/namespace.c
index 40b994a29e90d..79c50ad0ade5b 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -4389,7 +4389,7 @@ void kern_unmount(struct vfsmount *mnt)
/* release long term mount so mount point can be released */
if (!IS_ERR_OR_NULL(mnt)) {
real_mount(mnt)->mnt_ns = NULL;
- synchronize_rcu(); /* yecchhh... */
+ synchronize_rcu_expedited(); /* yecchhh... */
mntput(mnt);
}
}
next reply other threads:[~2022-02-14 21:21 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 19:05 Paul E. McKenney [this message]
2022-02-14 19:26 ` [PATCH RFC fs/namespace] Make kern_unmount() use synchronize_rcu_expedited() Chris Mason
2022-02-14 19:44 ` Paul E. McKenney
2022-02-14 20:55 ` Rik van Riel
2022-02-14 21:41 ` Paul E. McKenney
2022-02-15 18:28 ` Chris Mason
2022-04-26 6:59 ` Christoph Bartoschek
2022-04-26 14:09 ` Paul E. McKenney
2022-04-26 22:58 ` Christoph Bartoschek
2022-04-26 23:11 ` Paul E. McKenney
2022-04-27 12:19 ` Chris Mason
2022-04-27 15:01 ` Paul E. McKenney
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