From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Andrew Morton <akpm@linux-foundation.org>,
Oleg Nesterov <oleg@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Pavel Emelyanov <xemul@parallels.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Louis Rilling <louis.rilling@kerlabs.com>,
Mike Galbraith <efault@gmx.de>,
Christoph Hellwig <hch@infradead.org>,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH] vfs: Speed up deactivate_super for non-modular filesystems
Date: Mon, 7 May 2012 16:56:47 -0700 [thread overview]
Message-ID: <20120507235647.GH21152@linux.vnet.ibm.com> (raw)
In-Reply-To: <20120507221706.GI22082@ZenIV.linux.org.uk>
On Mon, May 07, 2012 at 11:17:06PM +0100, Al Viro wrote:
> On Mon, May 07, 2012 at 02:51:08PM -0700, Eric W. Biederman wrote:
>
> > /proc and similar non-modular filesystems do not need a rcu_barrier
> > in deactivate_locked_super. Being non-modular there is no danger
> > of the rcu callback running after the module is unloaded.
>
> There's more than just a module unload there, though - actual freeing
> struct super_block also happens past that rcu_barrier()...
Is there anything in there for which synchronous operation is required?
If not, one approach would be to drop the rcu_barrier() calls to a
workqueue or something similar.
Thanx, Paul
next prev parent reply other threads:[~2012-05-07 23:57 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1335604790.5995.22.camel@marge.simpson.net>
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[not found] ` <m1zk9rmyh4.fsf@fess.ebiederm.org>
[not found] ` <20120501134214.f6b44f4a.akpm@linux-foundation.org>
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[not found] ` <m1vckcdoey.fsf@fess.ebiederm.org>
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[not found] ` <m1zk9oc61j.fsf@fess.ebiederm.org>
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[not found] ` <m1fwbfd71h.fsf@fess.ebiederm.org>
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[not found] ` <1336201977.7346.22.camel@marge.simpson.net>
2012-05-07 21:51 ` [PATCH] vfs: Speed up deactivate_super for non-modular filesystems Eric W. Biederman
2012-05-07 22:17 ` Al Viro
2012-05-07 23:56 ` Paul E. McKenney [this message]
2012-05-08 1:07 ` Eric W. Biederman
2012-05-08 4:53 ` Mike Galbraith
2012-05-09 7:55 ` Nick Piggin
2012-05-09 11:02 ` Eric W. Biederman
2012-05-15 8:40 ` Nick Piggin
2012-05-16 0:34 ` Eric W. Biederman
2012-05-09 13:59 ` Paul E. McKenney
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