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From: Jonathan Corbet <corbet@lwn.net>
To: Andi Kleen <andi@firstfloor.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, andi@firstfloor.org,
	viro@ZenIV.linux.org.uk, oleg@redhat.com,
	linux-api@vger.kernel.org, alan@lxorguk.ukuu.org.uk
Subject: Re: [PATCH, RFC] Remove fasync() BKL usage, take 3325
Date: Thu, 22 Jan 2009 22:21:41 -0700	[thread overview]
Message-ID: <20090122222141.4a9501e1@tpl> (raw)
In-Reply-To: <20090122160935.GI15750@one.firstfloor.org>

On Thu, 22 Jan 2009 17:09:35 +0100
Andi Kleen <andi@firstfloor.org> wrote:

> > OK, replacing a lock_kernel() with a spin_lock(&global_lock) is
> > pretty straightforwad.  But it's really really sad.  It basically
> > leaves a great big FIXME in there.  It'd be better to fix it.  
> 
> Also it might be that it's even worse than the BKL.

I don't quite see how now.  Like the BKL, it's a spinlock.

> It would still require a bitlock because some state in the low
> level fasync needs to be protected.
> 
> Oleg has a proposal to do this using a flag bit which seemed
> reasonable to me.

I didn't see a reason to add a one-off custom locking regime for such a
non-hot-path situation.  But it would certainly work; if we want to go
that way I'll not fight it.

jon

  reply	other threads:[~2009-01-23  5:21 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-01-15 22:32 [PATCH, RFC] Remove fasync() BKL usage, take 3325 Jonathan Corbet
2009-01-22 14:51 ` Andrew Morton
2009-01-22 16:09   ` Andi Kleen
2009-01-23  5:21     ` Jonathan Corbet [this message]
2009-01-22 20:32   ` Christoph Hellwig
2009-01-23  4:56     ` Andi Kleen
2009-01-28  0:53       ` Andrew Morton
2009-01-28  0:55       ` Andrew Morton
2009-01-28  3:14         ` Oleg Nesterov
2009-01-28  3:57           ` Jonathan Corbet
2009-01-28  4:23             ` Oleg Nesterov
2009-01-28 14:13               ` Jonathan Corbet
2009-01-28 17:36           ` Christoph Hellwig
2009-01-28 17:44             ` Jonathan Corbet
2009-01-28 17:55               ` Christoph Hellwig
2009-01-28 18:13                 ` Matt Mackall
2009-01-28 21:05                   ` Jonathan Corbet
2009-01-28 18:14             ` David Daney
2009-01-29 14:37             ` Andi Kleen
2009-01-23  5:15   ` Jonathan Corbet
2009-01-23  5:31     ` Andrew Morton
2009-01-23  5:45       ` Matt Mackall
2009-01-23  6:15         ` Andi Kleen
2009-01-23 10:45           ` Bernd Petrovitsch
2009-01-23  5:54       ` Andi Kleen
2009-01-23  6:01         ` Jonathan Corbet
2009-01-23  6:57         ` Andrew Morton

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