From: Peter Zijlstra <peterz@infradead.org>
To: Oliver Neukum <oliver@neukum.org>
Cc: Greg KH <greg@kroah.com>, Ming Lei <tom.leiming@gmail.com>,
gregkh@suse.de, akpm@linux-foundation.org,
linux-kernel@vger.kernel.org, ostrikov@nvidia.com,
adobriyan@gmail.com, eric.dumazet@gmail.com, mingo@elte.hu
Subject: Re: [PATCH 3/3] kref: Remove the memory barriers
Date: Tue, 13 Dec 2011 10:12:20 +0100 [thread overview]
Message-ID: <1323767540.9082.4.camel@twins> (raw)
In-Reply-To: <201112122356.47545.oliver@neukum.org>
On Mon, 2011-12-12 at 23:56 +0100, Oliver Neukum wrote:
> I guess I worried not about the increment, but the decrement.
> Which makes me wonder what happens if you don't intend
> to get the kref again, but need to make sure it is usually freed,
> like:
>
> CPU A CPU B
>
> kref_get(p)
> start_io(p)
> [interrupt from IO]
> kref_put(p)
I would expect that if something was needed here, the io stack would
provide the barriers since the io completion will probably want to
change state set by the start_io thing.
Anyway, I would put this squarely outside the responsibility of kref.
next prev parent reply other threads:[~2011-12-13 9:13 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-10 10:43 [PATCH 0/3] kref: inline and barriers Peter Zijlstra
2011-12-10 10:43 ` [PATCH 1/3] kref: Inline all functions Peter Zijlstra
2011-12-10 14:32 ` Ming Lei
2011-12-10 14:59 ` Peter Zijlstra
2011-12-12 22:11 ` Greg KH
2011-12-13 9:36 ` Peter Zijlstra
2011-12-13 17:15 ` Greg KH
2011-12-13 18:52 ` Peter Zijlstra
2011-12-13 19:11 ` Greg KH
2011-12-13 19:36 ` Peter Zijlstra
2011-12-10 10:43 ` [PATCH 2/3] kref: Implement kref_put in terms of kref_sub Peter Zijlstra
2011-12-10 10:43 ` [PATCH 3/3] kref: Remove the memory barriers Peter Zijlstra
2011-12-10 14:07 ` Ming Lei
2011-12-10 14:58 ` Peter Zijlstra
2011-12-10 15:57 ` Ming Lei
2011-12-10 19:49 ` Peter Zijlstra
2011-12-11 2:22 ` Ming Lei
2011-12-11 12:47 ` Peter Zijlstra
2011-12-11 12:59 ` Ming Lei
2011-12-11 15:35 ` Peter Zijlstra
2011-12-11 20:42 ` Peter Zijlstra
2011-12-12 3:48 ` Ming Lei
2011-12-12 8:54 ` Peter Zijlstra
2011-12-12 9:57 ` Ming Lei
2011-12-12 10:12 ` Peter Zijlstra
2011-12-12 10:32 ` Ming Lei
2011-12-12 11:05 ` Peter Zijlstra
2011-12-12 11:19 ` Ming Lei
2011-12-12 11:13 ` Eric Dumazet
2011-12-12 11:15 ` Oliver Neukum
2011-12-12 10:20 ` Oliver Neukum
2011-12-12 19:30 ` Greg KH
2011-12-12 22:56 ` Oliver Neukum
2011-12-12 23:14 ` Greg KH
2011-12-13 11:51 ` Oliver Neukum
2011-12-13 9:12 ` Peter Zijlstra [this message]
2011-12-13 9:49 ` Oliver Neukum
2011-12-12 8:55 ` Peter Zijlstra
2011-12-12 15:24 ` Greg KH
2011-12-12 8:56 ` Peter Zijlstra
2011-12-12 10:10 ` Ming Lei
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