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Message-ID: <1323680078.16764.45.camel@twins>
Subject: Re: [PATCH 3/3] kref: Remove the memory barriers
From: Peter Zijlstra <peterz@infradead.org>
To: Ming Lei <tom.leiming@gmail.com>
Cc: 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, Oliver Neukum <oneukum@suse.de>
Date: Mon, 12 Dec 2011 09:54:38 +0100
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On Mon, 2011-12-12 at 11:48 +0800, Ming Lei wrote:
> For kref, maybe it is still multiple operations done on one cpu vs them
> being visible on another, but seems a bit implicit, see the common kref
> usage below:
> 
> CPU0                            CPU1
>                                         A:kref_init(&obj->ref)

how does CPU0 get a ref to obj?

> B:kref_get(&obj->ref)
> C:access obj                    E:access obj
>                                         F:kref_put(&ojb->ref)
> D:kref_put(obj->ref)