Date: Mon, 30 Jan 2006 10:43:02 -0800
From: Greg KH <greg@kroah.com>
To: Eric Dumazet <dada1@cosmosbay.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>, linux-kernel@vger.kernel.org,
       vserver@list.linux-vserver.org, Herbert Poetzl <herbert@13thfloor.at>,
       "Serge E. Hallyn" <serue@us.ibm.com>,
       Alan Cox <alan@lxorguk.ukuu.org.uk>, Dave Hansen <haveblue@us.ibm.com>,
       Arjan van de Ven <arjan@infradead.org>,
       Suleiman Souhlal <ssouhlal@FreeBSD.org>,
       Hubertus Franke <frankeh@watson.ibm.com>,
       Cedric Le Goater <clg@fr.ibm.com>, Kyle Moffett <mrmacman_g4@mac.com>
Subject: Re: [PATCH 1/5] pid: Implement task references.
Message-ID: <20060130184302.GA17457@kroah.com>
References: <m1psmba4bn.fsf@ebiederm.dsl.xmission.com> <m1lkwza479.fsf@ebiederm.dsl.xmission.com> <20060129190539.GA26794@kroah.com> <m1mzhe7l2c.fsf@ebiederm.dsl.xmission.com> <20060130045153.GC13244@kroah.com> <43DDA1E7.5010109@cosmosbay.com>
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On Mon, Jan 30, 2006 at 06:19:35AM +0100, Eric Dumazet wrote:
> Example of improvement in kref_put() :
> 
> [PATCH] kref : Avoid an atomic operation in kref_put() when the last 
> reference is dropped. On most platforms, atomic_read() is a plan read of 
> the counter and involves no atomic at all.

No, we wat to decrement and test at the same time, to protect against
any race where someone is incrementing right when we are dropping the
last reference.

So, thanks, but I'm not going to apply this.

greg k-h
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