From: Andi Kleen <andi@firstfloor.org>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Andi Kleen <andi@firstfloor.org>,
jolsa@redhat.com, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, fbl@redhat.com, nhorman@redhat.com,
davem@redhat.com, oleg@redhat.com, eric.dumazet@gmail.com
Subject: Re: [PATCH] net: fix race in the receive/select
Date: Wed, 1 Jul 2009 08:27:32 +0200 [thread overview]
Message-ID: <20090701062732.GK6760@one.firstfloor.org> (raw)
In-Reply-To: <20090701033924.GA29762@gondor.apana.org.au>
On Wed, Jul 01, 2009 at 11:39:24AM +0800, Herbert Xu wrote:
> Andi Kleen <andi@firstfloor.org> wrote:
> >
> > At least on x86 I can't see how it happens. mb() is only a compile
> > time barrier and the compiler doesn't optimize over indirect callbacks
> > like __pollwait() anyways.
>
> mb() does more than just a compiler barrier, it also issues mfence.
mfence is not needed for normal C code (not using non temporal
stores) in the Linux memory model on x86 and is a no-op. Only the compile
time barrier matters.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2009-07-01 6:27 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-25 12:25 [PATCH] net: fix race in the receive/select Jiri Olsa
2009-06-25 12:24 ` Oleg Nesterov
2009-06-26 1:31 ` Davide Libenzi
2009-06-26 1:59 ` Eric Dumazet
2009-06-26 2:04 ` Davide Libenzi
2009-06-26 2:11 ` David Miller
2009-06-26 2:19 ` Eric Dumazet
2009-06-26 3:14 ` Davide Libenzi
2009-06-26 5:42 ` Jarek Poplawski
2009-06-26 8:10 ` Jarek Poplawski
2009-06-26 13:57 ` Oleg Nesterov
2009-06-26 17:32 ` Davide Libenzi
2009-06-26 14:50 ` Oleg Nesterov
2009-06-26 18:12 ` Davide Libenzi
2009-06-26 18:17 ` David Miller
2009-06-26 19:35 ` Eric Dumazet
2009-06-29 9:34 ` Jiri Olsa
2009-06-28 11:10 ` Jarek Poplawski
2009-06-28 11:22 ` Jarek Poplawski
2009-06-28 18:04 ` Oleg Nesterov
2009-06-28 21:48 ` Jarek Poplawski
2009-06-29 9:27 ` Jiri Olsa
2009-06-26 13:46 ` Oleg Nesterov
2009-06-25 23:18 ` Eric Dumazet
2009-06-26 1:50 ` Tejun Heo
2009-06-29 9:12 ` Andi Kleen
2009-06-29 9:24 ` Jiri Olsa
2009-06-29 16:59 ` Zan Lynx
2009-06-29 17:29 ` Andi Kleen
2009-07-01 3:39 ` Herbert Xu
2009-07-01 6:27 ` Andi Kleen [this message]
2009-07-01 7:03 ` Herbert Xu
2009-07-01 7:22 ` Andi Kleen
2009-07-01 8:31 ` Herbert Xu
2009-07-01 8:44 ` Jiri Olsa
2009-07-01 10:58 ` Herbert Xu
2009-07-01 13:07 ` Herbert Xu
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