From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "David S. Miller" <davem@davemloft.net>
Cc: torvalds@osdl.org, herbert@gondor.apana.org.au, hugh@veritas.com,
paulus@samba.org, anton@samba.org, nickpiggin@yahoo.com.au,
akpm@osdl.org, andrea@suse.de, linux-kernel@vger.kernel.org
Subject: Re: Possible memory ordering bug in page reclaim?
Date: Sun, 16 Oct 2005 08:17:00 +1000 [thread overview]
Message-ID: <1129414620.7620.14.camel@gaston> (raw)
In-Reply-To: <20051015.122938.14078749.davem@davemloft.net>
On Sat, 2005-10-15 at 12:29 -0700, David S. Miller wrote:
> From: Linus Torvalds <torvalds@osdl.org>
> Date: Sat, 15 Oct 2005 09:57:47 -0700 (PDT)
>
> > On Sat, 15 Oct 2005, Herbert Xu wrote:
> > >
> > > Yes atomic_add_negative should always be a barrier.
> >
> > I disagree. That would be very expensive on anything but x86, where it
> > just happens to be true for other reasons. Atomics do _not_ implement
> > barriers.
>
> When they return values, they are defined to be barriers.
> It's even on the documentation :-)
Ahhh, good to know :)
/me should read the documentation sometimes....
Ben.
next prev parent reply other threads:[~2005-10-15 22:18 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-10-15 3:28 Possible memory ordering bug in page reclaim? Nick Piggin
2005-10-15 6:17 ` Hugh Dickins
2005-10-15 7:43 ` Benjamin Herrenschmidt
2005-10-15 8:00 ` Herbert Xu
2005-10-15 16:57 ` Linus Torvalds
2005-10-15 19:29 ` David S. Miller
2005-10-15 22:17 ` Benjamin Herrenschmidt [this message]
2005-10-16 0:04 ` Nick Piggin
2005-10-15 8:59 ` Nick Piggin
2005-10-15 12:08 ` Herbert Xu
2005-10-15 13:35 ` Nick Piggin
2005-10-15 18:00 ` Andrea Arcangeli
2005-10-15 19:48 ` Herbert Xu
2005-10-15 20:07 ` Andrea Arcangeli
2005-10-15 23:07 ` David S. Miller
2005-10-16 19:36 ` Ivan Kokshaysky
2005-10-17 4:29 ` David S. Miller
2005-10-17 7:23 ` Ivan Kokshaysky
2005-10-17 11:28 ` Andrea Arcangeli
2005-10-15 22:16 ` Benjamin Herrenschmidt
2005-10-15 23:13 ` David S. Miller
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