From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: heiko.carstens@de.ibm.com, horms@verge.net.au,
linux-kernel@vger.kernel.org, rpjday@mindspring.com, ak@suse.de,
netdev@vger.kernel.org, cfriesen@nortel.com,
akpm@linux-foundation.org, torvalds@linux-foundation.org,
jesper.juhl@gmail.com, linux-arch@vger.kernel.org, zlynx@acm.org,
schwidefsky@de.ibm.com, Chris Snook <csnook@redhat.com>,
davem@davemloft.net, wensong@linux-vs.org, wjiang@resilience.com,
David Howells <dhowells@redhat.com>
Subject: Re: [PATCH 6/24] make atomic_read() behave consistently on frv
Date: Wed, 15 Aug 2007 20:51:58 +0200 [thread overview]
Message-ID: <2cbda24e96a49c3ab7cf7039c515f9fc@kernel.crashing.org> (raw)
In-Reply-To: <46C140DD.3060509@yahoo.com.au>
> Well if there is only one memory location involved, then smp_rmb()
> isn't
> going to really do anything anyway, so it would be incorrect to use it.
rmb() orders *any* two reads; that includes two reads from the same
location.
> Consider that smp_rmb basically will do anything from flushing the
> pipeline to invalidating loads speculatively executed out of order.
> AFAIK
> it will not control the visibility of stores coming from other CPUs
> (that
> is up to the cache coherency).
The writer side should typically use wmb() whenever the reader side
uses rmb(), sure.
Segher
next prev parent reply other threads:[~2007-08-15 18:52 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-08-09 13:41 [PATCH 6/24] make atomic_read() behave consistently on frv Chris Snook
2007-08-09 16:54 ` Chris Snook
2007-08-10 9:23 ` David Howells
2007-08-10 19:54 ` Chris Snook
2007-08-11 0:54 ` Herbert Xu
2007-08-11 0:54 ` Herbert Xu
2007-08-11 4:29 ` Paul E. McKenney
2007-08-13 5:15 ` Herbert Xu
2007-08-13 6:03 ` Paul E. McKenney
2007-08-14 5:34 ` Nick Piggin
2007-08-14 7:26 ` Herbert Xu
2007-08-14 17:01 ` Paul E. McKenney
2007-08-14 22:01 ` Arnd Bergmann
2007-08-14 22:43 ` Paul E. McKenney
2007-08-15 13:29 ` Arnd Bergmann
2007-08-15 15:06 ` Michael Buesch
2007-08-15 13:30 ` Nick Piggin
2007-08-15 20:15 ` Paul E. McKenney
2007-08-16 1:09 ` Nick Piggin
2007-08-16 2:27 ` Paul E. McKenney
2007-08-11 8:47 ` David Howells
2007-08-13 6:44 ` Chris Snook
2007-08-14 5:42 ` Nick Piggin
2007-08-15 18:51 ` Segher Boessenkool [this message]
2007-08-15 19:18 ` Paul E. McKenney
2007-08-15 19:46 ` Segher Boessenkool
2007-08-15 19:59 ` Paul E. McKenney
2007-08-15 20:13 ` Segher Boessenkool
2007-08-15 20:38 ` Paul E. McKenney
2007-08-15 21:15 ` Segher Boessenkool
2007-08-16 1:20 ` Nick Piggin
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