From: Russell King <rmk+lkml@arm.linux.org.uk>
To: Linus Torvalds <torvalds@osdl.org>
Cc: David Howells <dhowells@redhat.com>,
Christoph Lameter <clameter@sgi.com>,
Nick Piggin <nickpiggin@yahoo.com.au>,
akpm@osdl.org, linux-arm-kernel@lists.arm.linux.org.uk,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org
Subject: Re: [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it
Date: Fri, 8 Dec 2006 19:04:03 +0000 [thread overview]
Message-ID: <20061208190403.GH31068@flint.arm.linux.org.uk> (raw)
In-Reply-To: <Pine.LNX.4.64.0612081045430.3516@woody.osdl.org>
On Fri, Dec 08, 2006 at 10:46:17AM -0800, Linus Torvalds wrote:
>
>
> On Fri, 8 Dec 2006, David Howells wrote:
> >
> > In fact I think more things have LL/SC than have CMPXCHG.
>
> But you cannot expose ll/sc to C, so that's a bogus argument.
Yes you can. Well, you can on ARM at least. Between the load exclusive
you can do anything you like until you hit the store exclusive. If you
haven't touched the location (with anything other than another load
exclusive) and no other CPU has issued a load exclusive, your store
exclusive succeeds. Whether you have branches, loads or stores to
other locations, etc. None of that matters.
Not so bogus as you make out.
--
Russell King
Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/
maintainer of:
next prev parent reply other threads:[~2006-12-08 19:04 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-12-06 16:43 [PATCH] WorkStruct: Implement generic UP cmpxchg() where an arch doesn't support it David Howells
2006-12-06 17:21 ` Linus Torvalds
2006-12-06 18:56 ` Christoph Lameter
2006-12-06 19:00 ` Russell King
2006-12-06 19:16 ` Christoph Lameter
2006-12-06 19:28 ` Linus Torvalds
2006-12-06 19:58 ` Russell King
2006-12-06 21:36 ` Matthew Wilcox
2006-12-06 21:52 ` Christoph Lameter
2006-12-06 22:05 ` Matthew Wilcox
2006-12-06 22:15 ` Christoph Lameter
2006-12-07 0:37 ` Roman Zippel
2006-12-07 0:54 ` Linus Torvalds
2006-12-07 1:05 ` Roman Zippel
2006-12-07 1:18 ` Linus Torvalds
2006-12-07 1:24 ` Roman Zippel
2006-12-07 1:36 ` Linus Torvalds
2006-12-07 1:44 ` Matthew Wilcox
2006-12-07 2:09 ` Douglas McNaught
2006-12-07 1:52 ` Roman Zippel
2006-12-07 9:23 ` Nick Piggin
2006-12-06 22:38 ` Linus Torvalds
2006-12-07 9:31 ` Nick Piggin
2006-12-07 13:20 ` Ivan Kokshaysky
2006-12-07 15:03 ` Russell King
2006-12-08 1:18 ` Nick Piggin
2006-12-08 8:56 ` Russell King
2006-12-08 16:06 ` Christoph Lameter
2006-12-08 16:31 ` Russell King
2006-12-08 16:43 ` Christoph Lameter
2006-12-08 16:47 ` Russell King
2006-12-08 16:53 ` Christoph Lameter
2006-12-08 16:58 ` Russell King
2006-12-08 16:56 ` David Howells
2006-12-08 17:06 ` Christoph Lameter
2006-12-08 17:18 ` Russell King
2006-12-08 17:23 ` Christoph Lameter
2006-12-08 19:15 ` Linus Torvalds
2006-12-08 19:31 ` Russell King
2006-12-08 19:37 ` Linus Torvalds
2006-12-08 19:43 ` Russell King
2006-12-08 20:01 ` Linus Torvalds
2006-12-08 18:46 ` Linus Torvalds
2006-12-08 19:04 ` Russell King [this message]
2006-12-08 19:35 ` Linus Torvalds
2006-12-08 19:59 ` Russell King
2006-12-08 20:34 ` Linus Torvalds
2006-12-11 11:04 ` David Howells
2006-12-08 22:33 ` Nick Piggin
2006-12-07 15:36 ` Linus Torvalds
2006-12-07 16:51 ` Ralf Baechle
2006-12-07 0:46 ` Ralf Baechle
2006-12-06 19:05 ` Linus Torvalds
2006-12-06 19:08 ` Al Viro
2006-12-06 19:25 ` Linus Torvalds
2006-12-06 19:29 ` Matthew Wilcox
2006-12-06 19:43 ` David Howells
2006-12-06 19:54 ` Linus Torvalds
2006-12-06 19:56 ` Linus Torvalds
2006-12-07 1:09 ` David Miller
2006-12-06 19:26 ` Matthew Wilcox
2006-12-06 19:29 ` Christoph Lameter
2006-12-06 19:36 ` Matthew Wilcox
2006-12-06 19:47 ` Christoph Lameter
2006-12-06 19:50 ` Matthew Wilcox
2006-12-06 20:11 ` Christoph Lameter
2006-12-06 20:17 ` Matthew Wilcox
2006-12-06 19:34 ` Linus Torvalds
2006-12-06 19:41 ` Matthew Wilcox
2006-12-06 19:45 ` David Howells
2006-12-06 20:00 ` Russell King
2006-12-07 15:06 ` Russell King
2006-12-08 15:32 ` Russell King
2006-12-06 19:12 ` Lennert Buytenhek
2006-12-06 19:47 ` David Howells
2006-12-06 20:09 ` Lennert Buytenhek
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