From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Nicolas Pitre <nico@cam.org>
Cc: Ingo Molnar <mingo@elte.hu>, Linus Torvalds <torvalds@osdl.org>,
lkml <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
Arjan van de Ven <arjanv@infradead.org>,
Jes Sorensen <jes@trained-monkey.org>,
Zwane Mwaikambo <zwane@arm.linux.org.uk>,
Oleg Nesterov <oleg@tv-sign.ru>,
David Howells <dhowells@redhat.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Benjamin LaHaise <bcrl@kvack.org>,
Steven Rostedt <rostedt@goodmis.org>,
Christoph Hellwig <hch@infradead.org>, Andi Kleen <ak@suse.de>,
Russell King <rmk+lkml@arm.linux.org.uk>
Subject: Re: [patch 2/5] mutex subsystem: add architecture specific mutex primitives
Date: Thu, 22 Dec 2005 19:03:32 +1100 [thread overview]
Message-ID: <43AA5DD4.1040606@yahoo.com.au> (raw)
In-Reply-To: <43AA5978.1060705@yahoo.com.au>
Nick Piggin wrote:
> I think ARMv6 has a decent atomic_cmpxchg implementation but does
> not define __HAVE_ARCH_CMPXCHG. It might be useful to try to use this
> for ARMv6 SMP for a slightly better trylock.
>
And on UP builds, it may simply be best to open code an interrupt unsafe
cmpxchg and use atomic_cmpxchg unconditionally on SMP builds (which I
think generates half decent code on all SMP architectures).
Just something to think about. Of course this will require the dreaded
preempt_disable() which might make it a showstopper.
--
SUSE Labs, Novell Inc.
Send instant messages to your online friends http://au.messenger.yahoo.com
next prev parent reply other threads:[~2005-12-22 8:03 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-12-21 15:54 [patch 0/8] mutex subsystem, ANNOUNCE Ingo Molnar
2005-12-21 16:04 ` Arjan van de Ven
2005-12-21 18:07 ` Jes Sorensen
2005-12-22 2:36 ` Nick Piggin
2005-12-22 2:57 ` Nick Piggin
2005-12-22 7:19 ` Ingo Molnar
2005-12-22 7:56 ` Nick Piggin
2005-12-22 8:00 ` Arjan van de Ven
2005-12-22 8:10 ` Nick Piggin
2005-12-22 8:21 ` Arjan van de Ven
2005-12-22 8:32 ` Nick Piggin
2005-12-22 8:24 ` Ingo Molnar
2005-12-22 8:37 ` Nick Piggin
2005-12-21 22:43 ` Nicolas Pitre
2005-12-21 22:43 ` [patch 1/3] mutex subsystem: fix additions to the ARM atomic.h Nicolas Pitre
2005-12-21 22:44 ` [patch 2/3] mutex subsystem: add new atomic primitives Nicolas Pitre
2005-12-21 22:44 ` [patch 3/3] mutex subsystem: move the core to the new atomic helpers Nicolas Pitre
2005-12-21 23:12 ` Ingo Molnar
2005-12-22 1:16 ` Matt Mackall
2005-12-22 6:50 ` Nicolas Pitre
2005-12-22 6:51 ` [patch 2/5] mutex subsystem: add architecture specific mutex primitives Nicolas Pitre
2005-12-22 7:44 ` Nick Piggin
2005-12-22 8:03 ` Nick Piggin [this message]
2005-12-22 6:52 ` [patch 1/5] mutex subsystem: fix asm-arm/atomic.h Nicolas Pitre
2005-12-22 6:53 ` [patch 3/5] mutex subsystem: move the core to the new atomic helpers Nicolas Pitre
2005-12-22 6:53 ` [patch 4/5] mutex subsystem: allow architecture defined fast path for mutex_lock_interruptible Nicolas Pitre
2005-12-22 6:53 ` [patch 5/5] mutex subsystem: allow for the fast path to be inlined Nicolas Pitre
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