From: jamie@shareable.org (Jamie Lokier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/1] [RFC] arm: add half-word __xchg
Date: Fri, 19 Mar 2010 01:49:06 +0000 [thread overview]
Message-ID: <20100319014906.GC14108@shareable.org> (raw)
In-Reply-To: <20100318135008.GA11800@Krystal>
Mathieu Desnoyers wrote:
> But.. thinking about it. It's bad to have a 2-byte xchg primitive that
> only works on UP and breaks the build on SMP. We should instead
> implement a workaround based on __cmpxchg4 to perform the 2-byte xchg().
This exposes why there should be __cmpxchg_bool() versions, which do
not loop, preferably in the generic kernel API, because the workaround
using __cmpxchg4 has to add yet another pointless loop nesting to all
cmpxchg users.
--- Jamie
next prev parent reply other threads:[~2010-03-19 1:49 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-10 16:22 __xchg for sizes other than 32bit Imre Deak
2010-03-10 17:35 ` Russell King - ARM Linux
2010-03-10 20:02 ` [PATCH] ARM support single byte cmpxchg and cmpxchg_local on ARMv6 Mathieu Desnoyers
2010-03-10 20:30 ` Russell King - ARM Linux
2010-03-10 21:15 ` Mathieu Desnoyers
2010-03-10 23:16 ` __xchg for sizes other than 32bit Jamie Lokier
2010-03-18 9:29 ` [PATCH 1/1] [RFC] arm: add half-word __xchg Alexander Shishkin
2010-03-18 12:32 ` Mathieu Desnoyers
2010-03-18 12:37 ` Alexander Shishkin
2010-03-18 13:33 ` Alexander Shishkin
2010-03-18 13:50 ` Mathieu Desnoyers
2010-03-18 16:33 ` Imre Deak
2010-03-18 17:21 ` Mathieu Desnoyers
2010-03-18 19:00 ` Imre Deak
2010-03-18 19:30 ` Mathieu Desnoyers
2010-03-19 1:49 ` Jamie Lokier [this message]
2010-03-19 2:12 ` Mathieu Desnoyers
2010-03-19 3:36 ` Jamie Lokier
2010-03-25 15:52 ` [PATCH 1/1] [RFCv2] " Alexander Shishkin
2010-03-25 16:42 ` Alexander Shishkin
2010-03-27 22:52 ` Russell King - ARM Linux
2010-03-28 0:14 ` Jamie Lokier
2010-03-28 0:18 ` Russell King - ARM Linux
2010-03-28 1:00 ` Mathieu Desnoyers
2010-03-28 14:39 ` Jamie Lokier
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