From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v2 02/20] documentation: Clarify failed cmpxchg memory ordering semantics
Date: Mon, 27 Jul 2015 14:00:53 +0100 [thread overview]
Message-ID: <20150727130053.GI3358@arm.com> (raw)
In-Reply-To: <20150727120201.GW19282@twins.programming.kicks-ass.net>
On Mon, Jul 27, 2015 at 01:02:01PM +0100, Peter Zijlstra wrote:
> On Mon, Jul 27, 2015 at 12:58:22PM +0100, Will Deacon wrote:
> > On Fri, Jul 24, 2015 at 11:41:53AM +0100, Will Deacon wrote:
> > > A failed cmpxchg does not provide any memory ordering guarantees, a
> > > property that is used to optimise the cmpxchg implementations on Alpha,
> > > PowerPC and arm64.
> > >
> > > This patch updates atomic_ops.txt and memory-barriers.txt to reflect
> > > this.
> > >
> > > Cc: Peter Zijlstra <peterz@infradead•org>
> > > Signed-off-by: Will Deacon <will.deacon@arm•com>
> > > ---
> > > Documentation/atomic_ops.txt | 4 +++-
> > > Documentation/memory-barriers.txt | 6 +++---
> > > 2 files changed, 6 insertions(+), 4 deletions(-)
> >
> > Peter: are you ok with me taking this via the arm64 tree (along with the
> > rest of the series), or would you prefer this patch routed through -tip?
>
> So I have this one queued, and typically these changes go through tip
> because the RCU tree also ends up there, and Paul is the typical source
> of patches there.
>
> So to minimize collisions on memory-barriers.txt i'd like to keep it if
> its not too much hassle.
No problem at all, just didn't want it to get dropped. Minimising conflicts
in memory-barriers.txt is definitely a good idea ;)
Thanks!
Will
next prev parent reply other threads:[~2015-07-27 13:00 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-24 10:41 [PATCH v2 00/20] arm64: support for 8.1 LSE atomic instructions Will Deacon
2015-07-24 10:41 ` [PATCH v2 01/20] arm64: rwlocks: don't fail trylock purely due to contention Will Deacon
2015-07-24 11:14 ` Catalin Marinas
2015-07-24 10:41 ` [PATCH v2 02/20] documentation: Clarify failed cmpxchg memory ordering semantics Will Deacon
2015-07-24 11:15 ` Catalin Marinas
2015-07-27 11:58 ` Will Deacon
2015-07-27 12:02 ` Peter Zijlstra
2015-07-27 13:00 ` Will Deacon [this message]
2015-07-24 10:41 ` [PATCH v2 03/20] arm64: cpufeature.h: add missing #include of kernel.h Will Deacon
2015-07-24 11:15 ` Catalin Marinas
2015-07-24 10:41 ` [PATCH v2 04/20] arm64: atomics: move ll/sc atomics into separate header file Will Deacon
2015-07-24 11:19 ` Catalin Marinas
2015-07-24 10:41 ` [PATCH v2 05/20] arm64: elf: advertise 8.1 atomic instructions as new hwcap Will Deacon
2015-07-24 11:24 ` Catalin Marinas
2015-07-24 10:41 ` [PATCH v2 06/20] arm64: alternatives: add cpu feature for lse atomics Will Deacon
2015-07-24 11:26 ` Catalin Marinas
2015-07-24 10:41 ` [PATCH v2 07/20] arm64: introduce CONFIG_ARM64_LSE_ATOMICS as fallback to ll/sc atomics Will Deacon
2015-07-24 11:38 ` Catalin Marinas
2015-07-24 10:41 ` [PATCH v2 08/20] arm64: atomics: patch in lse instructions when supported by the CPU Will Deacon
2015-07-24 14:43 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 09/20] arm64: locks: " Will Deacon
2015-07-24 15:08 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 10/20] arm64: bitops: " Will Deacon
2015-07-24 15:19 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 11/20] arm64: xchg: " Will Deacon
2015-07-24 15:19 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 12/20] arm64: cmpxchg: " Will Deacon
2015-07-24 15:21 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 13/20] arm64: cmpxchg_dbl: " Will Deacon
2015-07-24 15:29 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 14/20] arm64: cmpxchg: avoid "cc" clobber in ll/sc routines Will Deacon
2015-07-24 15:30 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 15/20] arm64: cmpxchg: avoid memory barrier on comparison failure Will Deacon
2015-07-24 15:32 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 16/20] arm64: atomics: tidy up common atomic{,64}_* macros Will Deacon
2015-07-24 15:40 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 17/20] arm64: atomics: prefetch the destination word for write prior to stxr Will Deacon
2015-07-24 15:42 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 18/20] arm64: atomics: implement atomic{, 64}_cmpxchg using cmpxchg Will Deacon
2015-07-24 15:44 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 19/20] arm64: atomic64_dec_if_positive: fix incorrect branch condition Will Deacon
2015-07-24 15:45 ` Catalin Marinas
2015-07-24 10:42 ` [PATCH v2 20/20] arm64: kconfig: select HAVE_CMPXCHG_LOCAL Will Deacon
2015-07-24 15:45 ` Catalin Marinas
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