From: Will Deacon <will@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "Xu, Yanfei" <yanfei.xu@windriver.com>,
mingo@redhat.com, longman@redhat.com, boqun.feng@gmail.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Documentation/atomic_t: Document cmpxchg() vs try_cmpxchg()
Date: Mon, 5 Jul 2021 16:21:36 +0100 [thread overview]
Message-ID: <20210705152136.GA19127@willie-the-truck> (raw)
In-Reply-To: <YOMgPeMOmmiK3tXO@hirez.programming.kicks-ass.net>
On Mon, Jul 05, 2021 at 05:07:41PM +0200, Peter Zijlstra wrote:
> On Mon, Jul 05, 2021 at 04:00:01PM +0200, Peter Zijlstra wrote:
>
> > No, when try_cmpxchg() fails it will update oldp. This is the reason old
> > is now a pointer too.
>
> Since you're not the first person confused by this, does the below
> clarify?
>
> ---
> Subject: Documentation/atomic_t: Document cmpxchg() vs try_cmpxchg()
> From: Peter Zijlstra <peterz@infradead.org>
> Date: Mon Jul 5 17:00:24 CEST 2021
>
> There seems to be a significant amount of confusion around the 'new'
> try_cmpxchg(), despite this being more like the C11
> atomic_compare_exchange_*() family. Add a few words of clarification
> on how cmpxchg() and try_cmpxchg() relate to one another.
>
> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
> ---
> Documentation/atomic_t.txt | 41 +++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 41 insertions(+)
With the "CMPXHG" typo fixed:
Acked-by: Will Deacon <will@kernel.org>
Will
next prev parent reply other threads:[~2021-07-05 15:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-30 15:35 [RFC][PATCH 0/4] locking/mutex: Some HANDOFF fixes Peter Zijlstra
2021-06-30 15:35 ` [RFC][PATCH 1/4] locking/mutex: Use try_cmpxchg() Peter Zijlstra
2021-07-05 11:59 ` Xu, Yanfei
2021-07-05 14:00 ` Peter Zijlstra
2021-07-05 14:52 ` Xu, Yanfei
2021-07-05 15:07 ` [PATCH] Documentation/atomic_t: Document cmpxchg() vs try_cmpxchg() Peter Zijlstra
2021-07-05 15:21 ` Will Deacon [this message]
2021-07-05 15:25 ` Xu, Yanfei
2021-07-05 17:12 ` Peter Zijlstra
2021-07-08 8:42 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2021-07-08 8:42 ` [tip: locking/core] locking/mutex: Use try_cmpxchg() tip-bot2 for Peter Zijlstra
2021-06-30 15:35 ` [RFC][PATCH 2/4] locking/mutex: Fix HANDOFF condition Peter Zijlstra
2021-07-08 8:42 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2021-06-30 15:35 ` [RFC][PATCH 3/4] locking/mutex: Introduce __mutex_trylock_or_handoff() Peter Zijlstra
2021-06-30 16:30 ` Waiman Long
2021-06-30 18:04 ` Peter Zijlstra
2021-07-08 8:42 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2021-06-30 15:35 ` [RFC][PATCH 4/4] locking/mutex: Add MUTEX_WARN_ON Peter Zijlstra
2021-07-08 8:42 ` [tip: locking/core] " tip-bot2 for Peter Zijlstra
2021-06-30 19:03 ` [RFC][PATCH 0/4] locking/mutex: Some HANDOFF fixes Waiman Long
2021-07-01 2:11 ` Xu, Yanfei
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