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From: Peter Zijlstra <peterz@infradead.org>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: x86@kernel.org, Dave Hansen <dave.hansen@linux.intel.com>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	linux-kernel@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
	WANG Xuerui <kernel@xen0n.name>,
	linux-arch@vger.kernel.org, Jun Yi <yijun@loongson.cn>,
	Huacai Chen <chenhuacai@kernel.org>,
	Ingo Molnar <mingo@redhat.com>, Matt Turner <mattst88@gmail.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	loongarch@lists.linux.dev, Thomas Gleixner <tglx@linutronix.de>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	linux-mips@vger.kernel.org, linux-perf-users@vger.kernel.org,
	linux-alpha@vger.kernel.org, Borislav Petkov <bp@alien8.de>,
	linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 3/5] locking/arch: Wire up local_try_cmpxchg
Date: Wed, 12 Apr 2023 13:32:31 +0200	[thread overview]
Message-ID: <20230412113231.GA628377@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230405141710.3551-4-ubizjak@gmail.com>

On Wed, Apr 05, 2023 at 04:17:08PM +0200, Uros Bizjak wrote:
> diff --git a/arch/powerpc/include/asm/local.h b/arch/powerpc/include/asm/local.h
> index bc4bd19b7fc2..45492fb5bf22 100644
> --- a/arch/powerpc/include/asm/local.h
> +++ b/arch/powerpc/include/asm/local.h
> @@ -90,6 +90,17 @@ static __inline__ long local_cmpxchg(local_t *l, long o, long n)
>  	return t;
>  }
>  
> +static __inline__ bool local_try_cmpxchg(local_t *l, long *po, long n)
> +{
> +	long o = *po, r;
> +
> +	r = local_cmpxchg(l, o, n);
> +	if (unlikely(r != o))
> +		*po = r;
> +
> +	return likely(r == o);
> +}
> +

Why is the ppc one different from the rest? Why can't it use the
try_cmpxchg_local() fallback and needs to have it open-coded?

  reply	other threads:[~2023-04-12 11:32 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-05 14:17 [PATCH v2 0/5] locking: Introduce local{,64}_try_cmpxchg Uros Bizjak
2023-04-05 14:17 ` [PATCH v2 1/5] locking/atomic: Add generic try_cmpxchg{,64}_local support Uros Bizjak
2023-04-11 11:10   ` Mark Rutland
2023-04-05 14:17 ` [PATCH v2 2/5] locking/generic: Wire up local{,64}_try_cmpxchg Uros Bizjak
2023-04-11 11:13   ` Mark Rutland
2023-04-05 14:17 ` [PATCH v2 3/5] locking/arch: Wire up local_try_cmpxchg Uros Bizjak
2023-04-12 11:32   ` Peter Zijlstra [this message]
2023-04-12 13:37     ` Uros Bizjak
2023-04-12 13:40       ` Peter Zijlstra
2023-05-17  7:41   ` Charlemagne Lasse
2023-04-05 14:17 ` [PATCH v2 4/5] locking/x86: Define arch_try_cmpxchg_local Uros Bizjak
2023-04-05 14:17 ` [PATCH v2 5/5] events: Illustrate the transition to local{,64}_try_cmpxchg Uros Bizjak
2023-04-05 16:37 ` [PATCH v2 0/5] locking: Introduce local{,64}_try_cmpxchg Dave Hansen
2023-04-05 18:53   ` Uros Bizjak
2023-04-06  8:25   ` David Laight
2023-04-06  8:38     ` Uros Bizjak
2023-04-06  9:01       ` David Laight
2023-04-11 11:35   ` Mark Rutland
2023-04-11 13:43     ` Dave Hansen
2023-04-11 21:34       ` David Laight

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