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From: Waiman Long <longman@redhat.com>
To: guoren@kernel.org, palmer@rivosinc.com, heiko@sntech.de,
	hch@infradead.org, arnd@arndb.de, peterz@infradead.org,
	will@kernel.org, boqun.feng@gmail.com, mingo@redhat.com,
	philipp.tomsich@vrull.eu, cmuellner@linux.com,
	linux-kernel@vger.kernel.org, David.Laight@ACULAB.COM
Cc: linux-riscv@lists.infradead.org, linux-csky@vger.kernel.org,
	Guo Ren <guoren@linux.alibaba.com>
Subject: Re: [PATCH V8 10/10] csky: Add qspinlock support
Date: Sun, 24 Jul 2022 22:08:34 -0400	[thread overview]
Message-ID: <0ea27d18-6d45-9673-38b7-78d59325f9d5@redhat.com> (raw)
In-Reply-To: <20220724122517.1019187-11-guoren@kernel.org>

On 7/24/22 08:25, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
>
> Enable qspinlock by the requirements mentioned in a8ad07e5240c9
> ("asm-generic: qspinlock: Indicate the use of mixed-size atomics").
>
> C-SKY only has "ldex/stex" for all atomic operations. So csky give a
> strong forward guarantee for "ldex/stex." That means when ldex grabbed
> the cache line into $L1, it would block other cores from snooping the
> address with several cycles.
>
> Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> ---
>   arch/csky/Kconfig               | 16 ++++++++++++++++
>   arch/csky/include/asm/Kbuild    |  2 ++
>   arch/csky/include/asm/cmpxchg.h | 20 ++++++++++++++++++++
>   3 files changed, 38 insertions(+)
>
> diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
> index dfdb436b6078..09f7d1f06bca 100644
> --- a/arch/csky/Kconfig
> +++ b/arch/csky/Kconfig
> @@ -354,6 +354,22 @@ config HAVE_EFFICIENT_UNALIGNED_STRING_OPS
>   	  Say Y here to enable EFFICIENT_UNALIGNED_STRING_OPS. Some CPU models could
>   	  deal with unaligned access by hardware.
>   
> +choice
> +	prompt "C-SKY spinlock type"
> +	default CSKY_TICKET_SPINLOCKS
> +
> +config CSKY_TICKET_SPINLOCKS
> +	bool "Using ticket spinlock"
> +
> +config CSKY_QUEUED_SPINLOCKS
> +	bool "Using queued spinlock"
> +	depends on SMP
> +	select ARCH_USE_QUEUED_SPINLOCKS
> +	help
> +	  Make sure your micro arch LL/SC has a strong forward progress guarantee.
> +	  Otherwise, stay at ticket-lock/combo-lock.

"combo-lock"? It is a cut-and-paste error. Right?

Cheers,
Longman


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  reply	other threads:[~2022-07-25  2:08 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-24 12:25 [PATCH V8 00/10] arch: Add qspinlock support with combo style guoren
2022-07-24 12:25 ` [PATCH V8 01/10] asm-generic: ticket-lock: Remove unnecessary atomic_read guoren
2022-07-24 12:25 ` [PATCH V8 02/10] asm-generic: ticket-lock: Use the same struct definitions with qspinlock guoren
2022-07-27 19:20   ` kernel test robot
2022-07-24 12:25 ` [PATCH V8 03/10] asm-generic: ticket-lock: Move into ticket_spinlock.h guoren
2022-07-24 12:25 ` [PATCH V8 04/10] asm-generic: spinlock: Add queued spinlock support in common header guoren
2022-07-24 12:25 ` [PATCH V8 05/10] riscv: Enable ARCH_INLINE_READ*/WRITE*/SPIN* guoren
2022-07-24 12:25 ` [PATCH V8 06/10] riscv: atomic: Clean up unnecessary acquire and release definitions guoren
2022-07-24 12:25 ` [PATCH V8 07/10] riscv: Add qspinlock support guoren
2022-07-28  0:04   ` kernel test robot
2022-07-28  3:35     ` Guo Ren
2022-07-28  8:14       ` Arnd Bergmann
2022-07-28  8:34         ` Guo Ren
2022-07-24 12:25 ` [PATCH V8 08/10] riscv: Add combo spinlock support guoren
2022-07-24 12:25 ` [PATCH V8 09/10] csky: Enable ARCH_INLINE_READ*/WRITE*/SPIN* guoren
2022-07-24 12:25 ` [PATCH V8 10/10] csky: Add qspinlock support guoren
2022-07-25  2:08   ` Waiman Long [this message]
2022-07-25  2:30     ` Guo Ren

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