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From: Conor Dooley <conor@kernel.org>
To: Atish Patra <atishp@rivosinc.com>
Cc: linux-kernel@vger.kernel.org, Albert Ou <aou@eecs.berkeley.edu>,
	Atish Patra <atishp@atishpatra.org>,
	Anup Patel <anup@brainfault.org>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	devicetree@vger.kernel.org, Jisheng Zhang <jszhang@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	linux-riscv@lists.infradead.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Rob Herring <robh+dt@kernel.org>
Subject: Re: [PATCH] RISC-V: Do not issue remote fences until smp is available
Date: Mon, 31 Oct 2022 19:11:56 +0000	[thread overview]
Message-ID: <Y2Ad/FaLE5qM01gR@spud> (raw)
In-Reply-To: <20221028231929.347918-1-atishp@rivosinc.com>

On Fri, Oct 28, 2022 at 04:19:29PM -0700, Atish Patra wrote:
> It is useless to issue remote fences if there is a single core
> available. It becomes a bottleneck for sbi based rfences where
> we will be making those ECALLs for no reason. Early code patching
> because of static calls end up in this path.
> 
> Signed-off-by: Atish Patra <atishp@rivosinc.com>

Hey Atish,
This doesn't apply for me to either fixes or for-next. What branch does
it apply to?
Thanks,
Conor.

> ---
>  arch/riscv/mm/cacheflush.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
> index f10cb47eac3a..7fafc8c26505 100644
> --- a/arch/riscv/mm/cacheflush.c
> +++ b/arch/riscv/mm/cacheflush.c
> @@ -19,6 +19,10 @@ void flush_icache_all(void)
>  {
>  	local_flush_icache_all();
>  
> +	/* No need to issue remote fence if only 1 cpu is online */
> +	if (num_online_cpus() == 1)
> +		return;
> +
>  	if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence())
>  		sbi_remote_fence_i(NULL);
>  	else
> -- 
> 2.34.1
> 

WARNING: multiple messages have this Message-ID (diff)
From: Conor Dooley <conor@kernel.org>
To: Atish Patra <atishp@rivosinc.com>
Cc: linux-kernel@vger.kernel.org, Albert Ou <aou@eecs.berkeley.edu>,
	Atish Patra <atishp@atishpatra.org>,
	Anup Patel <anup@brainfault.org>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	devicetree@vger.kernel.org, Jisheng Zhang <jszhang@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	linux-riscv@lists.infradead.org,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Rob Herring <robh+dt@kernel.org>
Subject: Re: [PATCH] RISC-V: Do not issue remote fences until smp is available
Date: Mon, 31 Oct 2022 19:11:56 +0000	[thread overview]
Message-ID: <Y2Ad/FaLE5qM01gR@spud> (raw)
In-Reply-To: <20221028231929.347918-1-atishp@rivosinc.com>

On Fri, Oct 28, 2022 at 04:19:29PM -0700, Atish Patra wrote:
> It is useless to issue remote fences if there is a single core
> available. It becomes a bottleneck for sbi based rfences where
> we will be making those ECALLs for no reason. Early code patching
> because of static calls end up in this path.
> 
> Signed-off-by: Atish Patra <atishp@rivosinc.com>

Hey Atish,
This doesn't apply for me to either fixes or for-next. What branch does
it apply to?
Thanks,
Conor.

> ---
>  arch/riscv/mm/cacheflush.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
> index f10cb47eac3a..7fafc8c26505 100644
> --- a/arch/riscv/mm/cacheflush.c
> +++ b/arch/riscv/mm/cacheflush.c
> @@ -19,6 +19,10 @@ void flush_icache_all(void)
>  {
>  	local_flush_icache_all();
>  
> +	/* No need to issue remote fence if only 1 cpu is online */
> +	if (num_online_cpus() == 1)
> +		return;
> +
>  	if (IS_ENABLED(CONFIG_RISCV_SBI) && !riscv_use_ipi_for_rfence())
>  		sbi_remote_fence_i(NULL);
>  	else
> -- 
> 2.34.1
> 

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  reply	other threads:[~2022-10-31 19:12 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-28 23:19 [PATCH] RISC-V: Do not issue remote fences until smp is available Atish Patra
2022-10-28 23:19 ` Atish Patra
2022-10-31 19:11 ` Conor Dooley [this message]
2022-10-31 19:11   ` Conor Dooley
2022-10-31 19:26   ` Atish Patra
2022-10-31 19:26     ` Atish Patra
2022-11-10 21:42     ` Palmer Dabbelt
2022-11-10 21:42       ` Palmer Dabbelt
2022-11-12  7:46       ` Atish Patra
2022-11-12  7:46         ` Atish Patra

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