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From: Mark Rutland <mark.rutland@arm.com>
To: andrey.konovalov@linux.dev
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
	Marco Elver <elver@google.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	kasan-dev@googlegroups.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Andrey Konovalov <andreyknvl@google.com>
Subject: Re: [PATCH 2/2] arm64: stacktrace: use non-atomic __set_bit
Date: Mon, 23 May 2022 12:34:15 +0100	[thread overview]
Message-ID: <YotxNzMfMdqw0uY2@FVFF77S0Q05N> (raw)
In-Reply-To: <a584e95f613d59c7ff45686c2805deb63bd61442.1653177005.git.andreyknvl@google.com>

On Sun, May 22, 2022 at 01:50:59AM +0200, andrey.konovalov@linux.dev wrote:
> From: Andrey Konovalov <andreyknvl@google.com>
> 
> Use the non-atomic version of set_bit() in arch/arm64/kernel/stacktrace.c,
> as there is no concurrent accesses to frame->prev_type.
> 
> This speeds up stack trace collection and improves the boot time of
> Generic KASAN by 2-5%.
> 
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  arch/arm64/kernel/stacktrace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index 33e96ae4b15f..03593d451b0a 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -103,7 +103,7 @@ static int notrace unwind_frame(struct task_struct *tsk,
>  		if (fp <= frame->prev_fp)
>  			return -EINVAL;
>  	} else {
> -		set_bit(frame->prev_type, frame->stacks_done);
> +		__set_bit(frame->prev_type, frame->stacks_done);
>  	}
>  
>  	/*
> -- 
> 2.25.1
> 

WARNING: multiple messages have this Message-ID (diff)
From: Mark Rutland <mark.rutland@arm.com>
To: andrey.konovalov@linux.dev
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
	Marco Elver <elver@google.com>,
	Alexander Potapenko <glider@google.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	kasan-dev@googlegroups.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Andrey Konovalov <andreyknvl@google.com>
Subject: Re: [PATCH 2/2] arm64: stacktrace: use non-atomic __set_bit
Date: Mon, 23 May 2022 12:34:15 +0100	[thread overview]
Message-ID: <YotxNzMfMdqw0uY2@FVFF77S0Q05N> (raw)
In-Reply-To: <a584e95f613d59c7ff45686c2805deb63bd61442.1653177005.git.andreyknvl@google.com>

On Sun, May 22, 2022 at 01:50:59AM +0200, andrey.konovalov@linux.dev wrote:
> From: Andrey Konovalov <andreyknvl@google.com>
> 
> Use the non-atomic version of set_bit() in arch/arm64/kernel/stacktrace.c,
> as there is no concurrent accesses to frame->prev_type.
> 
> This speeds up stack trace collection and improves the boot time of
> Generic KASAN by 2-5%.
> 
> Suggested-by: Mark Rutland <mark.rutland@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  arch/arm64/kernel/stacktrace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index 33e96ae4b15f..03593d451b0a 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -103,7 +103,7 @@ static int notrace unwind_frame(struct task_struct *tsk,
>  		if (fp <= frame->prev_fp)
>  			return -EINVAL;
>  	} else {
> -		set_bit(frame->prev_type, frame->stacks_done);
> +		__set_bit(frame->prev_type, frame->stacks_done);
>  	}
>  
>  	/*
> -- 
> 2.25.1
> 

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  reply	other threads:[~2022-05-23 11:34 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-21 23:50 [PATCH 1/2] arm64: kasan: do not instrument stacktrace.c andrey.konovalov
2022-05-21 23:50 ` andrey.konovalov
2022-05-21 23:50 ` [PATCH 2/2] arm64: stacktrace: use non-atomic __set_bit andrey.konovalov
2022-05-21 23:50   ` andrey.konovalov
2022-05-23 11:34   ` Mark Rutland [this message]
2022-05-23 11:34     ` Mark Rutland
2022-05-23 11:33 ` [PATCH 1/2] arm64: kasan: do not instrument stacktrace.c Mark Rutland
2022-05-23 11:33   ` Mark Rutland

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