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Subject[PATCH v2 2/2] arm64: stacktrace: use non-atomic __set_bit
Date
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>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
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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