* [PATCH] kprobes: drop the unnecessary unlikely()
@ 2022-06-13 4:25 l3b2w1
2022-06-15 0:15 ` Masami Hiramatsu
0 siblings, 1 reply; 2+ messages in thread
From: l3b2w1 @ 2022-06-13 4:25 UTC (permalink / raw)
To: mhiramat
Cc: naveen.n.rao, anil.s.keshavamurthy, davem, linux-kernel, binglei.wang
From: "binglei.wang" <l3b2w1@gmail.com>
!ap is likely when checking re-registering existing kprobe.
register_kprobe -> warn_kprobe_rereg -> __get_valid_kprobe
!ap is unlikely when checking whether the kprobe is valid
on enable/disable ocassion.
__disable_kprobe/enable_kprobe -> __get_valid_kprobe
Considering these two cases, choose to drop the unlikely() here.
Signed-off-by: binglei.wang <l3b2w1@gmail.com>
---
kernel/kprobes.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index f214f8c08..f4a829d98 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1504,7 +1504,7 @@ static struct kprobe *__get_valid_kprobe(struct kprobe *p)
lockdep_assert_held(&kprobe_mutex);
ap = get_kprobe(p->addr);
- if (unlikely(!ap))
+ if (!ap)
return NULL;
if (p != ap) {
--
2.27.0
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] kprobes: drop the unnecessary unlikely()
2022-06-13 4:25 [PATCH] kprobes: drop the unnecessary unlikely() l3b2w1
@ 2022-06-15 0:15 ` Masami Hiramatsu
0 siblings, 0 replies; 2+ messages in thread
From: Masami Hiramatsu @ 2022-06-15 0:15 UTC (permalink / raw)
To: l3b2w1
Cc: naveen.n.rao, anil.s.keshavamurthy, davem, linux-kernel, Steven Rostedt
On Mon, 13 Jun 2022 12:25:36 +0800
l3b2w1@gmail.com wrote:
> From: "binglei.wang" <l3b2w1@gmail.com>
>
> !ap is likely when checking re-registering existing kprobe.
> register_kprobe -> warn_kprobe_rereg -> __get_valid_kprobe
>
> !ap is unlikely when checking whether the kprobe is valid
> on enable/disable ocassion.
> __disable_kprobe/enable_kprobe -> __get_valid_kprobe
>
> Considering these two cases, choose to drop the unlikely() here.
>
> Signed-off-by: binglei.wang <l3b2w1@gmail.com>
This looks good to me.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Thank you!
> ---
> kernel/kprobes.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index f214f8c08..f4a829d98 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1504,7 +1504,7 @@ static struct kprobe *__get_valid_kprobe(struct kprobe *p)
> lockdep_assert_held(&kprobe_mutex);
>
> ap = get_kprobe(p->addr);
> - if (unlikely(!ap))
> + if (!ap)
> return NULL;
>
> if (p != ap) {
> --
> 2.27.0
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-06-13 4:25 [PATCH] kprobes: drop the unnecessary unlikely() l3b2w1
2022-06-15 0:15 ` Masami Hiramatsu
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