linux-kernel - Re: [PATCH v2] perf/core: restore __perf_remove_from_context when DETACH

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Message-ID: <6487969b.b907.19735e42e05.Coremail.00107082@163.com>
Date: Tue, 3 Jun 2025 21:03:55 +0800 (CST)
From: "David Wang" <00107082@....com>
To: "Peter Zijlstra" <peterz@...radead.org>
Cc: mingo@...hat.com, acme@...nel.org, namhyung@...nel.org, mingo@...nel.org,
	yeoreum.yun@....com, leo.yan@....com,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] perf/core: restore __perf_remove_from_context when
 DETACH_EXIT not set


At 2025-06-03 20:54:40, "Peter Zijlstra" <peterz@...radead.org> wrote:
>On Tue, Jun 03, 2025 at 02:50:56PM +0200, Peter Zijlstra wrote:
>> On Tue, Jun 03, 2025 at 06:44:58PM +0800, David Wang wrote:
>> 
>> 
>> > (As yeoreum.yun@....com pointed out,  the change in perf_remove_from_context() made
>> > perf_event_set_state() happened before list_del_event(), resulting in perf_cgroup_event_disable()
>> > not called.)
>> 
>> Aah, d'0h. Let me see what we should do there.
>
>Does this help? This way event_sched_out() will call
>perf_cgroup_event_disable().
>
>
>diff --git a/kernel/events/core.c b/kernel/events/core.c
>index f34c99f8ce8f..adbb0372825f 100644
>--- a/kernel/events/core.c
>+++ b/kernel/events/core.c
>@@ -2494,9 +2494,9 @@ __perf_remove_from_context(struct perf_event *event,
> 	if (flags & DETACH_REVOKE)
> 		state = PERF_EVENT_STATE_REVOKED;
> 	if (flags & DETACH_DEAD) {
>-		event->pending_disable = 1;
> 		state = PERF_EVENT_STATE_DEAD;
> 	}
>+	event->pending_disable = 1;
> 	event_sched_out(event, ctx);
> 	perf_event_set_state(event, min(event->state, state));
> 

Ok, I will give it a try and update later.