From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Adrian Hunter <adrian.hunter@intel.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Ian Rogers <irogers@google.com>, Ingo Molnar <mingo@redhat.com>,
Jiri Olsa <jolsa@kernel.org>, Marco Elver <elver@google.com>,
Mark Rutland <mark.rutland@arm.com>,
Namhyung Kim <namhyung@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Arnaldo Carvalho de Melo <acme@redhat.com>
Subject: Re: [PATCH v3 2/4] perf: Enqueue SIGTRAP always via task_work.
Date: Wed, 10 Apr 2024 15:47:02 +0200 [thread overview]
Message-ID: <20240410134702.dcWYciZB@linutronix.de> (raw)
In-Reply-To: <ZhZ54XAcBt50WEnE@localhost.localdomain>
On 2024-04-10 13:37:05 [+0200], Frederic Weisbecker wrote:
> > Couldn't we either flush _or_ remove the task_work in perf_release()?
>
> Right so the problem in perf_release() is that we may be dealing with task works
> of other tasks than current. In that case, task_work_cancel() is fine if it
> successes. But if it fails, you don't have the guarantee that the task work
> isn't concurrently running or about to run. And you have no way to know about
> that. So then you need some sort of flushing indeed.
Since perf_release() preemptible, a wait/sleep for completion would be
best (instead of flushing).
> Thanks.
>
> > > Thanks.
Sebastian
next prev parent reply other threads:[~2024-04-10 13:47 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-22 6:48 [PATCH v3 0/4] perf: Make SIGTRAP and __perf_pending_irq() work on RT Sebastian Andrzej Siewior
2024-03-22 6:48 ` [PATCH v3 1/4] perf: Move irq_work_queue() where the event is prepared Sebastian Andrzej Siewior
2024-03-22 6:48 ` [PATCH v3 2/4] perf: Enqueue SIGTRAP always via task_work Sebastian Andrzej Siewior
2024-04-08 21:29 ` Frederic Weisbecker
2024-04-09 8:57 ` Sebastian Andrzej Siewior
2024-04-09 12:36 ` Frederic Weisbecker
2024-04-09 13:47 ` Sebastian Andrzej Siewior
2024-04-10 11:37 ` Frederic Weisbecker
2024-04-10 13:47 ` Sebastian Andrzej Siewior [this message]
2024-04-10 14:00 ` Frederic Weisbecker
2024-04-10 14:06 ` Sebastian Andrzej Siewior
2024-04-10 14:42 ` Frederic Weisbecker
2024-04-10 14:48 ` Sebastian Andrzej Siewior
2024-04-10 14:50 ` Frederic Weisbecker
2024-03-22 6:48 ` [PATCH v3 3/4] perf: Remove perf_swevent_get_recursion_context() from perf_pending_task() Sebastian Andrzej Siewior
2024-04-08 22:06 ` Frederic Weisbecker
2024-04-09 6:25 ` Sebastian Andrzej Siewior
2024-04-09 10:35 ` Frederic Weisbecker
2024-04-09 10:54 ` Sebastian Andrzej Siewior
2024-04-09 12:00 ` Frederic Weisbecker
2024-04-09 13:33 ` Sebastian Andrzej Siewior
2024-04-10 10:38 ` Frederic Weisbecker
2024-04-10 12:51 ` Sebastian Andrzej Siewior
2024-04-10 13:58 ` Frederic Weisbecker
2024-03-22 6:48 ` [PATCH v3 4/4] perf: Split __perf_pending_irq() out of perf_pending_irq() Sebastian Andrzej Siewior
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