From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Valentin Schneider <valentin.schneider@arm.com>
Cc: linux-kernel@vger.kernel.org,
"Abhijeet Dharmapurikar" <adharmap@quicinc.com>,
"Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>,
"Dietmar Eggemann" <dietmar.eggemann@arm.com>,
"Steven Rostedt" <rostedt@goodmis.org>,
"Peter Zijlstra" <peterz@infradead.org>,
"Ingo Molnar" <mingo@kernel.org>,
"Vincent Guittot" <vincent.guittot@linaro.org>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Juri Lelli" <juri.lelli@redhat.com>,
"Daniel Bristot de Oliveira" <bristot@redhat.com>,
"Kees Cook" <keescook@chromium.org>,
"Andrew Morton" <akpm@linux-foundation.org>
Subject: Re: [RFC PATCH 2/2] sched/tracing: Add TASK_RTLOCK_WAIT to TASK_REPORT
Date: Fri, 14 Jan 2022 11:11:08 +0100 [thread overview]
Message-ID: <YeFMPNnCpiw9fs7e@linutronix.de> (raw)
In-Reply-To: <20211129123601.2101873-3-valentin.schneider@arm.com>
On 2021-11-29 12:36:01 [+0000], Valentin Schneider wrote:
> TASK_RTLOCK_WAIT currently isn't part of TASK_REPORT, thus a task blocking
> on an rtlock will appear as having a task state == 0, IOW TASK_RUNNING.
>
> The actual state is saved in p->saved_state, but reading it after reading
> p->__state has a few issues:
> o that could still be TASK_RUNNING in the case of e.g. rt_spin_lock
> o ttwu_state_match() might have changed that to TASK_RUNNING
>
> Add TASK_RTLOCK_WAIT to TASK_REPORT.
>
> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
We used to have the D state which was used in the locked case and was
sufficient. With the rework to TASK_RTLOCK_WAIT (which made other things
easier) we lost that. It makes debuging/ looking into the system more
obvious or does not hide things so why not.
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Sebastian
prev parent reply other threads:[~2022-01-14 10:11 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 12:35 [RFC PATCH 0/2] sched/tracing: sched_switch prev_state reported as TASK_RUNNING when it's not Valentin Schneider
2021-11-29 12:36 ` [RFC PATCH 1/2] sched/tracing: Don't re-read p->state when emitting sched_switch event Valentin Schneider
2021-11-29 16:39 ` kernel test robot
2021-11-29 16:39 ` kernel test robot
2021-11-29 16:59 ` kernel test robot
2021-11-29 16:59 ` kernel test robot
2021-12-08 20:12 ` Steven Rostedt
2021-12-09 13:02 ` Valentin Schneider
2021-11-29 12:36 ` [RFC PATCH 2/2] sched/tracing: Add TASK_RTLOCK_WAIT to TASK_REPORT Valentin Schneider
2021-12-08 20:34 ` Steven Rostedt
2022-01-14 10:11 ` Sebastian Andrzej Siewior [this message]
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