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From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: williams@redhat.com, daniel@bristot.me,
	"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
	Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Matthias Kaehlcke <mka@chromium.org>,
	"Joel Fernandes (Google)" <joel@joelfernandes.org>,
	Frederic Weisbecker <frederic@kernel.org>,
	Yangtao Li <tiny.windzz@gmail.com>,
	Tommaso Cucinotta <tommaso.cucinotta@santannapisa.it>
Subject: [RFC 0/3] preempt_tracer: Fix preempt_disable tracepoint
Date: Tue, 28 May 2019 17:16:21 +0200	[thread overview]
Message-ID: <cover.1559051152.git.bristot@redhat.com> (raw)

While playing with the model + working in a fix for the task
context & trace recursion, I ended up hitting two cases in which the
preempt_disable/enable tracepoint was supposed to happen, but didn't.

There is an explanation for each case in the log message.

This is an RFC exposing the problem, with possible ways to fix it.
But I bet there might be better solutions as well, so this is a real
RFC.

Daniel Bristot de Oliveira (3):
  softirq: Use preempt_latency_stop/start to trace preemption
  preempt_tracer: Disable IRQ while starting/stopping due to a
    preempt_counter change
  preempt_tracer: Use a percpu variable to control traceble calls

 kernel/sched/core.c | 66 ++++++++++++++++++++++++++++++++++-----------
 kernel/softirq.c    | 13 ++++-----
 2 files changed, 55 insertions(+), 24 deletions(-)

-- 
2.20.1


             reply	other threads:[~2019-05-28 15:16 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-28 15:16 Daniel Bristot de Oliveira [this message]
2019-05-28 15:16 ` [RFC 1/3] softirq: Use preempt_latency_stop/start to trace preemption Daniel Bristot de Oliveira
2019-05-29  8:29   ` Peter Zijlstra
2019-05-29  9:30   ` Joel Fernandes
2019-05-29 12:22     ` Steven Rostedt
2019-06-04 10:39       ` Daniel Bristot de Oliveira
2019-06-04 12:01         ` Steven Rostedt
2019-05-28 15:16 ` [RFC 2/3] preempt_tracer: Disable IRQ while starting/stopping due to a preempt_counter change Daniel Bristot de Oliveira
2019-05-29  8:33   ` Peter Zijlstra
2019-05-29  9:40     ` Daniel Bristot de Oliveira
2019-05-29 10:20       ` Peter Zijlstra
2019-05-29 12:39         ` Steven Rostedt
2019-05-29 13:19           ` Peter Zijlstra
2019-05-29 13:29             ` Peter Zijlstra
2019-05-29 13:42             ` Steven Rostedt
2019-05-29 13:49               ` Peter Zijlstra
2019-05-29 13:58                 ` Steven Rostedt
2019-05-29 13:51         ` Daniel Bristot de Oliveira
2019-05-29 18:21           ` Peter Zijlstra
2019-06-04 10:20             ` Daniel Bristot de Oliveira
2019-05-31  7:47       ` Joel Fernandes
2019-06-04 10:12         ` Daniel Bristot de Oliveira
2019-06-04 15:01           ` Steven Rostedt
2019-06-05 15:16             ` Joel Fernandes
2019-05-28 15:16 ` [RFC 3/3] preempt_tracer: Use a percpu variable to control traceble calls Daniel Bristot de Oliveira
2019-05-29  8:41   ` Peter Zijlstra
2019-05-29  9:48     ` Daniel Bristot de Oliveira

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