From: Steven Rostedt <rostedt@goodmis.org>
To: Viktor Rosendahl <viktor.rosendahl@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>,
linux-kernel@vger.kernel.org,
Joel Fernandes <joel@joelfernandes.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v5 1/4] ftrace: Implement fs notification for tracing_max_latency
Date: Wed, 4 Sep 2019 07:39:15 -0400 [thread overview]
Message-ID: <20190904073915.4a145a91@oasis.local.home> (raw)
In-Reply-To: <20190903132602.3440-2-viktor.rosendahl@gmail.com>
On Tue, 3 Sep 2019 15:25:59 +0200
Viktor Rosendahl <viktor.rosendahl@gmail.com> wrote:
> +void latency_fsnotify_stop(void)
> +{
> + /* Make sure all CPUs see caller's previous actions to stop tracer */
> + smp_wmb();
These memory barriers just look wrong. What exactly are you trying to protect here?
Where's the matching rmbs?
-- Steve
> + static_branch_disable(&latency_notify_key);
> + latency_fsnotify_process();
> +}
> +
> +void latency_fsnotify_start(void)
> +{
> + static_branch_enable(&latency_notify_key);
> + /* Make sure all CPUs see key value before caller continue */
> + smp_wmb();
> +}
> +
next prev parent reply other threads:[~2019-09-04 11:39 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 13:25 [PATCH v5 0/4] Some new features for the preempt/irqsoff tracers Viktor Rosendahl
2019-09-03 13:25 ` [PATCH v5 1/4] ftrace: Implement fs notification for tracing_max_latency Viktor Rosendahl
2019-09-04 4:00 ` Joel Fernandes
2019-09-04 8:19 ` Peter Zijlstra
2019-09-04 13:42 ` Joel Fernandes
2019-09-04 18:17 ` Viktor Rosendahl
2019-09-04 10:21 ` Paul E. McKenney
2019-09-04 8:20 ` Peter Zijlstra
2019-09-04 11:37 ` Steven Rostedt
2019-09-04 11:39 ` Steven Rostedt [this message]
2019-09-04 19:00 ` Viktor Rosendahl
2019-09-03 13:26 ` [PATCH v5 2/4] preemptirq_delay_test: Add the burst feature and a sysfs trigger Viktor Rosendahl
2019-09-04 11:42 ` Steven Rostedt
2019-09-04 19:10 ` Viktor Rosendahl
2019-09-05 16:52 ` Steven Rostedt
2019-09-05 18:27 ` Viktor Rosendahl
2019-09-03 13:26 ` [PATCH v5 3/4] Add the latency-collector to tools Viktor Rosendahl
2019-09-03 13:26 ` [PATCH v5 4/4] ftrace: Add an option for tracing console latencies Viktor Rosendahl
2019-09-04 5:02 ` kbuild test robot
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