All of lore.kernel.org
 help / color / mirror / Atom feed
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();
> +}
> +

  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190904073915.4a145a91@oasis.local.home \
    --to=rostedt@goodmis.org \
    --cc=joel@joelfernandes.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=viktor.rosendahl@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.