From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] tracing: Have the trace_event benchmark thread call cond_resched_rcu_qs()
Date: Tue, 11 Apr 2017 16:47:20 -0700 [thread overview]
Message-ID: <20170411234720.GB3956@linux.vnet.ibm.com> (raw)
In-Reply-To: <20170411185601.01b32a0e@gandalf.local.home>
On Tue, Apr 11, 2017 at 06:56:01PM -0400, Steven Rostedt wrote:
> On Tue, 11 Apr 2017 18:54:35 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:
>
> > From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
> >
> > The trace_event benchmark thread runs in kernel space in an infinite loop
> > while also calling cond_resched() in case anything else wants to schedule
> > in. Unfortunately, on a PREEMPT kernel, that makes it a nop, in which case,
> > this will never voluntarily schedule. That will cause synchronize_rcu_tasks()
> > to forever block on this thread, while it is running.
> >
> > This is exactly what cond_resched_rcu_qs() is for. Use that instead.
> >
> > Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
>
> This actually should be:
>
> Recommended-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
And:
Acked-by: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
> -- Steve
>
> > Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> > ---
>
prev parent reply other threads:[~2017-04-11 23:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-11 22:54 Steven Rostedt
2017-04-11 22:56 ` Steven Rostedt
2017-04-11 23:47 ` Paul E. McKenney [this message]
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