Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant

From	Steven Rostedt <rostedt@goodmis.org>
Newsgroups	linux.kernel
Subject	Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant
Date	2015-09-29 16:50 +0200
Message-ID	<qe4oa-ZN-33@gated-at.bofh.it> (permalink)
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On Tue, 29 Sep 2015 15:02:01 +0200
Peter Zijlstra <peterz@infradead.org> wrote:

> On Tue, Sep 29, 2015 at 02:55:13PM +0200, Frederic Weisbecker wrote:
> > On Tue, Sep 29, 2015 at 11:28:27AM +0200, Peter Zijlstra wrote:
> > >  #define init_task_preempt_count(p) do { \
> > > -	task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
> > > +	task_thread_info(p)->preempt_count = 2*PREEMPT_DISABLED; \
> > 
> > Since it's not quite obvious why we use this magic value without looking
> > at schedule_tail() details, maybe add a little comment? (Just "/* see schedule_tail() */").
> 
> Right, I fixed that in 12/11 v2. I'll change that around a bit.

I'll wait for v2 because this confused me too.

-- Steve
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Thread

[RFC][PATCH 02/11] sched: Create preempt_count invariant Peter Zijlstra <peterz@infradead.org> - 2015-09-29 11:50 +0200
  [tip:sched/core] sched/core: Create preempt_count invariant tip-bot for Peter Zijlstra <tipbot@zytor.com> - 2015-09-29 12:40 +0200
  Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant Frederic Weisbecker <fweisbec@gmail.com> - 2015-09-29 15:00 +0200
    Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant Peter Zijlstra <peterz@infradead.org> - 2015-09-29 15:10 +0200
      Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant Steven Rostedt <rostedt@goodmis.org> - 2015-09-29 16:50 +0200
  Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant Thomas Gleixner <tglx@linutronix.de> - 2015-09-29 15:20 +0200
    Re: [RFC][PATCH 02/11] sched: Create preempt_count invariant Peter Zijlstra <peterz@infradead.org> - 2015-09-29 16:20 +0200

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