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Date: Mon, 27 Oct 2014 14:41:03 +0100
From: Peter Zijlstra <peterz@infradead.org>
To: Mike Galbraith <umgwanakikbuti@gmail.com>
Cc: mingo@kernel.org, oleg@redhat.com, torvalds@linux-foundation.org,
        tglx@linutronix.de, ilya.dryomov@inktank.com,
        linux-kernel@vger.kernel.org, Eric Paris <eparis@redhat.com>,
        rafael.j.wysocki@intel.com
Subject: Re: [PATCH 00/11] nested sleeps, fixes and debug infrastructure
Message-ID: <20141027134103.GA10476@twins.programming.kicks-ass.net>
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On Thu, Oct 02, 2014 at 02:15:53PM +0200, Peter Zijlstra wrote:
> On Thu, Oct 02, 2014 at 12:22:51PM +0200, Peter Zijlstra wrote:

> > +#define __wait_event_freezable(wq, condition)				\
> > +	(void)___wait_event(wq, condition, TASK_INTERRUPTIBLE, 0, 0,	\
> > +			    schedule(); try_to_freeze())
> > +
> > +/**
> > + * wait_event - sleep until a condition gets true or freeze (for kthreads)
> > + * @wq: the waitqueue to wait on
> > + * @condition: a C expression for the event to wait for
> > + *
> > + * The process is put to sleep (TASK_INTERRUPTIBLE -- so as not to contribute
> > + * to system load) until the @condition evaluates to true. The
> > + * @condition is checked each time the waitqueue @wq is woken up.
> > + *
> > + * wake_up() has to be called after changing any variable that could
> > + * change the result of the wait condition.
> > + */
> > +#define wait_event_freezable(wq, condition)				\
> > +do {									\
> > +	WARN_ON_ONCE(!(current->flags & PF_KTHREAD));			\
> > +	might_sleep();							\
> > +	if (condition)							\
> > +		break;							\
> > +	__wait_event_freezable(wq, condition);				\
> > +} while (0)
> > +
> >  #define __wait_event_timeout(wq, condition, timeout)			\
> >  	___wait_event(wq, ___wait_cond_timeout(condition),		\
> >  		      TASK_UNINTERRUPTIBLE, 0, timeout,			\
> 
> Bah, that doesn't compile, because there already appears to be one,
> hidden in freezer.h. Now I can't actually tell if it does the same thing
> or not.
> 
> Rafael?

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