Re: workqueue code needing preemption disabled

From: Steven Rostedt
Date: Mon Mar 18 2013 - 12:30:51 EST

On Mon, 2013-03-18 at 12:27 -0400, Steven Rostedt wrote:

> IOW, what can happen in -rt here is:
> spin_lock_irq(&gcwq->lock);
> [...]
> <interrupt>
> -> preempt_schedule();
> schedule();
> try_to_wake_up_local();
> [...]
> spin_unlock_irq(&gcwq->lock);
> Again, with -rt, spin_lock_irq() does not prevent interrupts nor
> preemption.

If you happen to know the critical areas that require preemption to be
disabled for real, we can encapsulate them with:



These are currently only in the -rt patch, but it annotates locations
that require preemption to be disabled even when -rt converts spin_locks
into mutexes. These obviously can not contain spin_locks() as
spin_locks() can block and schedule out.

-- Steve

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