Am Mittwoch, 25. Juli 2007 schrieb John Sigler:

Karsten Wiese wrote:

quoted

John Sigler wrote:

quoted

Is there some form of priority inheritance? Does the IRQ handler get a 
priority boost if a high priority task is waiting for it?

No. But that would be "nice to have".

No to the first question? to the second question? or to both? :-)

To the second.
I checked some soundcard drivers some time ago in -rt kernels, looking for
that "priority boosted by consuming process threaded interrupt handler".
Then there was no such.

In kernel/futex.c does "PI" stand for Priority Inheritance?

I guess so, yes.

e.g.

/*
  * Priority Inheritance state:
  */
struct futex_pi_state {
	/*
	 * list of 'owned' pi_state instances - these have to be
	 * cleaned up in do_exit() if the task exits prematurely:
	 */
	struct list_head list;

	/*
	 * The PI object:
	 */
	struct rt_mutex pi_mutex;

	struct task_struct *owner;
	atomic_t refcount;

	union futex_key key;
};