Thomas Gleixner 0782e63bc6 sched: Handle priority boosted tasks proper in setscheduler()
Ronny reported that the following scenario is not handled correctly:

	T1 (prio = 10)
	   lock(rtmutex);

	T2 (prio = 20)
	   lock(rtmutex)
	      boost T1

	T1 (prio = 20)
	   sys_set_scheduler(prio = 30)
	   T1 prio = 30
	   ....
	   sys_set_scheduler(prio = 10)
	   T1 prio = 30

The last step is wrong as T1 should now be back at prio 20.

Commit c365c292d059 ("sched: Consider pi boosting in setscheduler()")
only handles the case where a boosted tasks tries to lower its
priority.

Fix it by taking the new effective priority into account for the
decision whether a change of the priority is required.

Reported-by: Ronny Meeus <ronny.meeus@gmail.com>
Tested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <stable@vger.kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Mike Galbraith <umgwanakikbuti@gmail.com>
Fixes: c365c292d059 ("sched: Consider pi boosting in setscheduler()")
Link: http://lkml.kernel.org/r/alpine.DEB.2.11.1505051806060.4225@nanos
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-05-08 11:53:55 +02:00
..
2015-04-27 23:11:49 -04:00
2015-04-17 09:04:08 -04:00
2015-04-21 09:33:10 -07:00
2015-04-21 09:42:58 -07:00
2015-04-11 22:27:55 -04:00
2014-10-09 22:26:04 -04:00
2014-08-08 15:57:18 -07:00
2015-04-12 21:03:31 +02:00
2015-04-12 20:58:24 +02:00
2015-02-24 08:41:07 +01:00
2014-09-10 15:42:12 -07:00
2015-04-30 09:35:41 -07:00
2014-12-04 14:34:54 -05:00
2014-12-22 15:40:48 +01:00
2015-01-17 10:02:23 +13:00
2015-04-15 15:06:55 -04:00
2014-12-10 17:41:10 -08:00
2015-04-06 11:16:04 -04:00