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Thomas Gleixner daf639f6ed sched: Handle priority boosted tasks proper in setscheduler() ... commit 0782e63bc6 upstream. 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 c365c292d0 ("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: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Fixes: c365c292d0 ("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> [ luis: backported to 3.16: adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com>		History 2015-05-28 10:00:00 +01:00
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deadline.h	sched/deadline: Add SCHED_DEADLINE structures & implementation	2014-01-13 13:41:06 +01:00
prio.h	sched: Consolidate open coded implementations of nice level frobbing into nice_to_rlimit() and rlimit_to_nice()	2014-05-22 11:16:36 +02:00
rt.h	sched: Handle priority boosted tasks proper in setscheduler()	2015-05-28 10:00:00 +01:00
sysctl.h	mm: update comment for DEFAULT_MAX_MAP_COUNT	2014-06-04 16:54:05 -07:00