On Thu, 14 Apr 2016, Xunlei Pang wrote: > We should deboost before waking the high-prio task such that > we don't run two tasks with the 'same' priority.
No. This is fundamentaly broken.
T1 (prio 0) lock(X)
--> preemption
T2 (prio 10) lock(X)
boost(T1)
schedule()
T1 (prio 10) unlock(X)
deboost()
(prio 0)
--> preemption
T3 (prio 5) ....
Classic priority inversion enabled by a mechanism to avoid it. Brilliant
stuff.
Thanks,
tglx
