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Subject[patch 00/12] (hr)timers: Prepare for PREEMPT_RT support
The following series brings the bulk of PREEMPT_RT specific changes for the
(hr)timer code:

- Handle timer deletion correctly under RT to avoid priority inversion
and life locks

This mechanism might be useful for VMs as well when a vCPU
executing a timer callback gets scheduled out and on another vCPU
del_timer_sync() or hrtimer_cancel() is invoked.

The mitigation would only work when paravirt spinlocks are
enabled. I've not implemented that, as I don't know whether this is a
real world issue. I just noticed that it is basically the same
problem. Adding it would be trivial.

- Prepare for moving most hrtimer callbacks into softirq context and mark
timers which need to expire in hard interrupt context even on RT so
they don't get moved.

The timerwheel still needs some special handling for IRQSAFE timers (grrrr)
which I'm still working on to find a less fugly solution.



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