| Date | Fri, 26 Jul 2019 20:30:48 +0200 | From | Thomas Gleixner <> | Subject | [patch 00/12] (hr)timers: Prepare for PREEMPT_RT support |
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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.
Thanks,
tglx
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