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SubjectRe: [patch 00/12] (hr)timers: Prepare for PREEMPT_RT support
On Fri, Jul 26, 2019 at 08:30:48PM +0200, Thomas Gleixner wrote:
> 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.
>

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

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