Re: [PATCH v10 clocksource 1/7] clocksource: Provide module parameters to inject delays in watchdog

From: Thomas Gleixner
Date: Mon Apr 26 2021 - 03:14:10 EST

On Sun, Apr 25 2021 at 21:07, Andi Kleen wrote:
>> occur between the reads of the two clocks. Yes, interrupts are disabled
>> across those two reads, but there are no shortage of things that can
>> delay interrupts-disabled regions of code ranging from SMI handlers to
>> vCPU preemption. It would be good to have some indication as to why
> I assume vCPU preemption here refers to preempt RT? I didn't think
> a standard kernel could preempt when interrupt are disabled.

Neither does Preempt-RT. It's about vCPU's being preempted by the
hypervisor which can happen anytime independent of the state of the