On (20/07/21 13:17), Sergey Senozhatsky wrote:
> Hello,
>
> RFC
>
> We noticed that in a number of cases when we wake_up_process()
> on arm64 guest we end up enqueuing that task on a preempted VCPU. The culprit
> appears to be the fact that arm64 guests are not aware of VCPU preemption
> as such, so when sched picks up an idle VCPU it always assumes that VCPU
> is available:
>
> wake_up_process()
> try_to_wake_up()
> select_task_rq_fair()
> available_idle_cpu()
> vcpu_is_preempted() // return false;
>
> Which is, obviously, not the case.
>
> This RFC patch set adds a simple vcpu_is_preempted() implementation so
> that scheduler can make better decisions when it search for the idle
> (v)CPU.
Hi,
A gentle ping.
-ss
