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SubjectRe: [RFC][PATCH 0/4] arm64:kvm: teach guest sched that VCPUs can be preempted
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On 2020/8/17 10:03, Sergey Senozhatsky wrote:
> 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
> _______________________________________________
> kvmarm mailing list
> kvmarm@lists.cs.columbia.edu
> https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
> .

Hi Sergey,

I have a set of patches similar to yours.

https://lore.kernel.org/lkml/20191226135833.1052-1-yezengruan@huawei.com/

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