Messages in this thread | | | Date | Mon, 17 Aug 2020 11:03:10 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [RFC][PATCH 0/4] arm64:kvm: teach guest sched that VCPUs can be preempted |
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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
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