Re: [PATCH] Add need_resched check before go to kvm_resched

[Anthony Liguori <anthony-rdkfGonbjUSkNkDKm+mE6A@public.gmane.org>]

Dong, Eddie wrote:
> In this case, IOCTL return to Qemu will trigger scheduling at least.
>   

I think a scheduling change won't happen until the next timer tick.  
AFAICT, there's nothing explicit in the ioctl return path that will 
result in rescheduling.

I'm not entirely confident in how the timer interrupt gets handled when 
it arrives in the guest.  My understanding is that while the timer 
interrupt is delivered in the host, since preempt is disabled, the 
rescheduling opportunity is lost even though the current task is marked 
as needing rescheduling.  I think the next time that bit will get 
checked is the next timer interrupt but I may be wrong.

Regards,

Anthony Liguori

> Maybe I miss something.
>
> thx,eddie
>
>   


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