Re: [RFC PATCH 1/3] kvm: keep track of which task is running a KVMvcpu

[Avi Kivity]

On 12/03/2010 04:50 PM, Rik van Riel wrote:
> On 12/02/2010 08:18 PM, Chris Wright wrote:
> > * Rik van Riel (riel@xxxxxxxxxx) wrote:
> > > Keep track of which task is running a KVM vcpu.  This helps us
> > > figure out later what task to wake up if we want to boost a
> > > vcpu that got preempted.
> > >
> > > Unfortunately there are no guarantees that the same task
> > > always keeps the same vcpu, so we can only track the task
> > > across a single "run" of the vcpu.
> >
> > So shouldn't it confine to KVM_RUN?  The other vcpu_load callers aren't
> > always a vcpu in a useful runnable state.
>
> Yeah, probably.  If you want I can move the setting of
> vcpu->task to kvm_vcpu_ioctl.

No need, it's not like something bad will happen.

What I'd really like to see is a soft binding between a vcpu and its 
thread, so directed yield works even if we're in qemu while we were 
scheduled out.  In fact it's not an unlikely pattern:

  spin_lock(&lock)
  ...
  writel(some_port_handled_by_qemu)
  ...
  spin_unlock(&lock)

but that can wait.

--
error compiling committee.c: too many arguments to function

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