Re: [Xen-devel] deadlock in the credit2

[Eunbyung Park <silverbottlep@xxxxxxxxx>]

> > > if ( d == current->domain )
> > > vcpu_schedule_lock_irq(current);
> > >
> > > It was very hard to understan for me..:) What does it exactly mean?
> > You're asking what "current" means?  "current" is a macro that always
> > resolves to the vcpu which is running on the current processor.
> >
> > sched_adjust() seems to be trying to avoid scheduling races in general
> > by pausing all vcpus before calling the per-scheduler function.  But
> > if a VM is calling the op on itself, the vcpu making the hypercall
> > can't pause itself.  So in that case (current->domain == d) will be
> > true, so sched_adjust() grab the schedule lock of that vm instead.
> >
> > But really all that locking should be handled in the scheduler
> > function, not by the generic code.  It knows best what needs to be
> > locked when.
This was what I really wanted to ask about.
Now I can understand what the generic scheduler code was going to say.
Thanks for your kindness.

--
Best Regards,
Eunbyung Park

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