Re: scheduler independent forced vcpu selection

[Stephan Diestelhorst <sd386@cl.cam.ac.uk>]

Ryan Harper schrieb:
> * Stephan Diestelhorst <sd386@cl.cam.ac.uk> [2005-05-18 09:04]:
> 
>>The timer assertion might be the old scheduling timer, which gets
>>probably reset, but not deleted beforehand... And the on runqueue
>>assertion suggests that you are 'stealing' the domain from the
>>schedulers queues without giving it a chance to notice.
> 
> 
> Looking at both bvt and sedf, the runqueue is ordered by some metric or
> another (evt, deadline respectively).  What I think we need is a way to
> swap positions in the runqueues.  That is, if the lock holder is
> runnable, I want the holder to run instead of current.  Is there some
> way to do this in a scheduler independent manner with the current set of
> scheduler ops defined in sched-if.h ?

How about blocking/pausing the currently running domain? I can't think
of another way of doing this in an scheduler independent fashion...

> I noticed that neither bvt or sedf implement the rem_task function which
> I thought could be used to help out with the 'stealing' by notifying the
> schedulers that prev was going away (removing it from the runqueue) but
> just removing the exec_domain from the runqueue didn't help.

That is really nasty, and just describes what I meant with "stealing" a
domain from the scheduler! :-)

> I'm including a patch that I'm currently using so you can get a better
> idea of the modifications to schedule.c I'm making.

Thanks,
  Stephan