Re: scheduler independent forced vcpu selection

[Ryan Harper <ryanh@us.ibm.com>]

* Stephan Diestelhorst <sd386@cl.cam.ac.uk> [2005-05-18 09:04]:
> > I'm working on a new hypercall, do_confer, which allows the directed
> > yielding of a vcpu to another vcpu.  It is mainly used when a vcpu fails
> > to acquire a spinlock, yielding to the lock holder instead of spinning. I
> > ported the ppc64 spinlock implementation for the i386 linux portion.  In
> > implementing the hypercall, I've been trying to figure out how to get
> > the scheduler (I've only played with bvt) to run the vcpu passed in the
> > hypercall (after some validation) but I've run into various bad state
> > situations (do_softirq pending != 0 assert, '!active_ac_timer(timer)'
> > failed , and __task_on_runqueue(prev) failed) which tells me I
> > don't fully understand all of the book-keeping that is needed.  Has
> > anyone thought about how to do this with either BVT or the new EDF
> > scheduler?

After some thought, domain_wake(), followed by
raise_softirq(SCHEDULE_SOFTIRQ) does what I want and removes the huge
mess I was making in __enter_scheduler().  

-- 
Ryan Harper
Software Engineer; Linux Technology Center
IBM Corp., Austin, Tx
(512) 838-9253   T/L: 678-9253
ryanh@us.ibm.com