Re: bad interaction between boosted idle vcpus and csched's tickling?

[Keir Fraser <keir.fraser@eu.citrix.com>]

On 07/05/2010 13:36, "Jan Beulich" <JBeulich@novell.com> wrote:

> Keir,
> 
> isn't there a problem after the change to handle tasklets in idle vcpus
> in that {default,acpi_processor}_idle() will put the vcpu to sleep with
> boosted priority still in place, hence preventing it from being tickled
> and/or needlessly tickling other CPUs?

See the comment above tasklet_list definition in tasklet.c: we always run
through the scheduler when tasklets are added/removed. That is explicitly to
get the idle thread's priority set correctly.

I think this could be handled better though, and also in the current
approach I actually still probably don't have enough raise_softirq() calls.
:-) I will take another look and see if I can make things more obvious and
robust.

 Thanks,
 Keir

> Jan
>