Re: FUSYN and RT

[Daniel Walker <dwalker@mvista.com>]

On Tue, 2005-04-12 at 13:29, Esben Nielsen wrote:

> You basicly need 3 priorities:
> 1) Actual: task->prio
> 2) Base prio with no RT locks taken: task->static_prio
> 3) Base prio with no Fusyn locks taken: task->??
> 
> So no, you will not need the same API, at all :-) Fusyn manipulates
> task->static_prio and only task->prio when no RT lock is taken. When the
> first RT-lock is taken/released it manipulates task->prio only. A release
> of a Fusyn will manipulate task->static_prio as well as task->prio.

mutex_setprio() , I don't know if you could call that an API but that's
what I was talking about.. They should both use that. I think it would
be better if the RT mutex (and fusyn) didn't depend on a field in the
task_struct to retain the old priority. That would make it easier ..

This goes back to the assumption that the locking isn't intermingled
once you get into the kernel . The RT mutex can safely save the owner
priority with out a Fusyn jumping in and changing it and the other way
around..

Daniel