Hi!

I'm thinking about adding the priority ceiling protocol to -rt
(implemented in a way so that you can select between priority
inheritance and priority ceiling with the kernel configurator).

Since this mechanism inherently avoids dead-locks, it could be
helpful for applications that need high safety integrity levels!?

The priority ceiling protocol is basically no rocket science
and implemented for other OSes for a while, so it should be
a no-brainer get it going with Linux. However. I'm struggling
at the point where it comes to SMP: it seems like when a task
acquires a lock, it is necessary to un-schedule any active
tasks on other cores sharing the same lock. This would be
very inefficient, of course, because tasks sharing a lock
couldn't run in parallel on different CPUs.

Does anybody know of any other priority inversion and
dead-lock avoidance mechanism that would efficiently work
on SMP?

Feedback is highly appreciated!

regards

Bernhard