Re: [PATCH] Abstracted Priority Inheritance for RT

From: Daniel Walker
Date: Wed Jun 01 2005 - 19:18:07 EST


On Wed, 2005-06-01 at 16:07 +0200, Esben Nielsen wrote:

>
> Do you plan to use that callback for priority inheritance?
> If so: It would lead to an recursive algorithm. That is not very nice in
> the kernel with a limited call-stack. It is not so much a problem if the
> mechanism is used in the kernel only, but if it is used for user-space
> locking, which can have unlimited neesting, it is potential problem.

There is an API for for priority inheritance, the call by is strictly
for the PI mechanism to signal when it changes a waiters priority , as
the result of PI.

It's somewhat explained in linux/pi.h . Currently the rt_mutex uses this
callback to move the waiter depending on it's new priority.

I'm not sure I see how this could become recursive, could you explain
more?

Daniel

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