Messages in this thread | | | Subject | Re: [PATCH v2 2/3] mutex: add support for reservation style locks, v2 | From | Peter Zijlstra <> | Date | Thu, 04 Apr 2013 18:49:18 +0200 |
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On Thu, 2013-04-04 at 15:31 +0200, Daniel Vetter wrote: > We've discussed this approach of using (rt-prio, age) instead of just > age > to determine the the "oldness" of a task for deadlock-breaking with > -EAGAIN. The problem is that through PI boosting or normal rt-prio > changes > while tasks are trying to acquire ww_mutexes you can create acyclic > loops > in the blocked-on graph of ww_mutexes after the fact and so cause > deadlocks. So we've convinced ourselves that this approche doesn't > work.
Could you pretty please draw me a picture, I'm having trouble seeing what you mean.
AFAICT as long as you boost Y while its the lock owner things should work out, no?
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