Messages in this thread | | | Date | Tue, 8 Feb 2005 22:20:23 +0100 (MET) | From | Esben Nielsen <> | Subject | Re: Real-Time Preemption and UML? |
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On Tue, 8 Feb 2005, Jeff Dike wrote:
> mingo@elte.hu said: > > Jeff, any objections against adding this change to UML at some point? > > No, not at all. I just need to understand what CONFIG_PREEMPT requires of > UML.
Ingo can probably tell you in much more detail. My problem when I tried to compile with CONFIG_PREEMPT_RT (not CONFIG_PREEMPT!) was that __SEMAPHORE_INITIALIZER didn't exist since the architecture specific semaphore.h is not included in that configuration. The reason again is that locking (not completions) is changed a lot under CONFIG_PREEMPT_RT to introduce muteces instead of raw spinlocks and priority inheritance to make these lockings behave deterministicly.
> > >From a quick read of Documentation/preempt-locking.txt, this looks like it's > implementing Rule #3 (unlock by the same task that locked), which looks fine. >
Now I don't really know who I am responding to. But both up()s now changed to complete()s are in something looking very much like an interrupt handler. But again, as I said, I didn't analyze the code in detail, I just made it compile and checked that it worked in bare 2.6.11-rc2 UML - which I am not too sure how to set up and use to begin with!
> Jeff >
Esben
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