Messages in this thread |  | | | Subject | Re: PI patch against 2.6.16-rt9 | | From | Thomas Gleixner <> | | Date | Tue, 28 Mar 2006 23:36:42 +0200 |
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On Tue, 2006-03-28 at 22:17 +0100, Esben Nielsen wrote: > I think we talk about the situation
No, we talk about existing lock chains L(0) --> L(n).
> B locks 1 C locks 2 D locks 3 > B locks 2, boosts C and block > A locks 2 > A is boost B > A drop it's spinlocks and is preempted > C unlocks 2 and auto unboosts > B is running > B locks 3, boosts C and blocks > A gets a CPU again > A boosts B > A boosts D > > Is there anything wrong with that? > And in the case where A==D there indeed is a deadlock which will be > detected.
If you get to L(x) the underlying dependencies might have changed already as well as the dependencies x ... n. We might get false positives in the deadlock detection that way, as a deadlock is an "atomic" state.
tglx
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