Messages in this thread | | | Subject | Re: [HACK] convert i_alloc_sem for direct_io.c craziness! | From | Peter Zijlstra <> | Date | Mon, 01 Oct 2007 22:39:16 +0200 |
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On Mon, 2007-10-01 at 12:52 -0700, Zach Brown wrote:
> Do you have any suggestions for locking constructs that RT would prefer?
Basically, anything that maps to a simple mutex. Anything more complex gets real messy real quick.
Locks that have non-exclusive states become non-deterministic because an unbounded number of contexts can be in this state. Hence acquisition of the exclusive state has unbounded time. Even when limited to a bounded number, the ramifications to the PI graph will get you a head-ache.
Also, non-owner locks, ie. semaphores (asymetric acquisition vs release contexts) are unusable because the lack of ownership undermines PI - who to boost?
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