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SubjectRe: [PATCH] i386 rw_semaphores fix
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> You need sterner testing stuff :) I hit the BUG at the end of rwsem_wake()
> in about a second running rwsem-4. Removed the BUG and everything stops
> in D state.
>
> Grab rwsem-4 from
>
> http://www.uow.edu.au/~andrewm/linux/rwsem.tar.gz
>
> It's very simple. But running fully in-kernel shortens the
> code paths enormously and allows you to find those little
> timing windows. Run rmsem-4 in two modes: one with
> the schedule() in sched() enabled, and also with it
> commented out. If it passes that, it works. When
> you remove the module it'll print out the number of
> read-grants versus write-grants. If these run at 6:1
> with schedule() disabled then you've kicked butt.
>
> Also, rwsem-4 checks that the rwsems are actually providing
> exclusion between readers and writers, and between
> writers and writers. A useful thing to check, that.

It now works (patch to follow).

schedule() enabled:
reads taken: 686273
writes taken: 193414

schedule() disabled:
reads taken: 585619
writes taken: 292997

David
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