On Fri, Feb 04, 2000 at 04:06:28AM +0100, Andrea Arcangeli wrote:
> I finished now to fixup the alpha port for 2.3.42 (the smp cpu map update
> part is from Jay Estabrook).
>
> I developed from scratch rw semaphores based on spinlocks. The overhead
> seems quite load by looking the code and they are at least quite obviously
> right ;). BTW, they are not architecture-dependent so other archs can cut
> and past if necessary.
So put them to include/asm-generic/semaphore.h (and put the .c code say into
a comment), but not to alpha which has them already done properly.
You really want those rw semaphores to be fast and small (because especially
rwsem will most probably be non-contended in down_read), whereas the spinlock
version is neither. It is good to have a generic version to fix some port
quickly, but it is bad to stay at that implementation forever.
Cheers,
Jakub
___________________________________________________________________
Jakub Jelinek | jakub@redhat.com | http://sunsite.mff.cuni.cz/~jj
Linux version 2.3.41 on a sparc64 machine (1343.49 BogoMips)
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