Messages in this thread | | | Date | Sun, 25 Sep 2005 17:19:12 +1000 | From | Nick Piggin <> | Subject | Re: [PATCH linux-2.6 01/04] brsem: implement big reader semaphore |
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Tejun Heo wrote: > 01_brsem_implement_brsem.patch > > This patch implements big reader semaphore - a rwsem with very > cheap reader-side operations and very expensive writer-side > operations. For details, please read comments at the top of > kern/brsem.c. >
This thing looks pretty overengineered. It is difficult to read with all the little wrapper functions and weird naming schemes.
What would be wrong with an array of NR_CPUS rwsems? The only tiny trick you would have to do AFAIKS is have up_read remember what rwsem down_read took, but that could be returned from down_read as a token.
I have been meaning to do something like this for mmap_sem to see what happens to page fault scalability (though the heavy write-side would make such a scheme unsuitable for mainline).
-- SUSE Labs, Novell Inc.
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