Re: pagefault scalability patches

On Thu, 2005-08-18 at 09:17 -0700, Christoph Lameter wrote:

On Thu, 18 Aug 2005, Nick Piggin wrote:

quoted

Nick Piggin wrote:

quoted

If the big ticket item is taking the ptl out of the anonymous fault
path, then we probably should forget my stuff

( for now :) )

I think we can gradually work atomic operations into various code paths 
where this will be advantageous and your work may be a very important base 
to get there.

Don't forget however that when doing things like tearing down page
tables, it's a lot more efficient to take 1 lock, then do a bunch of
things non-atomically, then drop that lock.

At least on PPC, the cost of a lock is approx. equivalent to the cost of
an atomic, and is measurable on such things.

That said, I think your approach for the anonymous page case is a good
first step for now. I'll have to adapt ppc64 to it but it shouldn't be
too hard.

Ben.


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