Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: large page patch (fwd) (fwd) | Date | Sat, 10 Aug 2002 20:59:36 +0200 |
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On Saturday 10 August 2002 20:20, Eric W. Biederman wrote: > Andrew Morton <akpm@zip.com.au> writes: > > The other worry is the ZONE_NORMAL space consumption of pte_chains. > > We've halved that, but it will still make high sharing levels > > unfeasible on the big ia32 machines. We are dependant upon large > > pages to solve that problem. (Resurrection of pte_highmem is in > > progress, but it doesn't work yet). > > There is a second method to address this. Pages can be swapped out > of the page tables and still remain in the page cache, the virtual > scan does this all of the time. This should allow for arbitrary > amounts of sharing. There is some overhead, in faulting the pages > back in but it is much better than cases that do not work. A simple > implementation would have a maximum pte_chain length.
Oh gosh, nice point. We could put together a lovely cooked benchmark where copy_page_range just fails to copy all the mmap pages, which are most of them in the bash test.
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