Re: large page patch (fwd) (fwd)

Rik van Riel
2002-08-10T19:52:22Z

On 10 Aug 2002, 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.

> 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.

Indeed. We need this same thing for page tables too, otherwise
a high sharing situation can easily "require" more page table
memory than the total amount of physical memory in the system ;)

regards,

Rik
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