Re: that page count overflow thing

From: William Lee Irwin III
Date: Mon May 21 2007 - 07:38:14 EST


On Sat, May 19, 2007 at 03:26:49PM -0700, David Miller wrote:
> I think we may be able to fix that one without making the
> counter larger, it's silly overhead for such an extreme
> case IMHO.
> Perhaps it might be possible to just make the counter stick at it's
> maximum, and when it's there we have an rbtree of external "large"
> counters, keyed by page struct address.
> So basically externalize counters that go over the maximally
> representable value. In this way only the idiotic cases pay
> the price.

This could be awkward with allocation requirements. How about an
open-addressed hash table? It can be made so large as to never
need to expand in advance with a very small constant factor space
overhead.


-- wli
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