Re: cp file /dev/zero <-> cache [was Re: increasing page size]

Benjamin C.R. LaHaise (
Tue, 7 Jul 1998 13:50:02 -0400 (EDT)

On Tue, 7 Jul 1998, Stephen C. Tweedie wrote:

[everyone has this thread fresh in their minds, right?]
> Oh dear. More arbitrary rules in the VM --- just what we need! And
> if we have more than one file trying to consume all of cache, what
> then? Each one gets 50%, bang, the rule falls over. And the 25%
> memory rule --- we expect that to work on 8MB machines as well as
> 512MB?

Right. I'd rather see a multi-level lru like policy (ie on each cache hit
it gets moved up one level in the cache, with the lru'd pages from a given
level being bumped to the head of the next lower level) used for the page
cache (it's kinda like the old dcache), whereby a data that is accessed
only once ends up being a prime target for replacement. Of course, this
can be done with the current aging scheme, it's just that the algorithms
used are O(nasty) rather than O(1).


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