Re: [PATCH] Caches that shrink automatically

From: Andreas Gruenbacher (
Date: Sun Aug 04 2002 - 08:11:27 EST

On Sunday 04 August 2002 13:30, Hans Reiser wrote:
> How do you ensure that caches have their (internal) aging hands pushed
> at a speed that is proportional to their memory usage, or is your design
> susceptible to all the usual complaints the unified memory manager crowd
> has about separate caches?

That's a policy/optimization issue; it's not even desirable to shrink the
caches with priorities proportional to their size---they would all tend to
become equally large.

The patch shrinks all the caches equally often, with the same priorities. The
caches can then decide themselves how they will react, depending on their
cache size and entry size, replacement strategy, taking care of page entry
clustering or not, etc.

The icache, dcache, and dqcache are shrunk using the same strategy (except the
priority is a constant for some of the caches, which could be coded in the
shrink function as well). This scheme has worked out pretty well so far,

For Extended Attributes we are currently using a very simple cache with LRU
entry replacement, and small entries. The cache doesn't grow very big,


 Andreas Gruenbacher SuSE Linux AG Deutschherrnstr. 15-19 D-90429 Nuernberg, Germany

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