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SubjectRe: [2.1.130-3] Page cache DEFINATELY too persistant... feature?
	Well, a further (unintentional) test shows that this isn't just a
problem with the buffer cache or with writes. I did a simple
"find . -name '*.c' | xargs grep shrink_mmap"

This command proceeded to fill my PAGE cache (and I assume it wasn't
doing much writing) and swap a lot of stuff out to disk as soon as free
memory was exhausted. I had at a small (~3Mb buffer cache), and at least
44 out of 63 Mb in the page cache.

So ONE problem, at least, is that the only strategy that seems to be
used to free memory is to swap, whereas in this case the page cache
should have been chopped. Is there a function that does something like
"free X number of pages from the page cache?" I really don't know
Linux's MM strategy, so perhaps this is expected behaviour, though it
seems kind of "unfair" to me.

If that problem were solved, the swapping problem with the buffers
wouldn't be nearly so bad, because I wouldn't have the page cache
sitting there and hogging 33% of my RAM. Maybe only 20% :)

Oh, the glories of running a "low memory machine!" (64Mb RAM) I should
really learn how the MM subsystem works...

Thanks,
-benRI
--
If E. Coli was a computer:
"OPERON.DLL: Mutation in LACTOSE.DLL. Entire system halted."

Benjamin Redelings I <>< http://sdcc13.ucsd.edu/~bredelin

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