Re: large files unnecessary trashing filesystem cache?
From: Andrew James Wade
Date: Wed Oct 19 2005 - 00:46:28 EST
On Wednesday 19 October 2005 00:37, Andrew Morton wrote:
> Andrew James Wade <andrew.j.wade@xxxxxxxxx> wrote:
> > Sometimes you want a single file to take up most of the memory; databases
> > spring to mind. Perhaps files/processes that take up a large proportion of
> > memory should be penalized by preferentially reclaiming their pages, but
> > limit the aggressiveness so that they can still take up most of the memory
> > if sufficiently persistent (and the rest of the system isn't thrashing).
> Yes. Basically any smart heuristic we apply here will have failure modes.
> For example, the person whose application does repeated linear reads of the
> first 100MB of a 4G file will get very upset.
As will any dumb heuristic for that matter; we'd need precognition to avoid
all of them. But we can hopefully make the failure modes rarer and more
predictable. I don't know how my proposal would fare, and as I do not have
the code to test the matter I think I shall drop it.
 Which could, on occasion, be provided by hinting.
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