Re: Subtle MM bug

["Stephen C. Tweedie" <sct@redhat.com>]

Hi,

On Sun, Jan 07, 2001 at 10:42:11PM -0800, Linus Torvalds wrote:
> 
> and just get rid of all the logic to try to "find the best mm". It's bogus
> anyway: we should get perfectly fair access patterns by just doing
> everything in round-robin

Definitely.

> Then, with something like the above, we just try to make sure that we scan
> the whole virtual memory space every once in a while. Make the "every once
> in a while" be some simple heuristic like "try to keep the active list to
> less than 50% of all memory".

... which will produce an enormous storm of soft page faults for
workloads involving mmaping large amounts of data or where we have
a lot of space devoted to anonymous pages, such as static
computational workloads.

The idea of an inactive list target is sound, but it needs to be based
on memory pressure: we don't need anything like 50% if we aren't under
any pressure, so compute-bound workloads with large data sets can
achieve stability.

--Stephen
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