Re: Google's mm problem - not reproduced on 2.4.13

Linus Torvalds
2001-11-02T20:31:01Z

In article <20011102181758Z16039-4784+420@humbolt.nl.linux.org>,
Daniel Phillips <phillips@bonn-fries.net> wrote:
>
>It's hard to see how that could be wrong. Plus, this test program does run
>under 2.4.9, it just uses way too much CPU on that kernel. So I'd say mm
>bug.

So how much memory is mlocked?

The locked memory will stay in the inactive list (it won't even ever be
activated, because we don't bother even scanning the mapped locked
regions), and the inactive list fills up with pages that are completely
worthless.

And the kernel will decide that because most of the unfreeable pages are
mapped, it needs to do VM scanning, which obviously doesn't help.

Why _does_ this thing do mlock, anyway? What's the point? And how much
does it try to lock?

If root wants to shoot himself in the head by mlocking all of memory,
that's not a VM problem, that's a stupid administrator problem.

Linus