On Tue, 11 Jul 2000, Andrea Arcangeli wrote:

On Tue, 11 Jul 2000, Rik van Riel wrote:

quoted

On Tue, 11 Jul 2000, Andrea Arcangeli wrote:

quoted

On Tue, 11 Jul 2000, Rik van Riel wrote:

quoted

No. You just wrote down the strongest argument in favour of one
unified queue for all types of memory usage.

Do that and download an dozen of iso image with gigabit ethernet
in background.

You need to forget about LRU for a moment. The fact that
LRU is fundamentally broken doesn't mean that it has
anything whatsoever to do with whether we age all pages
fairly or whether we prefer some pages over other pages.

If LRU is broken we need to fix that, a workaround like
your proposal doesn't fix anything in this case.

So tell me how with your design can I avoid the kernel to unmap anything
while running:

	cp /dev/zero .

forever.

Whatever aging algorithm you use if you wait enough time the
mapped pages will be thrown away eventually.

And that is correct behaviour. The problem with LRU is that the
"eventually" is too short, but proper page aging is as close to
LFU (least _frequently_ used) as it is to LRU. In that case any
page which was used only once (or was only used a long time ago)
will be freed before a page which has been used more often
recently will be.

This effectively and efficiently protects things like X, xterm
and other things which are used over and over again, while still
swapping out things which are not used at all.

regards,

Rik
--
"What you're running that piece of shit Gnome?!?!"
       -- Miguel de Icaza, UKUUG 2000

http://www.conectiva.com/		http://www.surriel.com/

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