* Re: memory management wishes...
[not found] <gordo-971117164959.A013341@gringo.telsur.cl>
@ 1997-11-17 21:15 ` Rik van Riel
0 siblings, 0 replies; only message in thread
From: Rik van Riel @ 1997-11-17 21:15 UTC (permalink / raw)
To: Gordon Oliver; +Cc: linux-mm
On Mon, 17 Nov 1997, Gordon Oliver wrote:
> ... Rik van Riel said ...
> >Send Linux memory-management wishes to me: I'm currently looking
> >for something to hack...
>
> I'd like to see an experiment done where some aggressive swapping code marks
> pages for swapping and makes them "non-resident" without actually doing the
> swapping. I.e.
> 1) mark pages for swapping aggressively, marking them non-resident
> in the page tables at the same time.
> 2) gather statistics for pages that have been marked non-resident,
> trying to figure out the "value" of a page.
> 3) Use these statistics to swap out little used pages rapidly...
>
> The advantage is that it gives the possibility of aggressively swapping without
> taking the entire penalty... I'm not sure if this will actually help in the
> end, but it is cool research, and might get a big win.
I believe this is what 'real' unixen already do, they have an
'inactive' list of not-so-often used pages that are ready to
be swapped out. They even prepage the head of the inactive list.
If a page from the inactive list _is_ used before being swapped
out, it is 'reactivated'.
To implement this we would need:
- a big chunk of memory to hold the list
- a mechanism to build the list
- a preswapping/freeing daemon (easy)
- the willingness to code all of this
Rik.
----------
Send Linux memory-management wishes to me: I'm currently looking
for something to hack...
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