Re: Long time spent in swap_out &co

[Rik van Riel <riel@conectiva.com.br>]

On 4 Jun 2000, John Fremlin wrote:

>         (a) The entire list of processes is scanned through each time
>         at least once. (Slow, and holding a lock.)

This is not very slow, since it only looks at something like
3 or 4 numbers and flags per process.

>         (b) The biggest rss is chosen. Admittedly the swap_cnt
>         heuristics help a bit but it means that a large process that
>         is on touching its pages will keep distracting attention from
>         more smaller processes that may or may not be more wasteful.

Please look at the 'assign' variable. We will chose the process
with the biggest swap_cnt until swap_cnt for *all* processes is
0.

Then we will reassign swap_cnt. This ensures that all processes
get scanned fairly.

Also, note the counter variable, we'll only scan up to a few
processes, and we'll return after we have freed just one page.

regards,

Rik
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