Swapping out old pages

["Karl Vogel" <kvo@mail.seagha.com>]

I recently became interested in all this VM stuff, so I'm not what you would
call an expert (more like a newbie), but when browsing through the 2.2 mm
sources, the following questions popped into my mind:

- why does the swap out algorithm select the task with the largest RSS to
free pages. If I'm not mistaken, the age of a page isn't considered?! Why is
that? Am I overlooking something? (doesn't this mean that if I start a new
large process, it's pages immediately get swapped out even though there are
other processes that haven't done anything in the past couple of hours)

- wouldn't it be beneficial if there is a parameter that allows you to
specify that after a certain age, a page is swapped out to make room for the
buffer cache. (even if the system has plenty of ram left - the idea is that:
if your system has alot of RAM, old/unused pages (e.g. init code from
daemons etc) are never swapped out and take away ram that can be used for
better things).




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