Re: Autoregulate swappiness & inactivation

From: Nick Piggin
Date: Thu Jul 08 2004 - 03:15:17 EST


Con Kolivas wrote:
Nick Piggin writes:


OK that's easy then. The OOM algorithm can be changed if it is
OOMing too easily.


I didn't say it was easy, just harder with; but whatever - I can get rid of it.


Please.

Secondly, can you please not mess with the exported sysctl. If you
think your "autoswappiness" calculation is better than the current
swappiness one, just completely replace it. Bonus points if you can
retain the swappiness knob in some capacity.



I agree and would like them all removed, but people just love to leave the knobs in place. While I dont think the knobs should still be there either, I'm not reluctant to leave something that innocuous if the users want them.


Well, get rid of the auto-tuning thing to start with, and merge
it into the swappiness calculation..

Regarding all these knobs, the main thing you want to avoid is
having loads of them because you can't find acceptable defaults.
I think "swappiness" is in the category of a good sysctl: it is
simple, meaningful to the admin, works, etc.

It has proven somewhat useful in testing ("set it to blah and see
if it still happens"). Or for people who know what they are doing.


Umm I think we're agreeing, no? I'm trying to leave the swappiness knob in for those who (think?) they know what they're doing. Somehow it needs to be turned to "manual" again.


No. Fold your all "autoswappiness" stuff directly into the
reclaim_mapped calculation that was previously keyed off swappiness.
Don't have it modify vm_swappiness at all: work directly on
reclaim_mapped.

Then, you should be able to retain the user's vm_swappiness input
into the system as well. If you can't figure out a good place to
put this in, don't worry about it to start with.

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