Re: [RFC] Using "page credits" as a solution for common thrashing scenarios

From: Eyal Lotem
Date: Tue Jun 08 2010 - 05:45:36 EST

Replying to a very old email :-)

On Wed, Nov 25, 2009 at 12:15 AM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> Eyal Lotem <eyal.lotem@xxxxxxxxx> writes:
> Replying to an old email.
>>   * I think it is wrong for the kernel to evict the 15 pages of the bash,
>>     xterm, X server's working set, as an example, in order for a
>>     misbehaving process to have 1000015 instead of 1000000 pages in its
>>     working set. EVEN if that misbehaving process is accessing its working
>>     set far more aggressively.
> One problem in practice tends to be that it's hard to realiably detect
> that a process is misbehaving. The 1000000 page process might be your
> critical database, while the 15 page process is something very
> unimportant.

Well, this solution doesn't really depend on any detection of
"misbehaving", it just goes about a more accurate way of defining page
importance. A simple solution to the problem you suggest is assigning
far more "credits" to the database than to the 15-page process.


> -Andi
> --
> ak@xxxxxxxxxxxxxxx -- Speaking for myself only.
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