Re: [PATCH 0/3] Reduce watermark-related problems with the per-cpuallocator V2

From: Christoph Lameter
Date: Mon Aug 23 2010 - 09:38:41 EST


On Mon, 23 Aug 2010, Mel Gorman wrote:

> > The maximum time for which the livelock can exists is the vm stat
> > interval. By default the counters are brought up to date at least once per
> > second or if a certain delta was violated. Drifts are controlled by the
> > delta configuration.
> >
>
> While there is a maximum time (2 seconds I think) the drift can exist
> in, a machine under enough pressure can make a mess of the watermarks
> during that time. If it wasn't the case, these livelocks with 0 pages
> free wouldn't be happening.

So because we go way beyond the watermarks we reach a state in which a
livelock exists that does not go away when the counters are finally
updated?


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