Re: The performance and behaviour of the anti-fragmentation relatedpatches

[Joel Schopp]

> > Exhibiting a workload where the list patch breaks down and the zone
> > patch rescues it might help if it's felt that the combination isn't as
> > good as lists in isolation. I'm sure one can be dredged up somewhere.
>
> I can't think of a workload that totally makes a mess out of list-based. 
> However, list-based makes no guarantees on availability. If a system 
> administrator knows they need between 10,000 and 100,000 huge pages and 
> doesn't want to waste memory pinning too many huge pages at boot-time, 
> the zone-based mechanism would be what he wanted.

From our testing with earlier versions of list based for memory hot-unplug on 
pSeries machines we were able to hot-unplug huge amounts of memory after running the 
nastiest workloads we could find for over a week.  Without the patches we were unable 
to hot-unplug anything within minutes of running the same workloads.

If something works for 99.999% of people (list based) and there is an easy way to 
configure it for the other 0.001% of the people ("zone" based) I call that a great 
solution.  I really don't understand what the resistance is to these patches.

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