Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19

Dave Hansen
2005-11-02T10:54:49Z

On Wed, 2005-11-02 at 20:48 +1100, Nick Piggin wrote:
> > So, if you have to add to NORMAL/DMA on the fly, how do you handle a
> > case where the new NORMAL/DMA ram is physically above
> > HIGHMEM/HOTPLUGGABLE? Is there any other course than to make a zone
> > required to be able to span other zones, and be noncontiguous? Would
> > that represent too much of a change to the current model?
> >
>
> Perhaps. Perhaps it wouldn't be required to get a solution that is
> "good enough" though.
>
> But if you can reclaim your ZONE_RECLAIMABLE, then you could reclaim
> it all and expand your normal zones into it, bottom up.

That's a good point. It would be slow, because you have to wait on page
reclaim, but it would work. I do worry a bit that this might make
adding memory to slow of an operation to be useful for short periods,
but we'll see how it actually behaves.

-- Dave