Re: Page allocator: Single Zone optimizations

Mel Gorman
2006-11-02T21:16:16Z

On Thu, 2 Nov 2006, Christoph Lameter wrote:

> On Thu, 2 Nov 2006, Mel Gorman wrote:
>
>> "Special way" to me is just "place them somewhere smart". If their location
>> was really important for hot-unplug, a placement policy could always use
>> MAX_ORDER_NR_PAGES at the lower PFNs in a zone for them. This should be easier
>> than introducing additional memory pools, zones or other mechanisms.
>
> This is going to be fine for hotplug in terms of a portion of a
> node going down. However, at some point we would like to have node
> plug and unplug.
>

Ok

> An unpluggable NUMA node must only allow movable memory and all non
> movable allocations will need to be redirected to other nodes.
>

That would be doable with antifrag. If a node is marked unpluggable and
gfpflags_to_rclmtype() == RCLM_NORCLM, then skip the node and fallback as
normal to the next node.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab