Re: [PATCH v2 resend] mm/memory_hotplug: Make unpopulated zones PCP structures unreachable during hot remove

[Vlastimil Babka]

On 4/12/21 4:08 PM, Mel Gorman wrote:
> On Mon, Apr 12, 2021 at 02:40:18PM +0200, Vlastimil Babka wrote:
>> On 4/12/21 2:08 PM, Mel Gorman wrote:
>
> the pageset structures in place would be much more straight-forward
> assuming the structures were not allocated in the zone that is being
> hot-removed.

I would expect this is not possible, at least for ZONE_MOVABLE, as the percpu
allocations should be GFP_KERNEL. And it's not realistic to expect offlining to
succeed at all without using ZONE_MOVABLE.

AFAIK even Oscar's work on using the node to self-contain its own structures is
only applicable to struct pages, not percpu allocations?