Re: [PATCH 0/4] mm,memory_hotplug: allocate memmap from hotadded memory

Michal Hocko
2019-04-03T08:49:18Z

On Wed 03-04-19 10:41:35, David Hildenbrand wrote:
> On 03.04.19 10:37, Michal Hocko wrote:
[...]
> > That being said it should be the caller of the hotplug code to tell
> > the vmemmap allocation strategy. For starter, I would only pack vmemmaps
> > for "regular" kernel zone memory. Movable zones should be more careful.
> > We can always re-evaluate later when there is a strong demand for huge
> > pages on movable zones but this is not the case now because those pages
> > are not really movable in practice.
>
> Remains the issue with potential different user trying to remove memory
> it didn't add in some other granularity. We then really have to identify
> and isolate that case.

Can you give an example of a sensible usecase that would require this?
--
Michal Hocko
SUSE Labs