Re: [PATCH] docs: reorder memory-hotplug documentation

From: Oscar Salvador
Date: Tue May 21 2019 - 12:13:44 EST


On Tue, May 21, 2019 at 12:41:50PM +0200, David Hildenbrand wrote:
> > +Future Work
> > +===========
> > +
> > + - allowing memory hot-add to ZONE_MOVABLE. maybe we need some switch like
> > + sysctl or new control file.
>
> ... that already works if I am not completely missing the point here

It does.

> > + - support HugeTLB page migration and offlining.
>
> ... I remember that Oscar was doing something in that area, Oscar?

Yes, in general offlinining on hugetlb pages was already working, but we did not
allow to offline 1GB-hugetlb pages on x86_64.
I removed that limitation with
("commit: 10eeadf3045c mm,memory_hotplug: unlock 1GB-hugetlb on x86_64") , so now
offlining on hugetlb pages should be fully operative.

> I'd vote for removing the future work part, this is pretty outdated.

Instead of removing it, I would rather make it consistent with the present.
E.g:

- Move page handling from memory-hotremove to offline stage
- Enable a way to allocate vmemmap pages from hot-added memory
etc.


--
Oscar Salvador
SUSE L3