Re: [RFC PATCH 0/5] mm, memory_hotplug: allocate memmap from hotadded memory

From: Michal Hocko
Date: Fri Jul 28 2017 - 08:01:52 EST


On Wed 26-07-17 10:33:28, Michal Hocko wrote:
[...]
> There is also one potential drawback, though. If somebody uses memory
> hotplug for 1G (gigantic) hugetlb pages then this scheme will not work
> for them obviously because each memory section will contain 2MB reserved
> area.

Actually I am wrong here. It is not each section in general. I have
completely forgot that we do large memblocks on x86_64 with a lot of
memory and then we hotadd 2GB memblocks and the altmap will allocate
from the beginign of the _memblock_ and so all the memmaps will end up
in the first memory section.
--
Michal Hocko
SUSE Labs