Re: [PATCH v2 1/1] mm, memory_hotplug: Initialize struct pages for the full memory section

Michal Hocko
2018-12-17T13:35:19Z

On Mon 17-12-18 14:29:04, David Hildenbrand wrote:
> On 17.12.18 13:28, Michal Hocko wrote:
> > On Mon 17-12-18 10:38:32, David Hildenbrand wrote:
> > [...]
> >> I am wondering if we should fix this on the memblock level instead than.
> >> Something like, before handing memory over to the page allocator, add
> >> memory as reserved up to the last section boundary. Or even when setting
> >> the physical memory limit (mem= scenario).
> >
> > Memory initialization is spread over several places and that makes it
> > really hard to grasp and maintain. I do not really see why we should
> > make memblock even more special. We do intialize the section worth of
> > memory here so it sounds like a proper place to quirk for incomplete
> > sections.
> >
>
> True as well. The reason I am asking is, that memblock usually takes
> care of physical memory holes.

Yes and no. It only reflects existing memory ranges (so yes it skips
over holes) and then it provides an API that platform/arch code can
abuse to cut holes into existing ranges.
--
Michal Hocko
SUSE Labs