Re: [PATCH 0/1] memory offline issues with hugepage size > memory block size

From: Michal Hocko
Date: Wed Sep 21 2016 - 15:22:09 EST

On Wed 21-09-16 11:27:48, Dave Hansen wrote:
> On 09/21/2016 11:20 AM, Michal Hocko wrote:
> > I would even question the per page block offlining itself. Why would
> > anybody want to offline few blocks rather than the whole node? What is
> > the usecase here?
> The original reason was so that you could remove a DIMM or a riser card
> full of DIMMs, which are certainly a subset of a node.

OK, I see, thanks for the clarification! I was always thinking more in
node rather than physical memory range hot-remove. I do agree that it
makes sense to free the whole gigantic huge page if we encounter a tail
page for the above use case because losing the gigantic page is
justified when the whole dim goes away.


Michal Hocko