Re: [RFC] mm/migrate: Add new migration reason MR_HUGETLB

From: Michal Hocko
Date: Wed Jan 31 2018 - 02:59:00 EST


On Wed 31-01-18 07:55:05, Anshuman Khandual wrote:
> On 01/30/2018 01:29 PM, Michal Hocko wrote:
> > On Tue 30-01-18 08:37:14, Anshuman Khandual wrote:
> >> alloc_contig_range() initiates compaction and eventual migration for
> >> the purpose of either CMA or HugeTLB allocation. At present, reason
> >> code remains the same MR_CMA for either of those cases. Lets add a
> >> new reason code which will differentiate the purpose of migration
> >> as HugeTLB allocation instead.
> > Why do we need it?
>
> The same reason why we have MR_CMA (maybe some other ones as well) at
> present, for reporting purpose through traces at the least. It just
> seemed like same reason code is being used for two different purpose
> of migration.

But do we have any real user asking for this kind of information?

--
Michal Hocko
SUSE Labs