On Wed 31-01-18 12:12:17, Andrew Morton wrote: > On Wed, 31 Jan 2018 08:58:52 +0100 Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > > 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? > > It seems a reasonable cleanup: reusing MR_CMA for hugetlb just because > it happens to do the right thing is a bit hacky - the two things aren't > particularly related and a reader could be excused for feeling > confusion. My bad! I thought this is a tracepoint thingy. But it seems to be only used as a migration reason for page_owner. Now it makes more sense. > But the change seems incomplete: > > > + if (migratetype == MIGRATE_CMA) > > + migrate_reason = MR_CMA; > > + else > > + migrate_reason = MR_HUGETLB; > > If we're going to do this cleanup then shouldn't we go all the way and > add MIGRATE_HUGETLB? Yes. We can expect more users of alloc_contig_range in future. Maybe we want to use MR_CONTIG_RANGE instead. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
