On Thu 27-07-17 13:30:31, Aneesh Kumar K.V wrote: > > > On 07/27/2017 12:58 PM, Michal Hocko wrote: > >On Thu 27-07-17 07:52:08, Aneesh Kumar K.V wrote: > >>Michal Hocko <mhocko@xxxxxxxxxx> writes: > >> > >>>Hi, > >>>I've just noticed that alloc_gigantic_page ignores movability of the > >>>gigantic page and it uses any existing zone. Considering that > >>>hugepage_migration_supported only supports 2MB and pgd level hugepages > >>>then 1GB pages are not migratable and as such allocating them from a > >>>movable zone will break the basic expectation of this zone. Standard > >>>hugetlb allocations try to avoid that by using htlb_alloc_mask and I > >>>believe we should do the same for gigantic pages as well. > >>> > >>>I suspect this behavior is not intentional. What do you think about the > >>>following untested patch? > >> > >> > >>I also noticed an unrelated issue with the usage of > >>start_isolate_page_range. On error we set the migrate type to > >>MIGRATE_MOVABLE. > > > >Why that should be a problem? I think it is perfectly OK to have > >MIGRATE_MOVABLE pageblocks inside kernel zones. > > > > we can pick pages with migrate type movable and if we fail to isolate won't > we set the migrate type of that pages to MOVABLE ? I do not see an immediate problem. GFP_KERNEL allocations can fallback to movable migrate pageblocks AFAIR. But I am not very much familiar with migratetypes. Vlastimil, could you have a look please? -- 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>
