On 13.01.22 16:46, Zi Yan wrote: > On 12 Jan 2022, at 6:04, David Hildenbrand wrote: > >> On 05.01.22 22:47, Zi Yan wrote: >>> From: Zi Yan <z...@nvidia.com> >>> >>> alloc_migration_target() is used by alloc_contig_range() and non-LRU >>> movable compound pages can be migrated. Current code does not allocate the >>> right page size for such pages. Check THP precisely using >>> is_transparent_huge() and add allocation support for non-LRU compound >>> pages. >> >> IIRC, we don't have any non-lru migratable pages that are coumpound >> pages. Read: not used and not supported :) > > OK, but nothing prevents one writing a driver that allocates compound > pages and provides address_space->migratepage() and > address_space->isolate_page(). > > Actually, to test this series, I write a kernel module that allocates > an order-10 page, gives it a fake address_space with migratepage() and > isolate_page(), __SetPageMovable() on it, then call alloc_contig_range() > on the page range. Apparently, my kernel module is not supported by > the kernel, thus, I added this patch. > > Do you have an alternative test to my kernel module, so that I do not > even need this patch myself? > >> Why is this required in the context of this series? > > It might not be required. I will drop it.
That's why I think it would be best dropping it. If you need it in different context, better submit it in different context. Makes this series easier to digest :) -- Thanks, David / dhildenb
