[v2,0/2] fix THP migration for CMA allocations

Message

Rik van Riel Feb. 27, 2020, 9:32 p.m. UTC

Transparent huge pages are allocated with __GFP_MOVABLE, and can end
up in CMA memory blocks. Transparent huge pages also have most of the
infrastructure in place to allow migration.

However, a few pieces were missing, causing THP migration to fail when
attempting to use CMA to allocate 1GB hugepages.

With these patches in place, THP migration from CMA blocks seems to
work, both for anonymous THPs and for tmpfs/shmem THPs.

v2:
- addressed comments by Vlastimil Babka and Zi Yan

Rik van Riel (2):
  mm,compaction,cma: add alloc_contig flag to compact_control
  mm,thp,compaction,cma: allow THP migration for CMA allocations

 mm/compaction.c | 16 +++++++++-------
 mm/internal.h   |  1 +
 mm/page_alloc.c |  7 +++++--
 3 files changed, 15 insertions(+), 9 deletions(-)