[PATCH 0/3] mm: thp: mapcount updates

[Andrea Arcangeli]

Hello,

1/3 is a bugfix and it fixes userland (not kernel) data corruption
with vfio (and in general device driver) page pinning done with
get_user_pages. More testing of it under any load is welcome (also not
necessarily a page pinning load using vfio).

Along with the above I'm sending also 2/3 and 3/3 but those are not
meant to be merged upstream quickly and they're very low priority and
furthermore 2/3 is not zero risk and it didn't get enough testing
yet. Queuing 2/3 in -mm to give it more exposure should be ok
though. 2/3 is only suitable for merging at the very opening of merge
window anyway.

Andrea Arcangeli (3):
  mm: thp: calculate the mapcount correctly for THP pages during WP
    faults
  mm: thp: microoptimize compound_mapcount()
  mm: thp: split_huge_pmd_address() comment improvement

 include/linux/mm.h   | 12 +++++++--
 include/linux/swap.h |  8 +++---
 mm/huge_memory.c     | 73 ++++++++++++++++++++++++++++++++++++++++++++--------
 mm/memory.c          | 22 ++++++++++------
 mm/swapfile.c        | 13 +++++-----
 5 files changed, 98 insertions(+), 30 deletions(-)