[PATCH v3 0/5] create hugetlb flags to consolidate state

[Mike Kravetz <mike.kravetz@oracle.com>]

While discussing a series of hugetlb fixes in [1], it became evident
that the hugetlb specific page state information is stored in a somewhat
haphazard manner.  Code dealing with state information would be easier
to read, understand and maintain if this information was stored in a
consistent manner.

This series uses page.private of the hugetlb head page for storing a
set of hugetlb specific page flags.  Routines are priovided for test,
set and clear of the flags.

[1] https://lore.kernel.org/r/20210106084739.63318-1-songmuchun@bytedance.com

v2 -> v3
  Fixed !CONFIG_HUGETLB_PAGE build bug and moved BUILD_BUG_ON to
  hugetlb_init (Oscar)
  Enhanced patch 3 (HPageTemporary flag) commit message (Oscar)
  Fixed typo enhanced coment in scan_movable_pages (Miaohe)
Patch -> v2
  Went back to functions similar to 'normal' page flags (Matthew/Muchun)
  Decided to leave check in unmap_and_move_huge_page and print warning
RFC -> PATCH
  Simplified to use a single set of flag manipulation routines (Oscar)
  Moved flags and routines to hugetlb.h (Muchun)
  Changed format of page flag names (Muchun)
  Changed subpool routine names (Matthew)
  More comments in code (Oscar)

Based on v5.11-rc4-mmotm-2021-01-21-20-07

Mike Kravetz (5):
  hugetlb: use page.private for hugetlb specific page flags
  hugetlb: convert page_huge_active() HPageMigratable flag
  hugetlb: only set HPageMigratable for migratable hstates
  hugetlb: convert PageHugeTemporary() to HPageTemporary flag
  hugetlb: convert PageHugeFreed to HPageFreed flag

 fs/hugetlbfs/inode.c       |  14 +---
 include/linux/hugetlb.h    |  91 ++++++++++++++++++++++
 include/linux/page-flags.h |   6 --
 mm/hugetlb.c               | 152 ++++++++++++-------------------------
 mm/memory_hotplug.c        |   9 ++-
 mm/migrate.c               |   9 +--
 6 files changed, 154 insertions(+), 127 deletions(-)

-- 
2.29.2