[PATCH v2 0/8] Return head pages from find_*_entry

[Matthew Wilcox (Oracle)]

This patch series started out as part of the THP patch set, but it has
some nice effects along the way and it seems worth splitting it out and
submitting separately.

Currently find_get_entry() and find_lock_entry() return the page
corresponding to the requested index, but the first thing most callers do
is find the head page, which we just threw away.  As part of auditing
all the callers, I found some misuses of the APIs and some plain
inefficiencies that I've fixed.

The diffstat is unflattering, but I added more kernel-doc and a new wrapper.

v2:
 - Rework how shmem_getpage_gfp() handles getting a head page back from
   find_lock_entry()
 - Renamed find_get_swap_page() to find_get_incore_page()
 - Make sure find_get_incore_page() doesn't return a head page
 - Fix the missing include of linux/shmem_fs.h
 - Move find_get_entry and find_lock_entry prototypes to mm/internal.h
 - Rename thp_valid_index() to thp_contains()
 - Fix thp_contains() for hugetlbfs and swapcache
 - Add find_lock_head() wrapper around pagecache_get_page()

Matthew Wilcox (Oracle) (8):
  mm: Factor find_get_incore_page out of mincore_page
  mm: Use find_get_incore_page in memcontrol
  mm: Optimise madvise WILLNEED
  proc: Optimise smaps for shmem entries
  i915: Use find_lock_page instead of find_lock_entry
  mm: Convert find_get_entry to return the head page
  mm/shmem: Return head page from find_lock_entry
  mm: Add find_lock_head

 drivers/gpu/drm/i915/gem/i915_gem_shmem.c |  4 +--
 fs/proc/task_mmu.c                        |  8 +----
 include/linux/pagemap.h                   | 43 +++++++++++++++++-----
 include/linux/swap.h                      |  7 ++++
 mm/filemap.c                              | 44 +++++++++++------------
 mm/internal.h                             |  3 ++
 mm/madvise.c                              | 21 ++++++-----
 mm/memcontrol.c                           | 24 ++-----------
 mm/mincore.c                              | 28 ++-------------
 mm/shmem.c                                | 20 +++++------
 mm/swap_state.c                           | 32 +++++++++++++++++
 11 files changed, 127 insertions(+), 107 deletions(-)

-- 
2.28.0