[PATCH v5 0/5] Batched page table updates for file-backed large folios

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

On page fault, filemap_map_pages() already retrieves a folio from the page
cache and iterates over it, which realised some savings.  This patch series
drives that further down by allowing filemap to tell the MM to map a
contiguous range of pages in the folio.  This improves performance by
batching the updates to the folio's refcount and the rmap counters.

Testing with a micro benchmark like will-it-scale.pagefault on a
48C/96T IceLake box showed:
   - batched rmap brings around 15% performance gain
   - batched refcount brings around 2% performance gain

v4:
 - Add the set_ptes() architecture interface
 - Change various interfaces to take (folio, struct page *, nr) instead of
   (folio, unsigned long start, nr)
 - Remove do_set_pte() instead of keeping a compat interface
 - Add a check in set_pte_range() to ensure that large anon folios are not
   being passed in yet (David Hildenbrand)
 - Save / restore the old vmf->pte pointer instead of passing a different
   pte pointer to set_pte_range()

Matthew Wilcox (Oracle) (1):
  mm: Add generic set_ptes()

Yin Fengwei (4):
  filemap: Add filemap_map_folio_range()
  rmap: add folio_add_file_rmap_range()
  mm: Convert do_set_pte() to set_pte_range()
  filemap: Batch PTE mappings

 Documentation/filesystems/locking.rst |   2 +-
 include/linux/mm.h                    |   3 +-
 include/linux/pgtable.h               |  27 +++++++
 include/linux/rmap.h                  |   2 +
 mm/filemap.c                          | 111 ++++++++++++++++----------
 mm/memory.c                           |  31 ++++---
 mm/rmap.c                             |  60 ++++++++++----
 7 files changed, 164 insertions(+), 72 deletions(-)

-- 
2.35.1