Subject: [PATCH v3 0/6] support batched checking of the young flag for MGLRU

From: Baolin Wang <[email-masked]>
Date: Fri, 6 Mar 2026 14:43:36 +0800

This is a follow-up to the previous work [1], to support batched checking
of the young flag for MGLRU.

Similarly, batched checking of young flag for large folios can improve
performance during large-folio reclamation when MGLRU is enabled. I
observed noticeable performance improvements (see patch 5) on an Arm64
machine that supports contiguous PTEs. All mm-selftests are passed.

Patch 1 - 3: cleanup patches.
Patch 4: add a new generic batched PTE helper: test_and_clear_young_ptes().
Patch 5: support batched young flag checking for MGLRU.
Patch 6: implement the Arm64 arch-specific test_and_clear_young_ptes().

[1] https://lore.kernel.org/all/[email-masked]/

Changes from v2:
v2: https://lore.kernel.org/all/[email-masked]/
 - Update the commit message of patch 5 (per David).
 - Fix some coding style issues (per David).
 - Remove 'cur_pte' variable in lru_gen_look_around() (per David).
 - Move 'ptes += nr;' to the suitable place in folio_referenced_one() (per David).
 - Add acked tag from David. Thanks.

Changes from v1:
v1: https://lore.kernel.org/all/[email-masked]/
 - Update some commit message (per David).
 - Fix some coding style issues (per David).
 - Use VM_WARN_ON_ONCE_FOLIO() instead of VM_WARN_ON_FOLIO() (per Rik).
 - Define a generic ptep_test_and_clear_young_notify() (per David).
 - Remove redundant 'nr > 1' check in folio_referenced_one() (per David).
 - Rename some variables' to make code more clear (per David).
 - Add a new patch to rename some functions (per David).
 - Update the young counters with the batched count for MGLRU.
 - Collect reviewed tags from Rik, Barry, Alistair and David. Thanks.

Baolin Wang (6):
  mm: use inline helper functions instead of ugly macros
  mm: rename ptep/pmdp_clear_young_notify() to
    ptep/pmdp_test_and_clear_young_notify()
  mm: rmap: add a ZONE_DEVICE folio warning in folio_referenced()
  mm: add a batched helper to clear the young flag for large folios
  mm: support batched checking of the young flag for MGLRU
  arm64: mm: implement the architecture-specific
    test_and_clear_young_ptes()

 arch/arm64/include/asm/pgtable.h | 18 +++++++----
 include/linux/mmu_notifier.h     | 54 --------------------------------
 include/linux/mmzone.h           |  5 +--
 include/linux/pgtable.h          | 37 ++++++++++++++++++++++
 mm/internal.h                    | 52 ++++++++++++++++++++++++++++++
 mm/rmap.c                        | 29 ++++++++---------
 mm/vmscan.c                      | 45 +++++++++++++++++++-------
 7 files changed, 152 insertions(+), 88 deletions(-)

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2.47.3