[PATCH v3 00/19] mm: Refactor bootmem gigantic hugepage allocation

[Muchun Song]

This series is split out from the earlier larger series "mm: Generalize
HVO for HugeTLB and device DAX" [1]. It collects the first 19 patches of
that series as a standalone set of fixes and preparatory cleanups around
bootmem HugeTLB handling, sparse initialization ordering, and related
vmemmap setup.

The first patches fix a few bugs found while reviewing the existing
code, including incorrect bootmem HVO handling, wrong vmemmap
registration arguments, a powerpc compound-vmemmap tracking bug, and
too-late initialization of gigantic bootmem HugeTLB struct pages.

The rest of the series reorders early memory initialization so the
relevant zone state is available before sparse and HugeTLB boot-time
setup runs, then simplifies the remaining bootmem gigantic hugepage
allocation path and removes code made obsolete by that rework.

At a high level:
  - patches [1-4] fix boot-time and arch-specific bugs
  - patches [5-12] reorder and simplify sparse/mm/hugetlb early init
  - patches [13-19] refactor bootmem gigantic hugepage allocation and
    remove obsolete helpers and state

Changes since v2:
  - patch 1: add a comment explaining why shared tail pages must be
    initialized from gather_bootmem_prealloc() before
    hugetlb_vmemmap_init() runs
  - patch 1: update the stale sparse-vmemmap comment to point to
    gather_bootmem_prealloc() as the shared-tail initialization site
  - patch 2: collect Acked-by from Oscar Salvador
  - patch 19: fold __init_page_from_nid() into __init_deferred_page()
    instead of only making it static

[1] https://lore.kernel.org/linux-mm/20260513130542.35604-1-songmuchun@xxxxxxxxxxxxx/

Muchun Song (19):
  mm/hugetlb: Fix boot panic with CONFIG_DEBUG_VM and HVO bootmem pages
  mm/hugetlb_vmemmap: Fix __hugetlb_vmemmap_optimize_folios()
  powerpc/mm: Fix wrong addr_pfn tracking in compound vmemmap population
  mm/hugetlb: Initialize gigantic bootmem hugepage struct pages earlier
  mm/mm_init: Simplify deferred_free_pages() migratetype init
  mm/sparse: Panic on memmap and usemap allocation failure
  mm/sparse: Move subsection_map_init() into sparse_init()
  mm/mm_init: Defer sparse_init() until after zone initialization
  mm/mm_init: Defer hugetlb reservation until after zone initialization
  mm/mm_init: Remove set_pageblock_order() call from sparse_init()
  mm/sparse: Move sparse_vmemmap_init_nid_late() into sparse_init_nid()
  mm/hugetlb_cma: Validate hugetlb CMA range by zone at reserve time
  mm/hugetlb: Refactor early boot gigantic hugepage allocation
  mm/hugetlb: Free cross-zone bootmem gigantic pages after allocation
  mm/hugetlb_vmemmap: Move bootmem HVO setup to early init
  mm/hugetlb: Remove obsolete bootmem cross-zone checks
  mm/sparse-vmemmap: Remove sparse_vmemmap_init_nid_late()
  mm/hugetlb: Remove unused bootmem cma field
  mm/mm_init: Fold __init_page_from_nid() into __init_deferred_page()

 arch/powerpc/mm/book3s64/radix_pgtable.c |   7 +-
 arch/powerpc/mm/hugetlbpage.c            |  13 +-
 include/linux/hugetlb.h                  |  24 +--
 include/linux/mmzone.h                   |   7 -
 mm/cma.c                                 |   3 +-
 mm/hugetlb.c                             | 259 +++++++++++------------
 mm/hugetlb_cma.c                         |  44 ++--
 mm/hugetlb_cma.h                         |   8 +-
 mm/hugetlb_vmemmap.c                     |  94 ++------
 mm/hugetlb_vmemmap.h                     |   5 -
 mm/internal.h                            |  14 +-
 mm/mm_init.c                             |  88 +++-----
 mm/sparse-vmemmap.c                      |  26 ++-
 mm/sparse.c                              |  48 +----
 14 files changed, 241 insertions(+), 399 deletions(-)


base-commit: 08484c504b55a98bd100527fbe10a3caf55ff3ff
-- 
2.54.0