linux.git/mm/sparse.c, branch v7.3-rc1

mm/sparse: keep mem_section_usage_size() internal

2026-08-25T01:43:06+00:00

mem_section_usage_size() is only needed by sparsemem implementation code
after commit ae751d567baa ("mm/bootmem_info: stop marking
mem_section_usage as MIX_SECTION_INFO"), so keeping the declaration in
mmzone.h now exposes the helper to all mmzone.h users for no reason.

Move the helper to sparse.h so sparse.c and sparse-vmemmap.c can share it
through the internal header.  While doing so, calculate the allocation
size with struct_size_t(), which ties the expression to the
pageblock_flags trailing array instead of open-coding the struct header
plus bitmap size.

Link: https://lore.kernel.org/20260805022536.1206575-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Acked-by: Mike Rapoport (Microsoft) 
Acked-by: David Hildenbrand (Arm) 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm/sparse: correct init section annotations

2026-08-25T01:42:58+00:00

The !SPARSEMEM_EXTREME stub of sparse_index_init() has no annotation but
the SPARSEMEM_EXTREME variant is __meminit.  So mark the stub __meminit
too.

mminit_validate_memmodel_limits() is only called by memory_present(),
which is __init.  So mark it __init.

sparse_usagebuf and sparse_usagebuf_end are only used by
sparse_init_early_section(), sparse_usage_init() and sparse_usage_fini(),
which are all __init.  So mark them __initdata.

Link: https://lore.kernel.org/20260731164758.1210668-1-ekffu200098@gmail.com
Signed-off-by: Sang-Heon Jeon 
Reviewed-by: Andrew Morton 
Acked-by: David Hildenbrand (Arm) 
Acked-by: Mike Rapoport (Microsoft) 
Reviewed-by: Anshuman Khandual 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm: split out sparse declarations from internal.h

2026-08-05T02:18:46+00:00

mm/internal.h becomes more and more bloated.

Move declarations related to SPARSE and SPARSE_VMEMMAP memory models to
a new mm/sparse.h header.

No functional changes.

Link: https://lore.kernel.org/20260709-internal-h-v2-2-695631425968@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) 
Acked-by: Muchun Song 
Acked-by: Vlastimil Babka (SUSE) 
Acked-by: David Hildenbrand (Arm) 
Acked-by: Lorenzo Stoakes 
Acked-by: Pratyush Yadav 
Acked-by: SJ Park 
Cc: Alexander Graf 
Cc: Alexander Potapenko 
Cc: Brendan Jackman 
Cc: Brendan Jackman 
Cc: Dennis Zhou 
Cc: Dmitry Vyukov 
Cc: Johannes Weiner 
Cc: Liam R. Howlett 
Cc: Marco Elver 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Pasha Tatashin 
Cc: Suren Baghdasaryan 
Cc: Tejun Heo 
Cc: "Uladzislau Rezki (Sony)" 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

mm: split out mm_init and memblock declarations from internal.h

2026-08-05T02:18:45+00:00

Patch series "mm: split a couple of headers from internal.h", v2.

mm/internal.h becomes more and more bloated.

Split declarations related to mm_init, memblock, vmalloc and sparse into
new headers.


This patch (of 3):

mm/internal.h becomes more and more bloated.

Move declarations for related to mm/mm_init.c and mm/memblock.c to a new
mm/mm_init.h header.

No functional changes.

[rppt@kernel.org: split stubfs from internal.h to mm_init.h]
  Link: https://lore.kernel.org/alJd1BLypyK9Mpaw@kernel.org
Link: https://lore.kernel.org/20260709-internal-h-v2-0-695631425968@kernel.org
Link: https://lore.kernel.org/20260709-internal-h-v2-1-695631425968@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) 
Acked-by: Muchun Song 
Acked-by: Vlastimil Babka (SUSE) 
Acked-by: David Hildenbrand (Arm) 
Acked-by: Lorenzo Stoakes 
Acked-by: Pratyush Yadav 
Acked-by: SJ Park 
Cc: Alexander Graf 
Cc: Alexander Potapenko 
Cc: Brendan Jackman 
Cc: Brendan Jackman 
Cc: Dennis Zhou 
Cc: Dmitry Vyukov 
Cc: Johannes Weiner 
Cc: Liam R. Howlett 
Cc: Marco Elver 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Pasha Tatashin 
Cc: Suren Baghdasaryan 
Cc: Tejun Heo 
Cc: "Uladzislau Rezki (Sony)" 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

mm/sparse: remove bootmem_info.h include

2026-08-05T02:18:42+00:00

No longer required, so let's remove it.

Link: https://lore.kernel.org/20260716-bootmem_info_part2-v2-9-4afc76c73d61@kernel.org
Signed-off-by: David Hildenbrand (Arm) 
Reviewed-by: Mike Rapoport (Microsoft) 
Reviewed-by: Muchun Song 
Reviewed-by: Dave Hansen 
Cc: Alexander Gordeev 
Cc: Andy Lutomirski 
Cc: "Borislav Petkov (AMD)" 
Cc: Brendan Jackman 
Cc: Brendan Jackman 
Cc: Christian Borntraeger 
Cc: Gerald Schaefer 
Cc: Heiko Carstens 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Johannes Weiner 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Oscar Salvador 
Cc: Peter Zijlstra 
Cc: Suren Baghdasaryan 
Cc: Sven Schnelle 
Cc: Vasily Gorbik 
Cc: Vlastimil Babka 
Cc: Zi Yan 
Signed-off-by: Andrew Morton

mm: fix ASSERT_EXCLUSIVE_BITS by passing memdesc_flags_t by pointer

2026-07-31T02:40:31+00:00

KCSAN reports a data race between page_to_nid()/folio_pgdat() reading
page->flags and folio_trylock()/folio_lock() concurrently doing
test_and_set_bit_lock(PG_locked, ...) on the same word, e.g.:

  BUG: KCSAN: data-race in __lruvec_stat_mod_folio / shmem_get_folio_gfp

The race is benign: nid/zone bits are set once at page init and never
overlap with PG_locked.  However, ASSERT_EXCLUSIVE_BITS() inside
memdesc_nid/zonenum() was checking a by-value copy of the flags word, not
the live page->flags, so it failed to annotate the real access.

Change memdesc_nid(), memdesc_zonenum(), memdesc_section(), and
memdesc_is_zone_device() to take a const memdesc_flags_t * and update all
callers to pass &page->flags / &folio->flags, so ASSERT_EXCLUSIVE_BITS()
operates on the actual shared word.

Guard the ASSERT_EXCLUSIVE_BITS() call in memdesc_zonenum() under
ZONES_WIDTH != 0 to avoid a zero-mask check on configs where the zone
field is absent.  memdesc_section() needs no such guard, since
SECTIONS_WIDTH is never 0 wherever SECTION_IN_PAGE_FLAGS is defined. 
Under CONFIG_NUMA=n, memdesc_nid() itself is stubbed to "return 0" instead
of reading page->flags, since NODES_MASK is 0 and the check can never
fire; page_to_nid()/folio_nid() now just call memdesc_nid()
unconditionally and rely on that stub, instead of duplicating the
CONFIG_NUMA split at each call site.

[zhuhui@kylinos.cn: v11]
  Link: https://lore.kernel.org/20260708083308.747930-1-hui.zhu@linux.dev
[ziy@nvidia.com: build fix]
  Link: https://lore.kernel.org/DJSGLP9VFLRI.355AAWR2VHIEL@nvidia.com
Link: https://lore.kernel.org/20260630070810.470763-1-hui.zhu@linux.dev
Signed-off-by: Hui Zhu 
Co-developed-by: David Hildenbrand (Arm) 
Signed-off-by: David Hildenbrand (Arm) 
Acked-by: David Hildenbrand (Arm) 
Cc: Axel Rasmussen 
Cc: Barry Song 
Cc: Kairui Song 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Shakeel Butt 
Cc: Suren Baghdasaryan 
Cc: Vlastimil Babka 
Cc: Wei Xu 
Cc: Yuanchu Xie 
Signed-off-by: Andrew Morton

mm/sparse-vmemmap: remove sparse_vmemmap_init_nid_late()

2026-07-29T04:12:00+00:00

hugetlb_vmemmap_init_late() no longer has any users, so the remaining
late-init path in sparse_vmemmap_init_nid_late() is dead code.

Remove sparse_vmemmap_init_nid_late() and its declarations.

Link: https://lore.kernel.org/20260612035903.2468601-18-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Acked-by: Mike Rapoport (Microsoft) 
Cc: "Aneesh Kumar K.V" 
Cc: David Hildenbrand 
Cc: Frank van der Linden 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Oscar Salvador 
Cc: Oscar Salvador (SUSE) 
Cc: "Ritesh Harjani (IBM)" 
Cc: Usama Arif 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm/sparse: move sparse_vmemmap_init_nid_late() into sparse_init_nid()

2026-07-29T04:11:58+00:00

sparse_vmemmap_init_nid_late() is still called separately from
mm_core_init_early(), away from the rest of the sparse initialization
path.

Now that sparse_init() runs after zone initialization, call
sparse_vmemmap_init_nid_late() from sparse_init_nid() instead.  This keeps
both sparse_vmemmap_init_nid_early() and sparse_vmemmap_init_nid_late() in
the sparse setup path.

Link: https://lore.kernel.org/20260612035903.2468601-12-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Reviewed-by: Mike Rapoport (Microsoft) 
Reviewed-by: Oscar Salvador (SUSE) 
Cc: "Aneesh Kumar K.V" 
Cc: David Hildenbrand 
Cc: Frank van der Linden 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Oscar Salvador 
Cc: "Ritesh Harjani (IBM)" 
Cc: Usama Arif 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm/mm_init: remove set_pageblock_order() call from sparse_init()

2026-07-29T04:11:58+00:00

free_area_init() already sets pageblock_order before sparse_init() runs
for CONFIG_HUGETLB_PAGE_SIZE_VARIABLE, so sparse_init() does not need to
call set_pageblock_order() again.

With that call removed, set_pageblock_order() is only used in
mm/mm_init.c.  Make it static.

Link: https://lore.kernel.org/20260612035903.2468601-11-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Reviewed-by: Mike Rapoport (Microsoft) 
Reviewed-by: Oscar Salvador (SUSE) 
Cc: "Aneesh Kumar K.V" 
Cc: David Hildenbrand 
Cc: Frank van der Linden 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Oscar Salvador (SUSE) 
Cc: "Ritesh Harjani (IBM)" 
Cc: Usama Arif 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton

mm/sparse: move subsection_map_init() into sparse_init()

2026-07-29T04:11:57+00:00

subsection_map_init() is part of sparse memory initialization, but it is
currently called from free_area_init().

Move it into sparse_init() so the sparse-specific setup stays together
instead of being split across the generic free_area_init() path.

Link: https://lore.kernel.org/20260612035903.2468601-8-songmuchun@bytedance.com
Signed-off-by: Muchun Song 
Acked-by: Mike Rapoport (Microsoft) 
Acked-by: Oscar Salvador 
Cc: "Aneesh Kumar K.V" 
Cc: David Hildenbrand 
Cc: Frank van der Linden 
Cc: Liam R. Howlett 
Cc: Lorenzo Stoakes 
Cc: Madhavan Srinivasan 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Oscar Salvador (SUSE) 
Cc: "Ritesh Harjani (IBM)" 
Cc: Usama Arif 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton