Subject: [PATCH v3 00/29] arch, mm: consolidate hugetlb early reservation

From: Mike Rapoport <[email-masked]>
Date: Sun, 11 Jan 2026 10:20:34 +0200

From: "Mike Rapoport (Microsoft)" <[email-masked]>

Hi,

Order in which early memory reservation for hugetlb happens depends on
architecture, on configuration options and on command line parameters.

Some architectures rely on the core MM to call hugetlb_bootmem_alloc()
while others call it very early to allow pre-allocation of HVO-style
vmemmap.

When hugetlb_cma is supported by an architecture it is initialized during
setup_arch() and then later hugetlb_init code needs to understand did it
happen or not.

To make everything consistent and unified, both reservation of hugetlb
memory from bootmem and creation of CMA areas for hugetlb must be called
from core MM initialization and it would have been a simple change.
However, HVO-style pre-initialization ordering requirements slightly
complicate things and for HVO pre-init to work sparse and memory map should
be initialized after hugetlb reservations.

This required pulling out the call to free_area_init() out of setup_arch()
path and moving it MM initialization and this is what the first 23 patches
do.

These changes are deliberately split into per-arch patches that change how
the zone limits are calculated for each architecture and the patches 22 and
23 just remove the calls to free_area_init() and sprase_init() from arch/*.

Patch 24 is a simple cleanup for MIPS.

Patches 25 and 26 actually consolidate hugetlb reservations and patches 27
and 28 perform some aftermath cleanups.

I tried to trim the distribution list and although it's still quite long
if you feel that someone was wrongly excluded please add them back.

The changes also available in git:
https://git.kernel.org/pub/scm/linux/kernel/git/rppt/linux.git/log/?h=hugetlb-init/v3

v3 changes:
* fix empty_zero_page initialization on arm
* fix ZONE_DMA limit calculation on powerpc
* add Acks

v2: https://lore.kernel.org/all/[email-masked]
* move the hugetlb and memory map initializaion to mm_core_init_early()
* add Acks

v1: https://lore.kernel.org/all/[email-masked]

Klara Modin (1):
  arm: make initialization of zero page independent of the memory map

Mike Rapoport (Microsoft) (28):
  alpha: introduce arch_zone_limits_init()
  arc: introduce arch_zone_limits_init()
  arm: introduce arch_zone_limits_init()
  arm64: introduce arch_zone_limits_init()
  csky: introduce arch_zone_limits_init()
  hexagon: introduce arch_zone_limits_init()
  loongarch: introduce arch_zone_limits_init()
  m68k: introduce arch_zone_limits_init()
  microblaze: introduce arch_zone_limits_init()
  mips: introduce arch_zone_limits_init()
  nios2: introduce arch_zone_limits_init()
  openrisc: introduce arch_zone_limits_init()
  parisc: introduce arch_zone_limits_init()
  powerpc: introduce arch_zone_limits_init()
  riscv: introduce arch_zone_limits_init()
  s390: introduce arch_zone_limits_init()
  sh: introduce arch_zone_limits_init()
  sparc: introduce arch_zone_limits_init()
  um: introduce arch_zone_limits_init()
  x86: introduce arch_zone_limits_init()
  xtensa: introduce arch_zone_limits_init()
  arch, mm: consolidate initialization of nodes, zones and memory map
  arch, mm: consolidate initialization of SPARSE memory model
  mips: drop paging_init()
  x86: don't reserve hugetlb memory in setup_arch()
  mm, arch: consolidate hugetlb CMA reservation
  mm/hugetlb: drop hugetlb_cma_check()
  Revert "mm/hugetlb: deal with multiple calls to hugetlb_bootmem_alloc"

 .../driver-api/cxl/linux/early-boot.rst       |  2 +-
 Documentation/mm/memory-model.rst             |  3 --
 .../translations/zh_CN/mm/memory-model.rst    |  2 -
 arch/alpha/kernel/setup.c                     |  1 -
 arch/alpha/mm/init.c                          | 16 ++++----
 arch/arc/mm/init.c                            | 37 +++++++++---------
 arch/arm/include/asm/pgtable.h                |  4 +-
 arch/arm/mm/init.c                            | 25 ++----------
 arch/arm/mm/mmu.c                             | 10 +----
 arch/arm/mm/nommu.c                           | 10 +----
 arch/arm64/include/asm/hugetlb.h              |  2 -
 arch/arm64/mm/hugetlbpage.c                   | 10 ++---
 arch/arm64/mm/init.c                          | 39 ++++++++-----------
 arch/csky/kernel/setup.c                      | 16 ++++----
 arch/hexagon/mm/init.c                        | 19 +++------
 arch/loongarch/include/asm/pgtable.h          |  2 -
 arch/loongarch/kernel/setup.c                 | 10 -----
 arch/loongarch/mm/init.c                      |  6 +--
 arch/m68k/mm/init.c                           |  8 ++--
 arch/m68k/mm/mcfmmu.c                         |  3 --
 arch/m68k/mm/motorola.c                       |  6 +--
 arch/m68k/mm/sun3mmu.c                        |  9 -----
 arch/microblaze/mm/init.c                     | 22 +++++------
 arch/mips/include/asm/pgalloc.h               |  2 -
 arch/mips/include/asm/pgtable.h               |  2 +-
 arch/mips/kernel/setup.c                      | 15 +------
 arch/mips/loongson64/numa.c                   | 10 ++---
 arch/mips/mm/init.c                           |  8 +---
 arch/mips/sgi-ip27/ip27-memory.c              |  8 +---
 arch/nios2/mm/init.c                          | 12 +++---
 arch/openrisc/mm/init.c                       | 10 +----
 arch/parisc/mm/init.c                         | 11 +-----
 arch/powerpc/include/asm/hugetlb.h            |  5 ---
 arch/powerpc/include/asm/setup.h              |  4 ++
 arch/powerpc/kernel/setup-common.c            |  1 -
 arch/powerpc/mm/hugetlbpage.c                 | 11 ++----
 arch/powerpc/mm/mem.c                         | 27 +++++--------
 arch/powerpc/mm/numa.c                        |  2 -
 arch/riscv/mm/hugetlbpage.c                   |  8 ++++
 arch/riscv/mm/init.c                          | 10 +----
 arch/s390/kernel/setup.c                      |  2 -
 arch/s390/mm/hugetlbpage.c                    |  8 ++++
 arch/s390/mm/init.c                           | 13 +++----
 arch/sh/mm/init.c                             | 12 +++---
 arch/sparc/mm/init_64.c                       | 17 +++-----
 arch/sparc/mm/srmmu.c                         | 17 ++++----
 arch/um/kernel/mem.c                          | 10 ++---
 arch/x86/kernel/setup.c                       |  5 ---
 arch/x86/mm/hugetlbpage.c                     |  8 ++++
 arch/x86/mm/init.c                            |  8 +---
 arch/x86/mm/init_32.c                         |  2 -
 arch/x86/mm/init_64.c                         |  4 --
 arch/x86/mm/mm_internal.h                     |  1 -
 arch/xtensa/mm/init.c                         | 14 +++----
 include/linux/hugetlb.h                       | 12 ++----
 include/linux/mm.h                            |  5 ++-
 include/linux/mmzone.h                        |  2 -
 init/main.c                                   |  1 +
 mm/hugetlb.c                                  | 13 -------
 mm/hugetlb_cma.c                              | 33 ++++++++--------
 mm/hugetlb_cma.h                              |  5 ---
 mm/hugetlb_vmemmap.c                          | 11 ------
 mm/internal.h                                 |  6 +++
 mm/mm_init.c                                  | 20 ++++++----
 64 files changed, 223 insertions(+), 414 deletions(-)

base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
-- 
2.51.0