[PATCH v7 0/4] add hugetlb_optimize_vmemmap sysctl

[Muchun Song]

This series is based on next-20220407.

This series amis to add hugetlb_optimize_vmemmap sysctl to enable or disable
the feature of optimizing vmemmap pages associated with HugeTLB pages.

v7:
  - Fix circular dependency issue reported by kernel test robot.
  - Introduce CONFIG_HUGETLB_PAGE_HAS_OPTIMIZE_VMEMMAP instead of
    STRUCT_PAGE_SIZE_IS_POWER_OF_2.
  - Add more comments into vm.rst to explain hugetlb_optimize_vmemmap (Andrew).
  - Drop the patch "sysctl: allow to set extra1 to SYSCTL_ONE".
  - Add a new patch "use kstrtobool for hugetlb_vmemmap param parsing".
  - Reuse static_key's refcount to count the number of HugeTLB pages with
    vmemmap pages optimized to simplify the lock scheme.

v6:
  - Remove "make syncconfig" from Kbuild.

v5:
  - Fix not working properly if one is workig off of a very clean build
    reported by Luis Chamberlain.
  - Add Suggested-by for Luis Chamberlain.

v4:
  - Introduce STRUCT_PAGE_SIZE_IS_POWER_OF_2 inspired by Luis.

v3:
  - Add pr_warn_once() (Mike).
  - Handle the transition from enabling to disabling (Luis)

v2:
  - Fix compilation when !CONFIG_MHP_MEMMAP_ON_MEMORY reported by kernel
    test robot <lkp@xxxxxxxxx>.
  - Move sysctl code from kernel/sysctl.c to mm/hugetlb_vmemmap.c.

Muchun Song (4):
  mm: hugetlb_vmemmap: introduce
    CONFIG_HUGETLB_PAGE_HAS_OPTIMIZE_VMEMMAP
  mm: memory_hotplug: override memmap_on_memory when
    hugetlb_free_vmemmap=on
  mm: hugetlb_vmemmap: use kstrtobool for hugetlb_vmemmap param parsing
  mm: hugetlb_vmemmap: add hugetlb_optimize_vmemmap sysctl

 Documentation/admin-guide/kernel-parameters.txt |   6 +-
 Documentation/admin-guide/sysctl/vm.rst         |  27 +++++++
 Kbuild                                          |  19 +++++
 arch/x86/mm/init_64.c                           |   2 +-
 include/linux/hugetlb.h                         |   2 +-
 include/linux/kconfig.h                         |   4 +
 include/linux/memory_hotplug.h                  |   9 +++
 include/linux/mm.h                              |   2 +-
 include/linux/page-flags.h                      |   2 +-
 kernel/autoconf_ext.c                           |  26 ++++++
 mm/hugetlb_vmemmap.c                            | 102 ++++++++++++++++++++----
 mm/hugetlb_vmemmap.h                            |   8 +-
 mm/memory_hotplug.c                             |  27 +++++--
 mm/sparse-vmemmap.c                             |   4 +-
 scripts/mod/Makefile                            |   2 +
 15 files changed, 207 insertions(+), 35 deletions(-)
 create mode 100644 kernel/autoconf_ext.c

-- 
2.11.0