This series is based on next-20220310. This series amis to add hugetlb_free_vmemmap sysctl to enable the feature of freeing vmemmap pages of HugeTLB pages. 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. Thanks. 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 STRUCT_PAGE_SIZE_IS_POWER_OF_2 mm: memory_hotplug: override memmap_on_memory when hugetlb_free_vmemmap=on sysctl: allow to set extra1 to SYSCTL_ONE mm: hugetlb_vmemmap: add hugetlb_free_vmemmap sysctl Documentation/admin-guide/sysctl/vm.rst | 14 ++++ Kbuild | 15 ++++- include/linux/memory_hotplug.h | 9 +++ include/linux/mm_types.h | 2 + include/linux/page-flags.h | 3 +- kernel/sysctl.c | 2 +- mm/hugetlb_vmemmap.c | 109 ++++++++++++++++++++++++-------- mm/hugetlb_vmemmap.h | 8 ++- mm/memory_hotplug.c | 27 ++++++-- mm/struct_page_size.c | 20 ++++++ 10 files changed, 171 insertions(+), 38 deletions(-) create mode 100644 mm/struct_page_size.c -- 2.11.0