[PATCH v8 0/4] add hugetlb_optimize_vmemmap sysctl

From: Muchun Song
Date: Wed Apr 13 2022 - 10:48:37 EST


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.

v8:
- Fix compilation (scripts/selinux/mdp/mdp.c) error when
CONFIG_SECURITY_SELINUX is selected.

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