[PATCH v2 0/2] hugetlb memcg accounting

[Nhat Pham]

Changelog:
v2:
	* Add a cgroup mount option to enable/disable the new hugetlb memcg
	  accounting behavior (patch 1) (suggested by Johannes Weiner).
	* Add a couple more ksft_print_msg() on error to aid debugging when
	  the selftest fails. (patch 2)

Currently, hugetlb memory usage is not acounted for in the memory
controller, which could lead to memory overprotection for cgroups with
hugetlb-backed memory. This has been observed in our production system.

This patch series rectifies this issue by charging the memcg when the
hugetlb folio is allocated, and uncharging when the folio is freed. In
addition, a new selftest is added to demonstrate and verify this new
behavior.

Nhat Pham (2):
  hugetlb: memcg: account hugetlb-backed memory in memory controller
  selftests: add a selftest to verify hugetlb usage in memcg

 Documentation/admin-guide/cgroup-v2.rst       |   9 +
 MAINTAINERS                                   |   2 +
 fs/hugetlbfs/inode.c                          |   2 +-
 include/linux/cgroup-defs.h                   |   5 +
 include/linux/hugetlb.h                       |   6 +-
 include/linux/memcontrol.h                    |   8 +
 kernel/cgroup/cgroup.c                        |  15 +-
 mm/hugetlb.c                                  |  23 +-
 mm/memcontrol.c                               |  41 +++
 tools/testing/selftests/cgroup/.gitignore     |   1 +
 tools/testing/selftests/cgroup/Makefile       |   2 +
 .../selftests/cgroup/test_hugetlb_memcg.c     | 234 ++++++++++++++++++
 12 files changed, 338 insertions(+), 10 deletions(-)
 create mode 100644 tools/testing/selftests/cgroup/test_hugetlb_memcg.c

-- 
2.34.1