[PATCH v2 0/2] mm: zswap: add per-memcg stat for incompressible pages

[Jiayuan Chen <jiayuan.chen@linux.dev>]

In containerized environments, knowing which cgroup is contributing
incompressible pages to zswap is essential for effective resource
management. This series adds a new per-memcg stat 'zswap_incomp' to
track incompressible pages, along with a selftest.

Patch 1: Add the per-memcg zswap_incomp stat and documentation
Patch 2: Add selftest for the new stat

Changes v1 -> v2:
https://lore.kernel.org/linux-mm/20260205053013.25134-1-jiayuan.chen@linux.dev/

- Rename zswpraw/MEMCG_ZSWAP_RAW to zswap_incomp/MEMCG_ZSWAP_INCOMP
  (Shakeel Butt, Yosry Ahmed)
- Drop zswap_is_incomp() helper, keep opencode (size == PAGE_SIZE) with
  comments explaining the incompressibility check (Yosry Ahmed)
- Add documentation in cgroup-v2.rst (Nhat Pham, SeongJae Park)
- Add selftest as a separate patch (Nhat Pham)
- Add reference link to Chris Li's discussion on the need for per-memcg
  incompressible page tracking (Nhat Pham)

Jiayuan Chen (2):
  mm: zswap: add per-memcg stat for incompressible pages
  selftests/cgroup: add test for zswap incompressible pages

 Documentation/admin-guide/cgroup-v2.rst     |  5 ++
 include/linux/memcontrol.h                  |  1 +
 mm/memcontrol.c                             |  8 ++
 tools/testing/selftests/cgroup/test_zswap.c | 96 +++++++++++++++++++++
 4 files changed, 110 insertions(+)

-- 
2.43.0