[v5,0/4] memcg: introduce per-memcg proactive reclaim

Message

Yosry Ahmed April 25, 2022, 7 p.m. UTC

This patch series adds a memory.reclaim proactive reclaim interface.
The rationale behind the interface and how it works are in the first
patch.

---

Changes in V5:
- Fixed comment formating and added Co-developed-by in patch 1.
- Modified selftest to work if swap is enabled or not, and retry
  multiple times to wait for background allocation before failing
  with a clear message.

Changes in V4:
mm/memcontrol.c:
- Return -EINTR on signal_pending().
- On the final retry, drain percpu lru caches hoping that it might
  introduce some evictable pages for reclaim.
- Simplified the retry loop as suggested by Dan Schatzberg.

selftests:
- Always return -errno on failure from cg_write() (whether open() or
  write() fail), also update cg_read() and read_text() to return -errno
  as well for consistency. Also make sure to correctly check that the
  whole buffer was written in cg_write().
- Added a maximum number of retries for the reclaim selftest.

Changes in V3:
- Fix cg_write() (in patch 2) to properly return -1 if open() fails
  and not fail if len == errno.
- Remove debug printf() in patch 3.

Changes in V2:
- Add the interface to root as well.
- Added a selftest.
- Documented the interface as a nested-keyed interface, which makes
  adding optional arguments in the future easier (see doc updates in the
  first patch).
- Modified the commit message to reflect changes and added a timeout
  argument as a suggested possible extension
- Return -EAGAIN if the kernel fails to reclaim the full requested
  amount.

---

Shakeel Butt (1):
  memcg: introduce per-memcg reclaim interface

Yosry Ahmed (3):
  selftests: cgroup: return -errno from cg_read()/cg_write() on failure
  selftests: cgroup: fix alloc_anon_noexit() instantly freeing memory
  selftests: cgroup: add a selftest for memory.reclaim

 Documentation/admin-guide/cgroup-v2.rst       |  21 ++++
 mm/memcontrol.c                               |  45 +++++++
 tools/testing/selftests/cgroup/cgroup_util.c  |  44 +++----
 .../selftests/cgroup/test_memcontrol.c        | 114 +++++++++++++++++-
 4 files changed, 197 insertions(+), 27 deletions(-)