Hi all,
This patch series introduces improvements to the cgroup selftests by adding
helper functions to better handle
asynchronous updates in cgroup statistics. These changes are especially useful
for managing cgroup stats like
memory.stat and cgroup.stat, which can be affected by delays (e.g., RCPU
callbacks and asynchronous rstat flushing).
v4:
- Patch 1/3: Adds the `cg_read_key_long_poll()` helper to poll cgroup keys
with retries and configurable intervals.
- Patch 2/3: Updates `test_memcg_sock()` to use `cg_read_key_long_poll()` for
handling delayed "sock" counter updates in memory.stat.
- Patch 3/3: Replaces `sleep` and retry logic in `test_kmem_dead_cgroups()`
with `cg_read_key_long_poll()` for waiting on `nr_dying_descendants`.
v3:
- Move `MEMCG_SOCKSTAT_WAIT_*` defines after the `#include` block as suggested.
v2:
- Clarify the rationale for the 3s timeout and mention the periodic rstat
flush interval (FLUSH_TIME = 2*HZ) in the comment.
- Replace hardcoded retry count and wait interval with macros to avoid magic
numbers and make the timeout calculation explicit.
Thanks to Michal Koutný for the suggestion to introduce the polling helper, and
to Lance Yang for the review.
Guopeng Zhang (3):
selftests: cgroup: Add cg_read_key_long_poll() to poll a cgroup key
with retries
selftests: cgroup: make test_memcg_sock robust against delayed sock
stats
selftests: cgroup: Replace sleep with cg_read_key_long_poll() for
waiting on nr_dying_descendants
.../selftests/cgroup/lib/cgroup_util.c | 21 +++++++++++++
.../cgroup/lib/include/cgroup_util.h | 5 +++
tools/testing/selftests/cgroup/test_kmem.c | 31 ++++++++-----------
.../selftests/cgroup/test_memcontrol.c | 20 +++++++++++-
4 files changed, 58 insertions(+), 19 deletions(-)
--
2.25.1
