Cgroup V2

2 articles

Linux 19 Sep 2026 4 min read

CLONE_INTO_CGROUP Places a Child in Its Target cgroup at Creation

CLONE_INTO_CGROUP Places a Child in Its Target cgroup at Creation A process created in one cgroup and moved to another has a short but real interval in the original cgroup. During that interval, accounting, resource controls, and freezer state come from the initial placement rather than the destination. Linux provides CLONE_INTO_CGROUP so clone3() can place the child in a cgroup v2 target as part of process creation. This changes the placement boundary. Instead of creating a task and repairing its cgroup membership afterward, the caller identifies the destination before the child exists.

Linux clone3

Linux 16 Sep 2026 6 min read

Linux cgroup memory.high Converts Overage into Reclaim Pressure

A cgroup can remain alive after its memory usage crosses memory.high. The boundary does not behave like a hard allocation ceiling: tasks in the cgroup are throttled and pushed into heavy reclaim pressure, and usage can remain above the configured value under extreme conditions. That behavior makes memory.high materially different from memory.max. The former converts excess usage into execution cost and reclaim work. The latter is a hard limit that can lead to a cgroup OOM when reclaim cannot reduce usage enough.

Linux cgroup v2