Integrated: 8356868: Not all cgroup parameters are made available

[Casper Norrbin]

On Thu, 22 May 2025 09:06:15 GMT, Casper Norrbin <cnorrbin at openjdk.org> wrote:

> Hi everyone,
> 
> This PR improves cgroup support by exposing additional parameters that are currently not available. These parameters would enable more advanced features that rely on CPU and memory usage data.
> 
> The new parameters are:
> 
> - CPU usage: `cpuacct.usage` (cgroup v1) and `cpu.stat` (cgroup v2), which allow precise tracking of consumed CPU time.
> 
> - Peak memory usage: `memory.peak` (cgroup v2). While the cgroup v1 equivalent (`memory.max_usage_in_bytes`) was already available, cgroup v2 previously returned `OSCONTAINER_ERROR` — this has now been fixed.
> 
> - Memory throttle limit: `memory.high` (cgroup v2). There is no direct equivalent in cgroup v1, but since most systems use cgroup v2, exposing this parameter enables finer-grained memory control for those systems.
> 
> Testing:
> - All container tests under `/test/hotspot/jtreg/containers/`
> - Manually inspected the new parameters in both cgroup v1 and v2 container environments with the relevant settings applied.

This pull request has now been integrated.

Changeset: 850bc203
Author:    Casper Norrbin <cnorrbin at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/850bc20306e5101d164566f9a8687707492b296b
Stats:     163 lines in 10 files changed: 148 ins; 0 del; 15 mod

8356868: Not all cgroup parameters are made available

Reviewed-by: sgehwolf, gziemski

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PR: https://git.openjdk.org/jdk/pull/25388