Re: [RFC PATCH v3 1/2] cgroup: cgroup.freeze.stat.local time accounting

From: Tiffany Yang
Date: Wed Aug 13 2025 - 21:32:20 EST


Tejun Heo <tj@xxxxxxxxxx> writes:

Hello,

Generally looks good to me. Some comments on cosmetics / interface.

On Mon, Aug 04, 2025 at 08:29:41PM -0700, Tiffany Yang wrote:
...
+ cgroup.freeze.stat.local

This was mentioned before and maybe I missed the following discussions but
given that cgroup.freeze is a part of core cgroup, cgroup.stat.local is
probably the right place. It's not great that cgroup.stat wouldn't be a
superset of cgroup.stat.local but we can add the hierarchical counter later
if necessary.

Got it. I had ended up opting for the "freeze"-specific name because
there was already a cgroup_local_stat_show that seemed to imply that
cgroup.stat.local was reserved for controllers with a struct
cgroup_subsys. I will update v4 with something similar for core!


+ A read-only flat-keyed file which exists in non-root cgroups.
+ The following entry is defined:
+
+ freeze_time_total

How about just frozen_usec? "_usec" is what we used in cpu.stat for time
stats.

Ack.


+ Cumulative time that this cgroup has spent between freezing and
+ thawing, regardless of whether by self or ancestor groups.
+ NB: (not) reaching "frozen" state is not accounted here.
+
+ Using the following ASCII representation of a cgroup's freezer
+ state, ::

It's a bit odd to include credit in a doc file. Maybe move it to the
description or add Co-developed-by: tag?


Will do! Thanks for looking over this :).

--
Tiffany Y. Yang