On Fri 14-02-20 11:53:11, Johannes Weiner wrote:
[...]

The proper solution to implement the kind of resource hierarchy you
want to express in cgroup2 is to reflect it in the cgroup tree. Yes,
the_workload might have been started by user 100 in session c2, but in
terms of resources, it's prioritized over system.slice and user.slice,
and so that's the level where it needs to sit:

                               root
                       /        |                 \
               system.slice  user.slice       the_workload
               /    |           |
           cron  journal     user-100.slice
                                |
                             session-c2.scope
                                |
                             misc

Then you can configure not just memory.low, but also a proper io
weight and a cpu weight. And the tree correctly reflects where the
workload is in the pecking order of who gets access to resources.

I have already mentioned that this would be the only solution when the
protection would work, right. But I am also saying that this a trivial
example where you simply _can_ move your workload to the 1st level. What
about those that need to reflect organization into the hierarchy. Please
have a look at http://lkml.kernel.org/r/20200214075916.GM31689-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org
Are you saying they are just not supported? Are they supposed to use
cgroup v1 for the organization and v2 for the resource control?
-- 
Michal Hocko
SUSE Labs