docs/sched_ext: document that cgroup CPU knobs are scheduler-dependent

The scheduler core communicates the initial cpu controller settings
to the BPF scheduler through ops.cgroup_init() and reports subsequent
changes through the corresponding ops.cgroup_set_*() callbacks.
Whether and how a knob takes effect is up to the loaded scheduler:
it may implement the corresponding callback partially or not at all,
so cpu.max, cpu.weight and friends can silently have no effect.

Document this in the basics section of sched-ext.rst.

Signed-off-by: Tao Cui <cuitao@kylinos.cn>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Tao Cui 2026-08-24 21:21:16 +08:00 • committed by Tejun Heo
commit 6586705bc2