[PATCH 1/2] Docs/admin-guide/cgroup-v2: document BPF scheduler callbacks for cpu.max and cpu.idle

From: luoliang

Date: Tue Aug 18 2026 - 23:13:06 EST


From: Liang Luo <luoliang@xxxxxxxxxx>

The cpu.weight and cpu.weight.nice entries already state that the files
also affect a BPF scheduler through the cgroup_set_weight callback.
However, cpu.max, cpu.max.burst and cpu.idle only mention the fair-class
scheduler, even though sched_ext implements the cgroup_set_bandwidth
(notified with the period/quota from cpu.max and the burst from
cpu.max.burst) and cgroup_set_idle callbacks from these interfaces.

Mirror the cpu.weight wording for the three entries so BPF scheduler
users can discover these notification points.

Signed-off-by: Liang Luo <luoliang@xxxxxxxxxx>
---
Documentation/admin-guide/cgroup-v2.rst | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst
index aed195a71cbf..3f77f15d0543 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1202,7 +1202,9 @@ will be referred to. All time durations are in microseconds.
$PERIOD duration. "max" for $MAX indicates no limit. If only
one number is written, $MAX is updated.

- This file affects only processes under the fair-class scheduler.
+ This file affects only processes under the fair-class scheduler and a BPF
+ scheduler with the ``cgroup_set_bandwidth`` callback depending on what
+ the callback actually does.

cpu.max.burst
A read-write single value file which exists on non-root
@@ -1210,7 +1212,9 @@ will be referred to. All time durations are in microseconds.

The burst in the range [0, $MAX].

- This file affects only processes under the fair-class scheduler.
+ This file affects only processes under the fair-class scheduler and a BPF
+ scheduler with the ``cgroup_set_bandwidth`` callback depending on what
+ the callback actually does.

cpu.pressure
A read-write nested-keyed file.
@@ -1262,7 +1266,9 @@ will be referred to. All time durations are in microseconds.
own relative priorities, but the cgroup itself will be treated as
very low priority relative to its peers.

- This file affects only processes under the fair-class scheduler.
+ This file affects only processes under the fair-class scheduler and a BPF
+ scheduler with the ``cgroup_set_idle`` callback depending on what the
+ callback actually does.

Memory
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2.43.0