diff options
| author | Michal Koutný <mkoutny@suse.com> | 2025-03-10 18:04:38 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-04-08 20:55:54 +0200 |
| commit | 277e0909754e9f3c82def97150d2f3ea700098f1 (patch) | |
| tree | 66bcdb7adc54ecea87cb003a2dde7da141a47777 /kernel | |
| parent | 61d3164fec2ed283645dc17fcc51959e8f361e18 (diff) | |
sched: Bypass bandwitdh checks with runtime disabled RT_GROUP_SCHED
When RT_GROUPs are compiled but not exposed, their bandwidth cannot
be configured (and it is not initialized for non-root task_groups neither).
Therefore bypass any checks of task vs task_group bandwidth.
This will achieve behavior very similar to setups that have
!CONFIG_RT_GROUP_SCHED and attach cpu controller to cgroup v2 hierarchy.
(On a related note, this may allow having RT tasks with
CONFIG_RT_GROUP_SCHED and cgroup v2 hierarchy.)
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250310170442.504716-7-mkoutny@suse.com
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/core.c | 6 | ||||
| -rw-r--r-- | kernel/sched/rt.c | 2 | ||||
| -rw-r--r-- | kernel/sched/syscalls.c | 3 |
3 files changed, 8 insertions, 3 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 32fb4c1100cb..6900ce5b9039 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -9206,11 +9206,15 @@ static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) struct task_struct *task; struct cgroup_subsys_state *css; + if (!rt_group_sched_enabled()) + goto scx_check; + cgroup_taskset_for_each(task, css, tset) { if (!sched_rt_can_attach(css_tg(css), task)) return -EINVAL; } -#endif +scx_check: +#endif /* CONFIG_RT_GROUP_SCHED */ return scx_cgroup_can_attach(tset); } diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index efa22bad31e1..5e82bfe56fdf 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -2864,7 +2864,7 @@ static int sched_rt_global_constraints(void) int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) { /* Don't accept real-time tasks when there is no way for them to run */ - if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) + if (rt_group_sched_enabled() && rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) return 0; return 1; diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c index 2bf528116fad..547c1f05b667 100644 --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -634,7 +634,8 @@ change: * Do not allow real-time tasks into groups that have no runtime * assigned. */ - if (rt_bandwidth_enabled() && rt_policy(policy) && + if (rt_group_sched_enabled() && + rt_bandwidth_enabled() && rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0 && !task_group_is_autogroup(task_group(p))) { retval = -EPERM; |