sched: Add RT_GROUP WARN checks for non-root task_groups

With CONFIG_RT_GROUP_SCHED but runtime disabling of RT_GROUPs we expect
the existence of the root task_group only and all rt_sched_entity'ies
should be queued on root's rt_rq.

If we get a non-root RT_GROUP something went wrong.

Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20250310170442.504716-9-mkoutny@suse.com
This commit is contained in:
Michal Koutný 2025-03-10 18:04:40 +01:00 committed by Peter Zijlstra
parent d6809c2f60
commit 87f1fb77d8

View file

@ -176,11 +176,14 @@ static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
/* Cannot fold with non-CONFIG_RT_GROUP_SCHED version, layout */
WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);
return rt_rq->rq;
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
WARN_ON(!rt_group_sched_enabled() && rt_se->rt_rq->tg != &root_task_group);
return rt_se->rt_rq;
}
@ -188,6 +191,7 @@ static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_se->rt_rq;
WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);
return rt_rq->rq;
}
@ -504,8 +508,10 @@ typedef struct task_group *rt_rq_iter_t;
static inline struct task_group *next_task_group(struct task_group *tg)
{
if (!rt_group_sched_enabled())
if (!rt_group_sched_enabled()) {
WARN_ON(tg != &root_task_group);
return NULL;
}
do {
tg = list_entry_rcu(tg->list.next,
@ -2607,8 +2613,9 @@ static int task_is_throttled_rt(struct task_struct *p, int cpu)
{
struct rt_rq *rt_rq;
#ifdef CONFIG_RT_GROUP_SCHED
#ifdef CONFIG_RT_GROUP_SCHED // XXX maybe add task_rt_rq(), see also sched_rt_period_rt_rq
rt_rq = task_group(p)->rt_rq[cpu];
WARN_ON(!rt_group_sched_enabled() && rt_rq->tg != &root_task_group);
#else
rt_rq = &cpu_rq(cpu)->rt;
#endif
@ -2718,6 +2725,9 @@ static int tg_rt_schedulable(struct task_group *tg, void *data)
tg->rt_bandwidth.rt_runtime && tg_has_rt_tasks(tg))
return -EBUSY;
if (WARN_ON(!rt_group_sched_enabled() && tg != &root_task_group))
return -EBUSY;
total = to_ratio(period, runtime);
/*