[v2,2/2] sched/rt: Return NULL when rt entity isn't a task in rt_task_of()
Commit Message
Before calling rt_task_of(), we need to make sure that the rt entity is
a task. There is also a warning in rt_task_of() if the rt entity isn't a
task. That means we need to check the rt entity twice. If the rt entity
isn't a task, return the task struct is meaningless.
Return NULL when rt entity isn't a task in rt_task_of(), and call
rt_task_of() instead of rt_entity_is_task() when we need a task_struct.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
v2: fix 'struct rt_rq' no member named 'highest_prio'.
v1: https://lore.kernel.org/all/20231201022704.3526377-1-yajun.deng@linux.dev/
---
kernel/sched/rt.c | 60 ++++++++++++++---------------------------------
1 file changed, 17 insertions(+), 43 deletions(-)
@@ -169,9 +169,9 @@ static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
-#ifdef CONFIG_SCHED_DEBUG
- WARN_ON_ONCE(!rt_entity_is_task(rt_se));
-#endif
+ if (!rt_entity_is_task(rt_se))
+ return NULL;
+
return container_of(rt_se, struct task_struct, rt);
}
@@ -1266,54 +1266,34 @@ static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_arr
rt_se->on_list = 0;
}
-static inline struct sched_statistics *
-__schedstats_from_rt_se(struct sched_rt_entity *rt_se)
-{
-#ifdef CONFIG_RT_GROUP_SCHED
- /* schedstats is not supported for rt group. */
- if (!rt_entity_is_task(rt_se))
- return NULL;
-#endif
-
- return &rt_task_of(rt_se)->stats;
-}
-
static inline void
update_stats_wait_start_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
- struct sched_statistics *stats;
- struct task_struct *p = NULL;
+ struct task_struct *p;
if (!schedstat_enabled())
return;
- if (rt_entity_is_task(rt_se))
- p = rt_task_of(rt_se);
-
- stats = __schedstats_from_rt_se(rt_se);
- if (!stats)
+ p = rt_task_of(rt_se);
+ if (!p)
return;
- __update_stats_wait_start(rq_of_rt_rq(rt_rq), p, stats);
+ __update_stats_wait_start(rq_of_rt_rq(rt_rq), p, &p->stats);
}
static inline void
update_stats_enqueue_sleeper_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
- struct sched_statistics *stats;
- struct task_struct *p = NULL;
+ struct task_struct *p;
if (!schedstat_enabled())
return;
- if (rt_entity_is_task(rt_se))
- p = rt_task_of(rt_se);
-
- stats = __schedstats_from_rt_se(rt_se);
- if (!stats)
+ p = rt_task_of(rt_se);
+ if (!p)
return;
- __update_stats_enqueue_sleeper(rq_of_rt_rq(rt_rq), p, stats);
+ __update_stats_enqueue_sleeper(rq_of_rt_rq(rt_rq), p, &p->stats);
}
static inline void
@@ -1330,34 +1310,28 @@ update_stats_enqueue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
static inline void
update_stats_wait_end_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
- struct sched_statistics *stats;
- struct task_struct *p = NULL;
+ struct task_struct *p;
if (!schedstat_enabled())
return;
- if (rt_entity_is_task(rt_se))
- p = rt_task_of(rt_se);
-
- stats = __schedstats_from_rt_se(rt_se);
- if (!stats)
+ p = rt_task_of(rt_se);
+ if (!p)
return;
- __update_stats_wait_end(rq_of_rt_rq(rt_rq), p, stats);
+ __update_stats_wait_end(rq_of_rt_rq(rt_rq), p, &p->stats);
}
static inline void
update_stats_dequeue_rt(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se,
int flags)
{
- struct task_struct *p = NULL;
+ struct task_struct *p;
if (!schedstat_enabled())
return;
- if (rt_entity_is_task(rt_se))
- p = rt_task_of(rt_se);
-
+ p = rt_task_of(rt_se);
if ((flags & DEQUEUE_SLEEP) && p) {
unsigned int state;