The member back in struct sched_rt_entity only related to RT_GROUP_SCHED,
it should not place out of RT_GROUP_SCHED, move back to RT_GROUP_SCHED
and rename it child.
Init child when parent isn't NULL in init_tg_rt_entry().
Introduce for_each_sched_rt_entity_reverse() to iterate rt_se from
top to down.
Signed-off-by: Yajun Deng <[email protected]>
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-lkp/[email protected]
---
V2 -> V3: Keep parent is NULL in init_tg_rt_entry().
V1 -> V2: Add WARN_ON_ONCE in init_tg_rt_entry().
---
include/linux/sched.h | 2 +-
kernel/sched/rt.c | 24 +++++++++++++++---------
2 files changed, 16 insertions(+), 10 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 177b3f3676ef..5635655d6c35 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -594,8 +594,8 @@ struct sched_rt_entity {
unsigned short on_rq;
unsigned short on_list;
- struct sched_rt_entity *back;
#ifdef CONFIG_RT_GROUP_SCHED
+ struct sched_rt_entity *child;
struct sched_rt_entity *parent;
/* rq on which this entity is (to be) queued: */
struct rt_rq *rt_rq;
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 00e0e5074115..9e0132959929 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -230,8 +230,10 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
if (!parent)
rt_se->rt_rq = &rq->rt;
- else
+ else {
rt_se->rt_rq = parent->my_q;
+ parent->child = rt_se;
+ }
rt_se->my_q = rt_rq;
rt_se->parent = parent;
@@ -564,6 +566,9 @@ static inline struct task_group *next_task_group(struct task_group *tg)
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = rt_se->parent)
+#define for_each_sched_rt_entity_reverse(rt_se) \
+ for (; rt_se; rt_se = rt_se->child)
+
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return rt_se->my_q;
@@ -669,6 +674,9 @@ typedef struct rt_rq *rt_rq_iter_t;
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
+#define for_each_sched_rt_entity_reverse(rt_se) \
+ for_each_sched_rt_entity(rt_se)
+
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return NULL;
@@ -1481,22 +1489,20 @@ static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flag
*/
static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
{
- struct sched_rt_entity *back = NULL;
+ struct sched_rt_entity *root;
unsigned int rt_nr_running;
- for_each_sched_rt_entity(rt_se) {
- rt_se->back = back;
- back = rt_se;
- }
+ for_each_sched_rt_entity(rt_se)
+ root = rt_se;
- rt_nr_running = rt_rq_of_se(back)->rt_nr_running;
+ rt_nr_running = rt_rq_of_se(root)->rt_nr_running;
- for (rt_se = back; rt_se; rt_se = rt_se->back) {
+ for_each_sched_rt_entity_reverse(rt_se) {
if (on_rt_rq(rt_se))
__dequeue_rt_entity(rt_se, flags);
}
- dequeue_top_rt_rq(rt_rq_of_se(back), rt_nr_running);
+ dequeue_top_rt_rq(rt_rq_of_se(root), rt_nr_running);
}
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
--
2.25.1