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. This would save a few bytes.
Init child when parent isn't NULL in init_tg_rt_entry() and introduce
for_each_sched_rt_entity_reverse() to iterate rt_se from top to down.
Signed-off-by: Yajun Deng <[email protected]>
---
v2: fix the "uninitialized symbol 'root'" warning
v1: https://lore.kernel.org/all/[email protected]/
---
include/linux/sched.h | 2 +-
kernel/sched/rt.c | 25 ++++++++++++++++---------
2 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7fcf1b82cfa6..cd05f4bb6a26 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 0597ba0f85ff..473a21b76c62 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 +1489,21 @@ 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 = NULL;
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) {
+ rt_se = root;
+ 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
Hi, Steve,
Kindly ping...
Thank.
On 2023/9/20 22:01, Yajun Deng wrote:
> 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. This would save a few bytes.
>
> Init child when parent isn't NULL in init_tg_rt_entry() and introduce
> for_each_sched_rt_entity_reverse() to iterate rt_se from top to down.
>
> Signed-off-by: Yajun Deng <[email protected]>
> ---
> v2: fix the "uninitialized symbol 'root'" warning
> v1: https://lore.kernel.org/all/[email protected]/
> ---
> include/linux/sched.h | 2 +-
> kernel/sched/rt.c | 25 ++++++++++++++++---------
> 2 files changed, 17 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 7fcf1b82cfa6..cd05f4bb6a26 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 0597ba0f85ff..473a21b76c62 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 +1489,21 @@ 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 = NULL;
> 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) {
> + rt_se = root;
> + 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)