diff mbox series

[v2] sched/rt: move back to RT_GROUP_SCHED and rename it child

Message ID 20230920140127.1671945-1-yajun.deng@linux.dev
State New
Headers
Series [v2] sched/rt: move back to RT_GROUP_SCHED and rename it child |

Commit Message

Yajun Deng Sept. 20, 2023, 2:01 p.m. UTC 
  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 <yajun.deng@linux.dev>
---
v2: fix the "uninitialized symbol 'root'" warning
v1: https://lore.kernel.org/all/20230919035114.2364567-1-yajun.deng@linux.dev/
---
 include/linux/sched.h |  2 +-
 kernel/sched/rt.c     | 25 ++++++++++++++++---------
 2 files changed, 17 insertions(+), 10 deletions(-)

Comments

Yajun Deng Sept. 28, 2023, 8:52 a.m. UTC | #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 <yajun.deng@linux.dev>
> ---
> v2: fix the "uninitialized symbol 'root'" warning
> v1: https://lore.kernel.org/all/20230919035114.2364567-1-yajun.deng@linux.dev/
> ---
>   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)
diff mbox series

Patch

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)