* [PATCH] sched/rt: move back to RT_GROUP_SCHED and rename it child
@ 2023-09-19 3:51 Yajun Deng
0 siblings, 0 replies; 4+ messages in thread
From: Yajun Deng @ 2023-09-19 3:51 UTC (permalink / raw)
To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
rostedt, bsegall, mgorman, bristot, vschneid
Cc: linux-kernel, Yajun Deng
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>
---
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..841f470026bb 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;
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
^ permalink raw reply [flat|nested] 4+ messages in thread* [PATCH] sched/rt: move back to RT_GROUP_SCHED and rename it child
@ 2023-08-01 6:27 Yajun Deng
2023-08-01 14:00 ` Steven Rostedt
0 siblings, 1 reply; 4+ messages in thread
From: Yajun Deng @ 2023-08-01 6:27 UTC (permalink / raw)
To: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
rostedt, bsegall, mgorman, bristot, vschneid
Cc: linux-kernel, Yajun Deng
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 in init_tg_rt_entry(). Also, remove the case parent is NULL
because this case is the same as rt_se is NULL and already returned.
Introduce for_each_sched_rt_entity_reverse() to iterate entries from
top to down.
Signed-off-by: Yajun Deng <yajun.deng@linux.dev>
---
include/linux/sched.h | 2 +-
kernel/sched/rt.c | 28 +++++++++++++++-------------
2 files changed, 16 insertions(+), 14 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..75efb1027b9f 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -228,13 +228,10 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
if (!rt_se)
return;
- if (!parent)
- rt_se->rt_rq = &rq->rt;
- else
- rt_se->rt_rq = parent->my_q;
-
+ rt_se->rt_rq = parent->my_q;
rt_se->my_q = rt_rq;
rt_se->parent = parent;
+ parent->child = rt_se;
INIT_LIST_HEAD(&rt_se->run_list);
}
@@ -564,6 +561,9 @@ 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 +669,9 @@ 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 +1484,21 @@ 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 *parent = 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)
+ parent = rt_se;
- rt_nr_running = rt_rq_of_se(back)->rt_nr_running;
+ rt_nr_running = rt_rq_of_se(parent)->rt_nr_running;
- for (rt_se = back; rt_se; rt_se = rt_se->back) {
+ rt_se = parent;
+ 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(parent), rt_nr_running);
}
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
--
2.25.1
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] sched/rt: move back to RT_GROUP_SCHED and rename it child
2023-08-01 6:27 Yajun Deng
@ 2023-08-01 14:00 ` Steven Rostedt
2023-08-01 14:02 ` Steven Rostedt
0 siblings, 1 reply; 4+ messages in thread
From: Steven Rostedt @ 2023-08-01 14:00 UTC (permalink / raw)
To: Yajun Deng
Cc: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
bsegall, mgorman, bristot, vschneid, linux-kernel
On Tue, 1 Aug 2023 14:27:14 +0800
Yajun Deng <yajun.deng@linux.dev> wrote:
> @@ -228,13 +228,10 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
> if (!rt_se)
> return;
>
> - if (!parent)
> - rt_se->rt_rq = &rq->rt;
> - else
> - rt_se->rt_rq = parent->my_q;
> -
> + rt_se->rt_rq = parent->my_q;
So when this is called with parent = NULL, this will crash?
-- Steve
> rt_se->my_q = rt_rq;
> rt_se->parent = parent;
> + parent->child = rt_se;
> INIT_LIST_HEAD(&rt_se->run_list);
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] sched/rt: move back to RT_GROUP_SCHED and rename it child
2023-08-01 14:00 ` Steven Rostedt
@ 2023-08-01 14:02 ` Steven Rostedt
0 siblings, 0 replies; 4+ messages in thread
From: Steven Rostedt @ 2023-08-01 14:02 UTC (permalink / raw)
To: Yajun Deng
Cc: mingo, peterz, juri.lelli, vincent.guittot, dietmar.eggemann,
bsegall, mgorman, bristot, vschneid, linux-kernel
On Tue, 1 Aug 2023 10:00:30 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Tue, 1 Aug 2023 14:27:14 +0800
> Yajun Deng <yajun.deng@linux.dev> wrote:
>
> > @@ -228,13 +228,10 @@ void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
> > if (!rt_se)
> > return;
Ah, I missed the second part of your change log where you said parent is
only NULL when rt_se is NULL.
I would then add:
if (!rt_se)
return;
if (WARN_ON_ONCE(!parent))
return;
-- Steve
> >
> > - if (!parent)
> > - rt_se->rt_rq = &rq->rt;
> > - else
> > - rt_se->rt_rq = parent->my_q;
> > -
> > + rt_se->rt_rq = parent->my_q;
>
> So when this is called with parent = NULL, this will crash?
>
> -- Steve
>
> > rt_se->my_q = rt_rq;
> > rt_se->parent = parent;
> > + parent->child = rt_se;
> > INIT_LIST_HEAD(&rt_se->run_list);
> > }
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
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2023-08-01 14:00 ` Steven Rostedt
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