[PATCH] sched/fair: Remove rq->load

[PATCH] sched/fair: Remove rq->load

[Dietmar Eggemann]

The CFS class is the only one maintaining and using the CPU wide load
(rq->load(.weight)). The last use case of the CPU wide load in CFS's
set_next_entity() can be replaced by using the load of the CFS class
(rq->cfs.load(.weight)) instead.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
---
 kernel/sched/debug.c | 2 --
 kernel/sched/fair.c  | 7 ++-----
 kernel/sched/sched.h | 2 --
 3 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 8039d62ae36e..1148f43dbd42 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -656,8 +656,6 @@ do {									\
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
 
 	P(nr_running);
-	SEQ_printf(m, "  .%-30s: %lu\n", "load",
-		   rq->load.weight);
 	P(nr_switches);
 	P(nr_load_updates);
 	P(nr_uninterruptible);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index a4d9e14bf138..73a6718f29cc 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2682,8 +2682,6 @@ static void
 account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	update_load_add(&cfs_rq->load, se->load.weight);
-	if (!parent_entity(se))
-		update_load_add(&rq_of(cfs_rq)->load, se->load.weight);
 #ifdef CONFIG_SMP
 	if (entity_is_task(se)) {
 		struct rq *rq = rq_of(cfs_rq);
@@ -2699,8 +2697,6 @@ static void
 account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	update_load_sub(&cfs_rq->load, se->load.weight);
-	if (!parent_entity(se))
-		update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
 #ifdef CONFIG_SMP
 	if (entity_is_task(se)) {
 		account_numa_dequeue(rq_of(cfs_rq), task_of(se));
@@ -4096,7 +4092,8 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 	 * least twice that of our own weight (i.e. dont track it
 	 * when there are only lesser-weight tasks around):
 	 */
-	if (schedstat_enabled() && rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
+	if (schedstat_enabled() &&
+	    rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) {
 		schedstat_set(se->statistics.slice_max,
 			max((u64)schedstat_val(se->statistics.slice_max),
 			    se->sum_exec_runtime - se->prev_sum_exec_runtime));
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index efa686eeff26..e4059e81e99c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -830,8 +830,6 @@ struct rq {
 	atomic_t nohz_flags;
 #endif /* CONFIG_NO_HZ_COMMON */
 
-	/* capture load from *all* tasks on this CPU: */
-	struct load_weight	load;
 	unsigned long		nr_load_updates;
 	u64			nr_switches;
 
-- 
2.17.1

Re: [PATCH] sched/fair: Remove rq->load

[Dietmar Eggemann]

Hi,

On 4/24/19 10:45 AM, Dietmar Eggemann wrote:
> The CFS class is the only one maintaining and using the CPU wide load
> (rq->load(.weight)). The last use case of the CPU wide load in CFS's
> set_next_entity() can be replaced by using the load of the CFS class
> (rq->cfs.load(.weight)) instead.
> 
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> ---
>   kernel/sched/debug.c | 2 --
>   kernel/sched/fair.c  | 7 ++-----
>   kernel/sched/sched.h | 2 --
>   3 files changed, 2 insertions(+), 9 deletions(-)
> 
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 8039d62ae36e..1148f43dbd42 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -656,8 +656,6 @@ do {									\
>   	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
>   
>   	P(nr_running);
> -	SEQ_printf(m, "  .%-30s: %lu\n", "load",
> -		   rq->load.weight);
>   	P(nr_switches);
>   	P(nr_load_updates);
>   	P(nr_uninterruptible);
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index a4d9e14bf138..73a6718f29cc 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -2682,8 +2682,6 @@ static void
>   account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
>   {
>   	update_load_add(&cfs_rq->load, se->load.weight);
> -	if (!parent_entity(se))
> -		update_load_add(&rq_of(cfs_rq)->load, se->load.weight);
>   #ifdef CONFIG_SMP
>   	if (entity_is_task(se)) {
>   		struct rq *rq = rq_of(cfs_rq);
> @@ -2699,8 +2697,6 @@ static void
>   account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
>   {
>   	update_load_sub(&cfs_rq->load, se->load.weight);
> -	if (!parent_entity(se))
> -		update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
>   #ifdef CONFIG_SMP
>   	if (entity_is_task(se)) {
>   		account_numa_dequeue(rq_of(cfs_rq), task_of(se));
> @@ -4096,7 +4092,8 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
>   	 * least twice that of our own weight (i.e. dont track it
>   	 * when there are only lesser-weight tasks around):
>   	 */
> -	if (schedstat_enabled() && rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
> +	if (schedstat_enabled() &&
> +	    rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) {
>   		schedstat_set(se->statistics.slice_max,
>   			max((u64)schedstat_val(se->statistics.slice_max),
>   			    se->sum_exec_runtime - se->prev_sum_exec_runtime));
> diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
> index efa686eeff26..e4059e81e99c 100644
> --- a/kernel/sched/sched.h
> +++ b/kernel/sched/sched.h
> @@ -830,8 +830,6 @@ struct rq {
>   	atomic_t nohz_flags;
>   #endif /* CONFIG_NO_HZ_COMMON */
>   
> -	/* capture load from *all* tasks on this CPU: */
> -	struct load_weight	load;
>   	unsigned long		nr_load_updates;
>   	u64			nr_switches;

Is there anything else I should do for this patch ?

Thanks,

-- Dietmar

Re: [PATCH] sched/fair: Remove rq->load

[Peter Zijlstra]

On Mon, May 06, 2019 at 12:46:00PM +0200, Dietmar Eggemann wrote:
> Is there anything else I should do for this patch ?

Got it now. Thanks!

[tip:sched/core] sched/fair: Remove rq->load

[tip-bot for Dietmar Eggemann]

Commit-ID:  f2bedc4705659216bd60948029ad8dfedf923ad9
Gitweb:     https://git.kernel.org/tip/f2bedc4705659216bd60948029ad8dfedf923ad9
Author:     Dietmar Eggemann <dietmar.eggemann@arm.com>
AuthorDate: Wed, 24 Apr 2019 09:45:56 +0100
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 3 Jun 2019 11:49:37 +0200

sched/fair: Remove rq->load

The CFS class is the only one maintaining and using the CPU wide load
(rq->load(.weight)). The last use case of the CPU wide load in CFS's
set_next_entity() can be replaced by using the load of the CFS class
(rq->cfs.load(.weight)) instead.

Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190424084556.604-1-dietmar.eggemann@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/sched/debug.c | 2 --
 kernel/sched/fair.c  | 7 ++-----
 kernel/sched/sched.h | 2 --
 3 files changed, 2 insertions(+), 9 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 678bfb9bd87f..150043e1d716 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -656,8 +656,6 @@ do {									\
 	SEQ_printf(m, "  .%-30s: %Ld.%06ld\n", #x, SPLIT_NS(rq->x))
 
 	P(nr_running);
-	SEQ_printf(m, "  .%-30s: %lu\n", "load",
-		   rq->load.weight);
 	P(nr_switches);
 	P(nr_load_updates);
 	P(nr_uninterruptible);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8691a8fffe40..08b1cb06f968 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2686,8 +2686,6 @@ static void
 account_entity_enqueue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	update_load_add(&cfs_rq->load, se->load.weight);
-	if (!parent_entity(se))
-		update_load_add(&rq_of(cfs_rq)->load, se->load.weight);
 #ifdef CONFIG_SMP
 	if (entity_is_task(se)) {
 		struct rq *rq = rq_of(cfs_rq);
@@ -2703,8 +2701,6 @@ static void
 account_entity_dequeue(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
 	update_load_sub(&cfs_rq->load, se->load.weight);
-	if (!parent_entity(se))
-		update_load_sub(&rq_of(cfs_rq)->load, se->load.weight);
 #ifdef CONFIG_SMP
 	if (entity_is_task(se)) {
 		account_numa_dequeue(rq_of(cfs_rq), task_of(se));
@@ -4100,7 +4096,8 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 	 * least twice that of our own weight (i.e. dont track it
 	 * when there are only lesser-weight tasks around):
 	 */
-	if (schedstat_enabled() && rq_of(cfs_rq)->load.weight >= 2*se->load.weight) {
+	if (schedstat_enabled() &&
+	    rq_of(cfs_rq)->cfs.load.weight >= 2*se->load.weight) {
 		schedstat_set(se->statistics.slice_max,
 			max((u64)schedstat_val(se->statistics.slice_max),
 			    se->sum_exec_runtime - se->prev_sum_exec_runtime));
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b52ed1ada0be..c308410675ed 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -830,8 +830,6 @@ struct rq {
 	atomic_t nohz_flags;
 #endif /* CONFIG_NO_HZ_COMMON */
 
-	/* capture load from *all* tasks on this CPU: */
-	struct load_weight	load;
 	unsigned long		nr_load_updates;
 	u64			nr_switches;