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* sched:
@ 2008-09-25  4:21 Bharata B Rao
  2008-09-25  4:23 ` sched: Maintain only task entities in cfs_rq->tasks list Bharata B Rao
  2008-09-25  9:14 ` sched: Peter Zijlstra
  0 siblings, 2 replies; 4+ messages in thread
From: Bharata B Rao @ 2008-09-25  4:21 UTC (permalink / raw)
  To: linux-kernel; +Cc: Srivatsa Vaddagiri, Peter Zijlstra, Ingo Molnar

Hi,

sched: Maintain only task entities in cfs_rq->tasks list.

cfs_rq->tasks list is used by the load balancer to iterate
over all the tasks. Currently it holds all the entities
(both task and group entities) because of which there is
a need to check for group entities explicitly during load
balancing. This patch changes the cfs_rq->tasks list to
hold only task entities.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched_fair.c |   26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -586,11 +586,12 @@ account_entity_enqueue(struct cfs_rq *cf
 	update_load_add(&cfs_rq->load, se->load.weight);
 	if (!parent_entity(se))
 		inc_cpu_load(rq_of(cfs_rq), se->load.weight);
-	if (entity_is_task(se))
+	if (entity_is_task(se)) {
 		add_cfs_task_weight(cfs_rq, se->load.weight);
+		list_add(&se->group_node, &cfs_rq->tasks);
+	}
 	cfs_rq->nr_running++;
 	se->on_rq = 1;
-	list_add(&se->group_node, &cfs_rq->tasks);
 }
 
 static void
@@ -599,11 +600,12 @@ account_entity_dequeue(struct cfs_rq *cf
 	update_load_sub(&cfs_rq->load, se->load.weight);
 	if (!parent_entity(se))
 		dec_cpu_load(rq_of(cfs_rq), se->load.weight);
-	if (entity_is_task(se))
+	if (entity_is_task(se)) {
 		add_cfs_task_weight(cfs_rq, -se->load.weight);
+		list_del_init(&se->group_node);
+	}
 	cfs_rq->nr_running--;
 	se->on_rq = 0;
-	list_del_init(&se->group_node);
 }
 
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -1445,19 +1447,9 @@ __load_balance_iterator(struct cfs_rq *c
 	if (next == &cfs_rq->tasks)
 		return NULL;
 
-	/* Skip over entities that are not tasks */
-	do {
-		se = list_entry(next, struct sched_entity, group_node);
-		next = next->next;
-	} while (next != &cfs_rq->tasks && !entity_is_task(se));
-
-	if (next == &cfs_rq->tasks)
-		return NULL;
-
-	cfs_rq->balance_iterator = next;
-
-	if (entity_is_task(se))
-		p = task_of(se);
+	se = list_entry(next, struct sched_entity, group_node);
+	p = task_of(se);
+	cfs_rq->balance_iterator = next->next;
 
 	return p;
 }

Regards,
Bharata.

^ permalink raw reply	[flat|nested] 4+ messages in thread

* sched: Maintain only task entities in cfs_rq->tasks list.
  2008-09-25  4:21 sched: Bharata B Rao
@ 2008-09-25  4:23 ` Bharata B Rao
  2008-09-25  9:14 ` sched: Peter Zijlstra
  1 sibling, 0 replies; 4+ messages in thread
From: Bharata B Rao @ 2008-09-25  4:23 UTC (permalink / raw)
  To: linux-kernel; +Cc: Srivatsa Vaddagiri, Peter Zijlstra, Ingo Molnar

Oops, missed the subject line in the last post :(

[repost]

sched: Maintain only task entities in cfs_rq->tasks list.

cfs_rq->tasks list is used by the load balancer to iterate
over all the tasks. Currently it holds all the entities
(both task and group entities) because of which there is
a need to check for group entities explicitly during load
balancing. This patch changes the cfs_rq->tasks list to
hold only task entities.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Ingo Molnar <mingo@elte.hu>
---
 kernel/sched_fair.c |   26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -586,11 +586,12 @@ account_entity_enqueue(struct cfs_rq *cf
 	update_load_add(&cfs_rq->load, se->load.weight);
 	if (!parent_entity(se))
 		inc_cpu_load(rq_of(cfs_rq), se->load.weight);
-	if (entity_is_task(se))
+	if (entity_is_task(se)) {
 		add_cfs_task_weight(cfs_rq, se->load.weight);
+		list_add(&se->group_node, &cfs_rq->tasks);
+	}
 	cfs_rq->nr_running++;
 	se->on_rq = 1;
-	list_add(&se->group_node, &cfs_rq->tasks);
 }
 
 static void
@@ -599,11 +600,12 @@ account_entity_dequeue(struct cfs_rq *cf
 	update_load_sub(&cfs_rq->load, se->load.weight);
 	if (!parent_entity(se))
 		dec_cpu_load(rq_of(cfs_rq), se->load.weight);
-	if (entity_is_task(se))
+	if (entity_is_task(se)) {
 		add_cfs_task_weight(cfs_rq, -se->load.weight);
+		list_del_init(&se->group_node);
+	}
 	cfs_rq->nr_running--;
 	se->on_rq = 0;
-	list_del_init(&se->group_node);
 }
 
 static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -1445,19 +1447,9 @@ __load_balance_iterator(struct cfs_rq *c
 	if (next == &cfs_rq->tasks)
 		return NULL;
 
-	/* Skip over entities that are not tasks */
-	do {
-		se = list_entry(next, struct sched_entity, group_node);
-		next = next->next;
-	} while (next != &cfs_rq->tasks && !entity_is_task(se));
-
-	if (next == &cfs_rq->tasks)
-		return NULL;
-
-	cfs_rq->balance_iterator = next;
-
-	if (entity_is_task(se))
-		p = task_of(se);
+	se = list_entry(next, struct sched_entity, group_node);
+	p = task_of(se);
+	cfs_rq->balance_iterator = next->next;
 
 	return p;
 }

^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: sched:
  2008-09-25  4:21 sched: Bharata B Rao
  2008-09-25  4:23 ` sched: Maintain only task entities in cfs_rq->tasks list Bharata B Rao
@ 2008-09-25  9:14 ` Peter Zijlstra
  2008-09-25  9:19   ` sched: Ingo Molnar
  1 sibling, 1 reply; 4+ messages in thread
From: Peter Zijlstra @ 2008-09-25  9:14 UTC (permalink / raw)
  To: bharata; +Cc: linux-kernel, Srivatsa Vaddagiri, Ingo Molnar

On Thu, 2008-09-25 at 09:51 +0530, Bharata B Rao wrote:
> Hi,
> 
> sched: Maintain only task entities in cfs_rq->tasks list.
> 
> cfs_rq->tasks list is used by the load balancer to iterate
> over all the tasks. Currently it holds all the entities
> (both task and group entities) because of which there is
> a need to check for group entities explicitly during load
> balancing. This patch changes the cfs_rq->tasks list to
> hold only task entities.

Looks fine. Thanks Bharata!

> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
> CC: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
> CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
> CC: Ingo Molnar <mingo@elte.hu>
> ---
>  kernel/sched_fair.c |   26 +++++++++-----------------
>  1 file changed, 9 insertions(+), 17 deletions(-)
> 
> --- a/kernel/sched_fair.c
> +++ b/kernel/sched_fair.c
> @@ -586,11 +586,12 @@ account_entity_enqueue(struct cfs_rq *cf
>  	update_load_add(&cfs_rq->load, se->load.weight);
>  	if (!parent_entity(se))
>  		inc_cpu_load(rq_of(cfs_rq), se->load.weight);
> -	if (entity_is_task(se))
> +	if (entity_is_task(se)) {
>  		add_cfs_task_weight(cfs_rq, se->load.weight);
> +		list_add(&se->group_node, &cfs_rq->tasks);
> +	}
>  	cfs_rq->nr_running++;
>  	se->on_rq = 1;
> -	list_add(&se->group_node, &cfs_rq->tasks);
>  }
>  
>  static void
> @@ -599,11 +600,12 @@ account_entity_dequeue(struct cfs_rq *cf
>  	update_load_sub(&cfs_rq->load, se->load.weight);
>  	if (!parent_entity(se))
>  		dec_cpu_load(rq_of(cfs_rq), se->load.weight);
> -	if (entity_is_task(se))
> +	if (entity_is_task(se)) {
>  		add_cfs_task_weight(cfs_rq, -se->load.weight);
> +		list_del_init(&se->group_node);
> +	}
>  	cfs_rq->nr_running--;
>  	se->on_rq = 0;
> -	list_del_init(&se->group_node);
>  }
>  
>  static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
> @@ -1445,19 +1447,9 @@ __load_balance_iterator(struct cfs_rq *c
>  	if (next == &cfs_rq->tasks)
>  		return NULL;
>  
> -	/* Skip over entities that are not tasks */
> -	do {
> -		se = list_entry(next, struct sched_entity, group_node);
> -		next = next->next;
> -	} while (next != &cfs_rq->tasks && !entity_is_task(se));
> -
> -	if (next == &cfs_rq->tasks)
> -		return NULL;
> -
> -	cfs_rq->balance_iterator = next;
> -
> -	if (entity_is_task(se))
> -		p = task_of(se);
> +	se = list_entry(next, struct sched_entity, group_node);
> +	p = task_of(se);
> +	cfs_rq->balance_iterator = next->next;
>  
>  	return p;
>  }
> 
> Regards,
> Bharata.


^ permalink raw reply	[flat|nested] 4+ messages in thread

* Re: sched:
  2008-09-25  9:14 ` sched: Peter Zijlstra
@ 2008-09-25  9:19   ` Ingo Molnar
  0 siblings, 0 replies; 4+ messages in thread
From: Ingo Molnar @ 2008-09-25  9:19 UTC (permalink / raw)
  To: Peter Zijlstra; +Cc: bharata, linux-kernel, Srivatsa Vaddagiri


* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:

> On Thu, 2008-09-25 at 09:51 +0530, Bharata B Rao wrote:
> > Hi,
> > 
> > sched: Maintain only task entities in cfs_rq->tasks list.
> > 
> > cfs_rq->tasks list is used by the load balancer to iterate
> > over all the tasks. Currently it holds all the entities
> > (both task and group entities) because of which there is
> > a need to check for group entities explicitly during load
> > balancing. This patch changes the cfs_rq->tasks list to
> > hold only task entities.
> 
> Looks fine. Thanks Bharata!

applied to tip/sched/devel, thanks!

	Ingo

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2008-09-25  9:20 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2008-09-25  4:21 sched: Bharata B Rao
2008-09-25  4:23 ` sched: Maintain only task entities in cfs_rq->tasks list Bharata B Rao
2008-09-25  9:14 ` sched: Peter Zijlstra
2008-09-25  9:19   ` sched: Ingo Molnar

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