sched: fair-group: de-couple load-balancing from the rb-trees
De-couple load-balancing from the rb-trees, so that I can change their
organization.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/init_task.h b/include/linux/init_task.h
index 1f74e1d..37a6f5b 100644
--- a/include/linux/init_task.h
+++ b/include/linux/init_task.h
@@ -151,6 +151,9 @@
.cpus_allowed = CPU_MASK_ALL, \
.mm = NULL, \
.active_mm = &init_mm, \
+ .se = { \
+ .group_node = LIST_HEAD_INIT(tsk.se.group_node), \
+ }, \
.rt = { \
.run_list = LIST_HEAD_INIT(tsk.rt.run_list), \
.time_slice = HZ, \
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 887f5db..be69140 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -946,6 +946,7 @@
struct sched_entity {
struct load_weight load; /* for load-balancing */
struct rb_node run_node;
+ struct list_head group_node;
unsigned int on_rq;
u64 exec_start;
diff --git a/kernel/sched.c b/kernel/sched.c
index ae1a3e9..3202462 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -384,8 +384,12 @@
struct rb_root tasks_timeline;
struct rb_node *rb_leftmost;
- struct rb_node *rb_load_balance_curr;
- /* 'curr' points to currently running entity on this cfs_rq.
+
+ struct list_head tasks;
+ struct list_head *balance_iterator;
+
+ /*
+ * 'curr' points to currently running entity on this cfs_rq.
* It is set to NULL otherwise (i.e when none are currently running).
*/
struct sched_entity *curr, *next;
@@ -2525,6 +2529,7 @@
INIT_LIST_HEAD(&p->rt.run_list);
p->se.on_rq = 0;
+ INIT_LIST_HEAD(&p->se.group_node);
#ifdef CONFIG_PREEMPT_NOTIFIERS
INIT_HLIST_HEAD(&p->preempt_notifiers);
@@ -7898,6 +7903,7 @@
static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
{
cfs_rq->tasks_timeline = RB_ROOT;
+ INIT_LIST_HEAD(&cfs_rq->tasks);
#ifdef CONFIG_FAIR_GROUP_SCHED
cfs_rq->rq = rq;
#endif
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 9e301a2..ed8ce32 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -533,6 +533,7 @@
add_cfs_task_weight(cfs_rq, se->load.weight);
cfs_rq->nr_running++;
se->on_rq = 1;
+ list_add(&se->group_node, &cfs_rq->tasks);
}
static void
@@ -545,6 +546,7 @@
add_cfs_task_weight(cfs_rq, -se->load.weight);
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)
@@ -1289,21 +1291,24 @@
* the current task:
*/
static struct task_struct *
-__load_balance_iterator(struct cfs_rq *cfs_rq, struct rb_node *curr)
+__load_balance_iterator(struct cfs_rq *cfs_rq, struct list_head *next)
{
struct task_struct *p = NULL;
struct sched_entity *se;
- if (!curr)
+ if (next == &cfs_rq->tasks)
return NULL;
/* Skip over entities that are not tasks */
do {
- se = rb_entry(curr, struct sched_entity, run_node);
- curr = rb_next(curr);
- } while (curr && !entity_is_task(se));
+ se = list_entry(next, struct sched_entity, group_node);
+ next = next->next;
+ } while (next != &cfs_rq->tasks && !entity_is_task(se));
- cfs_rq->rb_load_balance_curr = curr;
+ if (next == &cfs_rq->tasks)
+ return NULL;
+
+ cfs_rq->balance_iterator = next;
if (entity_is_task(se))
p = task_of(se);
@@ -1315,14 +1320,14 @@
{
struct cfs_rq *cfs_rq = arg;
- return __load_balance_iterator(cfs_rq, first_fair(cfs_rq));
+ return __load_balance_iterator(cfs_rq, cfs_rq->tasks.next);
}
static struct task_struct *load_balance_next_fair(void *arg)
{
struct cfs_rq *cfs_rq = arg;
- return __load_balance_iterator(cfs_rq, cfs_rq->rb_load_balance_curr);
+ return __load_balance_iterator(cfs_rq, cfs_rq->balance_iterator);
}
static unsigned long
