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authorPaul Turner <pjt@google.com>2012-10-04 13:18:31 +0200
committerIngo Molnar <mingo@kernel.org>2012-10-24 10:27:28 +0200
commit48a1675323fa1b7844e479ad2a4469f4558c0f79 (patch)
tree1f3127f19be8fca16574d6adfadd22693b8766f2 /kernel/sched/fair.c
parent82958366cfea1a50e7e90907b2d55ae29ed69974 (diff)
downloadlinaro-lsk-48a1675323fa1b7844e479ad2a4469f4558c0f79.tar.gz
sched: Refactor update_shares_cpu() -> update_blocked_avgs()
Now that running entities maintain their own load-averages the work we must do in update_shares() is largely restricted to the periodic decay of blocked entities. This allows us to be a little less pessimistic regarding our occupancy on rq->lock and the associated rq->clock updates required. Signed-off-by: Paul Turner <pjt@google.com> Reviewed-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120823141507.133999170@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c50
1 files changed, 23 insertions, 27 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 57fae95eed9..dcc27d8ae6b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3639,20 +3639,15 @@ next:
/*
* update tg->load_weight by folding this cpu's load_avg
*/
-static int update_shares_cpu(struct task_group *tg, int cpu)
+static void __update_blocked_averages_cpu(struct task_group *tg, int cpu)
{
- struct sched_entity *se;
- struct cfs_rq *cfs_rq;
- unsigned long flags;
- struct rq *rq;
-
- rq = cpu_rq(cpu);
- se = tg->se[cpu];
- cfs_rq = tg->cfs_rq[cpu];
+ struct sched_entity *se = tg->se[cpu];
+ struct cfs_rq *cfs_rq = tg->cfs_rq[cpu];
- raw_spin_lock_irqsave(&rq->lock, flags);
+ /* throttled entities do not contribute to load */
+ if (throttled_hierarchy(cfs_rq))
+ return;
- update_rq_clock(rq);
update_cfs_rq_blocked_load(cfs_rq, 1);
if (se) {
@@ -3669,32 +3664,33 @@ static int update_shares_cpu(struct task_group *tg, int cpu)
if (!se->avg.runnable_avg_sum && !cfs_rq->nr_running)
list_del_leaf_cfs_rq(cfs_rq);
} else {
+ struct rq *rq = rq_of(cfs_rq);
update_rq_runnable_avg(rq, rq->nr_running);
}
-
- raw_spin_unlock_irqrestore(&rq->lock, flags);
-
- return 0;
}
-static void update_shares(int cpu)
+static void update_blocked_averages(int cpu)
{
- struct cfs_rq *cfs_rq;
struct rq *rq = cpu_rq(cpu);
+ struct cfs_rq *cfs_rq;
+ unsigned long flags;
- rcu_read_lock();
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ update_rq_clock(rq);
/*
* Iterates the task_group tree in a bottom up fashion, see
* list_add_leaf_cfs_rq() for details.
*/
for_each_leaf_cfs_rq(rq, cfs_rq) {
- /* throttled entities do not contribute to load */
- if (throttled_hierarchy(cfs_rq))
- continue;
-
- update_shares_cpu(cfs_rq->tg, cpu);
+ /*
+ * Note: We may want to consider periodically releasing
+ * rq->lock about these updates so that creating many task
+ * groups does not result in continually extending hold time.
+ */
+ __update_blocked_averages_cpu(cfs_rq->tg, rq->cpu);
}
- rcu_read_unlock();
+
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
}
/*
@@ -3746,7 +3742,7 @@ static unsigned long task_h_load(struct task_struct *p)
return load;
}
#else
-static inline void update_shares(int cpu)
+static inline void update_blocked_averages(int cpu)
{
}
@@ -4813,7 +4809,7 @@ void idle_balance(int this_cpu, struct rq *this_rq)
*/
raw_spin_unlock(&this_rq->lock);
- update_shares(this_cpu);
+ update_blocked_averages(this_cpu);
rcu_read_lock();
for_each_domain(this_cpu, sd) {
unsigned long interval;
@@ -5068,7 +5064,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
int update_next_balance = 0;
int need_serialize;
- update_shares(cpu);
+ update_blocked_averages(cpu);
rcu_read_lock();
for_each_domain(cpu, sd) {