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[5/6,v7] sched: propagate asynchrous detach

Message ID 1478598827-32372-6-git-send-email-vincent.guittot@linaro.org
State Accepted
Commit 4e5160766fcc9f41bbd38bac11f92dce993644aa
Headers show

Commit Message

Vincent Guittot Nov. 8, 2016, 9:53 a.m. UTC 
A task can be asynchronously detached from cfs_rq when migrating
between CPUs. The load of the migrated task is then removed from
source cfs_rq during its next update. We use this event to set propagation
flag.

During the load balance, we take advantage of the update of blocked load
to propagate any pending changes.The propagation relies on patch
"sched: fix hierarchical order in rq->leaf_cfs_rq_list", which orders
children and parents, to ensure that it's done in one pass.

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>

---
 kernel/sched/fair.c | 6 ++++++
 1 file changed, 6 insertions(+)

-- 
2.7.4
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Patch

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e47bb046..8abed16 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3235,6 +3235,7 @@  update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
 		sub_positive(&sa->load_avg, r);
 		sub_positive(&sa->load_sum, r * LOAD_AVG_MAX);
 		removed_load = 1;
+		set_tg_cfs_propagate(cfs_rq);
 	}
 
 	if (atomic_long_read(&cfs_rq->removed_util_avg)) {
@@ -3242,6 +3243,7 @@  update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq)
 		sub_positive(&sa->util_avg, r);
 		sub_positive(&sa->util_sum, r * LOAD_AVG_MAX);
 		removed_util = 1;
+		set_tg_cfs_propagate(cfs_rq);
 	}
 
 	decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
@@ -6818,6 +6820,10 @@  static void update_blocked_averages(int cpu)
 
 		if (update_cfs_rq_load_avg(cfs_rq_clock_task(cfs_rq), cfs_rq, true))
 			update_tg_load_avg(cfs_rq, 0);
+
+		/* Propagate pending load changes to the parent */
+		if (cfs_rq->tg->se[cpu])
+			update_load_avg(cfs_rq->tg->se[cpu], 0);
 	}
 	raw_spin_unlock_irqrestore(&rq->lock, flags);
 }