sched: Allow update_cfs_load() to update global load
Refactor the global load updates from update_shares_cpu() so that
update_cfs_load() can update global load when it is more than ~10%
out of sync.
The new global_load parameter allows us to force an update, regardless of
the error factor so that we can synchronize w/ update_shares().
Signed-off-by: Paul Turner <pjt@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101115234938.377473595@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index e7e2f08..390ce30 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -539,7 +539,7 @@
return calc_delta_fair(sched_slice(cfs_rq, se), se);
}
-static void update_cfs_load(struct cfs_rq *cfs_rq);
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update);
static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta);
/*
@@ -565,7 +565,7 @@
#ifdef CONFIG_FAIR_GROUP_SCHED
cfs_rq->load_unacc_exec_time += delta_exec;
if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
- update_cfs_load(cfs_rq);
+ update_cfs_load(cfs_rq, 0);
update_cfs_shares(cfs_rq, 0);
}
#endif
@@ -704,7 +704,22 @@
}
#if defined CONFIG_SMP && defined CONFIG_FAIR_GROUP_SCHED
-static void update_cfs_load(struct cfs_rq *cfs_rq)
+static void update_cfs_rq_load_contribution(struct cfs_rq *cfs_rq,
+ int global_update)
+{
+ struct task_group *tg = cfs_rq->tg;
+ long load_avg;
+
+ load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
+ load_avg -= cfs_rq->load_contribution;
+
+ if (global_update || abs(load_avg) > cfs_rq->load_contribution / 8) {
+ atomic_add(load_avg, &tg->load_weight);
+ cfs_rq->load_contribution += load_avg;
+ }
+}
+
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
{
u64 period = sysctl_sched_shares_window;
u64 now, delta;
@@ -731,6 +746,11 @@
cfs_rq->load_avg += delta * load;
}
+ /* consider updating load contribution on each fold or truncate */
+ if (global_update || cfs_rq->load_period > period
+ || !cfs_rq->load_period)
+ update_cfs_rq_load_contribution(cfs_rq, global_update);
+
while (cfs_rq->load_period > period) {
/*
* Inline assembly required to prevent the compiler
@@ -790,7 +810,7 @@
reweight_entity(cfs_rq_of(se), se, shares);
}
#else /* CONFIG_FAIR_GROUP_SCHED */
-static inline void update_cfs_load(struct cfs_rq *cfs_rq)
+static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
{
}
@@ -920,7 +940,7 @@
* Update run-time statistics of the 'current'.
*/
update_curr(cfs_rq);
- update_cfs_load(cfs_rq);
+ update_cfs_load(cfs_rq, 0);
update_cfs_shares(cfs_rq, se->load.weight);
account_entity_enqueue(cfs_rq, se);
@@ -981,7 +1001,7 @@
if (se != cfs_rq->curr)
__dequeue_entity(cfs_rq, se);
se->on_rq = 0;
- update_cfs_load(cfs_rq);
+ update_cfs_load(cfs_rq, 0);
account_entity_dequeue(cfs_rq, se);
update_min_vruntime(cfs_rq);
update_cfs_shares(cfs_rq, 0);
@@ -1216,7 +1236,7 @@
for_each_sched_entity(se) {
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- update_cfs_load(cfs_rq);
+ update_cfs_load(cfs_rq, 0);
update_cfs_shares(cfs_rq, 0);
}
@@ -1246,7 +1266,7 @@
for_each_sched_entity(se) {
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- update_cfs_load(cfs_rq);
+ update_cfs_load(cfs_rq, 0);
update_cfs_shares(cfs_rq, 0);
}
@@ -2052,7 +2072,6 @@
struct cfs_rq *cfs_rq;
unsigned long flags;
struct rq *rq;
- long load_avg;
if (!tg->se[cpu])
return 0;
@@ -2063,12 +2082,7 @@
raw_spin_lock_irqsave(&rq->lock, flags);
update_rq_clock(rq);
- update_cfs_load(cfs_rq);
-
- load_avg = div64_u64(cfs_rq->load_avg, cfs_rq->load_period+1);
- load_avg -= cfs_rq->load_contribution;
- atomic_add(load_avg, &tg->load_weight);
- cfs_rq->load_contribution += load_avg;
+ update_cfs_load(cfs_rq, 1);
/*
* We need to update shares after updating tg->load_weight in