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-rw-r--r--kernel/sched/fair.c21
-rw-r--r--kernel/sched/sched.h12
2 files changed, 28 insertions, 5 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ef5eac773c70..e3ff3d1c4780 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5866,7 +5866,8 @@ static inline int sg_capacity_factor(struct lb_env *env, struct sched_group *gro
*/
static inline void update_sg_lb_stats(struct lb_env *env,
struct sched_group *group, int load_idx,
- int local_group, struct sg_lb_stats *sgs)
+ int local_group, struct sg_lb_stats *sgs,
+ bool *overload)
{
unsigned long load;
int i;
@@ -5884,6 +5885,10 @@ static inline void update_sg_lb_stats(struct lb_env *env,
sgs->group_load += load;
sgs->sum_nr_running += rq->nr_running;
+
+ if (rq->nr_running > 1)
+ *overload = true;
+
#ifdef CONFIG_NUMA_BALANCING
sgs->nr_numa_running += rq->nr_numa_running;
sgs->nr_preferred_running += rq->nr_preferred_running;
@@ -5994,6 +5999,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
struct sched_group *sg = env->sd->groups;
struct sg_lb_stats tmp_sgs;
int load_idx, prefer_sibling = 0;
+ bool overload = false;
if (child && child->flags & SD_PREFER_SIBLING)
prefer_sibling = 1;
@@ -6014,7 +6020,8 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
update_group_capacity(env->sd, env->dst_cpu);
}
- update_sg_lb_stats(env, sg, load_idx, local_group, sgs);
+ update_sg_lb_stats(env, sg, load_idx, local_group, sgs,
+ &overload);
if (local_group)
goto next_group;
@@ -6048,6 +6055,13 @@ next_group:
if (env->sd->flags & SD_NUMA)
env->fbq_type = fbq_classify_group(&sds->busiest_stat);
+
+ if (!env->sd->parent) {
+ /* update overload indicator if we are at root domain */
+ if (env->dst_rq->rd->overload != overload)
+ env->dst_rq->rd->overload = overload;
+ }
+
}
/**
@@ -6766,7 +6780,8 @@ static int idle_balance(struct rq *this_rq)
*/
this_rq->idle_stamp = rq_clock(this_rq);
- if (this_rq->avg_idle < sysctl_sched_migration_cost) {
+ if (this_rq->avg_idle < sysctl_sched_migration_cost ||
+ !this_rq->rd->overload) {
rcu_read_lock();
sd = rcu_dereference_check_sched_domain(this_rq->sd);
if (sd)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index eb8567610295..0191ed563bdd 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -477,6 +477,9 @@ struct root_domain {
cpumask_var_t span;
cpumask_var_t online;
+ /* Indicate more than one runnable task for any CPU */
+ bool overload;
+
/*
* The bit corresponding to a CPU gets set here if such CPU has more
* than one runnable -deadline task (as it is below for RT tasks).
@@ -1218,8 +1221,13 @@ static inline void add_nr_running(struct rq *rq, unsigned count)
rq->nr_running = prev_nr + count;
-#ifdef CONFIG_NO_HZ_FULL
if (prev_nr < 2 && rq->nr_running >= 2) {
+#ifdef CONFIG_SMP
+ if (!rq->rd->overload)
+ rq->rd->overload = true;
+#endif
+
+#ifdef CONFIG_NO_HZ_FULL
if (tick_nohz_full_cpu(rq->cpu)) {
/*
* Tick is needed if more than one task runs on a CPU.
@@ -1231,8 +1239,8 @@ static inline void add_nr_running(struct rq *rq, unsigned count)
*/
tick_nohz_full_kick_cpu(rq->cpu);
}
- }
#endif
+ }
}
static inline void sub_nr_running(struct rq *rq, unsigned count)