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Diffstat (limited to 'kernel/sched/fair.c')
-rw-r--r--kernel/sched/fair.c27
1 files changed, 25 insertions, 2 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8dbff6e7ad4f..cb225921bbca 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6619,6 +6619,7 @@ dequeue_throttle:
/* Working cpumask for: load_balance, load_balance_newidle. */
static DEFINE_PER_CPU(cpumask_var_t, load_balance_mask);
static DEFINE_PER_CPU(cpumask_var_t, select_rq_mask);
+static DEFINE_PER_CPU(cpumask_var_t, should_we_balance_tmpmask);
#ifdef CONFIG_NO_HZ_COMMON
@@ -9579,7 +9580,7 @@ static inline long sibling_imbalance(struct lb_env *env,
imbalance /= ncores_local + ncores_busiest;
/* Take advantage of resource in an empty sched group */
- if (imbalance == 0 && local->sum_nr_running == 0 &&
+ if (imbalance <= 1 && local->sum_nr_running == 0 &&
busiest->sum_nr_running > 1)
imbalance = 2;
@@ -9767,6 +9768,15 @@ static bool update_sd_pick_busiest(struct lb_env *env,
break;
case group_smt_balance:
+ /*
+ * Check if we have spare CPUs on either SMT group to
+ * choose has spare or fully busy handling.
+ */
+ if (sgs->idle_cpus != 0 || busiest->idle_cpus != 0)
+ goto has_spare;
+
+ fallthrough;
+
case group_fully_busy:
/*
* Select the fully busy group with highest avg_load. In
@@ -9806,6 +9816,7 @@ static bool update_sd_pick_busiest(struct lb_env *env,
else
return true;
}
+has_spare:
/*
* Select not overloaded group with lowest number of idle cpus
@@ -10917,6 +10928,7 @@ static int active_load_balance_cpu_stop(void *data);
static int should_we_balance(struct lb_env *env)
{
+ struct cpumask *swb_cpus = this_cpu_cpumask_var_ptr(should_we_balance_tmpmask);
struct sched_group *sg = env->sd->groups;
int cpu, idle_smt = -1;
@@ -10940,8 +10952,9 @@ static int should_we_balance(struct lb_env *env)
return 1;
}
+ cpumask_copy(swb_cpus, group_balance_mask(sg));
/* Try to find first idle CPU */
- for_each_cpu_and(cpu, group_balance_mask(sg), env->cpus) {
+ for_each_cpu_and(cpu, swb_cpus, env->cpus) {
if (!idle_cpu(cpu))
continue;
@@ -10953,6 +10966,14 @@ static int should_we_balance(struct lb_env *env)
if (!(env->sd->flags & SD_SHARE_CPUCAPACITY) && !is_core_idle(cpu)) {
if (idle_smt == -1)
idle_smt = cpu;
+ /*
+ * If the core is not idle, and first SMT sibling which is
+ * idle has been found, then its not needed to check other
+ * SMT siblings for idleness:
+ */
+#ifdef CONFIG_SCHED_SMT
+ cpumask_andnot(swb_cpus, swb_cpus, cpu_smt_mask(cpu));
+#endif
continue;
}
@@ -12918,6 +12939,8 @@ __init void init_sched_fair_class(void)
for_each_possible_cpu(i) {
zalloc_cpumask_var_node(&per_cpu(load_balance_mask, i), GFP_KERNEL, cpu_to_node(i));
zalloc_cpumask_var_node(&per_cpu(select_rq_mask, i), GFP_KERNEL, cpu_to_node(i));
+ zalloc_cpumask_var_node(&per_cpu(should_we_balance_tmpmask, i),
+ GFP_KERNEL, cpu_to_node(i));
#ifdef CONFIG_CFS_BANDWIDTH
INIT_CSD(&cpu_rq(i)->cfsb_csd, __cfsb_csd_unthrottle, cpu_rq(i));