3 files changed, 39 insertions, 2 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 1cff969f6646..62db0891025a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -778,6 +778,12 @@ late_initcall(sched_init_debug);
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
 
 /*
+ * ratelimit for updating the group shares.
+ * default: 0.5ms
+ */
+const_debug unsigned int sysctl_sched_shares_ratelimit = 500000;
+
+/*
  * period over which we measure -rt task cpu usage in us.
  * default: 1s
  */
@@ -1590,7 +1596,13 @@ tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd)
 
 static void update_shares(struct sched_domain *sd)
 {
-        walk_tg_tree(tg_nop, tg_shares_up, 0, sd);
+        u64 now = cpu_clock(raw_smp_processor_id());
+        s64 elapsed = now - sd->last_update;
+
+        if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) {
+                sd->last_update = now;
+                walk_tg_tree(tg_nop, tg_shares_up, 0, sd);
+        }
 }
 
 static void update_shares_locked(struct rq *rq, struct sched_domain *sd)
@@ -2199,6 +2211,22 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
         if (!sched_feat(SYNC_WAKEUPS))
                 sync = 0;
 
+#ifdef CONFIG_SMP
+        if (sched_feat(LB_WAKEUP_UPDATE)) {
+                struct sched_domain *sd;
+
+                this_cpu = raw_smp_processor_id();
+                cpu = task_cpu(p);
+
+                for_each_domain(this_cpu, sd) {
+                        if (cpu_isset(cpu, sd->span)) {
+                                update_shares(sd);
+                                break;
+                        }
+                }
+        }
+#endif
+
         smp_wmb();
         rq = task_rq_lock(p, &flags);
         old_state = p->state;
diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index d56e3053e746..7d616d2a2a3f 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -8,4 +8,5 @@ SCHED_FEAT(SYNC_WAKEUPS, 1)
 SCHED_FEAT(HRTICK, 1)
 SCHED_FEAT(DOUBLE_TICK, 0)
 SCHED_FEAT(ASYM_GRAN, 1)
-SCHED_FEAT(LB_BIAS, 0)
\ No newline at end of file
+SCHED_FEAT(LB_BIAS, 0)
+SCHED_FEAT(LB_WAKEUP_UPDATE, 1)
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 29116652dca8..fe8cdc80ff02 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -266,6 +266,14 @@ static struct ctl_table kern_table[] = {
         },
         {
                 .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "sched_shares_ratelimit",
+                .data           = &sysctl_sched_shares_ratelimit,
+                .maxlen         = sizeof(unsigned int),
+                .mode           = 0644,
+                .proc_handler   = &proc_dointvec,
+        },
+        {
+                .ctl_name       = CTL_UNNUMBERED,
                 .procname       = "sched_child_runs_first",
                 .data           = &sysctl_sched_child_runs_first,
                 .maxlen         = sizeof(unsigned int),