sched: update shares on wakeup

[linux-2.6-omap-h63xx.git] / kernel / sched.c

diff --git a/kernel/sched.c b/kernel/sched.c
index 1cff969f66463e8505386d4b4e5287bd852252ba..62db0891025aee964709c6dafeeec0e7be166492 100644 (file)
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -777,6 +777,12 @@ 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;