sched: Guarantee new group-entities always have weight

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d0a7b93ce05e24c882b375b2b78072a882a21b9a..305ef886219eef02214f9c0336378aa9236b5115 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2410,6 +2410,13 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
        if (idle)
                goto out_unlock;
 
+       /*
+        * if we have relooped after returning idle once, we need to update our
+        * status as actually running, so that other cpus doing
+        * __start_cfs_bandwidth will stop trying to cancel us.
+        */
+       cfs_b->timer_active = 1;
+
        __refill_cfs_bandwidth_runtime(cfs_b);
 
        if (!throttled) {
@@ -2682,11 +2689,11 @@ void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
         * (timer_active==0 becomes visible before the hrtimer call-back
         * terminates).  In either case we ensure that it's re-programmed
         */
-       while (unlikely(hrtimer_active(&cfs_b->period_timer))) {
+       while (unlikely(hrtimer_active(&cfs_b->period_timer)) &&
+              hrtimer_try_to_cancel(&cfs_b->period_timer) < 0) {
+               /* bounce the lock to allow do_sched_cfs_period_timer to run */
                raw_spin_unlock(&cfs_b->lock);
-               /* ensure cfs_b->lock is available while we wait */
-               hrtimer_cancel(&cfs_b->period_timer);
-
+               cpu_relax();
                raw_spin_lock(&cfs_b->lock);
                /* if someone else restarted the timer then we're done */
                if (cfs_b->timer_active)
@@ -6084,7 +6091,8 @@ void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
                se->cfs_rq = parent->my_q;
 
        se->my_q = cfs_rq;
-       update_load_set(&se->load, 0);
+       /* guarantee group entities always have weight */
+       update_load_set(&se->load, NICE_0_LOAD);
        se->parent = parent;
 }