1 files changed, 65 insertions, 12 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 04160d277e7a..9a1ddb84e26d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -600,7 +600,6 @@ struct rq {
         /* BKL stats */
         unsigned int bkl_count;
 #endif
-        struct lock_class_key rq_lock_key;
 };
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
@@ -809,9 +808,9 @@ const_debug unsigned int sysctl_sched_nr_migrate = 32;
 
 /*
  * ratelimit for updating the group shares.
- * default: 0.5ms
+ * default: 0.25ms
  */
-const_debug unsigned int sysctl_sched_shares_ratelimit = 500000;
+unsigned int sysctl_sched_shares_ratelimit = 250000;
 
 /*
  * period over which we measure -rt task cpu usage in us.
@@ -834,7 +833,7 @@ static inline u64 global_rt_period(void)
 
 static inline u64 global_rt_runtime(void)
 {
-        if (sysctl_sched_rt_period < 0)
+        if (sysctl_sched_rt_runtime < 0)
                 return RUNTIME_INF;
 
         return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
@@ -2759,10 +2758,10 @@ static void double_rq_lock(struct rq *rq1, struct rq *rq2)
         } else {
                 if (rq1 < rq2) {
                         spin_lock(&rq1->lock);
-                        spin_lock(&rq2->lock);
+                        spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
                 } else {
                         spin_lock(&rq2->lock);
-                        spin_lock(&rq1->lock);
+                        spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
                 }
         }
         update_rq_clock(rq1);
@@ -2805,14 +2804,21 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
                 if (busiest < this_rq) {
                         spin_unlock(&this_rq->lock);
                         spin_lock(&busiest->lock);
-                        spin_lock(&this_rq->lock);
+                        spin_lock_nested(&this_rq->lock, SINGLE_DEPTH_NESTING);
                         ret = 1;
                 } else
-                        spin_lock(&busiest->lock);
+                        spin_lock_nested(&busiest->lock, SINGLE_DEPTH_NESTING);
         }
         return ret;
 }
 
+static void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
+        __releases(busiest->lock)
+{
+        spin_unlock(&busiest->lock);
+        lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
+}
+
 /*
  * If dest_cpu is allowed for this process, migrate the task to it.
  * This is accomplished by forcing the cpu_allowed mask to only
@@ -3637,7 +3643,7 @@ redo:
                 ld_moved = move_tasks(this_rq, this_cpu, busiest,
                                         imbalance, sd, CPU_NEWLY_IDLE,
                                         &all_pinned);
-                spin_unlock(&busiest->lock);
+                double_unlock_balance(this_rq, busiest);
 
                 if (unlikely(all_pinned)) {
                         cpu_clear(cpu_of(busiest), *cpus);
@@ -3752,7 +3758,7 @@ static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
                 else
                         schedstat_inc(sd, alb_failed);
         }
-        spin_unlock(&target_rq->lock);
+        double_unlock_balance(busiest_rq, target_rq);
 }
 
 #ifdef CONFIG_NO_HZ
@@ -4663,6 +4669,52 @@ int __sched wait_for_completion_killable(struct completion *x)
 }
 EXPORT_SYMBOL(wait_for_completion_killable);
 
+/**
+ *      try_wait_for_completion - try to decrement a completion without blocking
+ *      @x:     completion structure
+ *
+ *      Returns: 0 if a decrement cannot be done without blocking
+ *               1 if a decrement succeeded.
+ *
+ *      If a completion is being used as a counting completion,
+ *      attempt to decrement the counter without blocking. This
+ *      enables us to avoid waiting if the resource the completion
+ *      is protecting is not available.
+ */
+bool try_wait_for_completion(struct completion *x)
+{
+        int ret = 1;
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done)
+                ret = 0;
+        else
+                x->done--;
+        spin_unlock_irq(&x->wait.lock);
+        return ret;
+}
+EXPORT_SYMBOL(try_wait_for_completion);
+
+/**
+ *      completion_done - Test to see if a completion has any waiters
+ *      @x:     completion structure
+ *
+ *      Returns: 0 if there are waiters (wait_for_completion() in progress)
+ *               1 if there are no waiters.
+ *
+ */
+bool completion_done(struct completion *x)
+{
+        int ret = 1;
+
+        spin_lock_irq(&x->wait.lock);
+        if (!x->done)
+                ret = 0;
+        spin_unlock_irq(&x->wait.lock);
+        return ret;
+}
+EXPORT_SYMBOL(completion_done);
+
 static long __sched
 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
 {
@@ -5734,6 +5786,8 @@ static inline void sched_init_granularity(void)
                 sysctl_sched_latency = limit;
 
         sysctl_sched_wakeup_granularity *= factor;
+
+        sysctl_sched_shares_ratelimit *= factor;
 }
 
 #ifdef CONFIG_SMP
@@ -8000,7 +8054,6 @@ void __init sched_init(void)
 
                 rq = cpu_rq(i);
                 spin_lock_init(&rq->lock);
-                lockdep_set_class(&rq->lock, &rq->rq_lock_key);
                 rq->nr_running = 0;
                 init_cfs_rq(&rq->cfs, rq);
                 init_rt_rq(&rq->rt, rq);
@@ -8457,8 +8510,8 @@ struct task_group *sched_create_group(struct task_group *parent)
         WARN_ON(!parent); /* root should already exist */
 
         tg->parent = parent;
-        list_add_rcu(&tg->siblings, &parent->children);
         INIT_LIST_HEAD(&tg->children);
+        list_add_rcu(&tg->siblings, &parent->children);
         spin_unlock_irqrestore(&task_group_lock, flags);
 
         return tg;