1 files changed, 128 insertions, 35 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 86f5a063f0b9..1dae85a1221a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -467,11 +467,17 @@ struct rt_rq {
         struct rt_prio_array active;
         unsigned long rt_nr_running;
 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
-        int highest_prio; /* highest queued rt task prio */
+        struct {
+                int curr; /* highest queued rt task prio */
+#ifdef CONFIG_SMP
+                int next; /* next highest */
+#endif
+        } highest_prio;
 #endif
 #ifdef CONFIG_SMP
         unsigned long rt_nr_migratory;
         int overloaded;
+        struct plist_head pushable_tasks;
 #endif
         int rt_throttled;
         u64 rt_time;
@@ -1323,8 +1329,8 @@ static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
  * slice expiry etc.
  */
 
-#define WEIGHT_IDLEPRIO         2
-#define WMULT_IDLEPRIO          (1 << 31)
+#define WEIGHT_IDLEPRIO                3
+#define WMULT_IDLEPRIO         1431655765
 
 /*
  * Nice levels are multiplicative, with a gentle 10% change for every
@@ -1610,21 +1616,42 @@ static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd)
 
 #endif
 
+#ifdef CONFIG_PREEMPT
+
 /*
- * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ * fair double_lock_balance: Safely acquires both rq->locks in a fair
+ * way at the expense of forcing extra atomic operations in all
+ * invocations.  This assures that the double_lock is acquired using the
+ * same underlying policy as the spinlock_t on this architecture, which
+ * reduces latency compared to the unfair variant below.  However, it
+ * also adds more overhead and therefore may reduce throughput.
  */
-static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+        __releases(this_rq->lock)
+        __acquires(busiest->lock)
+        __acquires(this_rq->lock)
+{
+        spin_unlock(&this_rq->lock);
+        double_rq_lock(this_rq, busiest);
+
+        return 1;
+}
+
+#else
+/*
+ * Unfair double_lock_balance: Optimizes throughput at the expense of
+ * latency by eliminating extra atomic operations when the locks are
+ * already in proper order on entry.  This favors lower cpu-ids and will
+ * grant the double lock to lower cpus over higher ids under contention,
+ * regardless of entry order into the function.
+ */
+static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
         __releases(this_rq->lock)
         __acquires(busiest->lock)
         __acquires(this_rq->lock)
 {
         int ret = 0;
 
-        if (unlikely(!irqs_disabled())) {
-                /* printk() doesn't work good under rq->lock */
-                spin_unlock(&this_rq->lock);
-                BUG_ON(1);
-        }
         if (unlikely(!spin_trylock(&busiest->lock))) {
                 if (busiest < this_rq) {
                         spin_unlock(&this_rq->lock);
@@ -1637,6 +1664,22 @@ static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
         return ret;
 }
 
+#endif /* CONFIG_PREEMPT */
+
+/*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+{
+        if (unlikely(!irqs_disabled())) {
+                /* printk() doesn't work good under rq->lock */
+                spin_unlock(&this_rq->lock);
+                BUG_ON(1);
+        }
+
+        return _double_lock_balance(this_rq, busiest);
+}
+
 static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
         __releases(busiest->lock)
 {
@@ -2274,6 +2317,16 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
         if (!sched_feat(SYNC_WAKEUPS))
                 sync = 0;
 
+        if (!sync) {
+                if (current->se.avg_overlap < sysctl_sched_migration_cost &&
+                          p->se.avg_overlap < sysctl_sched_migration_cost)
+                        sync = 1;
+        } else {
+                if (current->se.avg_overlap >= sysctl_sched_migration_cost ||
+                          p->se.avg_overlap >= sysctl_sched_migration_cost)
+                        sync = 0;
+        }
+
 #ifdef CONFIG_SMP
         if (sched_feat(LB_WAKEUP_UPDATE)) {
                 struct sched_domain *sd;
@@ -2472,6 +2525,8 @@ void sched_fork(struct task_struct *p, int clone_flags)
         /* Want to start with kernel preemption disabled. */
         task_thread_info(p)->preempt_count = 1;
 #endif
+        plist_node_init(&p->pushable_tasks, MAX_PRIO);
+
         put_cpu();
 }
 
@@ -2612,6 +2667,12 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
 {
         struct mm_struct *mm = rq->prev_mm;
         long prev_state;
+#ifdef CONFIG_SMP
+        int post_schedule = 0;
+
+        if (current->sched_class->needs_post_schedule)
+                post_schedule = current->sched_class->needs_post_schedule(rq);
+#endif
 
         rq->prev_mm = NULL;
 
@@ -2630,7 +2691,7 @@ static void finish_task_switch(struct rq *rq, struct task_struct *prev)
         finish_arch_switch(prev);
         finish_lock_switch(rq, prev);
 #ifdef CONFIG_SMP
-        if (current->sched_class->post_schedule)
+        if (post_schedule)
                 current->sched_class->post_schedule(rq);
 #endif
 
@@ -3011,6 +3072,16 @@ next:
         pulled++;
         rem_load_move -= p->se.load.weight;
 
+#ifdef CONFIG_PREEMPT
+        /*
+         * NEWIDLE balancing is a source of latency, so preemptible kernels
+         * will stop after the first task is pulled to minimize the critical
+         * section.
+         */
+        if (idle == CPU_NEWLY_IDLE)
+                goto out;
+#endif
+
         /*
          * We only want to steal up to the prescribed amount of weighted load.
          */
@@ -3057,9 +3128,15 @@ static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
                                 sd, idle, all_pinned, &this_best_prio);
                 class = class->next;
 
+#ifdef CONFIG_PREEMPT
+                /*
+                 * NEWIDLE balancing is a source of latency, so preemptible
+                 * kernels will stop after the first task is pulled to minimize
+                 * the critical section.
+                 */
                 if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
                         break;
-
+#endif
         } while (class && max_load_move > total_load_moved);
 
         return total_load_moved > 0;
@@ -3904,19 +3981,24 @@ int select_nohz_load_balancer(int stop_tick)
         int cpu = smp_processor_id();
 
         if (stop_tick) {
-                cpumask_set_cpu(cpu, nohz.cpu_mask);
                 cpu_rq(cpu)->in_nohz_recently = 1;
 
-                /*
-                 * If we are going offline and still the leader, give up!
-                 */
-                if (!cpu_active(cpu) &&
-                    atomic_read(&nohz.load_balancer) == cpu) {
+                if (!cpu_active(cpu)) {
+                        if (atomic_read(&nohz.load_balancer) != cpu)
+                                return 0;
+
+                        /*
+                         * If we are going offline and still the leader,
+                         * give up!
+                         */
                         if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
                                 BUG();
+
                         return 0;
                 }
 
+                cpumask_set_cpu(cpu, nohz.cpu_mask);
+
                 /* time for ilb owner also to sleep */
                 if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
                         if (atomic_read(&nohz.load_balancer) == cpu)
@@ -4464,7 +4546,7 @@ void __kprobes sub_preempt_count(int val)
         /*
          * Underflow?
          */
-       if (DEBUG_LOCKS_WARN_ON(val > preempt_count() - (!!kernel_locked())))
+        if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
                 return;
         /*
          * Is the spinlock portion underflowing?
@@ -5150,7 +5232,7 @@ int can_nice(const struct task_struct *p, const int nice)
  * sys_setpriority is a more generic, but much slower function that
  * does similar things.
  */
-asmlinkage long sys_nice(int increment)
+SYSCALL_DEFINE1(nice, int, increment)
 {
         long nice, retval;
 
@@ -5457,8 +5539,8 @@ do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
  * @policy: new policy.
  * @param: structure containing the new RT priority.
  */
-asmlinkage long
-sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy,
+                struct sched_param __user *, param)
 {
         /* negative values for policy are not valid */
         if (policy < 0)
@@ -5472,7 +5554,7 @@ sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
  * @pid: the pid in question.
  * @param: structure containing the new RT priority.
  */
-asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
 {
         return do_sched_setscheduler(pid, -1, param);
 }
@@ -5481,7 +5563,7 @@ asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
  * sys_sched_getscheduler - get the policy (scheduling class) of a thread
  * @pid: the pid in question.
  */
-asmlinkage long sys_sched_getscheduler(pid_t pid)
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
 {
         struct task_struct *p;
         int retval;
@@ -5506,7 +5588,7 @@ asmlinkage long sys_sched_getscheduler(pid_t pid)
  * @pid: the pid in question.
  * @param: structure containing the RT priority.
  */
-asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
 {
         struct sched_param lp;
         struct task_struct *p;
@@ -5624,8 +5706,8 @@ static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
  * @len: length in bytes of the bitmask pointed to by user_mask_ptr
  * @user_mask_ptr: user-space pointer to the new cpu mask
  */
-asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
-                                      unsigned long __user *user_mask_ptr)
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
+                unsigned long __user *, user_mask_ptr)
 {
         cpumask_var_t new_mask;
         int retval;
@@ -5672,8 +5754,8 @@ out_unlock:
  * @len: length in bytes of the bitmask pointed to by user_mask_ptr
  * @user_mask_ptr: user-space pointer to hold the current cpu mask
  */
-asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
-                                      unsigned long __user *user_mask_ptr)
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
+                unsigned long __user *, user_mask_ptr)
 {
         int ret;
         cpumask_var_t mask;
@@ -5702,7 +5784,7 @@ asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
  * This function yields the current CPU to other tasks. If there are no
  * other threads running on this CPU then this function will return.
  */
-asmlinkage long sys_sched_yield(void)
+SYSCALL_DEFINE0(sched_yield)
 {
         struct rq *rq = this_rq_lock();
 
@@ -5843,7 +5925,7 @@ long __sched io_schedule_timeout(long timeout)
  * this syscall returns the maximum rt_priority that can be used
  * by a given scheduling class.
  */
-asmlinkage long sys_sched_get_priority_max(int policy)
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
 {
         int ret = -EINVAL;
 
@@ -5868,7 +5950,7 @@ asmlinkage long sys_sched_get_priority_max(int policy)
  * this syscall returns the minimum rt_priority that can be used
  * by a given scheduling class.
  */
-asmlinkage long sys_sched_get_priority_min(int policy)
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
 {
         int ret = -EINVAL;
 
@@ -5893,8 +5975,8 @@ asmlinkage long sys_sched_get_priority_min(int policy)
  * this syscall writes the default timeslice value of a given process
  * into the user-space timespec buffer. A value of '0' means infinity.
  */
-asmlinkage
-long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
+                struct timespec __user *, interval)
 {
         struct task_struct *p;
         unsigned int time_slice;
@@ -8228,11 +8310,15 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
         __set_bit(MAX_RT_PRIO, array->bitmap);
 
 #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
-        rt_rq->highest_prio = MAX_RT_PRIO;
+        rt_rq->highest_prio.curr = MAX_RT_PRIO;
+#ifdef CONFIG_SMP
+        rt_rq->highest_prio.next = MAX_RT_PRIO;
+#endif
 #endif
 #ifdef CONFIG_SMP
         rt_rq->rt_nr_migratory = 0;
         rt_rq->overloaded = 0;
+        plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
 #endif
 
         rt_rq->rt_time = 0;
@@ -9074,6 +9160,13 @@ static int tg_schedulable(struct task_group *tg, void *data)
                 runtime = d->rt_runtime;
         }
 
+#ifdef CONFIG_USER_SCHED
+        if (tg == &root_task_group) {
+                period = global_rt_period();
+                runtime = global_rt_runtime();
+        }
+#endif
+
         /*
          * Cannot have more runtime than the period.
          */