Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits)
  sched: Change wait_for_completion_*_timeout() to return a signed long
  sched, autogroup: Fix reference leak
  sched, autogroup: Fix potential access to freed memory
  sched: Remove redundant CONFIG_CGROUP_SCHED ifdef
  sched: Fix interactivity bug by charging unaccounted run-time on entity re-weight
  sched: Move periodic share updates to entity_tick()
  printk: Use this_cpu_{read|write} api on printk_pending
  sched: Make pushable_tasks CONFIG_SMP dependant
  sched: Add 'autogroup' scheduling feature: automated per session task groups
  sched: Fix unregister_fair_sched_group()
  sched: Remove unused argument dest_cpu to migrate_task()
  mutexes, sched: Introduce arch_mutex_cpu_relax()
  sched: Add some clock info to sched_debug
  cpu: Remove incorrect BUG_ON
  cpu: Remove unused variable
  sched: Fix UP build breakage
  sched: Make task dump print all 15 chars of proc comm
  sched: Update tg->shares after cpu.shares write
  sched: Allow update_cfs_load() to update global load
  sched: Implement demand based update_cfs_load()
  ...

1 files changed, 138 insertions, 431 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 260132961a99..04949089e760 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -75,9 +75,11 @@
 
 #include <asm/tlb.h>
 #include <asm/irq_regs.h>
+#include <asm/mutex.h>
 
 #include "sched_cpupri.h"
 #include "workqueue_sched.h"
+#include "sched_autogroup.h"
 
 #define CREATE_TRACE_POINTS
 #include <trace/events/sched.h>
@@ -253,6 +255,8 @@ struct task_group {
         /* runqueue "owned" by this group on each cpu */
         struct cfs_rq **cfs_rq;
         unsigned long shares;
+
+        atomic_t load_weight;
 #endif
 
 #ifdef CONFIG_RT_GROUP_SCHED
@@ -268,24 +272,19 @@ struct task_group {
         struct task_group *parent;
         struct list_head siblings;
         struct list_head children;
+
+#ifdef CONFIG_SCHED_AUTOGROUP
+        struct autogroup *autogroup;
+#endif
 };
 
 #define root_task_group init_task_group
 
-/* task_group_lock serializes add/remove of task groups and also changes to
- * a task group's cpu shares.
- */
+/* task_group_lock serializes the addition/removal of task groups */
 static DEFINE_SPINLOCK(task_group_lock);
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 
-#ifdef CONFIG_SMP
-static int root_task_group_empty(void)
-{
-        return list_empty(&root_task_group.children);
-}
-#endif
-
 # define INIT_TASK_GROUP_LOAD   NICE_0_LOAD
 
 /*
@@ -342,6 +341,7 @@ struct cfs_rq {
          * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
          * list is used during load balance.
          */
+        int on_list;
         struct list_head leaf_cfs_rq_list;
         struct task_group *tg;  /* group that "owns" this runqueue */
 
@@ -360,14 +360,17 @@ struct cfs_rq {
         unsigned long h_load;
 
         /*
-         * this cpu's part of tg->shares
+         * Maintaining per-cpu shares distribution for group scheduling
+         *
+         * load_stamp is the last time we updated the load average
+         * load_last is the last time we updated the load average and saw load
+         * load_unacc_exec_time is currently unaccounted execution time
          */
-        unsigned long shares;
+        u64 load_avg;
+        u64 load_period;
+        u64 load_stamp, load_last, load_unacc_exec_time;
 
-        /*
-         * load.weight at the time we set shares
-         */
-        unsigned long rq_weight;
+        unsigned long load_contribution;
 #endif
 #endif
 };
@@ -605,11 +608,14 @@ static inline int cpu_of(struct rq *rq)
  */
 static inline struct task_group *task_group(struct task_struct *p)
 {
+        struct task_group *tg;
         struct cgroup_subsys_state *css;
 
         css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
                         lockdep_is_held(&task_rq(p)->lock));
-        return container_of(css, struct task_group, css);
+        tg = container_of(css, struct task_group, css);
+
+        return autogroup_task_group(p, tg);
 }
 
 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
@@ -793,20 +799,6 @@ late_initcall(sched_init_debug);
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
 
 /*
- * ratelimit for updating the group shares.
- * default: 0.25ms
- */
-unsigned int sysctl_sched_shares_ratelimit = 250000;
-unsigned int normalized_sysctl_sched_shares_ratelimit = 250000;
-
-/*
- * Inject some fuzzyness into changing the per-cpu group shares
- * this avoids remote rq-locks at the expense of fairness.
- * default: 4
- */
-unsigned int sysctl_sched_shares_thresh = 4;
-
-/*
  * period over which we average the RT time consumption, measured
  * in ms.
  *
@@ -1355,6 +1347,12 @@ static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
         lw->inv_weight = 0;
 }
 
+static inline void update_load_set(struct load_weight *lw, unsigned long w)
+{
+        lw->weight = w;
+        lw->inv_weight = 0;
+}
+
 /*
  * To aid in avoiding the subversion of "niceness" due to uneven distribution
  * of tasks with abnormal "nice" values across CPUs the contribution that
@@ -1543,101 +1541,6 @@ static unsigned long cpu_avg_load_per_task(int cpu)
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 
-static __read_mostly unsigned long __percpu *update_shares_data;
-
-static void __set_se_shares(struct sched_entity *se, unsigned long shares);
-
-/*
- * Calculate and set the cpu's group shares.
- */
-static void update_group_shares_cpu(struct task_group *tg, int cpu,
-                                    unsigned long sd_shares,
-                                    unsigned long sd_rq_weight,
-                                    unsigned long *usd_rq_weight)
-{
-        unsigned long shares, rq_weight;
-        int boost = 0;
-
-        rq_weight = usd_rq_weight[cpu];
-        if (!rq_weight) {
-                boost = 1;
-                rq_weight = NICE_0_LOAD;
-        }
-
-        /*
-         *             \Sum_j shares_j * rq_weight_i
-         * shares_i =  -----------------------------
-         *                  \Sum_j rq_weight_j
-         */
-        shares = (sd_shares * rq_weight) / sd_rq_weight;
-        shares = clamp_t(unsigned long, shares, MIN_SHARES, MAX_SHARES);
-
-        if (abs(shares - tg->se[cpu]->load.weight) >
-                        sysctl_sched_shares_thresh) {
-                struct rq *rq = cpu_rq(cpu);
-                unsigned long flags;
-
-                raw_spin_lock_irqsave(&rq->lock, flags);
-                tg->cfs_rq[cpu]->rq_weight = boost ? 0 : rq_weight;
-                tg->cfs_rq[cpu]->shares = boost ? 0 : shares;
-                __set_se_shares(tg->se[cpu], shares);
-                raw_spin_unlock_irqrestore(&rq->lock, flags);
-        }
-}
-
-/*
- * Re-compute the task group their per cpu shares over the given domain.
- * This needs to be done in a bottom-up fashion because the rq weight of a
- * parent group depends on the shares of its child groups.
- */
-static int tg_shares_up(struct task_group *tg, void *data)
-{
-        unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0;
-        unsigned long *usd_rq_weight;
-        struct sched_domain *sd = data;
-        unsigned long flags;
-        int i;
-
-        if (!tg->se[0])
-                return 0;
-
-        local_irq_save(flags);
-        usd_rq_weight = per_cpu_ptr(update_shares_data, smp_processor_id());
-
-        for_each_cpu(i, sched_domain_span(sd)) {
-                weight = tg->cfs_rq[i]->load.weight;
-                usd_rq_weight[i] = weight;
-
-                rq_weight += weight;
-                /*
-                 * If there are currently no tasks on the cpu pretend there
-                 * is one of average load so that when a new task gets to
-                 * run here it will not get delayed by group starvation.
-                 */
-                if (!weight)
-                        weight = NICE_0_LOAD;
-
-                sum_weight += weight;
-                shares += tg->cfs_rq[i]->shares;
-        }
-
-        if (!rq_weight)
-                rq_weight = sum_weight;
-
-        if ((!shares && rq_weight) || shares > tg->shares)
-                shares = tg->shares;
-
-        if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
-                shares = tg->shares;
-
-        for_each_cpu(i, sched_domain_span(sd))
-                update_group_shares_cpu(tg, i, shares, rq_weight, usd_rq_weight);
-
-        local_irq_restore(flags);
-
-        return 0;
-}
-
 /*
  * Compute the cpu's hierarchical load factor for each task group.
  * This needs to be done in a top-down fashion because the load of a child
@@ -1652,7 +1555,7 @@ static int tg_load_down(struct task_group *tg, void *data)
                 load = cpu_rq(cpu)->load.weight;
         } else {
                 load = tg->parent->cfs_rq[cpu]->h_load;
-                load *= tg->cfs_rq[cpu]->shares;
+                load *= tg->se[cpu]->load.weight;
                 load /= tg->parent->cfs_rq[cpu]->load.weight + 1;
         }
 
@@ -1661,34 +1564,11 @@ static int tg_load_down(struct task_group *tg, void *data)
         return 0;
 }
 
-static void update_shares(struct sched_domain *sd)
-{
-        s64 elapsed;
-        u64 now;
-
-        if (root_task_group_empty())
-                return;
-
-        now = local_clock();
-        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, sd);
-        }
-}
-
 static void update_h_load(long cpu)
 {
         walk_tg_tree(tg_load_down, tg_nop, (void *)cpu);
 }
 
-#else
-
-static inline void update_shares(struct sched_domain *sd)
-{
-}
-
 #endif
 
 #ifdef CONFIG_PREEMPT
@@ -1810,15 +1690,6 @@ static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
 
 #endif
 
-#ifdef CONFIG_FAIR_GROUP_SCHED
-static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares)
-{
-#ifdef CONFIG_SMP
-        cfs_rq->shares = shares;
-#endif
-}
-#endif
-
 static void calc_load_account_idle(struct rq *this_rq);
 static void update_sysctl(void);
 static int get_update_sysctl_factor(void);
@@ -2063,6 +1934,7 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
 #include "sched_idletask.c"
 #include "sched_fair.c"
 #include "sched_rt.c"
+#include "sched_autogroup.c"
 #include "sched_stoptask.c"
 #ifdef CONFIG_SCHED_DEBUG
 # include "sched_debug.c"
@@ -2255,10 +2127,8 @@ static int migration_cpu_stop(void *data);
  * The task's runqueue lock must be held.
  * Returns true if you have to wait for migration thread.
  */
-static bool migrate_task(struct task_struct *p, int dest_cpu)
+static bool migrate_task(struct task_struct *p, struct rq *rq)
 {
-        struct rq *rq = task_rq(p);
-
         /*
          * If the task is not on a runqueue (and not running), then
          * the next wake-up will properly place the task.
@@ -2438,18 +2308,15 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
                 return dest_cpu;
 
         /* No more Mr. Nice Guy. */
-        if (unlikely(dest_cpu >= nr_cpu_ids)) {
-                dest_cpu = cpuset_cpus_allowed_fallback(p);
-                /*
-                 * Don't tell them about moving exiting tasks or
-                 * kernel threads (both mm NULL), since they never
-                 * leave kernel.
-                 */
-                if (p->mm && printk_ratelimit()) {
-                        printk(KERN_INFO "process %d (%s) no "
-                               "longer affine to cpu%d\n",
-                               task_pid_nr(p), p->comm, cpu);
-                }
+        dest_cpu = cpuset_cpus_allowed_fallback(p);
+        /*
+         * Don't tell them about moving exiting tasks or
+         * kernel threads (both mm NULL), since they never
+         * leave kernel.
+         */
+        if (p->mm && printk_ratelimit()) {
+                printk(KERN_INFO "process %d (%s) no longer affine to cpu%d\n",
+                                task_pid_nr(p), p->comm, cpu);
         }
 
         return dest_cpu;
@@ -2785,7 +2652,9 @@ 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
+#ifdef CONFIG_SMP
         plist_node_init(&p->pushable_tasks, MAX_PRIO);
+#endif
 
         put_cpu();
 }
@@ -3549,7 +3418,7 @@ void sched_exec(void)
          * select_task_rq() can race against ->cpus_allowed
          */
         if (cpumask_test_cpu(dest_cpu, &p->cpus_allowed) &&
-            likely(cpu_active(dest_cpu)) && migrate_task(p, dest_cpu)) {
+            likely(cpu_active(dest_cpu)) && migrate_task(p, rq)) {
                 struct migration_arg arg = { p, dest_cpu };
 
                 task_rq_unlock(rq, &flags);
@@ -4214,7 +4083,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
                 if (task_thread_info(rq->curr) != owner || need_resched())
                         return 0;
 
-                cpu_relax();
+                arch_mutex_cpu_relax();
         }
 
         return 1;
@@ -4526,7 +4395,7 @@ EXPORT_SYMBOL(wait_for_completion_interruptible);
  * This waits for either a completion of a specific task to be signaled or for a
  * specified timeout to expire. It is interruptible. The timeout is in jiffies.
  */
-unsigned long __sched
+long __sched
 wait_for_completion_interruptible_timeout(struct completion *x,
                                           unsigned long timeout)
 {
@@ -4559,7 +4428,7 @@ EXPORT_SYMBOL(wait_for_completion_killable);
  * signaled or for a specified timeout to expire. It can be
  * interrupted by a kill signal. The timeout is in jiffies.
  */
-unsigned long __sched
+long __sched
 wait_for_completion_killable_timeout(struct completion *x,
                                      unsigned long timeout)
 {
@@ -4901,7 +4770,7 @@ static bool check_same_owner(struct task_struct *p)
 }
 
 static int __sched_setscheduler(struct task_struct *p, int policy,
-                                struct sched_param *param, bool user)
+                                const struct sched_param *param, bool user)
 {
         int retval, oldprio, oldpolicy = -1, on_rq, running;
         unsigned long flags;
@@ -5056,7 +4925,7 @@ recheck:
  * NOTE that the task may be already dead.
  */
 int sched_setscheduler(struct task_struct *p, int policy,
-                       struct sched_param *param)
+                       const struct sched_param *param)
 {
         return __sched_setscheduler(p, policy, param, true);
 }
@@ -5074,7 +4943,7 @@ EXPORT_SYMBOL_GPL(sched_setscheduler);
  * but our caller might not have that capability.
  */
 int sched_setscheduler_nocheck(struct task_struct *p, int policy,
-                               struct sched_param *param)
+                               const struct sched_param *param)
 {
         return __sched_setscheduler(p, policy, param, false);
 }
@@ -5590,7 +5459,7 @@ void sched_show_task(struct task_struct *p)
         unsigned state;
 
         state = p->state ? __ffs(p->state) + 1 : 0;
-        printk(KERN_INFO "%-13.13s %c", p->comm,
+        printk(KERN_INFO "%-15.15s %c", p->comm,
                 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
 #if BITS_PER_LONG == 32
         if (state == TASK_RUNNING)
@@ -5754,7 +5623,6 @@ static void update_sysctl(void)
         SET_SYSCTL(sched_min_granularity);
         SET_SYSCTL(sched_latency);
         SET_SYSCTL(sched_wakeup_granularity);
-        SET_SYSCTL(sched_shares_ratelimit);
 #undef SET_SYSCTL
 }
 
@@ -5830,7 +5698,7 @@ again:
                 goto out;
 
         dest_cpu = cpumask_any_and(cpu_active_mask, new_mask);
-        if (migrate_task(p, dest_cpu)) {
+        if (migrate_task(p, rq)) {
                 struct migration_arg arg = { p, dest_cpu };
                 /* Need help from migration thread: drop lock and wait. */
                 task_rq_unlock(rq, &flags);
@@ -5912,29 +5780,20 @@ static int migration_cpu_stop(void *data)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
+
 /*
- * Figure out where task on dead CPU should go, use force if necessary.
+ * Ensures that the idle task is using init_mm right before its cpu goes
+ * offline.
  */
-void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
+void idle_task_exit(void)
 {
-        struct rq *rq = cpu_rq(dead_cpu);
-        int needs_cpu, uninitialized_var(dest_cpu);
-        unsigned long flags;
+        struct mm_struct *mm = current->active_mm;
 
-        local_irq_save(flags);
+        BUG_ON(cpu_online(smp_processor_id()));
 
-        raw_spin_lock(&rq->lock);
-        needs_cpu = (task_cpu(p) == dead_cpu) && (p->state != TASK_WAKING);
-        if (needs_cpu)
-                dest_cpu = select_fallback_rq(dead_cpu, p);
-        raw_spin_unlock(&rq->lock);
-        /*
-         * It can only fail if we race with set_cpus_allowed(),
-         * in the racer should migrate the task anyway.
-         */
-        if (needs_cpu)
-                __migrate_task(p, dead_cpu, dest_cpu);
-        local_irq_restore(flags);
+        if (mm != &init_mm)
+                switch_mm(mm, &init_mm, current);
+        mmdrop(mm);
 }
 
 /*
@@ -5947,128 +5806,69 @@ void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
 static void migrate_nr_uninterruptible(struct rq *rq_src)
 {
         struct rq *rq_dest = cpu_rq(cpumask_any(cpu_active_mask));
-        unsigned long flags;
 
-        local_irq_save(flags);
-        double_rq_lock(rq_src, rq_dest);
         rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
         rq_src->nr_uninterruptible = 0;
-        double_rq_unlock(rq_src, rq_dest);
-        local_irq_restore(flags);
-}
-
-/* Run through task list and migrate tasks from the dead cpu. */
-static void migrate_live_tasks(int src_cpu)
-{
-        struct task_struct *p, *t;
-
-        read_lock(&tasklist_lock);
-
-        do_each_thread(t, p) {
-                if (p == current)
-                        continue;
-
-                if (task_cpu(p) == src_cpu)
-                        move_task_off_dead_cpu(src_cpu, p);
-        } while_each_thread(t, p);
-
-        read_unlock(&tasklist_lock);
 }
 
 /*
- * Schedules idle task to be the next runnable task on current CPU.
- * It does so by boosting its priority to highest possible.
- * Used by CPU offline code.
+ * remove the tasks which were accounted by rq from calc_load_tasks.
  */
-void sched_idle_next(void)
+static void calc_global_load_remove(struct rq *rq)
 {
-        int this_cpu = smp_processor_id();
-        struct rq *rq = cpu_rq(this_cpu);
-        struct task_struct *p = rq->idle;
-        unsigned long flags;
-
-        /* cpu has to be offline */
-        BUG_ON(cpu_online(this_cpu));
-
-        /*
-         * Strictly not necessary since rest of the CPUs are stopped by now
-         * and interrupts disabled on the current cpu.
-         */
-        raw_spin_lock_irqsave(&rq->lock, flags);
-
-        __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
-
-        activate_task(rq, p, 0);
-
-        raw_spin_unlock_irqrestore(&rq->lock, flags);
+        atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
+        rq->calc_load_active = 0;
 }
 
 /*
- * Ensures that the idle task is using init_mm right before its cpu goes
- * offline.
+ * Migrate all tasks from the rq, sleeping tasks will be migrated by
+ * try_to_wake_up()->select_task_rq().
+ *
+ * Called with rq->lock held even though we'er in stop_machine() and
+ * there's no concurrency possible, we hold the required locks anyway
+ * because of lock validation efforts.
  */
-void idle_task_exit(void)
-{
-        struct mm_struct *mm = current->active_mm;
-
-        BUG_ON(cpu_online(smp_processor_id()));
-
-        if (mm != &init_mm)
-                switch_mm(mm, &init_mm, current);
-        mmdrop(mm);
-}
-
-/* called under rq->lock with disabled interrupts */
-static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
+static void migrate_tasks(unsigned int dead_cpu)
 {
         struct rq *rq = cpu_rq(dead_cpu);
-
-        /* Must be exiting, otherwise would be on tasklist. */
-        BUG_ON(!p->exit_state);
-
-        /* Cannot have done final schedule yet: would have vanished. */
-        BUG_ON(p->state == TASK_DEAD);
-
-        get_task_struct(p);
+        struct task_struct *next, *stop = rq->stop;
+        int dest_cpu;
 
         /*
-         * Drop lock around migration; if someone else moves it,
-         * that's OK. No task can be added to this CPU, so iteration is
-         * fine.
+         * Fudge the rq selection such that the below task selection loop
+         * doesn't get stuck on the currently eligible stop task.
+         *
+         * We're currently inside stop_machine() and the rq is either stuck
+         * in the stop_machine_cpu_stop() loop, or we're executing this code,
+         * either way we should never end up calling schedule() until we're
+         * done here.
          */
-        raw_spin_unlock_irq(&rq->lock);
-        move_task_off_dead_cpu(dead_cpu, p);
-        raw_spin_lock_irq(&rq->lock);
-
-        put_task_struct(p);
-}
-
-/* release_task() removes task from tasklist, so we won't find dead tasks. */
-static void migrate_dead_tasks(unsigned int dead_cpu)
-{
-        struct rq *rq = cpu_rq(dead_cpu);
-        struct task_struct *next;
+        rq->stop = NULL;
 
         for ( ; ; ) {
-                if (!rq->nr_running)
+                /*
+                 * There's this thread running, bail when that's the only
+                 * remaining thread.
+                 */
+                if (rq->nr_running == 1)
                         break;
+
                 next = pick_next_task(rq);
-                if (!next)
-                        break;
+                BUG_ON(!next);
                 next->sched_class->put_prev_task(rq, next);
-                migrate_dead(dead_cpu, next);
 
+                /* Find suitable destination for @next, with force if needed. */
+                dest_cpu = select_fallback_rq(dead_cpu, next);
+                raw_spin_unlock(&rq->lock);
+
+                __migrate_task(next, dead_cpu, dest_cpu);
+
+                raw_spin_lock(&rq->lock);
         }
-}
 
-/*
- * remove the tasks which were accounted by rq from calc_load_tasks.
- */
-static void calc_global_load_remove(struct rq *rq)
-{
-        atomic_long_sub(rq->calc_load_active, &calc_load_tasks);
-        rq->calc_load_active = 0;
+        rq->stop = stop;
 }
+
 #endif /* CONFIG_HOTPLUG_CPU */
 
 #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
@@ -6278,15 +6078,13 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
         unsigned long flags;
         struct rq *rq = cpu_rq(cpu);
 
-        switch (action) {
+        switch (action & ~CPU_TASKS_FROZEN) {
 
         case CPU_UP_PREPARE:
-        case CPU_UP_PREPARE_FROZEN:
                 rq->calc_load_update = calc_load_update;
                 break;
 
         case CPU_ONLINE:
-        case CPU_ONLINE_FROZEN:
                 /* Update our root-domain */
                 raw_spin_lock_irqsave(&rq->lock, flags);
                 if (rq->rd) {
@@ -6298,30 +6096,19 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
                 break;
 
 #ifdef CONFIG_HOTPLUG_CPU
-        case CPU_DEAD:
-        case CPU_DEAD_FROZEN:
-                migrate_live_tasks(cpu);
-                /* Idle task back to normal (off runqueue, low prio) */
-                raw_spin_lock_irq(&rq->lock);
-                deactivate_task(rq, rq->idle, 0);
-                __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
-                rq->idle->sched_class = &idle_sched_class;
-                migrate_dead_tasks(cpu);
-                raw_spin_unlock_irq(&rq->lock);
-                migrate_nr_uninterruptible(rq);
-                BUG_ON(rq->nr_running != 0);
-                calc_global_load_remove(rq);
-                break;
-
         case CPU_DYING:
-        case CPU_DYING_FROZEN:
                 /* Update our root-domain */
                 raw_spin_lock_irqsave(&rq->lock, flags);
                 if (rq->rd) {
                         BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
                         set_rq_offline(rq);
                 }
+                migrate_tasks(cpu);
+                BUG_ON(rq->nr_running != 1); /* the migration thread */
                 raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+                migrate_nr_uninterruptible(rq);
+                calc_global_load_remove(rq);
                 break;
 #endif
         }
@@ -8052,15 +7839,13 @@ static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
 static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
-                                struct sched_entity *se, int cpu, int add,
+                                struct sched_entity *se, int cpu,
                                 struct sched_entity *parent)
 {
         struct rq *rq = cpu_rq(cpu);
         tg->cfs_rq[cpu] = cfs_rq;
         init_cfs_rq(cfs_rq, rq);
         cfs_rq->tg = tg;
-        if (add)
-                list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
 
         tg->se[cpu] = se;
         /* se could be NULL for init_task_group */
@@ -8073,15 +7858,14 @@ static 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;
-        se->load.weight = tg->shares;
-        se->load.inv_weight = 0;
+        update_load_set(&se->load, 0);
         se->parent = parent;
 }
 #endif
 
 #ifdef CONFIG_RT_GROUP_SCHED
 static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
-                struct sched_rt_entity *rt_se, int cpu, int add,
+                struct sched_rt_entity *rt_se, int cpu,
                 struct sched_rt_entity *parent)
 {
         struct rq *rq = cpu_rq(cpu);
@@ -8090,8 +7874,6 @@ static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
         init_rt_rq(rt_rq, rq);
         rt_rq->tg = tg;
         rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
-        if (add)
-                list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
 
         tg->rt_se[cpu] = rt_se;
         if (!rt_se)
@@ -8164,13 +7946,9 @@ void __init sched_init(void)
 #ifdef CONFIG_CGROUP_SCHED
         list_add(&init_task_group.list, &task_groups);
         INIT_LIST_HEAD(&init_task_group.children);
-
+        autogroup_init(&init_task);
 #endif /* CONFIG_CGROUP_SCHED */
 
-#if defined CONFIG_FAIR_GROUP_SCHED && defined CONFIG_SMP
-        update_shares_data = __alloc_percpu(nr_cpu_ids * sizeof(unsigned long),
-                                            __alignof__(unsigned long));
-#endif
         for_each_possible_cpu(i) {
                 struct rq *rq;
 
@@ -8184,7 +7962,6 @@ void __init sched_init(void)
 #ifdef CONFIG_FAIR_GROUP_SCHED
                 init_task_group.shares = init_task_group_load;
                 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
-#ifdef CONFIG_CGROUP_SCHED
                 /*
                  * How much cpu bandwidth does init_task_group get?
                  *
@@ -8204,16 +7981,13 @@ void __init sched_init(void)
                  * We achieve this by letting init_task_group's tasks sit
                  * directly in rq->cfs (i.e init_task_group->se[] = NULL).
                  */
-                init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
-#endif
+                init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, NULL);
 #endif /* CONFIG_FAIR_GROUP_SCHED */
 
                 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
 #ifdef CONFIG_RT_GROUP_SCHED
                 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
-#ifdef CONFIG_CGROUP_SCHED
-                init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
-#endif
+                init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, NULL);
 #endif
 
                 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
@@ -8486,7 +8260,7 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
                 if (!se)
                         goto err_free_rq;
 
-                init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent->se[i]);
+                init_tg_cfs_entry(tg, cfs_rq, se, i, parent->se[i]);
         }
 
         return 1;
@@ -8497,15 +8271,21 @@ err:
         return 0;
 }
 
-static inline void register_fair_sched_group(struct task_group *tg, int cpu)
-{
-        list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
-                        &cpu_rq(cpu)->leaf_cfs_rq_list);
-}
-
 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
 {
-        list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
+        struct rq *rq = cpu_rq(cpu);
+        unsigned long flags;
+
+        /*
+        * Only empty task groups can be destroyed; so we can speculatively
+        * check on_list without danger of it being re-added.
+        */
+        if (!tg->cfs_rq[cpu]->on_list)
+                return;
+
+        raw_spin_lock_irqsave(&rq->lock, flags);
+        list_del_leaf_cfs_rq(tg->cfs_rq[cpu]);
+        raw_spin_unlock_irqrestore(&rq->lock, flags);
 }
 #else /* !CONFG_FAIR_GROUP_SCHED */
 static inline void free_fair_sched_group(struct task_group *tg)
@@ -8518,10 +8298,6 @@ int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
         return 1;
 }
 
-static inline void register_fair_sched_group(struct task_group *tg, int cpu)
-{
-}
-
 static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
 {
 }
@@ -8576,7 +8352,7 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
                 if (!rt_se)
                         goto err_free_rq;
 
-                init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent->rt_se[i]);
+                init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
         }
 
         return 1;
@@ -8586,17 +8362,6 @@ err_free_rq:
 err:
         return 0;
 }
-
-static inline void register_rt_sched_group(struct task_group *tg, int cpu)
-{
-        list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
-                        &cpu_rq(cpu)->leaf_rt_rq_list);
-}
-
-static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
-{
-        list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
-}
 #else /* !CONFIG_RT_GROUP_SCHED */
 static inline void free_rt_sched_group(struct task_group *tg)
 {
@@ -8607,14 +8372,6 @@ int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
 {
         return 1;
 }
-
-static inline void register_rt_sched_group(struct task_group *tg, int cpu)
-{
-}
-
-static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
-{
-}
 #endif /* CONFIG_RT_GROUP_SCHED */
 
 #ifdef CONFIG_CGROUP_SCHED
@@ -8630,7 +8387,6 @@ struct task_group *sched_create_group(struct task_group *parent)
 {
         struct task_group *tg;
         unsigned long flags;
-        int i;
 
         tg = kzalloc(sizeof(*tg), GFP_KERNEL);
         if (!tg)
@@ -8643,10 +8399,6 @@ struct task_group *sched_create_group(struct task_group *parent)
                 goto err;
 
         spin_lock_irqsave(&task_group_lock, flags);
-        for_each_possible_cpu(i) {
-                register_fair_sched_group(tg, i);
-                register_rt_sched_group(tg, i);
-        }
         list_add_rcu(&tg->list, &task_groups);
 
         WARN_ON(!parent); /* root should already exist */
@@ -8676,11 +8428,11 @@ void sched_destroy_group(struct task_group *tg)
         unsigned long flags;
         int i;
 
-        spin_lock_irqsave(&task_group_lock, flags);
-        for_each_possible_cpu(i) {
+        /* end participation in shares distribution */
+        for_each_possible_cpu(i)
                 unregister_fair_sched_group(tg, i);
-                unregister_rt_sched_group(tg, i);
-        }
+
+        spin_lock_irqsave(&task_group_lock, flags);
         list_del_rcu(&tg->list);
         list_del_rcu(&tg->siblings);
         spin_unlock_irqrestore(&task_group_lock, flags);
@@ -8727,33 +8479,6 @@ void sched_move_task(struct task_struct *tsk)
 #endif /* CONFIG_CGROUP_SCHED */
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
-static void __set_se_shares(struct sched_entity *se, unsigned long shares)
-{
-        struct cfs_rq *cfs_rq = se->cfs_rq;
-        int on_rq;
-
-        on_rq = se->on_rq;
-        if (on_rq)
-                dequeue_entity(cfs_rq, se, 0);
-
-        se->load.weight = shares;
-        se->load.inv_weight = 0;
-
-        if (on_rq)
-                enqueue_entity(cfs_rq, se, 0);
-}
-
-static void set_se_shares(struct sched_entity *se, unsigned long shares)
-{
-        struct cfs_rq *cfs_rq = se->cfs_rq;
-        struct rq *rq = cfs_rq->rq;
-        unsigned long flags;
-
-        raw_spin_lock_irqsave(&rq->lock, flags);
-        __set_se_shares(se, shares);
-        raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
 static DEFINE_MUTEX(shares_mutex);
 
 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
@@ -8776,37 +8501,19 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
         if (tg->shares == shares)
                 goto done;
 
-        spin_lock_irqsave(&task_group_lock, flags);
-        for_each_possible_cpu(i)
-                unregister_fair_sched_group(tg, i);
-        list_del_rcu(&tg->siblings);
-        spin_unlock_irqrestore(&task_group_lock, flags);
-
-        /* wait for any ongoing reference to this group to finish */
-        synchronize_sched();
-
-        /*
-         * Now we are free to modify the group's share on each cpu
-         * w/o tripping rebalance_share or load_balance_fair.
-         */
         tg->shares = shares;
         for_each_possible_cpu(i) {
-                /*
-                 * force a rebalance
-                 */
-                cfs_rq_set_shares(tg->cfs_rq[i], 0);
-                set_se_shares(tg->se[i], shares);
+                struct rq *rq = cpu_rq(i);
+                struct sched_entity *se;
+
+                se = tg->se[i];
+                /* Propagate contribution to hierarchy */
+                raw_spin_lock_irqsave(&rq->lock, flags);
+                for_each_sched_entity(se)
+                        update_cfs_shares(group_cfs_rq(se), 0);
+                raw_spin_unlock_irqrestore(&rq->lock, flags);
         }
 
-        /*
-         * Enable load balance activity on this group, by inserting it back on
-         * each cpu's rq->leaf_cfs_rq_list.
-         */
-        spin_lock_irqsave(&task_group_lock, flags);
-        for_each_possible_cpu(i)
-                register_fair_sched_group(tg, i);
-        list_add_rcu(&tg->siblings, &tg->parent->children);
-        spin_unlock_irqrestore(&task_group_lock, flags);
 done:
         mutex_unlock(&shares_mutex);
         return 0;