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: (26 commits)
  sched: Resched proper CPU on yield_to()
  sched: Allow users with sufficient RLIMIT_NICE to change from SCHED_IDLE policy
  sched: Allow SCHED_BATCH to preempt SCHED_IDLE tasks
  sched: Clean up the IRQ_TIME_ACCOUNTING code
  sched: Add #ifdef around irq time accounting functions
  sched, autogroup: Stop claiming ownership of the root task group
  sched, autogroup: Stop going ahead if autogroup is disabled
  sched, autogroup, sysctl: Use proc_dointvec_minmax() instead
  sched: Fix the group_imb logic
  sched: Clean up some f_b_g() comments
  sched: Clean up remnants of sd_idle
  sched: Wholesale removal of sd_idle logic
  sched: Add yield_to(task, preempt) functionality
  sched: Use a buddy to implement yield_task_fair()
  sched: Limit the scope of clear_buddies
  sched: Check the right ->nr_running in yield_task_fair()
  sched: Avoid expensive initial update_cfs_load(), on UP too
  sched: Fix switch_from_fair()
  sched: Simplify the idle scheduling class
  softirqs: Account ksoftirqd time as cpustat softirq
  ...

15 files changed, 565 insertions, 261 deletions

diff --git a/include/asm-generic/cputime.h b/include/asm-generic/cputime.h
index 2bcc5c7c22a6..61e03dd7939e 100644
--- a/include/asm-generic/cputime.h
+++ b/include/asm-generic/cputime.h
@@ -30,6 +30,9 @@ typedef u64 cputime64_t;
 #define cputime64_to_jiffies64(__ct)    (__ct)
 #define jiffies64_to_cputime64(__jif)   (__jif)
 #define cputime_to_cputime64(__ct)      ((u64) __ct)
+#define cputime64_gt(__a, __b)          ((__a) >  (__b))
+
+#define nsecs_to_cputime64(__ct)        nsecs_to_jiffies64(__ct)
 
 
 /*
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index d746da19c6a2..2eb16e03422f 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -427,6 +427,13 @@ extern void raise_softirq(unsigned int nr);
  */
 DECLARE_PER_CPU(struct list_head [NR_SOFTIRQS], softirq_work_list);
 
+DECLARE_PER_CPU(struct task_struct *, ksoftirqd);
+
+static inline struct task_struct *this_cpu_ksoftirqd(void)
+{
+        return this_cpu_read(ksoftirqd);
+}
+
 /* Try to send a softirq to a remote cpu.  If this cannot be done, the
  * work will be queued to the local cpu.
  */
diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index 6811f4bfc6e7..922aa313c9f9 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -307,6 +307,7 @@ extern clock_t jiffies_to_clock_t(long x);
 extern unsigned long clock_t_to_jiffies(unsigned long x);
 extern u64 jiffies_64_to_clock_t(u64 x);
 extern u64 nsec_to_clock_t(u64 x);
+extern u64 nsecs_to_jiffies64(u64 n);
 extern unsigned long nsecs_to_jiffies(u64 n);
 
 #define TIMESTAMP_SIZE  30
diff --git a/include/linux/sched.h b/include/linux/sched.h
index c57e5278df83..214af2ed11b5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1058,6 +1058,7 @@ struct sched_class {
         void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
         void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
         void (*yield_task) (struct rq *rq);
+        bool (*yield_to_task) (struct rq *rq, struct task_struct *p, bool preempt);
 
         void (*check_preempt_curr) (struct rq *rq, struct task_struct *p, int flags);
 
@@ -1084,12 +1085,10 @@ struct sched_class {
         void (*task_tick) (struct rq *rq, struct task_struct *p, int queued);
         void (*task_fork) (struct task_struct *p);
 
-        void (*switched_from) (struct rq *this_rq, struct task_struct *task,
-                               int running);
-        void (*switched_to) (struct rq *this_rq, struct task_struct *task,
-                             int running);
+        void (*switched_from) (struct rq *this_rq, struct task_struct *task);
+        void (*switched_to) (struct rq *this_rq, struct task_struct *task);
         void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
-                             int oldprio, int running);
+                             int oldprio);
 
         unsigned int (*get_rr_interval) (struct rq *rq,
                                          struct task_struct *task);
@@ -1715,7 +1714,6 @@ extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *
 /*
  * Per process flags
  */
-#define PF_KSOFTIRQD    0x00000001      /* I am ksoftirqd */
 #define PF_STARTING     0x00000002      /* being created */
 #define PF_EXITING      0x00000004      /* getting shut down */
 #define PF_EXITPIDONE   0x00000008      /* pi exit done on shut down */
@@ -1945,8 +1943,6 @@ int sched_rt_handler(struct ctl_table *table, int write,
                 void __user *buffer, size_t *lenp,
                 loff_t *ppos);
 
-extern unsigned int sysctl_sched_compat_yield;
-
 #ifdef CONFIG_SCHED_AUTOGROUP
 extern unsigned int sysctl_sched_autogroup_enabled;
 
@@ -1977,6 +1973,7 @@ static inline int rt_mutex_getprio(struct task_struct *p)
 # define rt_mutex_adjust_pi(p)          do { } while (0)
 #endif
 
+extern bool yield_to(struct task_struct *p, bool preempt);
 extern void set_user_nice(struct task_struct *p, long nice);
 extern int task_prio(const struct task_struct *p);
 extern int task_nice(const struct task_struct *p);
diff --git a/kernel/sched.c b/kernel/sched.c
index 57a18e8d28c8..27125e413576 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -324,7 +324,7 @@ struct cfs_rq {
          * 'curr' points to currently running entity on this cfs_rq.
          * It is set to NULL otherwise (i.e when none are currently running).
          */
-        struct sched_entity *curr, *next, *last;
+        struct sched_entity *curr, *next, *last, *skip;
 
         unsigned int nr_spread_over;
 
@@ -1683,6 +1683,39 @@ static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
                 __release(rq2->lock);
 }
 
+#else /* CONFIG_SMP */
+
+/*
+ * double_rq_lock - safely lock two runqueues
+ *
+ * Note this does not disable interrupts like task_rq_lock,
+ * you need to do so manually before calling.
+ */
+static void double_rq_lock(struct rq *rq1, struct rq *rq2)
+        __acquires(rq1->lock)
+        __acquires(rq2->lock)
+{
+        BUG_ON(!irqs_disabled());
+        BUG_ON(rq1 != rq2);
+        raw_spin_lock(&rq1->lock);
+        __acquire(rq2->lock);   /* Fake it out ;) */
+}
+
+/*
+ * double_rq_unlock - safely unlock two runqueues
+ *
+ * Note this does not restore interrupts like task_rq_unlock,
+ * you need to do so manually after calling.
+ */
+static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
+        __releases(rq1->lock)
+        __releases(rq2->lock)
+{
+        BUG_ON(rq1 != rq2);
+        raw_spin_unlock(&rq1->lock);
+        __release(rq2->lock);
+}
+
 #endif
 
 static void calc_load_account_idle(struct rq *this_rq);
@@ -1877,7 +1910,7 @@ void account_system_vtime(struct task_struct *curr)
          */
         if (hardirq_count())
                 __this_cpu_add(cpu_hardirq_time, delta);
-        else if (in_serving_softirq() && !(curr->flags & PF_KSOFTIRQD))
+        else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
                 __this_cpu_add(cpu_softirq_time, delta);
 
         irq_time_write_end();
@@ -1917,8 +1950,40 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
                 sched_rt_avg_update(rq, irq_delta);
 }
 
+static int irqtime_account_hi_update(void)
+{
+        struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+        unsigned long flags;
+        u64 latest_ns;
+        int ret = 0;
+
+        local_irq_save(flags);
+        latest_ns = this_cpu_read(cpu_hardirq_time);
+        if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->irq))
+                ret = 1;
+        local_irq_restore(flags);
+        return ret;
+}
+
+static int irqtime_account_si_update(void)
+{
+        struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+        unsigned long flags;
+        u64 latest_ns;
+        int ret = 0;
+
+        local_irq_save(flags);
+        latest_ns = this_cpu_read(cpu_softirq_time);
+        if (cputime64_gt(nsecs_to_cputime64(latest_ns), cpustat->softirq))
+                ret = 1;
+        local_irq_restore(flags);
+        return ret;
+}
+
 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
 
+#define sched_clock_irqtime     (0)
+
 static void update_rq_clock_task(struct rq *rq, s64 delta)
 {
         rq->clock_task += delta;
@@ -2022,14 +2087,14 @@ inline int task_curr(const struct task_struct *p)
 
 static inline void check_class_changed(struct rq *rq, struct task_struct *p,
                                        const struct sched_class *prev_class,
-                                       int oldprio, int running)
+                                       int oldprio)
 {
         if (prev_class != p->sched_class) {
                 if (prev_class->switched_from)
-                        prev_class->switched_from(rq, p, running);
-                p->sched_class->switched_to(rq, p, running);
-        } else
-                p->sched_class->prio_changed(rq, p, oldprio, running);
+                        prev_class->switched_from(rq, p);
+                p->sched_class->switched_to(rq, p);
+        } else if (oldprio != p->prio)
+                p->sched_class->prio_changed(rq, p, oldprio);
 }
 
 static void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags)
@@ -2542,6 +2607,7 @@ static void __sched_fork(struct task_struct *p)
         p->se.sum_exec_runtime          = 0;
         p->se.prev_sum_exec_runtime     = 0;
         p->se.nr_migrations             = 0;
+        p->se.vruntime                  = 0;
 
 #ifdef CONFIG_SCHEDSTATS
         memset(&p->se.statistics, 0, sizeof(p->se.statistics));
@@ -3547,6 +3613,32 @@ static void account_guest_time(struct task_struct *p, cputime_t cputime,
 }
 
 /*
+ * Account system cpu time to a process and desired cpustat field
+ * @p: the process that the cpu time gets accounted to
+ * @cputime: the cpu time spent in kernel space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
+ * @target_cputime64: pointer to cpustat field that has to be updated
+ */
+static inline
+void __account_system_time(struct task_struct *p, cputime_t cputime,
+                        cputime_t cputime_scaled, cputime64_t *target_cputime64)
+{
+        cputime64_t tmp = cputime_to_cputime64(cputime);
+
+        /* Add system time to process. */
+        p->stime = cputime_add(p->stime, cputime);
+        p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
+        account_group_system_time(p, cputime);
+
+        /* Add system time to cpustat. */
+        *target_cputime64 = cputime64_add(*target_cputime64, tmp);
+        cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
+
+        /* Account for system time used */
+        acct_update_integrals(p);
+}
+
+/*
  * Account system cpu time to a process.
  * @p: the process that the cpu time gets accounted to
  * @hardirq_offset: the offset to subtract from hardirq_count()
@@ -3557,36 +3649,26 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
                          cputime_t cputime, cputime_t cputime_scaled)
 {
         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
-        cputime64_t tmp;
+        cputime64_t *target_cputime64;
 
         if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
                 account_guest_time(p, cputime, cputime_scaled);
                 return;
         }
 
-        /* Add system time to process. */
-        p->stime = cputime_add(p->stime, cputime);
-        p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);
-        account_group_system_time(p, cputime);
-
-        /* Add system time to cpustat. */
-        tmp = cputime_to_cputime64(cputime);
         if (hardirq_count() - hardirq_offset)
-                cpustat->irq = cputime64_add(cpustat->irq, tmp);
+                target_cputime64 = &cpustat->irq;
         else if (in_serving_softirq())
-                cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
+                target_cputime64 = &cpustat->softirq;
         else
-                cpustat->system = cputime64_add(cpustat->system, tmp);
-
-        cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
+                target_cputime64 = &cpustat->system;
 
-        /* Account for system time used */
-        acct_update_integrals(p);
+        __account_system_time(p, cputime, cputime_scaled, target_cputime64);
 }
 
 /*
  * Account for involuntary wait time.
- * @steal: the cpu time spent in involuntary wait
+ * @cputime: the cpu time spent in involuntary wait
  */
 void account_steal_time(cputime_t cputime)
 {
@@ -3614,6 +3696,73 @@ void account_idle_time(cputime_t cputime)
 
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING
 
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+/*
+ * Account a tick to a process and cpustat
+ * @p: the process that the cpu time gets accounted to
+ * @user_tick: is the tick from userspace
+ * @rq: the pointer to rq
+ *
+ * Tick demultiplexing follows the order
+ * - pending hardirq update
+ * - pending softirq update
+ * - user_time
+ * - idle_time
+ * - system time
+ *   - check for guest_time
+ *   - else account as system_time
+ *
+ * Check for hardirq is done both for system and user time as there is
+ * no timer going off while we are on hardirq and hence we may never get an
+ * opportunity to update it solely in system time.
+ * p->stime and friends are only updated on system time and not on irq
+ * softirq as those do not count in task exec_runtime any more.
+ */
+static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+                                                struct rq *rq)
+{
+        cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
+        cputime64_t tmp = cputime_to_cputime64(cputime_one_jiffy);
+        struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
+
+        if (irqtime_account_hi_update()) {
+                cpustat->irq = cputime64_add(cpustat->irq, tmp);
+        } else if (irqtime_account_si_update()) {
+                cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
+        } else if (this_cpu_ksoftirqd() == p) {
+                /*
+                 * ksoftirqd time do not get accounted in cpu_softirq_time.
+                 * So, we have to handle it separately here.
+                 * Also, p->stime needs to be updated for ksoftirqd.
+                 */
+                __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
+                                        &cpustat->softirq);
+        } else if (user_tick) {
+                account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
+        } else if (p == rq->idle) {
+                account_idle_time(cputime_one_jiffy);
+        } else if (p->flags & PF_VCPU) { /* System time or guest time */
+                account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
+        } else {
+                __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
+                                        &cpustat->system);
+        }
+}
+
+static void irqtime_account_idle_ticks(int ticks)
+{
+        int i;
+        struct rq *rq = this_rq();
+
+        for (i = 0; i < ticks; i++)
+                irqtime_account_process_tick(current, 0, rq);
+}
+#else /* CONFIG_IRQ_TIME_ACCOUNTING */
+static void irqtime_account_idle_ticks(int ticks) {}
+static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
+                                                struct rq *rq) {}
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
 /*
  * Account a single tick of cpu time.
  * @p: the process that the cpu time gets accounted to
@@ -3624,6 +3773,11 @@ void account_process_tick(struct task_struct *p, int user_tick)
         cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
         struct rq *rq = this_rq();
 
+        if (sched_clock_irqtime) {
+                irqtime_account_process_tick(p, user_tick, rq);
+                return;
+        }
+
         if (user_tick)
                 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
         else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
@@ -3649,6 +3803,12 @@ void account_steal_ticks(unsigned long ticks)
  */
 void account_idle_ticks(unsigned long ticks)
 {
+
+        if (sched_clock_irqtime) {
+                irqtime_account_idle_ticks(ticks);
+                return;
+        }
+
         account_idle_time(jiffies_to_cputime(ticks));
 }
 
@@ -4547,11 +4707,10 @@ void rt_mutex_setprio(struct task_struct *p, int prio)
 
         if (running)
                 p->sched_class->set_curr_task(rq);
-        if (on_rq) {
+        if (on_rq)
                 enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0);
 
-                check_class_changed(rq, p, prev_class, oldprio, running);
-        }
+        check_class_changed(rq, p, prev_class, oldprio);
         task_rq_unlock(rq, &flags);
 }
 
@@ -4799,12 +4958,15 @@ recheck:
                             param->sched_priority > rlim_rtprio)
                                 return -EPERM;
                 }
+
                 /*
-                 * Like positive nice levels, dont allow tasks to
-                 * move out of SCHED_IDLE either:
+                 * Treat SCHED_IDLE as nice 20. Only allow a switch to
+                 * SCHED_NORMAL if the RLIMIT_NICE would normally permit it.
                  */
-                if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
-                        return -EPERM;
+                if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) {
+                        if (!can_nice(p, TASK_NICE(p)))
+                                return -EPERM;
+                }
 
                 /* can't change other user's priorities */
                 if (!check_same_owner(p))
@@ -4879,11 +5041,10 @@ recheck:
 
         if (running)
                 p->sched_class->set_curr_task(rq);
-        if (on_rq) {
+        if (on_rq)
                 activate_task(rq, p, 0);
 
-                check_class_changed(rq, p, prev_class, oldprio, running);
-        }
+        check_class_changed(rq, p, prev_class, oldprio);
         __task_rq_unlock(rq);
         raw_spin_unlock_irqrestore(&p->pi_lock, flags);
 
@@ -5300,6 +5461,65 @@ void __sched yield(void)
 }
 EXPORT_SYMBOL(yield);
 
+/**
+ * yield_to - yield the current processor to another thread in
+ * your thread group, or accelerate that thread toward the
+ * processor it's on.
+ *
+ * It's the caller's job to ensure that the target task struct
+ * can't go away on us before we can do any checks.
+ *
+ * Returns true if we indeed boosted the target task.
+ */
+bool __sched yield_to(struct task_struct *p, bool preempt)
+{
+        struct task_struct *curr = current;
+        struct rq *rq, *p_rq;
+        unsigned long flags;
+        bool yielded = 0;
+
+        local_irq_save(flags);
+        rq = this_rq();
+
+again:
+        p_rq = task_rq(p);
+        double_rq_lock(rq, p_rq);
+        while (task_rq(p) != p_rq) {
+                double_rq_unlock(rq, p_rq);
+                goto again;
+        }
+
+        if (!curr->sched_class->yield_to_task)
+                goto out;
+
+        if (curr->sched_class != p->sched_class)
+                goto out;
+
+        if (task_running(p_rq, p) || p->state)
+                goto out;
+
+        yielded = curr->sched_class->yield_to_task(rq, p, preempt);
+        if (yielded) {
+                schedstat_inc(rq, yld_count);
+                /*
+                 * Make p's CPU reschedule; pick_next_entity takes care of
+                 * fairness.
+                 */
+                if (preempt && rq != p_rq)
+                        resched_task(p_rq->curr);
+        }
+
+out:
+        double_rq_unlock(rq, p_rq);
+        local_irq_restore(flags);
+
+        if (yielded)
+                schedule();
+
+        return yielded;
+}
+EXPORT_SYMBOL_GPL(yield_to);
+
 /*
  * This task is about to go to sleep on IO. Increment rq->nr_iowait so
  * that process accounting knows that this is a task in IO wait state.
@@ -7773,6 +7993,10 @@ static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
         INIT_LIST_HEAD(&cfs_rq->tasks);
 #ifdef CONFIG_FAIR_GROUP_SCHED
         cfs_rq->rq = rq;
+        /* allow initial update_cfs_load() to truncate */
+#ifdef CONFIG_SMP
+        cfs_rq->load_stamp = 1;
+#endif
 #endif
         cfs_rq->min_vruntime = (u64)(-(1LL << 20));
 }
@@ -8086,6 +8310,8 @@ EXPORT_SYMBOL(__might_sleep);
 #ifdef CONFIG_MAGIC_SYSRQ
 static void normalize_task(struct rq *rq, struct task_struct *p)
 {
+        const struct sched_class *prev_class = p->sched_class;
+        int old_prio = p->prio;
         int on_rq;
 
         on_rq = p->se.on_rq;
@@ -8096,6 +8322,8 @@ static void normalize_task(struct rq *rq, struct task_struct *p)
                 activate_task(rq, p, 0);
                 resched_task(rq->curr);
         }
+
+        check_class_changed(rq, p, prev_class, old_prio);
 }
 
 void normalize_rt_tasks(void)
@@ -8487,7 +8715,7 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
                 /* Propagate contribution to hierarchy */
                 raw_spin_lock_irqsave(&rq->lock, flags);
                 for_each_sched_entity(se)
-                        update_cfs_shares(group_cfs_rq(se), 0);
+                        update_cfs_shares(group_cfs_rq(se));
                 raw_spin_unlock_irqrestore(&rq->lock, flags);
         }
 
diff --git a/kernel/sched_autogroup.c b/kernel/sched_autogroup.c
index 9fb656283157..5946ac515602 100644
--- a/kernel/sched_autogroup.c
+++ b/kernel/sched_autogroup.c
@@ -12,7 +12,6 @@ static atomic_t autogroup_seq_nr;
 static void __init autogroup_init(struct task_struct *init_task)
 {
         autogroup_default.tg = &root_task_group;
-        root_task_group.autogroup = &autogroup_default;
         kref_init(&autogroup_default.kref);
         init_rwsem(&autogroup_default.lock);
         init_task->signal->autogroup = &autogroup_default;
@@ -130,7 +129,7 @@ task_wants_autogroup(struct task_struct *p, struct task_group *tg)
 
 static inline bool task_group_is_autogroup(struct task_group *tg)
 {
-        return tg != &root_task_group && tg->autogroup;
+        return !!tg->autogroup;
 }
 
 static inline struct task_group *
@@ -161,11 +160,15 @@ autogroup_move_group(struct task_struct *p, struct autogroup *ag)
 
         p->signal->autogroup = autogroup_kref_get(ag);
 
+        if (!ACCESS_ONCE(sysctl_sched_autogroup_enabled))
+                goto out;
+
         t = p;
         do {
                 sched_move_task(t);
         } while_each_thread(p, t);
 
+out:
         unlock_task_sighand(p, &flags);
         autogroup_kref_put(prev);
 }
@@ -247,10 +250,14 @@ void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
 {
         struct autogroup *ag = autogroup_task_get(p);
 
+        if (!task_group_is_autogroup(ag->tg))
+                goto out;
+
         down_read(&ag->lock);
         seq_printf(m, "/autogroup-%ld nice %d\n", ag->id, ag->nice);
         up_read(&ag->lock);
 
+out:
         autogroup_kref_put(ag);
 }
 #endif /* CONFIG_PROC_FS */
@@ -258,9 +265,7 @@ void proc_sched_autogroup_show_task(struct task_struct *p, struct seq_file *m)
 #ifdef CONFIG_SCHED_DEBUG
 static inline int autogroup_path(struct task_group *tg, char *buf, int buflen)
 {
-        int enabled = ACCESS_ONCE(sysctl_sched_autogroup_enabled);
-
-        if (!enabled || !tg->autogroup)
+        if (!task_group_is_autogroup(tg))
                 return 0;
 
         return snprintf(buf, buflen, "%s-%ld", "/autogroup", tg->autogroup->id);
diff --git a/kernel/sched_autogroup.h b/kernel/sched_autogroup.h
index 7b859ffe5dad..05577055cfca 100644
--- a/kernel/sched_autogroup.h
+++ b/kernel/sched_autogroup.h
@@ -1,6 +1,11 @@
 #ifdef CONFIG_SCHED_AUTOGROUP
 
 struct autogroup {
+        /*
+         * reference doesn't mean how many thread attach to this
+         * autogroup now. It just stands for the number of task
+         * could use this autogroup.
+         */
         struct kref             kref;
         struct task_group       *tg;
         struct rw_semaphore     lock;
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index eb6cb8edd075..7bacd83a4158 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -179,7 +179,7 @@ void print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq)
 
         raw_spin_lock_irqsave(&rq->lock, flags);
         if (cfs_rq->rb_leftmost)
-                MIN_vruntime = (__pick_next_entity(cfs_rq))->vruntime;
+                MIN_vruntime = (__pick_first_entity(cfs_rq))->vruntime;
         last = __pick_last_entity(cfs_rq);
         if (last)
                 max_vruntime = last->vruntime;
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 0c26e2df450e..3f7ec9e27ee1 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -69,14 +69,6 @@ static unsigned int sched_nr_latency = 8;
 unsigned int sysctl_sched_child_runs_first __read_mostly;
 
 /*
- * sys_sched_yield() compat mode
- *
- * This option switches the agressive yield implementation of the
- * old scheduler back on.
- */
-unsigned int __read_mostly sysctl_sched_compat_yield;
-
-/*
  * SCHED_OTHER wake-up granularity.
  * (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
  *
@@ -419,7 +411,7 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
         rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
 }
 
-static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq)
+static struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq)
 {
         struct rb_node *left = cfs_rq->rb_leftmost;
 
@@ -429,6 +421,17 @@ static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq)
         return rb_entry(left, struct sched_entity, run_node);
 }
 
+static struct sched_entity *__pick_next_entity(struct sched_entity *se)
+{
+        struct rb_node *next = rb_next(&se->run_node);
+
+        if (!next)
+                return NULL;
+
+        return rb_entry(next, struct sched_entity, run_node);
+}
+
+#ifdef CONFIG_SCHED_DEBUG
 static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
 {
         struct rb_node *last = rb_last(&cfs_rq->tasks_timeline);
@@ -443,7 +446,6 @@ static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq)
  * Scheduling class statistics methods:
  */
 
-#ifdef CONFIG_SCHED_DEBUG
 int sched_proc_update_handler(struct ctl_table *table, int write,
                 void __user *buffer, size_t *lenp,
                 loff_t *ppos)
@@ -540,7 +542,7 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
 }
 
 static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update);
-static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta);
+static void update_cfs_shares(struct cfs_rq *cfs_rq);
 
 /*
  * Update the current task's runtime statistics. Skip current tasks that
@@ -733,6 +735,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
             now - cfs_rq->load_last > 4 * period) {
                 cfs_rq->load_period = 0;
                 cfs_rq->load_avg = 0;
+                delta = period - 1;
         }
 
         cfs_rq->load_stamp = now;
@@ -763,16 +766,15 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
                 list_del_leaf_cfs_rq(cfs_rq);
 }
 
-static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
-                                long weight_delta)
+static long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
 {
         long load_weight, load, shares;
 
-        load = cfs_rq->load.weight + weight_delta;
+        load = cfs_rq->load.weight;
 
         load_weight = atomic_read(&tg->load_weight);
-        load_weight -= cfs_rq->load_contribution;
         load_weight += load;
+        load_weight -= cfs_rq->load_contribution;
 
         shares = (tg->shares * load);
         if (load_weight)
@@ -790,7 +792,7 @@ static void update_entity_shares_tick(struct cfs_rq *cfs_rq)
 {
         if (cfs_rq->load_unacc_exec_time > sysctl_sched_shares_window) {
                 update_cfs_load(cfs_rq, 0);
-                update_cfs_shares(cfs_rq, 0);
+                update_cfs_shares(cfs_rq);
         }
 }
 # else /* CONFIG_SMP */
@@ -798,8 +800,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 {
 }
 
-static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg,
-                                long weight_delta)
+static inline long calc_cfs_shares(struct cfs_rq *cfs_rq, struct task_group *tg)
 {
         return tg->shares;
 }
@@ -824,7 +825,7 @@ static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,
                 account_entity_enqueue(cfs_rq, se);
 }
 
-static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
+static void update_cfs_shares(struct cfs_rq *cfs_rq)
 {
         struct task_group *tg;
         struct sched_entity *se;
@@ -838,7 +839,7 @@ static void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
         if (likely(se->load.weight == tg->shares))
                 return;
 #endif
-        shares = calc_cfs_shares(cfs_rq, tg, weight_delta);
+        shares = calc_cfs_shares(cfs_rq, tg);
 
         reweight_entity(cfs_rq_of(se), se, shares);
 }
@@ -847,7 +848,7 @@ static void update_cfs_load(struct cfs_rq *cfs_rq, int global_update)
 {
 }
 
-static inline void update_cfs_shares(struct cfs_rq *cfs_rq, long weight_delta)
+static inline void update_cfs_shares(struct cfs_rq *cfs_rq)
 {
 }
 
@@ -978,8 +979,8 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
          */
         update_curr(cfs_rq);
         update_cfs_load(cfs_rq, 0);
-        update_cfs_shares(cfs_rq, se->load.weight);
         account_entity_enqueue(cfs_rq, se);
+        update_cfs_shares(cfs_rq);
 
         if (flags & ENQUEUE_WAKEUP) {
                 place_entity(cfs_rq, se, 0);
@@ -996,19 +997,49 @@ enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
                 list_add_leaf_cfs_rq(cfs_rq);
 }
 
-static void __clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
+static void __clear_buddies_last(struct sched_entity *se)
+{
+        for_each_sched_entity(se) {
+                struct cfs_rq *cfs_rq = cfs_rq_of(se);
+                if (cfs_rq->last == se)
+                        cfs_rq->last = NULL;
+                else
+                        break;
+        }
+}
+
+static void __clear_buddies_next(struct sched_entity *se)
 {
-        if (!se || cfs_rq->last == se)
-                cfs_rq->last = NULL;
+        for_each_sched_entity(se) {
+                struct cfs_rq *cfs_rq = cfs_rq_of(se);
+                if (cfs_rq->next == se)
+                        cfs_rq->next = NULL;
+                else
+                        break;
+        }
+}
 
-        if (!se || cfs_rq->next == se)
-                cfs_rq->next = NULL;
+static void __clear_buddies_skip(struct sched_entity *se)
+{
+        for_each_sched_entity(se) {
+                struct cfs_rq *cfs_rq = cfs_rq_of(se);
+                if (cfs_rq->skip == se)
+                        cfs_rq->skip = NULL;
+                else
+                        break;
+        }
 }
 
 static void clear_buddies(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
-        for_each_sched_entity(se)
-                __clear_buddies(cfs_rq_of(se), se);
+        if (cfs_rq->last == se)
+                __clear_buddies_last(se);
+
+        if (cfs_rq->next == se)
+                __clear_buddies_next(se);
+
+        if (cfs_rq->skip == se)
+                __clear_buddies_skip(se);
 }
 
 static void
@@ -1041,7 +1072,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags)
         update_cfs_load(cfs_rq, 0);
         account_entity_dequeue(cfs_rq, se);
         update_min_vruntime(cfs_rq);
-        update_cfs_shares(cfs_rq, 0);
+        update_cfs_shares(cfs_rq);
 
         /*
          * Normalize the entity after updating the min_vruntime because the
@@ -1084,7 +1115,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
                 return;
 
         if (cfs_rq->nr_running > 1) {
-                struct sched_entity *se = __pick_next_entity(cfs_rq);
+                struct sched_entity *se = __pick_first_entity(cfs_rq);
                 s64 delta = curr->vruntime - se->vruntime;
 
                 if (delta < 0)
@@ -1128,13 +1159,27 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
 static int
 wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
 
+/*
+ * Pick the next process, keeping these things in mind, in this order:
+ * 1) keep things fair between processes/task groups
+ * 2) pick the "next" process, since someone really wants that to run
+ * 3) pick the "last" process, for cache locality
+ * 4) do not run the "skip" process, if something else is available
+ */
 static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
 {
-        struct sched_entity *se = __pick_next_entity(cfs_rq);
+        struct sched_entity *se = __pick_first_entity(cfs_rq);
         struct sched_entity *left = se;
 
-        if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
-                se = cfs_rq->next;
+        /*
+         * Avoid running the skip buddy, if running something else can
+         * be done without getting too unfair.
+         */
+        if (cfs_rq->skip == se) {
+                struct sched_entity *second = __pick_next_entity(se);
+                if (second && wakeup_preempt_entity(second, left) < 1)
+                        se = second;
+        }
 
         /*
          * Prefer last buddy, try to return the CPU to a preempted task.
@@ -1142,6 +1187,12 @@ static struct sched_entity *pick_next_entity(struct cfs_rq *cfs_rq)
         if (cfs_rq->last && wakeup_preempt_entity(cfs_rq->last, left) < 1)
                 se = cfs_rq->last;
 
+        /*
+         * Someone really wants this to run. If it's not unfair, run it.
+         */
+        if (cfs_rq->next && wakeup_preempt_entity(cfs_rq->next, left) < 1)
+                se = cfs_rq->next;
+
         clear_buddies(cfs_rq, se);
 
         return se;
@@ -1282,7 +1333,7 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
                 struct cfs_rq *cfs_rq = cfs_rq_of(se);
 
                 update_cfs_load(cfs_rq, 0);
-                update_cfs_shares(cfs_rq, 0);
+                update_cfs_shares(cfs_rq);
         }
 
         hrtick_update(rq);
@@ -1312,58 +1363,12 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
                 struct cfs_rq *cfs_rq = cfs_rq_of(se);
 
                 update_cfs_load(cfs_rq, 0);
-                update_cfs_shares(cfs_rq, 0);
+                update_cfs_shares(cfs_rq);
         }
 
         hrtick_update(rq);
 }
 
-/*
- * sched_yield() support is very simple - we dequeue and enqueue.
- *
- * If compat_yield is turned on then we requeue to the end of the tree.
- */
-static void yield_task_fair(struct rq *rq)
-{
-        struct task_struct *curr = rq->curr;
-        struct cfs_rq *cfs_rq = task_cfs_rq(curr);
-        struct sched_entity *rightmost, *se = &curr->se;
-
-        /*
-         * Are we the only task in the tree?
-         */
-        if (unlikely(cfs_rq->nr_running == 1))
-                return;
-
-        clear_buddies(cfs_rq, se);
-
-        if (likely(!sysctl_sched_compat_yield) && curr->policy != SCHED_BATCH) {
-                update_rq_clock(rq);
-                /*
-                 * Update run-time statistics of the 'current'.
-                 */
-                update_curr(cfs_rq);
-
-                return;
-        }
-        /*
-         * Find the rightmost entry in the rbtree:
-         */
-        rightmost = __pick_last_entity(cfs_rq);
-        /*
-         * Already in the rightmost position?
-         */
-        if (unlikely(!rightmost || entity_before(rightmost, se)))
-                return;
-
-        /*
-         * Minimally necessary key value to be last in the tree:
-         * Upon rescheduling, sched_class::put_prev_task() will place
-         * 'current' within the tree based on its new key value.
-         */
-        se->vruntime = rightmost->vruntime + 1;
-}
-
 #ifdef CONFIG_SMP
 
 static void task_waking_fair(struct rq *rq, struct task_struct *p)
@@ -1834,6 +1839,14 @@ static void set_next_buddy(struct sched_entity *se)
         }
 }
 
+static void set_skip_buddy(struct sched_entity *se)
+{
+        if (likely(task_of(se)->policy != SCHED_IDLE)) {
+                for_each_sched_entity(se)
+                        cfs_rq_of(se)->skip = se;
+        }
+}
+
 /*
  * Preempt the current task with a newly woken task if needed:
  */
@@ -1857,16 +1870,18 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
         if (test_tsk_need_resched(curr))
                 return;
 
+        /* Idle tasks are by definition preempted by non-idle tasks. */
+        if (unlikely(curr->policy == SCHED_IDLE) &&
+            likely(p->policy != SCHED_IDLE))
+                goto preempt;
+
         /*
-         * Batch and idle tasks do not preempt (their preemption is driven by
-         * the tick):
+         * Batch and idle tasks do not preempt non-idle tasks (their preemption
+         * is driven by the tick):
          */
         if (unlikely(p->policy != SCHED_NORMAL))
                 return;
 
-        /* Idle tasks are by definition preempted by everybody. */
-        if (unlikely(curr->policy == SCHED_IDLE))
-                goto preempt;
 
         if (!sched_feat(WAKEUP_PREEMPT))
                 return;
@@ -1932,6 +1947,51 @@ static void put_prev_task_fair(struct rq *rq, struct task_struct *prev)
         }
 }
 
+/*
+ * sched_yield() is very simple
+ *
+ * The magic of dealing with the ->skip buddy is in pick_next_entity.
+ */
+static void yield_task_fair(struct rq *rq)
+{
+        struct task_struct *curr = rq->curr;
+        struct cfs_rq *cfs_rq = task_cfs_rq(curr);
+        struct sched_entity *se = &curr->se;
+
+        /*
+         * Are we the only task in the tree?
+         */
+        if (unlikely(rq->nr_running == 1))
+                return;
+
+        clear_buddies(cfs_rq, se);
+
+        if (curr->policy != SCHED_BATCH) {
+                update_rq_clock(rq);
+                /*
+                 * Update run-time statistics of the 'current'.
+                 */
+                update_curr(cfs_rq);
+        }
+
+        set_skip_buddy(se);
+}
+
+static bool yield_to_task_fair(struct rq *rq, struct task_struct *p, bool preempt)
+{
+        struct sched_entity *se = &p->se;
+
+        if (!se->on_rq)
+                return false;
+
+        /* Tell the scheduler that we'd really like pse to run next. */
+        set_next_buddy(se);
+
+        yield_task_fair(rq);
+
+        return true;
+}
+
 #ifdef CONFIG_SMP
 /**************************************************
  * Fair scheduling class load-balancing methods:
@@ -2123,7 +2183,7 @@ static int update_shares_cpu(struct task_group *tg, int cpu)
          * We need to update shares after updating tg->load_weight in
          * order to adjust the weight of groups with long running tasks.
          */
-        update_cfs_shares(cfs_rq, 0);
+        update_cfs_shares(cfs_rq);
 
         raw_spin_unlock_irqrestore(&rq->lock, flags);
 
@@ -2610,7 +2670,6 @@ fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
  * @this_cpu: Cpu for which load balance is currently performed.
  * @idle: Idle status of this_cpu
  * @load_idx: Load index of sched_domain of this_cpu for load calc.
- * @sd_idle: Idle status of the sched_domain containing group.
  * @local_group: Does group contain this_cpu.
  * @cpus: Set of cpus considered for load balancing.
  * @balance: Should we balance.
@@ -2618,7 +2677,7 @@ fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
  */
 static inline void update_sg_lb_stats(struct sched_domain *sd,
                         struct sched_group *group, int this_cpu,
-                        enum cpu_idle_type idle, int load_idx, int *sd_idle,
+                        enum cpu_idle_type idle, int load_idx,
                         int local_group, const struct cpumask *cpus,
                         int *balance, struct sg_lb_stats *sgs)
 {
@@ -2638,9 +2697,6 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
         for_each_cpu_and(i, sched_group_cpus(group), cpus) {
                 struct rq *rq = cpu_rq(i);
 
-                if (*sd_idle && rq->nr_running)
-                        *sd_idle = 0;
-
                 /* Bias balancing toward cpus of our domain */
                 if (local_group) {
                         if (idle_cpu(i) && !first_idle_cpu) {
@@ -2685,7 +2741,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
 
         /*
          * Consider the group unbalanced when the imbalance is larger
-         * than the average weight of two tasks.
+         * than the average weight of a task.
          *
          * APZ: with cgroup the avg task weight can vary wildly and
          *      might not be a suitable number - should we keep a
@@ -2695,7 +2751,7 @@ static inline void update_sg_lb_stats(struct sched_domain *sd,
         if (sgs->sum_nr_running)
                 avg_load_per_task = sgs->sum_weighted_load / sgs->sum_nr_running;
 
-        if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task && max_nr_running > 1)
+        if ((max_cpu_load - min_cpu_load) >= avg_load_per_task && max_nr_running > 1)
                 sgs->group_imb = 1;
 
         sgs->group_capacity = DIV_ROUND_CLOSEST(group->cpu_power, SCHED_LOAD_SCALE);
@@ -2755,15 +2811,13 @@ static bool update_sd_pick_busiest(struct sched_domain *sd,
  * @sd: sched_domain whose statistics are to be updated.
  * @this_cpu: Cpu for which load balance is currently performed.
  * @idle: Idle status of this_cpu
- * @sd_idle: Idle status of the sched_domain containing sg.
  * @cpus: Set of cpus considered for load balancing.
  * @balance: Should we balance.
  * @sds: variable to hold the statistics for this sched_domain.
  */
 static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
-                        enum cpu_idle_type idle, int *sd_idle,
-                        const struct cpumask *cpus, int *balance,
-                        struct sd_lb_stats *sds)
+                        enum cpu_idle_type idle, const struct cpumask *cpus,
+                        int *balance, struct sd_lb_stats *sds)
 {
         struct sched_domain *child = sd->child;
         struct sched_group *sg = sd->groups;
@@ -2781,7 +2835,7 @@ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
 
                 local_group = cpumask_test_cpu(this_cpu, sched_group_cpus(sg));
                 memset(&sgs, 0, sizeof(sgs));
-                update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx, sd_idle,
+                update_sg_lb_stats(sd, sg, this_cpu, idle, load_idx,
                                 local_group, cpus, balance, &sgs);
 
                 if (local_group && !(*balance))
@@ -3033,7 +3087,6 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
  * @imbalance: Variable which stores amount of weighted load which should
  *              be moved to restore balance/put a group to idle.
  * @idle: The idle status of this_cpu.
- * @sd_idle: The idleness of sd
  * @cpus: The set of CPUs under consideration for load-balancing.
  * @balance: Pointer to a variable indicating if this_cpu
  *      is the appropriate cpu to perform load balancing at this_level.
@@ -3046,7 +3099,7 @@ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
 static struct sched_group *
 find_busiest_group(struct sched_domain *sd, int this_cpu,
                    unsigned long *imbalance, enum cpu_idle_type idle,
-                   int *sd_idle, const struct cpumask *cpus, int *balance)
+                   const struct cpumask *cpus, int *balance)
 {
         struct sd_lb_stats sds;
 
@@ -3056,22 +3109,11 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
          * Compute the various statistics relavent for load balancing at
          * this level.
          */
-        update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
-                                        balance, &sds);
-
-        /* Cases where imbalance does not exist from POV of this_cpu */
-        /* 1) this_cpu is not the appropriate cpu to perform load balancing
-         *    at this level.
-         * 2) There is no busy sibling group to pull from.
-         * 3) This group is the busiest group.
-         * 4) This group is more busy than the avg busieness at this
-         *    sched_domain.
-         * 5) The imbalance is within the specified limit.
-         *
-         * Note: when doing newidle balance, if the local group has excess
-         * capacity (i.e. nr_running < group_capacity) and the busiest group
-         * does not have any capacity, we force a load balance to pull tasks
-         * to the local group. In this case, we skip past checks 3, 4 and 5.
+        update_sd_lb_stats(sd, this_cpu, idle, cpus, balance, &sds);
+
+        /*
+         * this_cpu is not the appropriate cpu to perform load balancing at
+         * this level.
          */
         if (!(*balance))
                 goto ret;
@@ -3080,41 +3122,55 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
             check_asym_packing(sd, &sds, this_cpu, imbalance))
                 return sds.busiest;
 
+        /* There is no busy sibling group to pull tasks from */
         if (!sds.busiest || sds.busiest_nr_running == 0)
                 goto out_balanced;
 
-        /*  SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
+        /*
+         * If the busiest group is imbalanced the below checks don't
+         * work because they assumes all things are equal, which typically
+         * isn't true due to cpus_allowed constraints and the like.
+         */
+        if (sds.group_imb)
+                goto force_balance;
+
+        /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
         if (idle == CPU_NEWLY_IDLE && sds.this_has_capacity &&
                         !sds.busiest_has_capacity)
                 goto force_balance;
 
+        /*
+         * If the local group is more busy than the selected busiest group
+         * don't try and pull any tasks.
+         */
         if (sds.this_load >= sds.max_load)
                 goto out_balanced;
 
+        /*
+         * Don't pull any tasks if this group is already above the domain
+         * average load.
+         */
         sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
-
         if (sds.this_load >= sds.avg_load)
                 goto out_balanced;
 
-        /*
-         * In the CPU_NEWLY_IDLE, use imbalance_pct to be conservative.
-         * And to check for busy balance use !idle_cpu instead of
-         * CPU_NOT_IDLE. This is because HT siblings will use CPU_NOT_IDLE
-         * even when they are idle.
-         */
-        if (idle == CPU_NEWLY_IDLE || !idle_cpu(this_cpu)) {
-                if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
-                        goto out_balanced;
-        } else {
+        if (idle == CPU_IDLE) {
                 /*
                  * This cpu is idle. If the busiest group load doesn't
                  * have more tasks than the number of available cpu's and
                  * there is no imbalance between this and busiest group
                  * wrt to idle cpu's, it is balanced.
                  */
-                if ((sds.this_idle_cpus  <= sds.busiest_idle_cpus + 1) &&
+                if ((sds.this_idle_cpus <= sds.busiest_idle_cpus + 1) &&
                     sds.busiest_nr_running <= sds.busiest_group_weight)
                         goto out_balanced;
+        } else {
+                /*
+                 * In the CPU_NEWLY_IDLE, CPU_NOT_IDLE cases, use
+                 * imbalance_pct to be conservative.
+                 */
+                if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
+                        goto out_balanced;
         }
 
 force_balance:
@@ -3193,7 +3249,7 @@ find_busiest_queue(struct sched_domain *sd, struct sched_group *group,
 /* Working cpumask for load_balance and load_balance_newidle. */
 static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
 
-static int need_active_balance(struct sched_domain *sd, int sd_idle, int idle,
+static int need_active_balance(struct sched_domain *sd, int idle,
                                int busiest_cpu, int this_cpu)
 {
         if (idle == CPU_NEWLY_IDLE) {
@@ -3225,10 +3281,6 @@ static int need_active_balance(struct sched_domain *sd, int sd_idle, int idle,
                  * move_tasks() will succeed.  ld_moved will be true and this
                  * active balance code will not be triggered.
                  */
-                if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
-                    !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
-                        return 0;
-
                 if (sched_mc_power_savings < POWERSAVINGS_BALANCE_WAKEUP)
                         return 0;
         }
@@ -3246,7 +3298,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
                         struct sched_domain *sd, enum cpu_idle_type idle,
                         int *balance)
 {
-        int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
+        int ld_moved, all_pinned = 0, active_balance = 0;
         struct sched_group *group;
         unsigned long imbalance;
         struct rq *busiest;
@@ -3255,20 +3307,10 @@ static int load_balance(int this_cpu, struct rq *this_rq,
 
         cpumask_copy(cpus, cpu_active_mask);
 
-        /*
-         * When power savings policy is enabled for the parent domain, idle
-         * sibling can pick up load irrespective of busy siblings. In this case,
-         * let the state of idle sibling percolate up as CPU_IDLE, instead of
-         * portraying it as CPU_NOT_IDLE.
-         */
-        if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
-            !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
-                sd_idle = 1;
-
         schedstat_inc(sd, lb_count[idle]);
 
 redo:
-        group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
+        group = find_busiest_group(sd, this_cpu, &imbalance, idle,
                                    cpus, balance);
 
         if (*balance == 0)
@@ -3330,8 +3372,7 @@ redo:
                 if (idle != CPU_NEWLY_IDLE)
                         sd->nr_balance_failed++;
 
-                if (need_active_balance(sd, sd_idle, idle, cpu_of(busiest),
-                                        this_cpu)) {
+                if (need_active_balance(sd, idle, cpu_of(busiest), this_cpu)) {
                         raw_spin_lock_irqsave(&busiest->lock, flags);
 
                         /* don't kick the active_load_balance_cpu_stop,
@@ -3386,10 +3427,6 @@ redo:
                         sd->balance_interval *= 2;
         }
 
-        if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
-            !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
-                ld_moved = -1;
-
         goto out;
 
 out_balanced:
@@ -3403,11 +3440,7 @@ out_one_pinned:
                         (sd->balance_interval < sd->max_interval))
                 sd->balance_interval *= 2;
 
-        if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
-            !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
-                ld_moved = -1;
-        else
-                ld_moved = 0;
+        ld_moved = 0;
 out:
         return ld_moved;
 }
@@ -3831,8 +3864,7 @@ static void rebalance_domains(int cpu, enum cpu_idle_type idle)
                         if (load_balance(cpu, rq, sd, idle, &balance)) {
                                 /*
                                  * We've pulled tasks over so either we're no
-                                 * longer idle, or one of our SMT siblings is
-                                 * not idle.
+                                 * longer idle.
                                  */
                                 idle = CPU_NOT_IDLE;
                         }
@@ -4079,33 +4111,62 @@ static void task_fork_fair(struct task_struct *p)
  * Priority of the task has changed. Check to see if we preempt
  * the current task.
  */
-static void prio_changed_fair(struct rq *rq, struct task_struct *p,
-                              int oldprio, int running)
+static void
+prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
 {
+        if (!p->se.on_rq)
+                return;
+
         /*
          * Reschedule if we are currently running on this runqueue and
          * our priority decreased, or if we are not currently running on
          * this runqueue and our priority is higher than the current's
          */
-        if (running) {
+        if (rq->curr == p) {
                 if (p->prio > oldprio)
                         resched_task(rq->curr);
         } else
                 check_preempt_curr(rq, p, 0);
 }
 
+static void switched_from_fair(struct rq *rq, struct task_struct *p)
+{
+        struct sched_entity *se = &p->se;
+        struct cfs_rq *cfs_rq = cfs_rq_of(se);
+
+        /*
+         * Ensure the task's vruntime is normalized, so that when its
+         * switched back to the fair class the enqueue_entity(.flags=0) will
+         * do the right thing.
+         *
+         * If it was on_rq, then the dequeue_entity(.flags=0) will already
+         * have normalized the vruntime, if it was !on_rq, then only when
+         * the task is sleeping will it still have non-normalized vruntime.
+         */
+        if (!se->on_rq && p->state != TASK_RUNNING) {
+                /*
+                 * Fix up our vruntime so that the current sleep doesn't
+                 * cause 'unlimited' sleep bonus.
+                 */
+                place_entity(cfs_rq, se, 0);
+                se->vruntime -= cfs_rq->min_vruntime;
+        }
+}
+
 /*
  * We switched to the sched_fair class.
  */
-static void switched_to_fair(struct rq *rq, struct task_struct *p,
-                             int running)
+static void switched_to_fair(struct rq *rq, struct task_struct *p)
 {
+        if (!p->se.on_rq)
+                return;
+
         /*
          * We were most likely switched from sched_rt, so
          * kick off the schedule if running, otherwise just see
          * if we can still preempt the current task.
          */
-        if (running)
+        if (rq->curr == p)
                 resched_task(rq->curr);
         else
                 check_preempt_curr(rq, p, 0);
@@ -4171,6 +4232,7 @@ static const struct sched_class fair_sched_class = {
         .enqueue_task           = enqueue_task_fair,
         .dequeue_task           = dequeue_task_fair,
         .yield_task             = yield_task_fair,
+        .yield_to_task          = yield_to_task_fair,
 
         .check_preempt_curr     = check_preempt_wakeup,
 
@@ -4191,6 +4253,7 @@ static const struct sched_class fair_sched_class = {
         .task_fork              = task_fork_fair,
 
         .prio_changed           = prio_changed_fair,
+        .switched_from          = switched_from_fair,
         .switched_to            = switched_to_fair,
 
         .get_rr_interval        = get_rr_interval_fair,
diff --git a/kernel/sched_idletask.c b/kernel/sched_idletask.c
index 9fa0f402c87c..c82f26c1b7c3 100644
--- a/kernel/sched_idletask.c
+++ b/kernel/sched_idletask.c
@@ -52,31 +52,15 @@ static void set_curr_task_idle(struct rq *rq)
 {
 }
 
-static void switched_to_idle(struct rq *rq, struct task_struct *p,
-                             int running)
+static void switched_to_idle(struct rq *rq, struct task_struct *p)
 {
-        /* Can this actually happen?? */
-        if (running)
-                resched_task(rq->curr);
-        else
-                check_preempt_curr(rq, p, 0);
+        BUG();
 }
 
-static void prio_changed_idle(struct rq *rq, struct task_struct *p,
-                              int oldprio, int running)
+static void
+prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
 {
-        /* This can happen for hot plug CPUS */
-
-        /*
-         * Reschedule if we are currently running on this runqueue and
-         * our priority decreased, or if we are not currently running on
-         * this runqueue and our priority is higher than the current's
-         */
-        if (running) {
-                if (p->prio > oldprio)
-                        resched_task(rq->curr);
-        } else
-                check_preempt_curr(rq, p, 0);
+        BUG();
 }
 
 static unsigned int get_rr_interval_idle(struct rq *rq, struct task_struct *task)
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
index 01f75a5f17af..db308cb08b75 100644
--- a/kernel/sched_rt.c
+++ b/kernel/sched_rt.c
@@ -1599,8 +1599,7 @@ static void rq_offline_rt(struct rq *rq)
  * When switch from the rt queue, we bring ourselves to a position
  * that we might want to pull RT tasks from other runqueues.
  */
-static void switched_from_rt(struct rq *rq, struct task_struct *p,
-                           int running)
+static void switched_from_rt(struct rq *rq, struct task_struct *p)
 {
         /*
          * If there are other RT tasks then we will reschedule
@@ -1609,7 +1608,7 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p,
          * we may need to handle the pulling of RT tasks
          * now.
          */
-        if (!rq->rt.rt_nr_running)
+        if (p->se.on_rq && !rq->rt.rt_nr_running)
                 pull_rt_task(rq);
 }
 
@@ -1628,8 +1627,7 @@ static inline void init_sched_rt_class(void)
  * with RT tasks. In this case we try to push them off to
  * other runqueues.
  */
-static void switched_to_rt(struct rq *rq, struct task_struct *p,
-                           int running)
+static void switched_to_rt(struct rq *rq, struct task_struct *p)
 {
         int check_resched = 1;
 
@@ -1640,7 +1638,7 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p,
          * If that current running task is also an RT task
          * then see if we can move to another run queue.
          */
-        if (!running) {
+        if (p->se.on_rq && rq->curr != p) {
 #ifdef CONFIG_SMP
                 if (rq->rt.overloaded && push_rt_task(rq) &&
                     /* Don't resched if we changed runqueues */
@@ -1656,10 +1654,13 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p,
  * Priority of the task has changed. This may cause
  * us to initiate a push or pull.
  */
-static void prio_changed_rt(struct rq *rq, struct task_struct *p,
-                            int oldprio, int running)
+static void
+prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
 {
-        if (running) {
+        if (!p->se.on_rq)
+                return;
+
+        if (rq->curr == p) {
 #ifdef CONFIG_SMP
                 /*
                  * If our priority decreases while running, we
diff --git a/kernel/sched_stoptask.c b/kernel/sched_stoptask.c
index 2bf6b47058c1..84ec9bcf82d9 100644
--- a/kernel/sched_stoptask.c
+++ b/kernel/sched_stoptask.c
@@ -59,14 +59,13 @@ static void set_curr_task_stop(struct rq *rq)
 {
 }
 
-static void switched_to_stop(struct rq *rq, struct task_struct *p,
-                             int running)
+static void switched_to_stop(struct rq *rq, struct task_struct *p)
 {
         BUG(); /* its impossible to change to this class */
 }
 
-static void prio_changed_stop(struct rq *rq, struct task_struct *p,
-                              int oldprio, int running)
+static void
+prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
 {
         BUG(); /* how!?, what priority? */
 }
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 68eb5efec388..0cee50487629 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -54,7 +54,7 @@ EXPORT_SYMBOL(irq_stat);
 
 static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp;
 
-static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
+DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
 
 char *softirq_to_name[NR_SOFTIRQS] = {
         "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK", "BLOCK_IOPOLL",
@@ -721,7 +721,6 @@ static int run_ksoftirqd(void * __bind_cpu)
 {
         set_current_state(TASK_INTERRUPTIBLE);
 
-        current->flags |= PF_KSOFTIRQD;
         while (!kthread_should_stop()) {
                 preempt_disable();
                 if (!local_softirq_pending()) {
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 19b9d85e06cc..51054fea5d99 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -361,20 +361,13 @@ static struct ctl_table kern_table[] = {
                 .mode           = 0644,
                 .proc_handler   = sched_rt_handler,
         },
-        {
-                .procname       = "sched_compat_yield",
-                .data           = &sysctl_sched_compat_yield,
-                .maxlen         = sizeof(unsigned int),
-                .mode           = 0644,
-                .proc_handler   = proc_dointvec,
-        },
 #ifdef CONFIG_SCHED_AUTOGROUP
         {
                 .procname       = "sched_autogroup_enabled",
                 .data           = &sysctl_sched_autogroup_enabled,
                 .maxlen         = sizeof(unsigned int),
                 .mode           = 0644,
-                .proc_handler   = proc_dointvec,
+                .proc_handler   = proc_dointvec_minmax,
                 .extra1         = &zero,
                 .extra2         = &one,
         },
diff --git a/kernel/time.c b/kernel/time.c
index 32174359576f..55337a816b20 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -645,7 +645,7 @@ u64 nsec_to_clock_t(u64 x)
 }
 
 /**
- * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
+ * nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
  *
  * @n:  nsecs in u64
  *
@@ -657,7 +657,7 @@ u64 nsec_to_clock_t(u64 x)
  *   NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
  *   ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
  */
-unsigned long nsecs_to_jiffies(u64 n)
+u64 nsecs_to_jiffies64(u64 n)
 {
 #if (NSEC_PER_SEC % HZ) == 0
         /* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
@@ -674,6 +674,25 @@ unsigned long nsecs_to_jiffies(u64 n)
 #endif
 }
 
+
+/**
+ * nsecs_to_jiffies - Convert nsecs in u64 to jiffies
+ *
+ * @n:  nsecs in u64
+ *
+ * Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
+ * And this doesn't return MAX_JIFFY_OFFSET since this function is designed
+ * for scheduler, not for use in device drivers to calculate timeout value.
+ *
+ * note:
+ *   NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
+ *   ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
+ */
+unsigned long nsecs_to_jiffies(u64 n)
+{
+        return (unsigned long)nsecs_to_jiffies64(n);
+}
+
 #if (BITS_PER_LONG < 64)
 u64 get_jiffies_64(void)
 {