ARM64: sched: fix bug: avoid infinite loop
[firefly-linux-kernel-4.4.55.git] / kernel / sched / fair.c
index c11bc73929163a879d5b94d638833dcc0c550f79..67629fa15d58e44b72c428afdb37cf31024381d5 100644 (file)
@@ -34,6 +34,7 @@
 #include <trace/events/sched.h>
 
 #include "sched.h"
+#include "tune.h"
 
 /*
  * Targeted preemption latency for CPU-bound tasks:
@@ -2586,6 +2587,7 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa,
 
        scale_freq = arch_scale_freq_capacity(NULL, cpu);
        scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
+       trace_sched_contrib_scale_f(cpu, scale_freq, scale_cpu);
 
        /* delta_w is the amount already accumulated against our next period */
        delta_w = sa->period_contrib;
@@ -2729,6 +2731,10 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg)
 
        if (update_cfs_rq_load_avg(now, cfs_rq) && update_tg)
                update_tg_load_avg(cfs_rq, 0);
+
+       if (entity_is_task(se))
+               trace_sched_load_avg_task(task_of(se), &se->avg);
+       trace_sched_load_avg_cpu(cpu, cfs_rq);
 }
 
 static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
@@ -2949,6 +2955,7 @@ static void enqueue_sleeper(struct cfs_rq *cfs_rq, struct sched_entity *se)
                        }
 
                        trace_sched_stat_blocked(tsk, delta);
+                       trace_sched_blocked_reason(tsk);
 
                        /*
                         * Blocking time is in units of nanosecs, so shift by
@@ -4144,6 +4151,21 @@ static inline void hrtick_update(struct rq *rq)
 }
 #endif
 
+static inline unsigned long boosted_cpu_util(int cpu);
+
+static void update_capacity_of(int cpu)
+{
+       unsigned long req_cap;
+
+       if (!sched_freq())
+               return;
+
+       /* Convert scale-invariant capacity to cpu. */
+       req_cap = boosted_cpu_util(cpu);
+       req_cap = req_cap * SCHED_CAPACITY_SCALE / capacity_orig_of(cpu);
+       set_cfs_cpu_capacity(cpu, true, req_cap);
+}
+
 static bool cpu_overutilized(int cpu);
 
 /*
@@ -4156,7 +4178,8 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 {
        struct cfs_rq *cfs_rq;
        struct sched_entity *se = &p->se;
-       int task_new = !(flags & ENQUEUE_WAKEUP);
+       int task_new = flags & ENQUEUE_WAKEUP_NEW;
+       int task_wakeup = flags & ENQUEUE_WAKEUP;
 
        for_each_sched_entity(se) {
                if (se->on_rq)
@@ -4193,6 +4216,18 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
                if (!task_new && !rq->rd->overutilized &&
                    cpu_overutilized(rq->cpu))
                        rq->rd->overutilized = true;
+
+               schedtune_enqueue_task(p, cpu_of(rq));
+
+               /*
+                * We want to potentially trigger a freq switch
+                * request only for tasks that are waking up; this is
+                * because we get here also during load balancing, but
+                * in these cases it seems wise to trigger as single
+                * request after load balancing is done.
+                */
+               if (task_new || task_wakeup)
+                       update_capacity_of(cpu_of(rq));
        }
        hrtick_update(rq);
 }
@@ -4251,9 +4286,25 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
                update_cfs_shares(cfs_rq);
        }
 
-       if (!se)
+       if (!se) {
                sub_nr_running(rq, 1);
+               schedtune_dequeue_task(p, cpu_of(rq));
 
+               /*
+                * We want to potentially trigger a freq switch
+                * request only for tasks that are going to sleep;
+                * this is because we get here also during load
+                * balancing, but in these cases it seems wise to
+                * trigger as single request after load balancing is
+                * done.
+                */
+               if (task_sleep) {
+                       if (rq->cfs.nr_running)
+                               update_capacity_of(cpu_of(rq));
+                       else if (sched_freq())
+                               set_cfs_cpu_capacity(cpu_of(rq), false, 0);
+               }
+       }
        hrtick_update(rq);
 }
 
@@ -4480,15 +4531,6 @@ static unsigned long target_load(int cpu, int type)
        return max(rq->cpu_load[type-1], total);
 }
 
-static unsigned long capacity_of(int cpu)
-{
-       return cpu_rq(cpu)->cpu_capacity;
-}
-
-static unsigned long capacity_orig_of(int cpu)
-{
-       return cpu_rq(cpu)->cpu_capacity_orig;
-}
 
 static unsigned long cpu_avg_load_per_task(int cpu)
 {
@@ -4661,56 +4703,13 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
  * Returns the current capacity of cpu after applying both
  * cpu and freq scaling.
  */
-static unsigned long capacity_curr_of(int cpu)
+unsigned long capacity_curr_of(int cpu)
 {
        return cpu_rq(cpu)->cpu_capacity_orig *
               arch_scale_freq_capacity(NULL, cpu)
               >> SCHED_CAPACITY_SHIFT;
 }
 
-/*
- * cpu_util returns the amount of capacity of a CPU that is used by CFS
- * tasks. The unit of the return value must be the one of capacity so we can
- * compare the utilization with the capacity of the CPU that is available for
- * CFS task (ie cpu_capacity).
- *
- * cfs_rq.avg.util_avg is the sum of running time of runnable tasks plus the
- * recent utilization of currently non-runnable tasks on a CPU. It represents
- * the amount of utilization of a CPU in the range [0..capacity_orig] where
- * capacity_orig is the cpu_capacity available at the highest frequency
- * (arch_scale_freq_capacity()).
- * The utilization of a CPU converges towards a sum equal to or less than the
- * current capacity (capacity_curr <= capacity_orig) of the CPU because it is
- * the running time on this CPU scaled by capacity_curr.
- *
- * Nevertheless, cfs_rq.avg.util_avg can be higher than capacity_curr or even
- * higher than capacity_orig because of unfortunate rounding in
- * cfs.avg.util_avg or just after migrating tasks and new task wakeups until
- * the average stabilizes with the new running time. We need to check that the
- * utilization stays within the range of [0..capacity_orig] and cap it if
- * necessary. Without utilization capping, a group could be seen as overloaded
- * (CPU0 utilization at 121% + CPU1 utilization at 80%) whereas CPU1 has 20% of
- * available capacity. We allow utilization to overshoot capacity_curr (but not
- * capacity_orig) as it useful for predicting the capacity required after task
- * migrations (scheduler-driven DVFS).
- */
-static unsigned long __cpu_util(int cpu, int delta)
-{
-       unsigned long util = cpu_rq(cpu)->cfs.avg.util_avg;
-       unsigned long capacity = capacity_orig_of(cpu);
-
-       delta += util;
-       if (delta < 0)
-               return 0;
-
-       return (delta >= capacity) ? capacity : delta;
-}
-
-static unsigned long cpu_util(int cpu)
-{
-       return __cpu_util(cpu, 0);
-}
-
 static inline bool energy_aware(void)
 {
        return sched_feat(ENERGY_AWARE);
@@ -4724,6 +4723,19 @@ struct energy_env {
        int                     src_cpu;
        int                     dst_cpu;
        int                     energy;
+       int                     payoff;
+       struct task_struct      *task;
+       struct {
+               int before;
+               int after;
+               int delta;
+               int diff;
+       } nrg;
+       struct {
+               int before;
+               int after;
+               int delta;
+       } cap;
 };
 
 /*
@@ -4854,6 +4866,7 @@ static int sched_group_energy(struct energy_env *eenv)
                struct sched_group *sg_shared_cap = NULL;
 
                cpu = cpumask_first(&visit_cpus);
+               cpumask_clear_cpu(cpu, &visit_cpus);
 
                /*
                 * Is the group utilization affected by cpus outside this
@@ -4890,6 +4903,22 @@ static int sched_group_energy(struct energy_env *eenv)
                                        eenv->sg_cap = sg;
 
                                cap_idx = find_new_capacity(eenv, sg->sge);
+
+                               if (sg->group_weight == 1) {
+                                       /* Remove capacity of src CPU (before task move) */
+                                       if (eenv->util_delta == 0 &&
+                                           cpumask_test_cpu(eenv->src_cpu, sched_group_cpus(sg))) {
+                                               eenv->cap.before = sg->sge->cap_states[cap_idx].cap;
+                                               eenv->cap.delta -= eenv->cap.before;
+                                       }
+                                       /* Add capacity of dst CPU  (after task move) */
+                                       if (eenv->util_delta != 0 &&
+                                           cpumask_test_cpu(eenv->dst_cpu, sched_group_cpus(sg))) {
+                                               eenv->cap.after = sg->sge->cap_states[cap_idx].cap;
+                                               eenv->cap.delta += eenv->cap.after;
+                                       }
+                               }
+
                                idle_idx = group_idle_state(sg);
                                group_util = group_norm_util(eenv, sg);
                                sg_busy_energy = (group_util * sg->sge->cap_states[cap_idx].power)
@@ -4900,8 +4929,12 @@ static int sched_group_energy(struct energy_env *eenv)
 
                                total_energy += sg_busy_energy + sg_idle_energy;
 
-                               if (!sd->child)
-                                       cpumask_xor(&visit_cpus, &visit_cpus, sched_group_cpus(sg));
+                               if (!sd->child) {
+                                       int i;
+
+                                       for_each_cpu(i, sched_group_cpus(sg))
+                                               cpumask_clear_cpu(i, &visit_cpus);
+                               }
 
                                if (cpumask_equal(sched_group_cpus(sg), sched_group_cpus(eenv->sg_top)))
                                        goto next_cpu;
@@ -4921,6 +4954,44 @@ static inline bool cpu_in_sg(struct sched_group *sg, int cpu)
        return cpu != -1 && cpumask_test_cpu(cpu, sched_group_cpus(sg));
 }
 
+#ifdef CONFIG_SCHED_TUNE
+static int energy_diff_evaluate(struct energy_env *eenv)
+{
+       unsigned int boost;
+       int nrg_delta;
+
+       /* Return energy diff when boost margin is 0 */
+#ifdef CONFIG_CGROUP_SCHEDTUNE
+       boost = schedtune_task_boost(eenv->task);
+#else
+       boost = get_sysctl_sched_cfs_boost();
+#endif
+       if (boost == 0)
+               return eenv->nrg.diff;
+
+       /* Compute normalized energy diff */
+       nrg_delta = schedtune_normalize_energy(eenv->nrg.diff);
+       eenv->nrg.delta = nrg_delta;
+
+       eenv->payoff = schedtune_accept_deltas(
+                       eenv->nrg.delta,
+                       eenv->cap.delta,
+                       eenv->task);
+
+       /*
+        * When SchedTune is enabled, the energy_diff() function will return
+        * the computed energy payoff value. Since the energy_diff() return
+        * value is expected to be negative by its callers, this evaluation
+        * function return a negative value each time the evaluation return a
+        * positive payoff, which is the condition for the acceptance of
+        * a scheduling decision
+        */
+       return -eenv->payoff;
+}
+#else /* CONFIG_SCHED_TUNE */
+#define energy_diff_evaluate(eenv) eenv->nrg.diff
+#endif
+
 /*
  * energy_diff(): Estimate the energy impact of changing the utilization
  * distribution. eenv specifies the change: utilisation amount, source, and
@@ -4938,6 +5009,8 @@ static int energy_diff(struct energy_env *eenv)
                .util_delta     = 0,
                .src_cpu        = eenv->src_cpu,
                .dst_cpu        = eenv->dst_cpu,
+               .nrg            = { 0, 0, 0, 0},
+               .cap            = { 0, 0, 0 },
        };
 
        if (eenv->src_cpu == eenv->dst_cpu)
@@ -4959,13 +5032,22 @@ static int energy_diff(struct energy_env *eenv)
                                return 0; /* Invalid result abort */
                        energy_before += eenv_before.energy;
 
+                       /* Keep track of SRC cpu (before) capacity */
+                       eenv->cap.before = eenv_before.cap.before;
+                       eenv->cap.delta = eenv_before.cap.delta;
+
                        if (sched_group_energy(eenv))
                                return 0; /* Invalid result abort */
                        energy_after += eenv->energy;
                }
        } while (sg = sg->next, sg != sd->groups);
 
-       return energy_after-energy_before;
+       eenv->nrg.before = energy_before;
+       eenv->nrg.after = energy_after;
+       eenv->nrg.diff = eenv->nrg.after - eenv->nrg.before;
+       eenv->payoff = 0;
+
+       return energy_diff_evaluate(eenv);
 }
 
 /*
@@ -5064,13 +5146,15 @@ static inline unsigned long task_util(struct task_struct *p)
        return p->se.avg.util_avg;
 }
 
-static unsigned int capacity_margin = 1280; /* ~20% margin */
+unsigned int capacity_margin = 1280; /* ~20% margin */
+
+static inline unsigned long boosted_task_util(struct task_struct *task);
 
 static inline bool __task_fits(struct task_struct *p, int cpu, int util)
 {
        unsigned long capacity = capacity_of(cpu);
 
-       util += task_util(p);
+       util += boosted_task_util(p);
 
        return (capacity * 1024) > (util * capacity_margin);
 }
@@ -5078,7 +5162,7 @@ static inline bool __task_fits(struct task_struct *p, int cpu, int util)
 static inline bool task_fits_max(struct task_struct *p, int cpu)
 {
        unsigned long capacity = capacity_of(cpu);
-       unsigned long max_capacity = cpu_rq(cpu)->rd->max_cpu_capacity;
+       unsigned long max_capacity = cpu_rq(cpu)->rd->max_cpu_capacity.val;
 
        if (capacity == max_capacity)
                return true;
@@ -5099,6 +5183,115 @@ static bool cpu_overutilized(int cpu)
        return (capacity_of(cpu) * 1024) < (cpu_util(cpu) * capacity_margin);
 }
 
+#ifdef CONFIG_SCHED_TUNE
+
+static unsigned long
+schedtune_margin(unsigned long signal, unsigned long boost)
+{
+       unsigned long long margin = 0;
+
+       /*
+        * Signal proportional compensation (SPC)
+        *
+        * The Boost (B) value is used to compute a Margin (M) which is
+        * proportional to the complement of the original Signal (S):
+        *   M = B * (SCHED_LOAD_SCALE - S)
+        * The obtained M could be used by the caller to "boost" S.
+        */
+       margin  = SCHED_LOAD_SCALE - signal;
+       margin *= boost;
+
+       /*
+        * Fast integer division by constant:
+        *  Constant   :                 (C) = 100
+        *  Precision  : 0.1%            (P) = 0.1
+        *  Reference  : C * 100 / P     (R) = 100000
+        *
+        * Thus:
+        *  Shift bits : ceil(log(R,2))  (S) = 17
+        *  Mult const : round(2^S/C)    (M) = 1311
+        *
+        *
+        */
+       margin  *= 1311;
+       margin >>= 17;
+
+       return margin;
+}
+
+static inline unsigned int
+schedtune_cpu_margin(unsigned long util, int cpu)
+{
+       unsigned int boost;
+
+#ifdef CONFIG_CGROUP_SCHEDTUNE
+       boost = schedtune_cpu_boost(cpu);
+#else
+       boost = get_sysctl_sched_cfs_boost();
+#endif
+       if (boost == 0)
+               return 0;
+
+       return schedtune_margin(util, boost);
+}
+
+static inline unsigned long
+schedtune_task_margin(struct task_struct *task)
+{
+       unsigned int boost;
+       unsigned long util;
+       unsigned long margin;
+
+#ifdef CONFIG_CGROUP_SCHEDTUNE
+       boost = schedtune_task_boost(task);
+#else
+       boost = get_sysctl_sched_cfs_boost();
+#endif
+       if (boost == 0)
+               return 0;
+
+       util = task_util(task);
+       margin = schedtune_margin(util, boost);
+
+       return margin;
+}
+
+#else /* CONFIG_SCHED_TUNE */
+
+static inline unsigned int
+schedtune_cpu_margin(unsigned long util, int cpu)
+{
+       return 0;
+}
+
+static inline unsigned int
+schedtune_task_margin(struct task_struct *task)
+{
+       return 0;
+}
+
+#endif /* CONFIG_SCHED_TUNE */
+
+static inline unsigned long
+boosted_cpu_util(int cpu)
+{
+       unsigned long util = cpu_util(cpu);
+       unsigned long margin = schedtune_cpu_margin(util, cpu);
+
+       trace_sched_boost_cpu(cpu, util, margin);
+
+       return util + margin;
+}
+
+static inline unsigned long
+boosted_task_util(struct task_struct *task)
+{
+       unsigned long util = task_util(task);
+       unsigned long margin = schedtune_task_margin(task);
+
+       return util + margin;
+}
+
 /*
  * find_idlest_group finds and returns the least busy CPU group within the
  * domain.
@@ -5287,6 +5480,87 @@ done:
        return target;
 }
 
+static int energy_aware_wake_cpu(struct task_struct *p, int target)
+{
+       struct sched_domain *sd;
+       struct sched_group *sg, *sg_target;
+       int target_max_cap = INT_MAX;
+       int target_cpu = task_cpu(p);
+       int i;
+
+       sd = rcu_dereference(per_cpu(sd_ea, task_cpu(p)));
+
+       if (!sd)
+               return target;
+
+       sg = sd->groups;
+       sg_target = sg;
+
+       /*
+        * Find group with sufficient capacity. We only get here if no cpu is
+        * overutilized. We may end up overutilizing a cpu by adding the task,
+        * but that should not be any worse than select_idle_sibling().
+        * load_balance() should sort it out later as we get above the tipping
+        * point.
+        */
+       do {
+               /* Assuming all cpus are the same in group */
+               int max_cap_cpu = group_first_cpu(sg);
+
+               /*
+                * Assume smaller max capacity means more energy-efficient.
+                * Ideally we should query the energy model for the right
+                * answer but it easily ends up in an exhaustive search.
+                */
+               if (capacity_of(max_cap_cpu) < target_max_cap &&
+                   task_fits_max(p, max_cap_cpu)) {
+                       sg_target = sg;
+                       target_max_cap = capacity_of(max_cap_cpu);
+               }
+       } while (sg = sg->next, sg != sd->groups);
+
+       /* Find cpu with sufficient capacity */
+       for_each_cpu_and(i, tsk_cpus_allowed(p), sched_group_cpus(sg_target)) {
+               /*
+                * p's blocked utilization is still accounted for on prev_cpu
+                * so prev_cpu will receive a negative bias due to the double
+                * accounting. However, the blocked utilization may be zero.
+                */
+               int new_util = cpu_util(i) + boosted_task_util(p);
+
+               if (new_util > capacity_orig_of(i))
+                       continue;
+
+               if (new_util < capacity_curr_of(i)) {
+                       target_cpu = i;
+                       if (cpu_rq(i)->nr_running)
+                               break;
+               }
+
+               /* cpu has capacity at higher OPP, keep it as fallback */
+               if (target_cpu == task_cpu(p))
+                       target_cpu = i;
+       }
+
+       if (target_cpu != task_cpu(p)) {
+               struct energy_env eenv = {
+                       .util_delta     = task_util(p),
+                       .src_cpu        = task_cpu(p),
+                       .dst_cpu        = target_cpu,
+                       .task           = p,
+               };
+
+               /* Not enough spare capacity on previous cpu */
+               if (cpu_overutilized(task_cpu(p)))
+                       return target_cpu;
+
+               if (energy_diff(&eenv) >= 0)
+                       return task_cpu(p);
+       }
+
+       return target_cpu;
+}
+
 /*
  * select_task_rq_fair: Select target runqueue for the waking task in domains
  * that have the 'sd_flag' flag set. In practice, this is SD_BALANCE_WAKE,
@@ -5309,8 +5583,9 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
        int sync = wake_flags & WF_SYNC;
 
        if (sd_flag & SD_BALANCE_WAKE)
-               want_affine = !wake_wide(p) && task_fits_max(p, cpu) &&
-                             cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
+               want_affine = (!wake_wide(p) && task_fits_max(p, cpu) &&
+                             cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) ||
+                             energy_aware();
 
        rcu_read_lock();
        for_each_domain(cpu, tmp) {
@@ -5340,7 +5615,9 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
        }
 
        if (!sd) {
-               if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
+               if (energy_aware() && !cpu_rq(cpu)->rd->overutilized)
+                       new_cpu = energy_aware_wake_cpu(p, prev_cpu);
+               else if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */
                        new_cpu = select_idle_sibling(p, new_cpu);
 
        } else while (sd) {
@@ -5656,6 +5933,8 @@ again:
        if (hrtick_enabled(rq))
                hrtick_start_fair(rq, p);
 
+       rq->misfit_task = !task_fits_max(p, rq->cpu);
+
        return p;
 simple:
        cfs_rq = &rq->cfs;
@@ -5677,9 +5956,12 @@ simple:
        if (hrtick_enabled(rq))
                hrtick_start_fair(rq, p);
 
+       rq->misfit_task = !task_fits_max(p, rq->cpu);
+
        return p;
 
 idle:
+       rq->misfit_task = 0;
        /*
         * This is OK, because current is on_cpu, which avoids it being picked
         * for load-balance and preemption/IRQs are still disabled avoiding
@@ -5892,6 +6174,13 @@ static unsigned long __read_mostly max_load_balance_interval = HZ/10;
 
 enum fbq_type { regular, remote, all };
 
+enum group_type {
+       group_other = 0,
+       group_misfit_task,
+       group_imbalanced,
+       group_overloaded,
+};
+
 #define LBF_ALL_PINNED 0x01
 #define LBF_NEED_BREAK 0x02
 #define LBF_DST_PINNED  0x04
@@ -5921,6 +6210,7 @@ struct lb_env {
        unsigned int            loop_max;
 
        enum fbq_type           fbq_type;
+       enum group_type         busiest_group_type;
        struct list_head        tasks;
 };
 
@@ -6247,6 +6537,10 @@ static void attach_one_task(struct rq *rq, struct task_struct *p)
 {
        raw_spin_lock(&rq->lock);
        attach_task(rq, p);
+       /*
+        * We want to potentially raise target_cpu's OPP.
+        */
+       update_capacity_of(cpu_of(rq));
        raw_spin_unlock(&rq->lock);
 }
 
@@ -6268,6 +6562,11 @@ static void attach_tasks(struct lb_env *env)
                attach_task(env->dst_rq, p);
        }
 
+       /*
+        * We want to potentially raise env.dst_cpu's OPP.
+        */
+       update_capacity_of(env->dst_cpu);
+
        raw_spin_unlock(&env->dst_rq->lock);
 }
 
@@ -6363,12 +6662,6 @@ static unsigned long task_h_load(struct task_struct *p)
 
 /********** Helpers for find_busiest_group ************************/
 
-enum group_type {
-       group_other = 0,
-       group_imbalanced,
-       group_overloaded,
-};
-
 /*
  * sg_lb_stats - stats of a sched_group required for load_balancing
  */
@@ -6384,6 +6677,7 @@ struct sg_lb_stats {
        unsigned int group_weight;
        enum group_type group_type;
        int group_no_capacity;
+       int group_misfit_task; /* A cpu has a task too big for its capacity */
 #ifdef CONFIG_NUMA_BALANCING
        unsigned int nr_numa_running;
        unsigned int nr_preferred_running;
@@ -6475,19 +6769,57 @@ static unsigned long scale_rt_capacity(int cpu)
 
        used = div_u64(avg, total);
 
+       /*
+        * deadline bandwidth is defined at system level so we must
+        * weight this bandwidth with the max capacity of the system.
+        * As a reminder, avg_bw is 20bits width and
+        * scale_cpu_capacity is 10 bits width
+        */
+       used += div_u64(rq->dl.avg_bw, arch_scale_cpu_capacity(NULL, cpu));
+
        if (likely(used < SCHED_CAPACITY_SCALE))
                return SCHED_CAPACITY_SCALE - used;
 
        return 1;
 }
 
+void init_max_cpu_capacity(struct max_cpu_capacity *mcc)
+{
+       raw_spin_lock_init(&mcc->lock);
+       mcc->val = 0;
+       mcc->cpu = -1;
+}
+
 static void update_cpu_capacity(struct sched_domain *sd, int cpu)
 {
        unsigned long capacity = arch_scale_cpu_capacity(sd, cpu);
        struct sched_group *sdg = sd->groups;
+       struct max_cpu_capacity *mcc;
+       unsigned long max_capacity;
+       int max_cap_cpu;
+       unsigned long flags;
 
        cpu_rq(cpu)->cpu_capacity_orig = capacity;
 
+       mcc = &cpu_rq(cpu)->rd->max_cpu_capacity;
+
+       raw_spin_lock_irqsave(&mcc->lock, flags);
+       max_capacity = mcc->val;
+       max_cap_cpu = mcc->cpu;
+
+       if ((max_capacity > capacity && max_cap_cpu == cpu) ||
+           (max_capacity < capacity)) {
+               mcc->val = capacity;
+               mcc->cpu = cpu;
+#ifdef CONFIG_SCHED_DEBUG
+               raw_spin_unlock_irqrestore(&mcc->lock, flags);
+               //pr_info("CPU%d: update max cpu_capacity %lu\n", cpu, capacity);
+               goto skip_unlock;
+#endif
+       }
+       raw_spin_unlock_irqrestore(&mcc->lock, flags);
+
+skip_unlock: __attribute__ ((unused));
        capacity *= scale_rt_capacity(cpu);
        capacity >>= SCHED_CAPACITY_SHIFT;
 
@@ -6496,13 +6828,14 @@ static void update_cpu_capacity(struct sched_domain *sd, int cpu)
 
        cpu_rq(cpu)->cpu_capacity = capacity;
        sdg->sgc->capacity = capacity;
+       sdg->sgc->max_capacity = capacity;
 }
 
 void update_group_capacity(struct sched_domain *sd, int cpu)
 {
        struct sched_domain *child = sd->child;
        struct sched_group *group, *sdg = sd->groups;
-       unsigned long capacity;
+       unsigned long capacity, max_capacity;
        unsigned long interval;
 
        interval = msecs_to_jiffies(sd->balance_interval);
@@ -6515,6 +6848,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
        }
 
        capacity = 0;
+       max_capacity = 0;
 
        if (child->flags & SD_OVERLAP) {
                /*
@@ -6539,11 +6873,12 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
                         */
                        if (unlikely(!rq->sd)) {
                                capacity += capacity_of(cpu);
-                               continue;
+                       } else {
+                               sgc = rq->sd->groups->sgc;
+                               capacity += sgc->capacity;
                        }
 
-                       sgc = rq->sd->groups->sgc;
-                       capacity += sgc->capacity;
+                       max_capacity = max(capacity, max_capacity);
                }
        } else  {
                /*
@@ -6553,12 +6888,16 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
 
                group = child->groups;
                do {
-                       capacity += group->sgc->capacity;
+                       struct sched_group_capacity *sgc = group->sgc;
+
+                       capacity += sgc->capacity;
+                       max_capacity = max(sgc->max_capacity, max_capacity);
                        group = group->next;
                } while (group != child->groups);
        }
 
        sdg->sgc->capacity = capacity;
+       sdg->sgc->max_capacity = max_capacity;
 }
 
 /*
@@ -6653,6 +6992,18 @@ group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs)
        return false;
 }
 
+
+/*
+ * group_smaller_cpu_capacity: Returns true if sched_group sg has smaller
+ * per-cpu capacity than sched_group ref.
+ */
+static inline bool
+group_smaller_cpu_capacity(struct sched_group *sg, struct sched_group *ref)
+{
+       return sg->sgc->max_capacity + capacity_margin - SCHED_LOAD_SCALE <
+                                                       ref->sgc->max_capacity;
+}
+
 static inline enum
 group_type group_classify(struct sched_group *group,
                          struct sg_lb_stats *sgs)
@@ -6663,6 +7014,9 @@ group_type group_classify(struct sched_group *group,
        if (sg_imbalanced(group))
                return group_imbalanced;
 
+       if (sgs->group_misfit_task)
+               return group_misfit_task;
+
        return group_other;
 }
 
@@ -6710,8 +7064,11 @@ static inline void update_sg_lb_stats(struct lb_env *env,
                if (idle_cpu(i))
                        sgs->idle_cpus++;
 
-               if (cpu_overutilized(i))
+               if (cpu_overutilized(i)) {
                        *overutilized = true;
+                       if (!sgs->group_misfit_task && rq->misfit_task)
+                               sgs->group_misfit_task = capacity_of(i);
+               }
        }
 
        /* Adjust by relative CPU capacity of the group */
@@ -6753,9 +7110,25 @@ static bool update_sd_pick_busiest(struct lb_env *env,
        if (sgs->group_type < busiest->group_type)
                return false;
 
+       /*
+        * Candidate sg doesn't face any serious load-balance problems
+        * so don't pick it if the local sg is already filled up.
+        */
+       if (sgs->group_type == group_other &&
+           !group_has_capacity(env, &sds->local_stat))
+               return false;
+
        if (sgs->avg_load <= busiest->avg_load)
                return false;
 
+       /*
+        * Candiate sg has no more than one task per cpu and has higher
+        * per-cpu capacity. No reason to pull tasks to less capable cpus.
+        */
+       if (sgs->sum_nr_running <= sgs->group_weight &&
+           group_smaller_cpu_capacity(sds->local, sg))
+               return false;
+
        /* This is the busiest node in its class. */
        if (!(env->sd->flags & SD_ASYM_PACKING))
                return true;
@@ -6861,6 +7234,15 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
                        sgs->group_type = group_classify(sg, sgs);
                }
 
+               /*
+                * Ignore task groups with misfit tasks if local group has no
+                * capacity or if per-cpu capacity isn't higher.
+                */
+               if (sgs->group_type == group_misfit_task &&
+                   (!group_has_capacity(env, &sds->local_stat) ||
+                    !group_smaller_cpu_capacity(sg, sds->local)))
+                       sgs->group_type = group_other;
+
                if (update_sd_pick_busiest(env, sds, sg, sgs)) {
                        sds->busiest = sg;
                        sds->busiest_stat = *sgs;
@@ -7037,6 +7419,22 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
         */
        if (busiest->avg_load <= sds->avg_load ||
            local->avg_load >= sds->avg_load) {
+               /* Misfitting tasks should be migrated in any case */
+               if (busiest->group_type == group_misfit_task) {
+                       env->imbalance = busiest->group_misfit_task;
+                       return;
+               }
+
+               /*
+                * Busiest group is overloaded, local is not, use the spare
+                * cycles to maximize throughput
+                */
+               if (busiest->group_type == group_overloaded &&
+                   local->group_type <= group_misfit_task) {
+                       env->imbalance = busiest->load_per_task;
+                       return;
+               }
+
                env->imbalance = 0;
                return fix_small_imbalance(env, sds);
        }
@@ -7070,6 +7468,11 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
                (sds->avg_load - local->avg_load) * local->group_capacity
        ) / SCHED_CAPACITY_SCALE;
 
+       /* Boost imbalance to allow misfit task to be balanced. */
+       if (busiest->group_type == group_misfit_task)
+               env->imbalance = max_t(long, env->imbalance,
+                                    busiest->group_misfit_task);
+
        /*
         * if *imbalance is less than the average load per runnable task
         * there is no guarantee that any tasks will be moved so we'll have
@@ -7111,6 +7514,10 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
         * this level.
         */
        update_sd_lb_stats(env, &sds);
+
+       if (energy_aware() && !env->dst_rq->rd->overutilized)
+               goto out_balanced;
+
        local = &sds.local_stat;
        busiest = &sds.busiest_stat;
 
@@ -7139,6 +7546,11 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
            busiest->group_no_capacity)
                goto force_balance;
 
+       /* Misfitting tasks should be dealt with regardless of the avg load */
+       if (busiest->group_type == group_misfit_task) {
+               goto force_balance;
+       }
+
        /*
         * If the local group is busier than the selected busiest group
         * don't try and pull any tasks.
@@ -7162,7 +7574,8 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
                 * might end up to just move the imbalance on another group
                 */
                if ((busiest->group_type != group_overloaded) &&
-                               (local->idle_cpus <= (busiest->idle_cpus + 1)))
+                   (local->idle_cpus <= (busiest->idle_cpus + 1)) &&
+                   !group_smaller_cpu_capacity(sds.busiest, sds.local))
                        goto out_balanced;
        } else {
                /*
@@ -7175,6 +7588,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
        }
 
 force_balance:
+       env->busiest_group_type = busiest->group_type;
        /* Looks like there is an imbalance. Compute it */
        calculate_imbalance(env, &sds);
        return sds.busiest;
@@ -7233,7 +7647,8 @@ static struct rq *find_busiest_queue(struct lb_env *env,
                 */
 
                if (rq->nr_running == 1 && wl > env->imbalance &&
-                   !check_cpu_capacity(rq, env->sd))
+                   !check_cpu_capacity(rq, env->sd) &&
+                   env->busiest_group_type != group_misfit_task)
                        continue;
 
                /*
@@ -7422,6 +7837,11 @@ more_balance:
                 * ld_moved     - cumulative load moved across iterations
                 */
                cur_ld_moved = detach_tasks(&env);
+               /*
+                * We want to potentially lower env.src_cpu's OPP.
+                */
+               if (cur_ld_moved)
+                       update_capacity_of(env.src_cpu);
 
                /*
                 * We've detached some tasks from busiest_rq. Every
@@ -7655,8 +8075,9 @@ static int idle_balance(struct rq *this_rq)
         */
        this_rq->idle_stamp = rq_clock(this_rq);
 
-       if (this_rq->avg_idle < sysctl_sched_migration_cost ||
-           !this_rq->rd->overload) {
+       if (!energy_aware() &&
+           (this_rq->avg_idle < sysctl_sched_migration_cost ||
+            !this_rq->rd->overload)) {
                rcu_read_lock();
                sd = rcu_dereference_check_sched_domain(this_rq->sd);
                if (sd)
@@ -7791,8 +8212,13 @@ static int active_load_balance_cpu_stop(void *data)
                schedstat_inc(sd, alb_count);
 
                p = detach_one_task(&env);
-               if (p)
+               if (p) {
                        schedstat_inc(sd, alb_pushed);
+                       /*
+                        * We want to potentially lower env.src_cpu's OPP.
+                        */
+                       update_capacity_of(env.src_cpu);
+               }
                else
                        schedstat_inc(sd, alb_failed);
        }
@@ -8172,12 +8598,13 @@ static inline bool nohz_kick_needed(struct rq *rq)
        if (time_before(now, nohz.next_balance))
                return false;
 
-       if (rq->nr_running >= 2)
+       if (rq->nr_running >= 2 &&
+           (!energy_aware() || cpu_overutilized(cpu)))
                return true;
 
        rcu_read_lock();
        sd = rcu_dereference(per_cpu(sd_busy, cpu));
-       if (sd) {
+       if (sd && !energy_aware()) {
                sgc = sd->groups->sgc;
                nr_busy = atomic_read(&sgc->nr_busy_cpus);
 
@@ -8286,6 +8713,8 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued)
 
        if (!rq->rd->overutilized && cpu_overutilized(task_cpu(curr)))
                rq->rd->overutilized = true;
+
+       rq->misfit_task = !task_fits_max(curr, rq->cpu);
 }
 
 /*