Merge tag 'v4.2' into p/abusse/merge_upgrade
[projects/modsched/linux.git] / kernel / sched / cfs / fair.c
index fea7d33..d113c3b 100644 (file)
@@ -23,6 +23,7 @@
 #include <linux/latencytop.h>
 #include <linux/sched.h>
 #include <linux/cpumask.h>
+#include <linux/cpuidle.h>
 #include <linux/slab.h>
 #include <linux/profile.h>
 #include <linux/interrupt.h>
@@ -140,9 +141,9 @@ static inline void update_load_set(struct load_weight *lw, unsigned long w)
  *
  * This idea comes from the SD scheduler of Con Kolivas:
  */
-static int get_update_sysctl_factor(void)
+static unsigned int get_update_sysctl_factor(void)
 {
-       unsigned int cpus = min_t(int, num_online_cpus(), 8);
+       unsigned int cpus = min_t(unsigned int, num_online_cpus(), 8);
        unsigned int factor;
 
        switch (sysctl_sched_tunable_scaling) {
@@ -575,7 +576,7 @@ int sched_proc_update_handler(struct ctl_table *table, int write,
                loff_t *ppos)
 {
        int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
-       int factor = get_update_sysctl_factor();
+       unsigned int factor = get_update_sysctl_factor();
 
        if (ret || !write)
                return ret;
@@ -665,20 +666,22 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
 }
 
 #ifdef CONFIG_SMP
+static int select_idle_sibling(struct task_struct *p, int cpu);
 static unsigned long task_h_load(struct task_struct *p);
 
 static inline void __update_task_entity_contrib(struct sched_entity *se);
+static inline void __update_task_entity_utilization(struct sched_entity *se);
 
 /* Give new task start runnable values to heavy its load in infant time */
 void init_task_runnable_average(struct task_struct *p)
 {
        u32 slice;
 
-       p->se.avg.decay_count = 0;
        slice = sched_slice(task_cfs_rq(p), &p->se) >> 10;
-       p->se.avg.runnable_avg_sum = slice;
-       p->se.avg.runnable_avg_period = slice;
+       p->se.avg.runnable_avg_sum = p->se.avg.running_avg_sum = slice;
+       p->se.avg.avg_period = slice;
        __update_task_entity_contrib(&p->se);
+       __update_task_entity_utilization(&p->se);
 }
 #else
 void init_task_runnable_average(struct task_struct *p)
@@ -724,6 +727,11 @@ static void update_curr(struct cfs_rq *cfs_rq)
        account_cfs_rq_runtime(cfs_rq, delta_exec);
 }
 
+static void update_curr_fair(struct rq *rq)
+{
+       update_curr(cfs_rq_of(&rq->curr->se));
+}
+
 static inline void
 update_stats_wait_start(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
@@ -826,11 +834,12 @@ static unsigned int task_nr_scan_windows(struct task_struct *p)
 
 static unsigned int task_scan_min(struct task_struct *p)
 {
+       unsigned int scan_size = READ_ONCE(sysctl_numa_balancing_scan_size);
        unsigned int scan, floor;
        unsigned int windows = 1;
 
-       if (sysctl_numa_balancing_scan_size < MAX_SCAN_WINDOW)
-               windows = MAX_SCAN_WINDOW / sysctl_numa_balancing_scan_size;
+       if (scan_size < MAX_SCAN_WINDOW)
+               windows = MAX_SCAN_WINDOW / scan_size;
        floor = 1000 / windows;
 
        scan = sysctl_numa_balancing_scan_period_min / task_nr_scan_windows(p);
@@ -865,7 +874,6 @@ struct numa_group {
        spinlock_t lock; /* nr_tasks, tasks */
        int nr_tasks;
        pid_t gid;
-       struct list_head task_list;
 
        struct rcu_head rcu;
        nodemask_t active_nodes;
@@ -893,18 +901,24 @@ pid_t task_numa_group_id(struct task_struct *p)
        return p->numa_group ? p->numa_group->gid : 0;
 }
 
-static inline int task_faults_idx(int nid, int priv)
+/*
+ * The averaged statistics, shared & private, memory & cpu,
+ * occupy the first half of the array. The second half of the
+ * array is for current counters, which are averaged into the
+ * first set by task_numa_placement.
+ */
+static inline int task_faults_idx(enum numa_faults_stats s, int nid, int priv)
 {
-       return NR_NUMA_HINT_FAULT_TYPES * nid + priv;
+       return NR_NUMA_HINT_FAULT_TYPES * (s * nr_node_ids + nid) + priv;
 }
 
 static inline unsigned long task_faults(struct task_struct *p, int nid)
 {
-       if (!p->numa_faults_memory)
+       if (!p->numa_faults)
                return 0;
 
-       return p->numa_faults_memory[task_faults_idx(nid, 0)] +
-               p->numa_faults_memory[task_faults_idx(nid, 1)];
+       return p->numa_faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+               p->numa_faults[task_faults_idx(NUMA_MEM, nid, 1)];
 }
 
 static inline unsigned long group_faults(struct task_struct *p, int nid)
@@ -912,14 +926,79 @@ static inline unsigned long group_faults(struct task_struct *p, int nid)
        if (!p->numa_group)
                return 0;
 
-       return p->numa_group->faults[task_faults_idx(nid, 0)] +
-               p->numa_group->faults[task_faults_idx(nid, 1)];
+       return p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 0)] +
+               p->numa_group->faults[task_faults_idx(NUMA_MEM, nid, 1)];
 }
 
 static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
 {
-       return group->faults_cpu[task_faults_idx(nid, 0)] +
-               group->faults_cpu[task_faults_idx(nid, 1)];
+       return group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 0)] +
+               group->faults_cpu[task_faults_idx(NUMA_MEM, nid, 1)];
+}
+
+/* Handle placement on systems where not all nodes are directly connected. */
+static unsigned long score_nearby_nodes(struct task_struct *p, int nid,
+                                       int maxdist, bool task)
+{
+       unsigned long score = 0;
+       int node;
+
+       /*
+        * All nodes are directly connected, and the same distance
+        * from each other. No need for fancy placement algorithms.
+        */
+       if (sched_numa_topology_type == NUMA_DIRECT)
+               return 0;
+
+       /*
+        * This code is called for each node, introducing N^2 complexity,
+        * which should be ok given the number of nodes rarely exceeds 8.
+        */
+       for_each_online_node(node) {
+               unsigned long faults;
+               int dist = node_distance(nid, node);
+
+               /*
+                * The furthest away nodes in the system are not interesting
+                * for placement; nid was already counted.
+                */
+               if (dist == sched_max_numa_distance || node == nid)
+                       continue;
+
+               /*
+                * On systems with a backplane NUMA topology, compare groups
+                * of nodes, and move tasks towards the group with the most
+                * memory accesses. When comparing two nodes at distance
+                * "hoplimit", only nodes closer by than "hoplimit" are part
+                * of each group. Skip other nodes.
+                */
+               if (sched_numa_topology_type == NUMA_BACKPLANE &&
+                                       dist > maxdist)
+                       continue;
+
+               /* Add up the faults from nearby nodes. */
+               if (task)
+                       faults = task_faults(p, node);
+               else
+                       faults = group_faults(p, node);
+
+               /*
+                * On systems with a glueless mesh NUMA topology, there are
+                * no fixed "groups of nodes". Instead, nodes that are not
+                * directly connected bounce traffic through intermediate
+                * nodes; a numa_group can occupy any set of nodes.
+                * The further away a node is, the less the faults count.
+                * This seems to result in good task placement.
+                */
+               if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+                       faults *= (sched_max_numa_distance - dist);
+                       faults /= (sched_max_numa_distance - LOCAL_DISTANCE);
+               }
+
+               score += faults;
+       }
+
+       return score;
 }
 
 /*
@@ -928,11 +1007,12 @@ static inline unsigned long group_faults_cpu(struct numa_group *group, int nid)
  * larger multiplier, in order to group tasks together that are almost
  * evenly spread out between numa nodes.
  */
-static inline unsigned long task_weight(struct task_struct *p, int nid)
+static inline unsigned long task_weight(struct task_struct *p, int nid,
+                                       int dist)
 {
-       unsigned long total_faults;
+       unsigned long faults, total_faults;
 
-       if (!p->numa_faults_memory)
+       if (!p->numa_faults)
                return 0;
 
        total_faults = p->total_numa_faults;
@@ -940,15 +1020,29 @@ static inline unsigned long task_weight(struct task_struct *p, int nid)
        if (!total_faults)
                return 0;
 
-       return 1000 * task_faults(p, nid) / total_faults;
+       faults = task_faults(p, nid);
+       faults += score_nearby_nodes(p, nid, dist, true);
+
+       return 1000 * faults / total_faults;
 }
 
-static inline unsigned long group_weight(struct task_struct *p, int nid)
+static inline unsigned long group_weight(struct task_struct *p, int nid,
+                                        int dist)
 {
-       if (!p->numa_group || !p->numa_group->total_faults)
+       unsigned long faults, total_faults;
+
+       if (!p->numa_group)
+               return 0;
+
+       total_faults = p->numa_group->total_faults;
+
+       if (!total_faults)
                return 0;
 
-       return 1000 * group_faults(p, nid) / p->numa_group->total_faults;
+       faults = group_faults(p, nid);
+       faults += score_nearby_nodes(p, nid, dist, false);
+
+       return 1000 * faults / total_faults;
 }
 
 bool should_numa_migrate_memory(struct task_struct *p, struct page * page,
@@ -1038,7 +1132,8 @@ struct numa_stats {
  */
 static void update_numa_stats(struct numa_stats *ns, int nid)
 {
-       int cpu, cpus = 0;
+       int smt, cpu, cpus = 0;
+       unsigned long capacity;
 
        memset(ns, 0, sizeof(*ns));
        for_each_cpu(cpu, cpumask_of_node(nid)) {
@@ -1062,9 +1157,12 @@ static void update_numa_stats(struct numa_stats *ns, int nid)
        if (!cpus)
                return;
 
-       ns->load = (ns->load * SCHED_CAPACITY_SCALE) / ns->compute_capacity;
-       ns->task_capacity =
-               DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE);
+       /* smt := ceil(cpus / capacity), assumes: 1 < smt_power < 2 */
+       smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, ns->compute_capacity);
+       capacity = cpus / smt; /* cores */
+
+       ns->task_capacity = min_t(unsigned, capacity,
+               DIV_ROUND_CLOSEST(ns->compute_capacity, SCHED_CAPACITY_SCALE));
        ns->has_free_capacity = (ns->nr_running < ns->task_capacity);
 }
 
@@ -1077,6 +1175,7 @@ struct task_numa_env {
        struct numa_stats src_stats, dst_stats;
 
        int imbalance_pct;
+       int dist;
 
        struct task_struct *best_task;
        long best_imp;
@@ -1096,18 +1195,30 @@ static void task_numa_assign(struct task_numa_env *env,
        env->best_cpu = env->dst_cpu;
 }
 
-static bool load_too_imbalanced(long orig_src_load, long orig_dst_load,
-                               long src_load, long dst_load,
+static bool load_too_imbalanced(long src_load, long dst_load,
                                struct task_numa_env *env)
 {
        long imb, old_imb;
+       long orig_src_load, orig_dst_load;
+       long src_capacity, dst_capacity;
+
+       /*
+        * The load is corrected for the CPU capacity available on each node.
+        *
+        * src_load        dst_load
+        * ------------ vs ---------
+        * src_capacity    dst_capacity
+        */
+       src_capacity = env->src_stats.compute_capacity;
+       dst_capacity = env->dst_stats.compute_capacity;
 
        /* We care about the slope of the imbalance, not the direction. */
        if (dst_load < src_load)
                swap(dst_load, src_load);
 
        /* Is the difference below the threshold? */
-       imb = dst_load * 100 - src_load * env->imbalance_pct;
+       imb = dst_load * src_capacity * 100 -
+             src_load * dst_capacity * env->imbalance_pct;
        if (imb <= 0)
                return false;
 
@@ -1115,10 +1226,14 @@ static bool load_too_imbalanced(long orig_src_load, long orig_dst_load,
         * The imbalance is above the allowed threshold.
         * Compare it with the old imbalance.
         */
+       orig_src_load = env->src_stats.load;
+       orig_dst_load = env->dst_stats.load;
+
        if (orig_dst_load < orig_src_load)
                swap(orig_dst_load, orig_src_load);
 
-       old_imb = orig_dst_load * 100 - orig_src_load * env->imbalance_pct;
+       old_imb = orig_dst_load * src_capacity * 100 -
+                 orig_src_load * dst_capacity * env->imbalance_pct;
 
        /* Would this change make things worse? */
        return (imb > old_imb);
@@ -1136,15 +1251,33 @@ static void task_numa_compare(struct task_numa_env *env,
        struct rq *src_rq = cpu_rq(env->src_cpu);
        struct rq *dst_rq = cpu_rq(env->dst_cpu);
        struct task_struct *cur;
-       long orig_src_load, src_load;
-       long orig_dst_load, dst_load;
+       long src_load, dst_load;
        long load;
-       long imp = (groupimp > 0) ? groupimp : taskimp;
+       long imp = env->p->numa_group ? groupimp : taskimp;
+       long moveimp = imp;
+       int dist = env->dist;
 
        rcu_read_lock();
-       cur = ACCESS_ONCE(dst_rq->curr);
-       if (cur->pid == 0) /* idle */
+
+       raw_spin_lock_irq(&dst_rq->lock);
+       cur = dst_rq->curr;
+       /*
+        * No need to move the exiting task, and this ensures that ->curr
+        * wasn't reaped and thus get_task_struct() in task_numa_assign()
+        * is safe under RCU read lock.
+        * Note that rcu_read_lock() itself can't protect from the final
+        * put_task_struct() after the last schedule().
+        */
+       if ((cur->flags & PF_EXITING) || is_idle_task(cur))
                cur = NULL;
+       raw_spin_unlock_irq(&dst_rq->lock);
+
+       /*
+        * Because we have preemption enabled we can get migrated around and
+        * end try selecting ourselves (current == env->p) as a swap candidate.
+        */
+       if (cur == env->p)
+               goto unlock;
 
        /*
         * "imp" is the fault differential for the source task between the
@@ -1163,8 +1296,8 @@ static void task_numa_compare(struct task_numa_env *env,
                 * in any group then look only at task weights.
                 */
                if (cur->numa_group == env->p->numa_group) {
-                       imp = taskimp + task_weight(cur, env->src_nid) -
-                             task_weight(cur, env->dst_nid);
+                       imp = taskimp + task_weight(cur, env->src_nid, dist) -
+                             task_weight(cur, env->dst_nid, dist);
                        /*
                         * Add some hysteresis to prevent swapping the
                         * tasks within a group over tiny differences.
@@ -1177,26 +1310,21 @@ static void task_numa_compare(struct task_numa_env *env,
                         * itself (not part of a group), use the task weight
                         * instead.
                         */
-                       if (env->p->numa_group)
-                               imp = groupimp;
-                       else
-                               imp = taskimp;
-
                        if (cur->numa_group)
-                               imp += group_weight(cur, env->src_nid) -
-                                      group_weight(cur, env->dst_nid);
+                               imp += group_weight(cur, env->src_nid, dist) -
+                                      group_weight(cur, env->dst_nid, dist);
                        else
-                               imp += task_weight(cur, env->src_nid) -
-                                      task_weight(cur, env->dst_nid);
+                               imp += task_weight(cur, env->src_nid, dist) -
+                                      task_weight(cur, env->dst_nid, dist);
                }
        }
 
-       if (imp < env->best_imp)
+       if (imp <= env->best_imp && moveimp <= env->best_imp)
                goto unlock;
 
        if (!cur) {
                /* Is there capacity at our destination? */
-               if (env->src_stats.has_free_capacity &&
+               if (env->src_stats.nr_running <= env->src_stats.task_capacity &&
                    !env->dst_stats.has_free_capacity)
                        goto unlock;
 
@@ -1204,20 +1332,34 @@ static void task_numa_compare(struct task_numa_env *env,
        }
 
        /* Balance doesn't matter much if we're running a task per cpu */
-       if (src_rq->nr_running == 1 && dst_rq->nr_running == 1)
+       if (imp > env->best_imp && src_rq->nr_running == 1 &&
+                       dst_rq->nr_running == 1)
                goto assign;
 
        /*
         * In the overloaded case, try and keep the load balanced.
         */
 balance:
-       orig_dst_load = env->dst_stats.load;
-       orig_src_load = env->src_stats.load;
-
-       /* XXX missing capacity terms */
        load = task_h_load(env->p);
-       dst_load = orig_dst_load + load;
-       src_load = orig_src_load - load;
+       dst_load = env->dst_stats.load + load;
+       src_load = env->src_stats.load - load;
+
+       if (moveimp > imp && moveimp > env->best_imp) {
+               /*
+                * If the improvement from just moving env->p direction is
+                * better than swapping tasks around, check if a move is
+                * possible. Store a slightly smaller score than moveimp,
+                * so an actually idle CPU will win.
+                */
+               if (!load_too_imbalanced(src_load, dst_load, env)) {
+                       imp = moveimp - 1;
+                       cur = NULL;
+                       goto assign;
+               }
+       }
+
+       if (imp <= env->best_imp)
+               goto unlock;
 
        if (cur) {
                load = task_h_load(cur);
@@ -1225,10 +1367,16 @@ balance:
                src_load += load;
        }
 
-       if (load_too_imbalanced(orig_src_load, orig_dst_load,
-                               src_load, dst_load, env))
+       if (load_too_imbalanced(src_load, dst_load, env))
                goto unlock;
 
+       /*
+        * One idle CPU per node is evaluated for a task numa move.
+        * Call select_idle_sibling to maybe find a better one.
+        */
+       if (!cur)
+               env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu);
+
 assign:
        task_numa_assign(env, cur, imp);
 unlock:
@@ -1250,6 +1398,30 @@ static void task_numa_find_cpu(struct task_numa_env *env,
        }
 }
 
+/* Only move tasks to a NUMA node less busy than the current node. */
+static bool numa_has_capacity(struct task_numa_env *env)
+{
+       struct numa_stats *src = &env->src_stats;
+       struct numa_stats *dst = &env->dst_stats;
+
+       if (src->has_free_capacity && !dst->has_free_capacity)
+               return false;
+
+       /*
+        * Only consider a task move if the source has a higher load
+        * than the destination, corrected for CPU capacity on each node.
+        *
+        *      src->load                dst->load
+        * --------------------- vs ---------------------
+        * src->compute_capacity    dst->compute_capacity
+        */
+       if (src->load * dst->compute_capacity >
+           dst->load * src->compute_capacity)
+               return true;
+
+       return false;
+}
+
 static int task_numa_migrate(struct task_struct *p)
 {
        struct task_numa_env env = {
@@ -1266,7 +1438,7 @@ static int task_numa_migrate(struct task_struct *p)
        };
        struct sched_domain *sd;
        unsigned long taskweight, groupweight;
-       int nid, ret;
+       int nid, ret, dist;
        long taskimp, groupimp;
 
        /*
@@ -1294,40 +1466,53 @@ static int task_numa_migrate(struct task_struct *p)
                return -EINVAL;
        }
 
-       taskweight = task_weight(p, env.src_nid);
-       groupweight = group_weight(p, env.src_nid);
-       update_numa_stats(&env.src_stats, env.src_nid);
        env.dst_nid = p->numa_preferred_nid;
-       taskimp = task_weight(p, env.dst_nid) - taskweight;
-       groupimp = group_weight(p, env.dst_nid) - groupweight;
+       dist = env.dist = node_distance(env.src_nid, env.dst_nid);
+       taskweight = task_weight(p, env.src_nid, dist);
+       groupweight = group_weight(p, env.src_nid, dist);
+       update_numa_stats(&env.src_stats, env.src_nid);
+       taskimp = task_weight(p, env.dst_nid, dist) - taskweight;
+       groupimp = group_weight(p, env.dst_nid, dist) - groupweight;
        update_numa_stats(&env.dst_stats, env.dst_nid);
 
-       /* If the preferred nid has free capacity, try to use it. */
-       if (env.dst_stats.has_free_capacity)
+       /* Try to find a spot on the preferred nid. */
+       if (numa_has_capacity(&env))
                task_numa_find_cpu(&env, taskimp, groupimp);
 
-       /* No space available on the preferred nid. Look elsewhere. */
-       if (env.best_cpu == -1) {
+       /*
+        * Look at other nodes in these cases:
+        * - there is no space available on the preferred_nid
+        * - the task is part of a numa_group that is interleaved across
+        *   multiple NUMA nodes; in order to better consolidate the group,
+        *   we need to check other locations.
+        */
+       if (env.best_cpu == -1 || (p->numa_group &&
+                       nodes_weight(p->numa_group->active_nodes) > 1)) {
                for_each_online_node(nid) {
                        if (nid == env.src_nid || nid == p->numa_preferred_nid)
                                continue;
 
+                       dist = node_distance(env.src_nid, env.dst_nid);
+                       if (sched_numa_topology_type == NUMA_BACKPLANE &&
+                                               dist != env.dist) {
+                               taskweight = task_weight(p, env.src_nid, dist);
+                               groupweight = group_weight(p, env.src_nid, dist);
+                       }
+
                        /* Only consider nodes where both task and groups benefit */
-                       taskimp = task_weight(p, nid) - taskweight;
-                       groupimp = group_weight(p, nid) - groupweight;
+                       taskimp = task_weight(p, nid, dist) - taskweight;
+                       groupimp = group_weight(p, nid, dist) - groupweight;
                        if (taskimp < 0 && groupimp < 0)
                                continue;
 
+                       env.dist = dist;
                        env.dst_nid = nid;
                        update_numa_stats(&env.dst_stats, env.dst_nid);
-                       task_numa_find_cpu(&env, taskimp, groupimp);
+                       if (numa_has_capacity(&env))
+                               task_numa_find_cpu(&env, taskimp, groupimp);
                }
        }
 
-       /* No better CPU than the current one was found. */
-       if (env.best_cpu == -1)
-               return -EAGAIN;
-
        /*
         * If the task is part of a workload that spans multiple NUMA nodes,
         * and is migrating into one of the workload's active nodes, remember
@@ -1336,8 +1521,19 @@ static int task_numa_migrate(struct task_struct *p)
         * A task that migrated to a second choice node will be better off
         * trying for a better one later. Do not set the preferred node here.
         */
-       if (p->numa_group && node_isset(env.dst_nid, p->numa_group->active_nodes))
-               sched_setnuma(p, env.dst_nid);
+       if (p->numa_group) {
+               if (env.best_cpu == -1)
+                       nid = env.src_nid;
+               else
+                       nid = env.dst_nid;
+
+               if (node_isset(nid, p->numa_group->active_nodes))
+                       sched_setnuma(p, env.dst_nid);
+       }
+
+       /* No better CPU than the current one was found. */
+       if (env.best_cpu == -1)
+               return -EAGAIN;
 
        /*
         * Reset the scan period if the task is being rescheduled on an
@@ -1365,7 +1561,7 @@ static void numa_migrate_preferred(struct task_struct *p)
        unsigned long interval = HZ;
 
        /* This task has no NUMA fault statistics yet */
-       if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults_memory))
+       if (unlikely(p->numa_preferred_nid == -1 || !p->numa_faults))
                return;
 
        /* Periodically retry migrating the task to the preferred node */
@@ -1415,12 +1611,12 @@ static void update_numa_active_node_mask(struct numa_group *numa_group)
 /*
  * When adapting the scan rate, the period is divided into NUMA_PERIOD_SLOTS
  * increments. The more local the fault statistics are, the higher the scan
- * period will be for the next scan window. If local/remote ratio is below
- * NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS) the
- * scan period will decrease
+ * period will be for the next scan window. If local/(local+remote) ratio is
+ * below NUMA_PERIOD_THRESHOLD (where range of ratio is 1..NUMA_PERIOD_SLOTS)
+ * the scan period will decrease. Aim for 70% local accesses.
  */
 #define NUMA_PERIOD_SLOTS 10
-#define NUMA_PERIOD_THRESHOLD 3
+#define NUMA_PERIOD_THRESHOLD 7
 
 /*
  * Increase the scan period (slow down scanning) if the majority of
@@ -1441,9 +1637,11 @@ static void update_task_scan_period(struct task_struct *p,
        /*
         * If there were no record hinting faults then either the task is
         * completely idle or all activity is areas that are not of interest
-        * to automatic numa balancing. Scan slower
+        * to automatic numa balancing. Related to that, if there were failed
+        * migration then it implies we are migrating too quickly or the local
+        * node is overloaded. In either case, scan slower
         */
-       if (local + shared == 0) {
+       if (local + shared == 0 || p->numa_faults_locality[2]) {
                p->numa_scan_period = min(p->numa_scan_period_max,
                        p->numa_scan_period << 1);
 
@@ -1477,7 +1675,7 @@ static void update_task_scan_period(struct task_struct *p,
                 * scanning faster if shared accesses dominate as it may
                 * simply bounce migrations uselessly
                 */
-               ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared));
+               ratio = DIV_ROUND_UP(private * NUMA_PERIOD_SLOTS, (private + shared + 1));
                diff = (diff * ratio) / NUMA_PERIOD_SLOTS;
        }
 
@@ -1505,7 +1703,7 @@ static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
                *period = now - p->last_task_numa_placement;
        } else {
                delta = p->se.avg.runnable_avg_sum;
-               *period = p->se.avg.runnable_avg_period;
+               *period = p->se.avg.avg_period;
        }
 
        p->last_sum_exec_runtime = runtime;
@@ -1514,6 +1712,94 @@ static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
        return delta;
 }
 
+/*
+ * Determine the preferred nid for a task in a numa_group. This needs to
+ * be done in a way that produces consistent results with group_weight,
+ * otherwise workloads might not converge.
+ */
+static int preferred_group_nid(struct task_struct *p, int nid)
+{
+       nodemask_t nodes;
+       int dist;
+
+       /* Direct connections between all NUMA nodes. */
+       if (sched_numa_topology_type == NUMA_DIRECT)
+               return nid;
+
+       /*
+        * On a system with glueless mesh NUMA topology, group_weight
+        * scores nodes according to the number of NUMA hinting faults on
+        * both the node itself, and on nearby nodes.
+        */
+       if (sched_numa_topology_type == NUMA_GLUELESS_MESH) {
+               unsigned long score, max_score = 0;
+               int node, max_node = nid;
+
+               dist = sched_max_numa_distance;
+
+               for_each_online_node(node) {
+                       score = group_weight(p, node, dist);
+                       if (score > max_score) {
+                               max_score = score;
+                               max_node = node;
+                       }
+               }
+               return max_node;
+       }
+
+       /*
+        * Finding the preferred nid in a system with NUMA backplane
+        * interconnect topology is more involved. The goal is to locate
+        * tasks from numa_groups near each other in the system, and
+        * untangle workloads from different sides of the system. This requires
+        * searching down the hierarchy of node groups, recursively searching
+        * inside the highest scoring group of nodes. The nodemask tricks
+        * keep the complexity of the search down.
+        */
+       nodes = node_online_map;
+       for (dist = sched_max_numa_distance; dist > LOCAL_DISTANCE; dist--) {
+               unsigned long max_faults = 0;
+               nodemask_t max_group = NODE_MASK_NONE;
+               int a, b;
+
+               /* Are there nodes at this distance from each other? */
+               if (!find_numa_distance(dist))
+                       continue;
+
+               for_each_node_mask(a, nodes) {
+                       unsigned long faults = 0;
+                       nodemask_t this_group;
+                       nodes_clear(this_group);
+
+                       /* Sum group's NUMA faults; includes a==b case. */
+                       for_each_node_mask(b, nodes) {
+                               if (node_distance(a, b) < dist) {
+                                       faults += group_faults(p, b);
+                                       node_set(b, this_group);
+                                       node_clear(b, nodes);
+                               }
+                       }
+
+                       /* Remember the top group. */
+                       if (faults > max_faults) {
+                               max_faults = faults;
+                               max_group = this_group;
+                               /*
+                                * subtle: at the smallest distance there is
+                                * just one node left in each "group", the
+                                * winner is the preferred nid.
+                                */
+                               nid = a;
+                       }
+               }
+               /* Next round, evaluate the nodes within max_group. */
+               if (!max_faults)
+                       break;
+               nodes = max_group;
+       }
+       return nid;
+}
+
 static void task_numa_placement(struct task_struct *p)
 {
        int seq, nid, max_nid = -1, max_group_nid = -1;
@@ -1523,7 +1809,12 @@ static void task_numa_placement(struct task_struct *p)
        u64 runtime, period;
        spinlock_t *group_lock = NULL;
 
-       seq = ACCESS_ONCE(p->mm->numa_scan_seq);
+       /*
+        * The p->mm->numa_scan_seq field gets updated without
+        * exclusive access. Use READ_ONCE() here to ensure
+        * that the field is read in a single access:
+        */
+       seq = READ_ONCE(p->mm->numa_scan_seq);
        if (p->numa_scan_seq == seq)
                return;
        p->numa_scan_seq = seq;
@@ -1541,18 +1832,23 @@ static void task_numa_placement(struct task_struct *p)
 
        /* Find the node with the highest number of faults */
        for_each_online_node(nid) {
+               /* Keep track of the offsets in numa_faults array */
+               int mem_idx, membuf_idx, cpu_idx, cpubuf_idx;
                unsigned long faults = 0, group_faults = 0;
-               int priv, i;
+               int priv;
 
                for (priv = 0; priv < NR_NUMA_HINT_FAULT_TYPES; priv++) {
                        long diff, f_diff, f_weight;
 
-                       i = task_faults_idx(nid, priv);
+                       mem_idx = task_faults_idx(NUMA_MEM, nid, priv);
+                       membuf_idx = task_faults_idx(NUMA_MEMBUF, nid, priv);
+                       cpu_idx = task_faults_idx(NUMA_CPU, nid, priv);
+                       cpubuf_idx = task_faults_idx(NUMA_CPUBUF, nid, priv);
 
                        /* Decay existing window, copy faults since last scan */
-                       diff = p->numa_faults_buffer_memory[i] - p->numa_faults_memory[i] / 2;
-                       fault_types[priv] += p->numa_faults_buffer_memory[i];
-                       p->numa_faults_buffer_memory[i] = 0;
+                       diff = p->numa_faults[membuf_idx] - p->numa_faults[mem_idx] / 2;
+                       fault_types[priv] += p->numa_faults[membuf_idx];
+                       p->numa_faults[membuf_idx] = 0;
 
                        /*
                         * Normalize the faults_from, so all tasks in a group
@@ -1562,21 +1858,27 @@ static void task_numa_placement(struct task_struct *p)
                         * faults are less important.
                         */
                        f_weight = div64_u64(runtime << 16, period + 1);
-                       f_weight = (f_weight * p->numa_faults_buffer_cpu[i]) /
+                       f_weight = (f_weight * p->numa_faults[cpubuf_idx]) /
                                   (total_faults + 1);
-                       f_diff = f_weight - p->numa_faults_cpu[i] / 2;
-                       p->numa_faults_buffer_cpu[i] = 0;
+                       f_diff = f_weight - p->numa_faults[cpu_idx] / 2;
+                       p->numa_faults[cpubuf_idx] = 0;
 
-                       p->numa_faults_memory[i] += diff;
-                       p->numa_faults_cpu[i] += f_diff;
-                       faults += p->numa_faults_memory[i];
+                       p->numa_faults[mem_idx] += diff;
+                       p->numa_faults[cpu_idx] += f_diff;
+                       faults += p->numa_faults[mem_idx];
                        p->total_numa_faults += diff;
                        if (p->numa_group) {
-                               /* safe because we can only change our own group */
-                               p->numa_group->faults[i] += diff;
-                               p->numa_group->faults_cpu[i] += f_diff;
+                               /*
+                                * safe because we can only change our own group
+                                *
+                                * mem_idx represents the offset for a given
+                                * nid and priv in a specific region because it
+                                * is at the beginning of the numa_faults array.
+                                */
+                               p->numa_group->faults[mem_idx] += diff;
+                               p->numa_group->faults_cpu[mem_idx] += f_diff;
                                p->numa_group->total_faults += diff;
-                               group_faults += p->numa_group->faults[i];
+                               group_faults += p->numa_group->faults[mem_idx];
                        }
                }
 
@@ -1595,30 +1897,17 @@ static void task_numa_placement(struct task_struct *p)
 
        if (p->numa_group) {
                update_numa_active_node_mask(p->numa_group);
-               /*
-                * If the preferred task and group nids are different,
-                * iterate over the nodes again to find the best place.
-                */
-               if (max_nid != max_group_nid) {
-                       unsigned long weight, max_weight = 0;
-
-                       for_each_online_node(nid) {
-                               weight = task_weight(p, nid) + group_weight(p, nid);
-                               if (weight > max_weight) {
-                                       max_weight = weight;
-                                       max_nid = nid;
-                               }
-                       }
-               }
-
                spin_unlock_irq(group_lock);
+               max_nid = preferred_group_nid(p, max_group_nid);
        }
 
-       /* Preferred node as the node with the most faults */
-       if (max_faults && max_nid != p->numa_preferred_nid) {
-               /* Update the preferred nid and migrate task if possible */
-               sched_setnuma(p, max_nid);
-               numa_migrate_preferred(p);
+       if (max_faults) {
+               /* Set the new preferred node */
+               if (max_nid != p->numa_preferred_nid)
+                       sched_setnuma(p, max_nid);
+
+               if (task_node(p) != p->numa_preferred_nid)
+                       numa_migrate_preferred(p);
        }
 }
 
@@ -1652,7 +1941,6 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
 
                atomic_set(&grp->refcount, 1);
                spin_lock_init(&grp->lock);
-               INIT_LIST_HEAD(&grp->task_list);
                grp->gid = p->pid;
                /* Second half of the array tracks nids where faults happen */
                grp->faults_cpu = grp->faults + NR_NUMA_HINT_FAULT_TYPES *
@@ -1661,17 +1949,16 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
                node_set(task_node(current), grp->active_nodes);
 
                for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
-                       grp->faults[i] = p->numa_faults_memory[i];
+                       grp->faults[i] = p->numa_faults[i];
 
                grp->total_faults = p->total_numa_faults;
 
-               list_add(&p->numa_entry, &grp->task_list);
                grp->nr_tasks++;
                rcu_assign_pointer(p->numa_group, grp);
        }
 
        rcu_read_lock();
-       tsk = ACCESS_ONCE(cpu_rq(cpu)->curr);
+       tsk = READ_ONCE(cpu_rq(cpu)->curr);
 
        if (!cpupid_match_pid(tsk, cpupid))
                goto no_join;
@@ -1720,13 +2007,12 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
        double_lock_irq(&my_grp->lock, &grp->lock);
 
        for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
-               my_grp->faults[i] -= p->numa_faults_memory[i];
-               grp->faults[i] += p->numa_faults_memory[i];
+               my_grp->faults[i] -= p->numa_faults[i];
+               grp->faults[i] += p->numa_faults[i];
        }
        my_grp->total_faults -= p->total_numa_faults;
        grp->total_faults += p->total_numa_faults;
 
-       list_move(&p->numa_entry, &grp->task_list);
        my_grp->nr_tasks--;
        grp->nr_tasks++;
 
@@ -1746,27 +2032,23 @@ no_join:
 void task_numa_free(struct task_struct *p)
 {
        struct numa_group *grp = p->numa_group;
-       void *numa_faults = p->numa_faults_memory;
+       void *numa_faults = p->numa_faults;
        unsigned long flags;
        int i;
 
        if (grp) {
                spin_lock_irqsave(&grp->lock, flags);
                for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
-                       grp->faults[i] -= p->numa_faults_memory[i];
+                       grp->faults[i] -= p->numa_faults[i];
                grp->total_faults -= p->total_numa_faults;
 
-               list_del(&p->numa_entry);
                grp->nr_tasks--;
                spin_unlock_irqrestore(&grp->lock, flags);
-               rcu_assign_pointer(p->numa_group, NULL);
+               RCU_INIT_POINTER(p->numa_group, NULL);
                put_numa_group(grp);
        }
 
-       p->numa_faults_memory = NULL;
-       p->numa_faults_buffer_memory = NULL;
-       p->numa_faults_cpu= NULL;
-       p->numa_faults_buffer_cpu = NULL;
+       p->numa_faults = NULL;
        kfree(numa_faults);
 }
 
@@ -1788,29 +2070,15 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
        if (!p->mm)
                return;
 
-       /* Do not worry about placement if exiting */
-       if (p->state == TASK_DEAD)
-               return;
-
        /* Allocate buffer to track faults on a per-node basis */
-       if (unlikely(!p->numa_faults_memory)) {
-               int size = sizeof(*p->numa_faults_memory) *
+       if (unlikely(!p->numa_faults)) {
+               int size = sizeof(*p->numa_faults) *
                           NR_NUMA_HINT_FAULT_BUCKETS * nr_node_ids;
 
-               p->numa_faults_memory = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
-               if (!p->numa_faults_memory)
+               p->numa_faults = kzalloc(size, GFP_KERNEL|__GFP_NOWARN);
+               if (!p->numa_faults)
                        return;
 
-               BUG_ON(p->numa_faults_buffer_memory);
-               /*
-                * The averaged statistics, shared & private, memory & cpu,
-                * occupy the first half of the array. The second half of the
-                * array is for current counters, which are averaged into the
-                * first set by task_numa_placement.
-                */
-               p->numa_faults_cpu = p->numa_faults_memory + (2 * nr_node_ids);
-               p->numa_faults_buffer_memory = p->numa_faults_memory + (4 * nr_node_ids);
-               p->numa_faults_buffer_cpu = p->numa_faults_memory + (6 * nr_node_ids);
                p->total_numa_faults = 0;
                memset(p->numa_faults_locality, 0, sizeof(p->numa_faults_locality));
        }
@@ -1849,15 +2117,25 @@ void task_numa_fault(int last_cpupid, int mem_node, int pages, int flags)
 
        if (migrated)
                p->numa_pages_migrated += pages;
+       if (flags & TNF_MIGRATE_FAIL)
+               p->numa_faults_locality[2] += pages;
 
-       p->numa_faults_buffer_memory[task_faults_idx(mem_node, priv)] += pages;
-       p->numa_faults_buffer_cpu[task_faults_idx(cpu_node, priv)] += pages;
+       p->numa_faults[task_faults_idx(NUMA_MEMBUF, mem_node, priv)] += pages;
+       p->numa_faults[task_faults_idx(NUMA_CPUBUF, cpu_node, priv)] += pages;
        p->numa_faults_locality[local] += pages;
 }
 
 static void reset_ptenuma_scan(struct task_struct *p)
 {
-       ACCESS_ONCE(p->mm->numa_scan_seq)++;
+       /*
+        * We only did a read acquisition of the mmap sem, so
+        * p->mm->numa_scan_seq is written to without exclusive access
+        * and the update is not guaranteed to be atomic. That's not
+        * much of an issue though, since this is just used for
+        * statistical sampling. Use READ_ONCE/WRITE_ONCE, which are not
+        * expensive, to avoid any form of compiler optimizations:
+        */
+       WRITE_ONCE(p->mm->numa_scan_seq, READ_ONCE(p->mm->numa_scan_seq) + 1);
        p->mm->numa_scan_offset = 0;
 }
 
@@ -1930,8 +2208,10 @@ void task_numa_work(struct callback_head *work)
                vma = mm->mmap;
        }
        for (; vma; vma = vma->vm_next) {
-               if (!vma_migratable(vma) || !vma_policy_mof(p, vma))
+               if (!vma_migratable(vma) || !vma_policy_mof(vma) ||
+                       is_vm_hugetlb_page(vma) || (vma->vm_flags & VM_MIXEDMAP)) {
                        continue;
+               }
 
                /*
                 * Shared library pages mapped by multiple processes are not
@@ -2195,8 +2475,8 @@ static __always_inline u64 decay_load(u64 val, u64 n)
 
        /*
         * As y^PERIOD = 1/2, we can combine
-        *    y^n = 1/2^(n/PERIOD) * k^(n%PERIOD)
-        * With a look-up table which covers k^n (n<PERIOD)
+        *    y^n = 1/2^(n/PERIOD) * y^(n%PERIOD)
+        * With a look-up table which covers y^n (n<PERIOD)
         *
         * To achieve constant time decay_load.
         */
@@ -2266,13 +2546,15 @@ static u32 __compute_runnable_contrib(u64 n)
  *   load_avg = u_0` + y*(u_0 + u_1*y + u_2*y^2 + ... )
  *            = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}]
  */
-static __always_inline int __update_entity_runnable_avg(u64 now,
+static __always_inline int __update_entity_runnable_avg(u64 now, int cpu,
                                                        struct sched_avg *sa,
-                                                       int runnable)
+                                                       int runnable,
+                                                       int running)
 {
        u64 delta, periods;
        u32 runnable_contrib;
        int delta_w, decayed = 0;
+       unsigned long scale_freq = arch_scale_freq_capacity(NULL, cpu);
 
        delta = now - sa->last_runnable_update;
        /*
@@ -2294,7 +2576,7 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
        sa->last_runnable_update = now;
 
        /* delta_w is the amount already accumulated against our next period */
-       delta_w = sa->runnable_avg_period % 1024;
+       delta_w = sa->avg_period % 1024;
        if (delta + delta_w >= 1024) {
                /* period roll-over */
                decayed = 1;
@@ -2307,7 +2589,10 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
                delta_w = 1024 - delta_w;
                if (runnable)
                        sa->runnable_avg_sum += delta_w;
-               sa->runnable_avg_period += delta_w;
+               if (running)
+                       sa->running_avg_sum += delta_w * scale_freq
+                               >> SCHED_CAPACITY_SHIFT;
+               sa->avg_period += delta_w;
 
                delta -= delta_w;
 
@@ -2317,20 +2602,28 @@ static __always_inline int __update_entity_runnable_avg(u64 now,
 
                sa->runnable_avg_sum = decay_load(sa->runnable_avg_sum,
                                                  periods + 1);
-               sa->runnable_avg_period = decay_load(sa->runnable_avg_period,
+               sa->running_avg_sum = decay_load(sa->running_avg_sum,
+                                                 periods + 1);
+               sa->avg_period = decay_load(sa->avg_period,
                                                     periods + 1);
 
                /* Efficiently calculate \sum (1..n_period) 1024*y^i */
                runnable_contrib = __compute_runnable_contrib(periods);
                if (runnable)
                        sa->runnable_avg_sum += runnable_contrib;
-               sa->runnable_avg_period += runnable_contrib;
+               if (running)
+                       sa->running_avg_sum += runnable_contrib * scale_freq
+                               >> SCHED_CAPACITY_SHIFT;
+               sa->avg_period += runnable_contrib;
        }
 
        /* Remainder of delta accrued against u_0` */
        if (runnable)
                sa->runnable_avg_sum += delta;
-       sa->runnable_avg_period += delta;
+       if (running)
+               sa->running_avg_sum += delta * scale_freq
+                       >> SCHED_CAPACITY_SHIFT;
+       sa->avg_period += delta;
 
        return decayed;
 }
@@ -2342,11 +2635,13 @@ static inline u64 __synchronize_entity_decay(struct sched_entity *se)
        u64 decays = atomic64_read(&cfs_rq->decay_counter);
 
        decays -= se->avg.decay_count;
+       se->avg.decay_count = 0;
        if (!decays)
                return 0;
 
        se->avg.load_avg_contrib = decay_load(se->avg.load_avg_contrib, decays);
-       se->avg.decay_count = 0;
+       se->avg.utilization_avg_contrib =
+               decay_load(se->avg.utilization_avg_contrib, decays);
 
        return decays;
 }
@@ -2361,6 +2656,9 @@ static inline void __update_cfs_rq_tg_load_contrib(struct cfs_rq *cfs_rq,
        tg_contrib = cfs_rq->runnable_load_avg + cfs_rq->blocked_load_avg;
        tg_contrib -= cfs_rq->tg_load_contrib;
 
+       if (!tg_contrib)
+               return;
+
        if (force_update || abs(tg_contrib) > cfs_rq->tg_load_contrib / 8) {
                atomic_long_add(tg_contrib, &tg->load_avg);
                cfs_rq->tg_load_contrib += tg_contrib;
@@ -2379,7 +2677,7 @@ static inline void __update_tg_runnable_avg(struct sched_avg *sa,
 
        /* The fraction of a cpu used by this cfs_rq */
        contrib = div_u64((u64)sa->runnable_avg_sum << NICE_0_SHIFT,
-                         sa->runnable_avg_period + 1);
+                         sa->avg_period + 1);
        contrib -= cfs_rq->tg_runnable_contrib;
 
        if (abs(contrib) > cfs_rq->tg_runnable_contrib / 64) {
@@ -2432,7 +2730,8 @@ static inline void __update_group_entity_contrib(struct sched_entity *se)
 
 static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
 {
-       __update_entity_runnable_avg(rq_clock_task(rq), &rq->avg, runnable);
+       __update_entity_runnable_avg(rq_clock_task(rq), cpu_of(rq), &rq->avg,
+                       runnable, runnable);
        __update_tg_runnable_avg(&rq->avg, &rq->cfs);
 }
 #else /* CONFIG_FAIR_GROUP_SCHED */
@@ -2450,7 +2749,7 @@ static inline void __update_task_entity_contrib(struct sched_entity *se)
 
        /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */
        contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight);
-       contrib /= (se->avg.runnable_avg_period + 1);
+       contrib /= (se->avg.avg_period + 1);
        se->avg.load_avg_contrib = scale_load(contrib);
 }
 
@@ -2469,6 +2768,30 @@ static long __update_entity_load_avg_contrib(struct sched_entity *se)
        return se->avg.load_avg_contrib - old_contrib;
 }
 
+
+static inline void __update_task_entity_utilization(struct sched_entity *se)
+{
+       u32 contrib;
+
+       /* avoid overflowing a 32-bit type w/ SCHED_LOAD_SCALE */
+       contrib = se->avg.running_avg_sum * scale_load_down(SCHED_LOAD_SCALE);
+       contrib /= (se->avg.avg_period + 1);
+       se->avg.utilization_avg_contrib = scale_load(contrib);
+}
+
+static long __update_entity_utilization_avg_contrib(struct sched_entity *se)
+{
+       long old_contrib = se->avg.utilization_avg_contrib;
+
+       if (entity_is_task(se))
+               __update_task_entity_utilization(se);
+       else
+               se->avg.utilization_avg_contrib =
+                                       group_cfs_rq(se)->utilization_load_avg;
+
+       return se->avg.utilization_avg_contrib - old_contrib;
+}
+
 static inline void subtract_blocked_load_contrib(struct cfs_rq *cfs_rq,
                                                 long load_contrib)
 {
@@ -2485,7 +2808,8 @@ static inline void update_entity_load_avg(struct sched_entity *se,
                                          int update_cfs_rq)
 {
        struct cfs_rq *cfs_rq = cfs_rq_of(se);
-       long contrib_delta;
+       long contrib_delta, utilization_delta;
+       int cpu = cpu_of(rq_of(cfs_rq));
        u64 now;
 
        /*
@@ -2497,18 +2821,22 @@ static inline void update_entity_load_avg(struct sched_entity *se,
        else
                now = cfs_rq_clock_task(group_cfs_rq(se));
 
-       if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq))
+       if (!__update_entity_runnable_avg(now, cpu, &se->avg, se->on_rq,
+                                       cfs_rq->curr == se))
                return;
 
        contrib_delta = __update_entity_load_avg_contrib(se);
+       utilization_delta = __update_entity_utilization_avg_contrib(se);
 
        if (!update_cfs_rq)
                return;
 
-       if (se->on_rq)
+       if (se->on_rq) {
                cfs_rq->runnable_load_avg += contrib_delta;
-       else
+               cfs_rq->utilization_load_avg += utilization_delta;
+       } else {
                subtract_blocked_load_contrib(cfs_rq, -contrib_delta);
+       }
 }
 
 /*
@@ -2583,6 +2911,7 @@ static inline void enqueue_entity_load_avg(struct cfs_rq *cfs_rq,
        }
 
        cfs_rq->runnable_load_avg += se->avg.load_avg_contrib;
+       cfs_rq->utilization_load_avg += se->avg.utilization_avg_contrib;
        /* we force update consideration on load-balancer moves */
        update_cfs_rq_blocked_load(cfs_rq, !wakeup);
 }
@@ -2601,6 +2930,7 @@ static inline void dequeue_entity_load_avg(struct cfs_rq *cfs_rq,
        update_cfs_rq_blocked_load(cfs_rq, !sleep);
 
        cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib;
+       cfs_rq->utilization_load_avg -= se->avg.utilization_avg_contrib;
        if (sleep) {
                cfs_rq->blocked_load_avg += se->avg.load_avg_contrib;
                se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter);
@@ -2899,7 +3229,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
        ideal_runtime = sched_slice(cfs_rq, curr);
        delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime;
        if (delta_exec > ideal_runtime) {
-               resched_task(rq_of(cfs_rq)->curr);
+               resched_curr(rq_of(cfs_rq));
                /*
                 * The current task ran long enough, ensure it doesn't get
                 * re-elected due to buddy favours.
@@ -2923,7 +3253,7 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
                return;
 
        if (delta > ideal_runtime)
-               resched_task(rq_of(cfs_rq)->curr);
+               resched_curr(rq_of(cfs_rq));
 }
 
 static void
@@ -2938,6 +3268,7 @@ set_next_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
                 */
                update_stats_wait_end(cfs_rq, se);
                __dequeue_entity(cfs_rq, se);
+               update_entity_load_avg(se, 1);
        }
 
        update_stats_curr_start(cfs_rq, se);
@@ -3063,7 +3394,7 @@ entity_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr, int queued)
         * validating it and just reschedule.
         */
        if (queued) {
-               resched_task(rq_of(cfs_rq)->curr);
+               resched_curr(rq_of(cfs_rq));
                return;
        }
        /*
@@ -3173,16 +3504,7 @@ static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
        if (cfs_b->quota == RUNTIME_INF)
                amount = min_amount;
        else {
-               /*
-                * If the bandwidth pool has become inactive, then at least one
-                * period must have elapsed since the last consumption.
-                * Refresh the global state and ensure bandwidth timer becomes
-                * active.
-                */
-               if (!cfs_b->timer_active) {
-                       __refill_cfs_bandwidth_runtime(cfs_b);
-                       __start_cfs_bandwidth(cfs_b, false);
-               }
+               start_cfs_bandwidth(cfs_b);
 
                if (cfs_b->runtime > 0) {
                        amount = min(cfs_b->runtime, min_amount);
@@ -3254,7 +3576,7 @@ static void __account_cfs_rq_runtime(struct cfs_rq *cfs_rq, u64 delta_exec)
         * hierarchy can be throttled
         */
        if (!assign_cfs_rq_runtime(cfs_rq) && likely(cfs_rq->curr))
-               resched_task(rq_of(cfs_rq)->curr);
+               resched_curr(rq_of(cfs_rq));
 }
 
 static __always_inline
@@ -3331,6 +3653,7 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
        struct cfs_bandwidth *cfs_b = tg_cfs_bandwidth(cfs_rq->tg);
        struct sched_entity *se;
        long task_delta, dequeue = 1;
+       bool empty;
 
        se = cfs_rq->tg->se[cpu_of(rq_of(cfs_rq))];
 
@@ -3360,9 +3683,21 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
        cfs_rq->throttled = 1;
        cfs_rq->throttled_clock = rq_clock(rq);
        raw_spin_lock(&cfs_b->lock);
-       list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
-       if (!cfs_b->timer_active)
-               __start_cfs_bandwidth(cfs_b, false);
+       empty = list_empty(&cfs_b->throttled_cfs_rq);
+
+       /*
+        * Add to the _head_ of the list, so that an already-started
+        * distribute_cfs_runtime will not see us
+        */
+       list_add_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
+
+       /*
+        * If we're the first throttled task, make sure the bandwidth
+        * timer is running.
+        */
+       if (empty)
+               start_cfs_bandwidth(cfs_b);
+
        raw_spin_unlock(&cfs_b->lock);
 }
 
@@ -3410,14 +3745,15 @@ void unthrottle_cfs_rq(struct cfs_rq *cfs_rq)
 
        /* determine whether we need to wake up potentially idle cpu */
        if (rq->curr == rq->idle && rq->cfs.nr_running)
-               resched_task(rq->curr);
+               resched_curr(rq);
 }
 
 static u64 distribute_cfs_runtime(struct cfs_bandwidth *cfs_b,
                u64 remaining, u64 expires)
 {
        struct cfs_rq *cfs_rq;
-       u64 runtime = remaining;
+       u64 runtime;
+       u64 starting_runtime = remaining;
 
        rcu_read_lock();
        list_for_each_entry_rcu(cfs_rq, &cfs_b->throttled_cfs_rq,
@@ -3448,7 +3784,7 @@ next:
        }
        rcu_read_unlock();
 
-       return remaining;
+       return starting_runtime - remaining;
 }
 
 /*
@@ -3476,13 +3812,6 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
        if (cfs_b->idle && !throttled)
                goto out_deactivate;
 
-       /*
-        * if we have relooped after returning idle once, we need to update our
-        * status as actually running, so that other cpus doing
-        * __start_cfs_bandwidth will stop trying to cancel us.
-        */
-       cfs_b->timer_active = 1;
-
        __refill_cfs_bandwidth_runtime(cfs_b);
 
        if (!throttled) {
@@ -3494,22 +3823,17 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
        /* account preceding periods in which throttling occurred */
        cfs_b->nr_throttled += overrun;
 
-       /*
-        * There are throttled entities so we must first use the new bandwidth
-        * to unthrottle them before making it generally available.  This
-        * ensures that all existing debts will be paid before a new cfs_rq is
-        * allowed to run.
-        */
-       runtime = cfs_b->runtime;
        runtime_expires = cfs_b->runtime_expires;
-       cfs_b->runtime = 0;
 
        /*
-        * This check is repeated as we are holding onto the new bandwidth
-        * while we unthrottle.  This can potentially race with an unthrottled
-        * group trying to acquire new bandwidth from the global pool.
+        * This check is repeated as we are holding onto the new bandwidth while
+        * we unthrottle. This can potentially race with an unthrottled group
+        * trying to acquire new bandwidth from the global pool. This can result
+        * in us over-using our runtime if it is all used during this loop, but
+        * only by limited amounts in that extreme case.
         */
-       while (throttled && runtime > 0) {
+       while (throttled && cfs_b->runtime > 0) {
+               runtime = cfs_b->runtime;
                raw_spin_unlock(&cfs_b->lock);
                /* we can't nest cfs_b->lock while distributing bandwidth */
                runtime = distribute_cfs_runtime(cfs_b, runtime,
@@ -3517,10 +3841,10 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
                raw_spin_lock(&cfs_b->lock);
 
                throttled = !list_empty(&cfs_b->throttled_cfs_rq);
+
+               cfs_b->runtime -= min(runtime, cfs_b->runtime);
        }
 
-       /* return (any) remaining runtime */
-       cfs_b->runtime = runtime;
        /*
         * While we are ensured activity in the period following an
         * unthrottle, this also covers the case in which the new bandwidth is
@@ -3532,7 +3856,6 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
        return 0;
 
 out_deactivate:
-       cfs_b->timer_active = 0;
        return 1;
 }
 
@@ -3547,7 +3870,7 @@ static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
  * Are we near the end of the current quota period?
  *
  * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the
- * hrtimer base being cleared by __hrtimer_start_range_ns. In the case of
+ * hrtimer base being cleared by hrtimer_start. In the case of
  * migrate_hrtimers, base is never cleared, so we are fine.
  */
 static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
@@ -3575,8 +3898,9 @@ static void start_cfs_slack_bandwidth(struct cfs_bandwidth *cfs_b)
        if (runtime_refresh_within(cfs_b, min_left))
                return;
 
-       start_bandwidth_timer(&cfs_b->slack_timer,
-                               ns_to_ktime(cfs_bandwidth_slack_period));
+       hrtimer_start(&cfs_b->slack_timer,
+                       ns_to_ktime(cfs_bandwidth_slack_period),
+                       HRTIMER_MODE_REL);
 }
 
 /* we know any runtime found here is valid as update_curr() precedes return */
@@ -3631,10 +3955,9 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
                return;
        }
 
-       if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice) {
+       if (cfs_b->quota != RUNTIME_INF && cfs_b->runtime > slice)
                runtime = cfs_b->runtime;
-               cfs_b->runtime = 0;
-       }
+
        expires = cfs_b->runtime_expires;
        raw_spin_unlock(&cfs_b->lock);
 
@@ -3645,7 +3968,7 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
 
        raw_spin_lock(&cfs_b->lock);
        if (expires == cfs_b->runtime_expires)
-               cfs_b->runtime = runtime;
+               cfs_b->runtime -= min(runtime, cfs_b->runtime);
        raw_spin_unlock(&cfs_b->lock);
 }
 
@@ -3697,6 +4020,7 @@ static enum hrtimer_restart sched_cfs_slack_timer(struct hrtimer *timer)
 {
        struct cfs_bandwidth *cfs_b =
                container_of(timer, struct cfs_bandwidth, slack_timer);
+
        do_sched_cfs_slack_timer(cfs_b);
 
        return HRTIMER_NORESTART;
@@ -3706,20 +4030,19 @@ static enum hrtimer_restart sched_cfs_period_timer(struct hrtimer *timer)
 {
        struct cfs_bandwidth *cfs_b =
                container_of(timer, struct cfs_bandwidth, period_timer);
-       ktime_t now;
        int overrun;
        int idle = 0;
 
        raw_spin_lock(&cfs_b->lock);
        for (;;) {
-               now = hrtimer_cb_get_time(timer);
-               overrun = hrtimer_forward(timer, now, cfs_b->period);
-
+               overrun = hrtimer_forward_now(timer, cfs_b->period);
                if (!overrun)
                        break;
 
                idle = do_sched_cfs_period_timer(cfs_b, overrun);
        }
+       if (idle)
+               cfs_b->period_active = 0;
        raw_spin_unlock(&cfs_b->lock);
 
        return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
@@ -3733,7 +4056,7 @@ void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
        cfs_b->period = ns_to_ktime(default_cfs_period());
 
        INIT_LIST_HEAD(&cfs_b->throttled_cfs_rq);
-       hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+       hrtimer_init(&cfs_b->period_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED);
        cfs_b->period_timer.function = sched_cfs_period_timer;
        hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
        cfs_b->slack_timer.function = sched_cfs_slack_timer;
@@ -3745,36 +4068,40 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
        INIT_LIST_HEAD(&cfs_rq->throttled_list);
 }
 
-/* requires cfs_b->lock, may release to reprogram timer */
-void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b, bool force)
+void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
 {
-       /*
-        * The timer may be active because we're trying to set a new bandwidth
-        * period or because we're racing with the tear-down path
-        * (timer_active==0 becomes visible before the hrtimer call-back
-        * terminates).  In either case we ensure that it's re-programmed
-        */
-       while (unlikely(hrtimer_active(&cfs_b->period_timer)) &&
-              hrtimer_try_to_cancel(&cfs_b->period_timer) < 0) {
-               /* bounce the lock to allow do_sched_cfs_period_timer to run */
-               raw_spin_unlock(&cfs_b->lock);
-               cpu_relax();
-               raw_spin_lock(&cfs_b->lock);
-               /* if someone else restarted the timer then we're done */
-               if (!force && cfs_b->timer_active)
-                       return;
-       }
+       lockdep_assert_held(&cfs_b->lock);
 
-       cfs_b->timer_active = 1;
-       start_bandwidth_timer(&cfs_b->period_timer, cfs_b->period);
+       if (!cfs_b->period_active) {
+               cfs_b->period_active = 1;
+               hrtimer_forward_now(&cfs_b->period_timer, cfs_b->period);
+               hrtimer_start_expires(&cfs_b->period_timer, HRTIMER_MODE_ABS_PINNED);
+       }
 }
 
 static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
 {
+       /* init_cfs_bandwidth() was not called */
+       if (!cfs_b->throttled_cfs_rq.next)
+               return;
+
        hrtimer_cancel(&cfs_b->period_timer);
        hrtimer_cancel(&cfs_b->slack_timer);
 }
 
+static void __maybe_unused update_runtime_enabled(struct rq *rq)
+{
+       struct cfs_rq *cfs_rq;
+
+       for_each_leaf_cfs_rq(rq, cfs_rq) {
+               struct cfs_bandwidth *cfs_b = &cfs_rq->tg->cfs_bandwidth;
+
+               raw_spin_lock(&cfs_b->lock);
+               cfs_rq->runtime_enabled = cfs_b->quota != RUNTIME_INF;
+               raw_spin_unlock(&cfs_b->lock);
+       }
+}
+
 static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
 {
        struct cfs_rq *cfs_rq;
@@ -3788,6 +4115,12 @@ static void __maybe_unused unthrottle_offline_cfs_rqs(struct rq *rq)
                 * there's some valid quota amount
                 */
                cfs_rq->runtime_remaining = 1;
+               /*
+                * Offline rq is schedulable till cpu is completely disabled
+                * in take_cpu_down(), so we prevent new cfs throttling here.
+                */
+               cfs_rq->runtime_enabled = 0;
+
                if (cfs_rq_throttled(cfs_rq))
                        unthrottle_cfs_rq(cfs_rq);
        }
@@ -3831,6 +4164,7 @@ static inline struct cfs_bandwidth *tg_cfs_bandwidth(struct task_group *tg)
        return NULL;
 }
 static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
+static inline void update_runtime_enabled(struct rq *rq) {}
 static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
 
 #endif /* CONFIG_CFS_BANDWIDTH */
@@ -3854,17 +4188,9 @@ static void hrtick_start_fair(struct rq *rq, struct task_struct *p)
 
                if (delta < 0) {
                        if (rq->curr == p)
-                               resched_task(p);
+                               resched_curr(rq);
                        return;
                }
-
-               /*
-                * Don't schedule slices shorter than 10000ns, that just
-                * doesn't make sense. Rely on vruntime for fairness.
-                */
-               if (rq->curr != p)
-                       delta = max_t(s64, 10000LL, delta);
-
                hrtick_start(rq, delta);
        }
 }
@@ -4005,37 +4331,220 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
 }
 
 #ifdef CONFIG_SMP
-/* Used instead of source_load when we know the type == 0 */
-static unsigned long weighted_cpuload(const int cpu)
-{
-       return cpu_rq(cpu)->cfs.runnable_load_avg;
-}
 
 /*
- * Return a low guess at the load of a migration-source cpu weighted
- * according to the scheduling class and "nice" value.
+ * per rq 'load' arrray crap; XXX kill this.
+ */
+
+/*
+ * The exact cpuload at various idx values, calculated at every tick would be
+ * load = (2^idx - 1) / 2^idx * load + 1 / 2^idx * cur_load
  *
- * We want to under-estimate the load of migration sources, to
- * balance conservatively.
+ * If a cpu misses updates for n-1 ticks (as it was idle) and update gets called
+ * on nth tick when cpu may be busy, then we have:
+ * load = ((2^idx - 1) / 2^idx)^(n-1) * load
+ * load = (2^idx - 1) / 2^idx) * load + 1 / 2^idx * cur_load
+ *
+ * decay_load_missed() below does efficient calculation of
+ * load = ((2^idx - 1) / 2^idx)^(n-1) * load
+ * avoiding 0..n-1 loop doing load = ((2^idx - 1) / 2^idx) * load
+ *
+ * The calculation is approximated on a 128 point scale.
+ * degrade_zero_ticks is the number of ticks after which load at any
+ * particular idx is approximated to be zero.
+ * degrade_factor is a precomputed table, a row for each load idx.
+ * Each column corresponds to degradation factor for a power of two ticks,
+ * based on 128 point scale.
+ * Example:
+ * row 2, col 3 (=12) says that the degradation at load idx 2 after
+ * 8 ticks is 12/128 (which is an approximation of exact factor 3^8/4^8).
+ *
+ * With this power of 2 load factors, we can degrade the load n times
+ * by looking at 1 bits in n and doing as many mult/shift instead of
+ * n mult/shifts needed by the exact degradation.
  */
-static unsigned long source_load(int cpu, int type)
+#define DEGRADE_SHIFT          7
+static const unsigned char
+               degrade_zero_ticks[CPU_LOAD_IDX_MAX] = {0, 8, 32, 64, 128};
+static const unsigned char
+               degrade_factor[CPU_LOAD_IDX_MAX][DEGRADE_SHIFT + 1] = {
+                                       {0, 0, 0, 0, 0, 0, 0, 0},
+                                       {64, 32, 8, 0, 0, 0, 0, 0},
+                                       {96, 72, 40, 12, 1, 0, 0},
+                                       {112, 98, 75, 43, 15, 1, 0},
+                                       {120, 112, 98, 76, 45, 16, 2} };
+
+/*
+ * Update cpu_load for any missed ticks, due to tickless idle. The backlog
+ * would be when CPU is idle and so we just decay the old load without
+ * adding any new load.
+ */
+static unsigned long
+decay_load_missed(unsigned long load, unsigned long missed_updates, int idx)
 {
-       struct rq *rq = cpu_rq(cpu);
-       unsigned long total = weighted_cpuload(cpu);
+       int j = 0;
 
-       if (type == 0 || !sched_feat(LB_BIAS))
-               return total;
+       if (!missed_updates)
+               return load;
 
-       return min(rq->cpu_load[type-1], total);
+       if (missed_updates >= degrade_zero_ticks[idx])
+               return 0;
+
+       if (idx == 1)
+               return load >> missed_updates;
+
+       while (missed_updates) {
+               if (missed_updates % 2)
+                       load = (load * degrade_factor[idx][j]) >> DEGRADE_SHIFT;
+
+               missed_updates >>= 1;
+               j++;
+       }
+       return load;
 }
 
 /*
- * Return a high guess at the load of a migration-target cpu weighted
- * according to the scheduling class and "nice" value.
+ * Update rq->cpu_load[] statistics. This function is usually called every
+ * scheduler tick (TICK_NSEC). With tickless idle this will not be called
+ * every tick. We fix it up based on jiffies.
  */
-static unsigned long target_load(int cpu, int type)
+static void __update_cpu_load(struct rq *this_rq, unsigned long this_load,
+                             unsigned long pending_updates)
 {
-       struct rq *rq = cpu_rq(cpu);
+       int i, scale;
+
+       this_rq->nr_load_updates++;
+
+       /* Update our load: */
+       this_rq->cpu_load[0] = this_load; /* Fasttrack for idx 0 */
+       for (i = 1, scale = 2; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
+               unsigned long old_load, new_load;
+
+               /* scale is effectively 1 << i now, and >> i divides by scale */
+
+               old_load = this_rq->cpu_load[i];
+               old_load = decay_load_missed(old_load, pending_updates - 1, i);
+               new_load = this_load;
+               /*
+                * Round up the averaging division if load is increasing. This
+                * prevents us from getting stuck on 9 if the load is 10, for
+                * example.
+                */
+               if (new_load > old_load)
+                       new_load += scale - 1;
+
+               this_rq->cpu_load[i] = (old_load * (scale - 1) + new_load) >> i;
+       }
+
+       sched_avg_update(this_rq);
+}
+
+#ifdef CONFIG_NO_HZ_COMMON
+/*
+ * There is no sane way to deal with nohz on smp when using jiffies because the
+ * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
+ * causing off-by-one errors in observed deltas; {0,2} instead of {1,1}.
+ *
+ * Therefore we cannot use the delta approach from the regular tick since that
+ * would seriously skew the load calculation. However we'll make do for those
+ * updates happening while idle (nohz_idle_balance) or coming out of idle
+ * (tick_nohz_idle_exit).
+ *
+ * This means we might still be one tick off for nohz periods.
+ */
+
+/*
+ * Called from nohz_idle_balance() to update the load ratings before doing the
+ * idle balance.
+ */
+static void update_idle_cpu_load(struct rq *this_rq)
+{
+       unsigned long curr_jiffies = READ_ONCE(jiffies);
+       unsigned long load = this_rq->cfs.runnable_load_avg;
+       unsigned long pending_updates;
+
+       /*
+        * bail if there's load or we're actually up-to-date.
+        */
+       if (load || curr_jiffies == this_rq->last_load_update_tick)
+               return;
+
+       pending_updates = curr_jiffies - this_rq->last_load_update_tick;
+       this_rq->last_load_update_tick = curr_jiffies;
+
+       __update_cpu_load(this_rq, load, pending_updates);
+}
+
+/*
+ * Called from tick_nohz_idle_exit() -- try and fix up the ticks we missed.
+ */
+void update_cpu_load_nohz(void)
+{
+       struct rq *this_rq = this_rq();
+       unsigned long curr_jiffies = READ_ONCE(jiffies);
+       unsigned long pending_updates;
+
+       if (curr_jiffies == this_rq->last_load_update_tick)
+               return;
+
+       raw_spin_lock(&this_rq->lock);
+       pending_updates = curr_jiffies - this_rq->last_load_update_tick;
+       if (pending_updates) {
+               this_rq->last_load_update_tick = curr_jiffies;
+               /*
+                * We were idle, this means load 0, the current load might be
+                * !0 due to remote wakeups and the sort.
+                */
+               __update_cpu_load(this_rq, 0, pending_updates);
+       }
+       raw_spin_unlock(&this_rq->lock);
+}
+#endif /* CONFIG_NO_HZ */
+
+/*
+ * Called from scheduler_tick()
+ */
+void update_cpu_load_active(struct rq *this_rq)
+{
+       unsigned long load = this_rq->cfs.runnable_load_avg;
+       /*
+        * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().
+        */
+       this_rq->last_load_update_tick = jiffies;
+       __update_cpu_load(this_rq, load, 1);
+}
+
+/* Used instead of source_load when we know the type == 0 */
+static unsigned long weighted_cpuload(const int cpu)
+{
+       return cpu_rq(cpu)->cfs.runnable_load_avg;
+}
+
+/*
+ * Return a low guess at the load of a migration-source cpu weighted
+ * according to the scheduling class and "nice" value.
+ *
+ * We want to under-estimate the load of migration sources, to
+ * balance conservatively.
+ */
+static unsigned long source_load(int cpu, int type)
+{
+       struct rq *rq = cpu_rq(cpu);
+       unsigned long total = weighted_cpuload(cpu);
+
+       if (type == 0 || !sched_feat(LB_BIAS))
+               return total;
+
+       return min(rq->cpu_load[type-1], total);
+}
+
+/*
+ * Return a high guess at the load of a migration-target cpu weighted
+ * according to the scheduling class and "nice" value.
+ */
+static unsigned long target_load(int cpu, int type)
+{
+       struct rq *rq = cpu_rq(cpu);
        unsigned long total = weighted_cpuload(cpu);
 
        if (type == 0 || !sched_feat(LB_BIAS))
@@ -4049,10 +4558,15 @@ 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)
 {
        struct rq *rq = cpu_rq(cpu);
-       unsigned long nr_running = ACCESS_ONCE(rq->nr_running);
+       unsigned long nr_running = READ_ONCE(rq->cfs.h_nr_running);
        unsigned long load_avg = rq->cfs.runnable_load_avg;
 
        if (nr_running)
@@ -4178,7 +4692,7 @@ static long effective_load(struct task_group *tg, int cpu, long wl, long wg)
                 * wl = S * s'_i; see (2)
                 */
                if (W > 0 && w < W)
-                       wl = (w * tg->shares) / W;
+                       wl = (w * (long)tg->shares) / W;
                else
                        wl = tg->shares;
 
@@ -4241,8 +4755,8 @@ static int wake_wide(struct task_struct *p)
 static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
 {
        s64 this_load, load;
+       s64 this_eff_load, prev_eff_load;
        int idx, this_cpu, prev_cpu;
-       unsigned long tl_per_task;
        struct task_group *tg;
        unsigned long weight;
        int balanced;
@@ -4285,47 +4799,30 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
         * Otherwise check if either cpus are near enough in load to allow this
         * task to be woken on this_cpu.
         */
-       if (this_load > 0) {
-               s64 this_eff_load, prev_eff_load;
+       this_eff_load = 100;
+       this_eff_load *= capacity_of(prev_cpu);
 
-               this_eff_load = 100;
-               this_eff_load *= capacity_of(prev_cpu);
+       prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
+       prev_eff_load *= capacity_of(this_cpu);
+
+       if (this_load > 0) {
                this_eff_load *= this_load +
                        effective_load(tg, this_cpu, weight, weight);
 
-               prev_eff_load = 100 + (sd->imbalance_pct - 100) / 2;
-               prev_eff_load *= capacity_of(this_cpu);
                prev_eff_load *= load + effective_load(tg, prev_cpu, 0, weight);
+       }
 
-               balanced = this_eff_load <= prev_eff_load;
-       } else
-               balanced = true;
-
-       /*
-        * If the currently running task will sleep within
-        * a reasonable amount of time then attract this newly
-        * woken task:
-        */
-       if (sync && balanced)
-               return 1;
+       balanced = this_eff_load <= prev_eff_load;
 
        schedstat_inc(p, se.statistics.nr_wakeups_affine_attempts);
-       tl_per_task = cpu_avg_load_per_task(this_cpu);
 
-       if (balanced ||
-           (this_load <= load &&
-            this_load + target_load(prev_cpu, idx) <= tl_per_task)) {
-               /*
-                * This domain has SD_WAKE_AFFINE and
-                * p is cache cold in this domain, and
-                * there is no bad imbalance.
-                */
-               schedstat_inc(sd, ttwu_move_affine);
-               schedstat_inc(p, se.statistics.nr_wakeups_affine);
+       if (!balanced)
+               return 0;
 
-               return 1;
-       }
-       return 0;
+       schedstat_inc(sd, ttwu_move_affine);
+       schedstat_inc(p, se.statistics.nr_wakeups_affine);
+
+       return 1;
 }
 
 /*
@@ -4393,20 +4890,46 @@ static int
 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
 {
        unsigned long load, min_load = ULONG_MAX;
-       int idlest = -1;
+       unsigned int min_exit_latency = UINT_MAX;
+       u64 latest_idle_timestamp = 0;
+       int least_loaded_cpu = this_cpu;
+       int shallowest_idle_cpu = -1;
        int i;
 
        /* Traverse only the allowed CPUs */
        for_each_cpu_and(i, sched_group_cpus(group), tsk_cpus_allowed(p)) {
-               load = weighted_cpuload(i);
-
-               if (load < min_load || (load == min_load && i == this_cpu)) {
-                       min_load = load;
-                       idlest = i;
+               if (idle_cpu(i)) {
+                       struct rq *rq = cpu_rq(i);
+                       struct cpuidle_state *idle = idle_get_state(rq);
+                       if (idle && idle->exit_latency < min_exit_latency) {
+                               /*
+                                * We give priority to a CPU whose idle state
+                                * has the smallest exit latency irrespective
+                                * of any idle timestamp.
+                                */
+                               min_exit_latency = idle->exit_latency;
+                               latest_idle_timestamp = rq->idle_stamp;
+                               shallowest_idle_cpu = i;
+                       } else if ((!idle || idle->exit_latency == min_exit_latency) &&
+                                  rq->idle_stamp > latest_idle_timestamp) {
+                               /*
+                                * If equal or no active idle state, then
+                                * the most recently idled CPU might have
+                                * a warmer cache.
+                                */
+                               latest_idle_timestamp = rq->idle_stamp;
+                               shallowest_idle_cpu = i;
+                       }
+               } else if (shallowest_idle_cpu == -1) {
+                       load = weighted_cpuload(i);
+                       if (load < min_load || (load == min_load && i == this_cpu)) {
+                               min_load = load;
+                               least_loaded_cpu = i;
+                       }
                }
        }
 
-       return idlest;
+       return shallowest_idle_cpu != -1 ? shallowest_idle_cpu : least_loaded_cpu;
 }
 
 /*
@@ -4453,6 +4976,33 @@ next:
 done:
        return target;
 }
+/*
+ * get_cpu_usage 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 usage with the capacity of the CPU that is available for CFS
+ * task (ie cpu_capacity).
+ * cfs.utilization_load_avg is the sum of running time of runnable tasks on a
+ * CPU. It represents the amount of utilization of a CPU in the range
+ * [0..SCHED_LOAD_SCALE].  The usage of a CPU can't be higher than the full
+ * capacity of the CPU because it's about the running time on this CPU.
+ * Nevertheless, cfs.utilization_load_avg can be higher than SCHED_LOAD_SCALE
+ * because of unfortunate rounding in avg_period and running_load_avg or just
+ * after migrating tasks until the average stabilizes with the new running
+ * time. So we need to check that the usage stays into the range
+ * [0..cpu_capacity_orig] and cap if necessary.
+ * Without capping the usage, a group could be seen as overloaded (CPU0 usage
+ * at 121% + CPU1 usage at 80%) whereas CPU1 has 20% of available capacity
+ */
+static int get_cpu_usage(int cpu)
+{
+       unsigned long usage = cpu_rq(cpu)->cfs.utilization_load_avg;
+       unsigned long capacity = capacity_orig_of(cpu);
+
+       if (usage >= SCHED_LOAD_SCALE)
+               return capacity;
+
+       return (usage * capacity) >> SCHED_LOAD_SHIFT;
+}
 
 /*
  * select_task_rq_fair: Select target runqueue for the waking task in domains
@@ -4475,14 +5025,8 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f
        int want_affine = 0;
        int sync = wake_flags & WF_SYNC;
 
-       if (p->nr_cpus_allowed == 1)
-               return prev_cpu;
-
-       if (sd_flag & SD_BALANCE_WAKE) {
-               if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
-                       want_affine = 1;
-               new_cpu = prev_cpu;
-       }
+       if (sd_flag & SD_BALANCE_WAKE)
+               want_affine = cpumask_test_cpu(cpu, tsk_cpus_allowed(p));
 
        rcu_read_lock();
        for_each_domain(cpu, tmp) {
@@ -4669,7 +5213,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
                return;
 
        /*
-        * This is possible from callers such as move_task(), in which we
+        * This is possible from callers such as attach_tasks(), in which we
         * unconditionally check_prempt_curr() after an enqueue (which may have
         * lead to a throttle).  This both saves work and prevents false
         * next-buddy nomination below.
@@ -4723,7 +5267,7 @@ static void check_preempt_wakeup(struct rq *rq, struct task_struct *p, int wake_
        return;
 
 preempt:
-       resched_task(curr);
+       resched_curr(rq);
        /*
         * Only set the backward buddy when the current task is still
         * on the rq. This can happen when a wakeup gets interleaved
@@ -4773,18 +5317,21 @@ again:
                 * entity, update_curr() will update its vruntime, otherwise
                 * forget we've ever seen it.
                 */
-               if (curr && curr->on_rq)
-                       update_curr(cfs_rq);
-               else
-                       curr = NULL;
+               if (curr) {
+                       if (curr->on_rq)
+                               update_curr(cfs_rq);
+                       else
+                               curr = NULL;
 
-               /*
-                * This call to check_cfs_rq_runtime() will do the throttle and
-                * dequeue its entity in the parent(s). Therefore the 'simple'
-                * nr_running test will indeed be correct.
-                */
-               if (unlikely(check_cfs_rq_runtime(cfs_rq)))
-                       goto simple;
+                       /*
+                        * This call to check_cfs_rq_runtime() will do the
+                        * throttle and dequeue its entity in the parent(s).
+                        * Therefore the 'simple' nr_running test will indeed
+                        * be correct.
+                        */
+                       if (unlikely(check_cfs_rq_runtime(cfs_rq)))
+                               goto simple;
+               }
 
                se = pick_next_entity(cfs_rq, curr);
                cfs_rq = group_cfs_rq(se);
@@ -4845,7 +5392,15 @@ simple:
        return p;
 
 idle:
+       /*
+        * This is OK, because current is on_cpu, which avoids it being picked
+        * for load-balance and preemption/IRQs are still disabled avoiding
+        * further scheduler activity on it and we're being very careful to
+        * re-start the picking loop.
+        */
+       lockdep_unpin_lock(&rq->lock);
        new_tasks = idle_balance(rq);
+       lockdep_pin_lock(&rq->lock);
        /*
         * Because idle_balance() releases (and re-acquires) rq->lock, it is
         * possible for any higher priority task to appear. In that case we
@@ -4904,7 +5459,7 @@ static void yield_task_fair(struct rq *rq)
                 * so we don't do microscopic update in schedule()
                 * and double the fastpath cost.
                 */
-                rq->skip_clock_update = 1;
+               rq_clock_skip_update(rq, true);
        }
 
        set_skip_buddy(se);
@@ -5077,28 +5632,18 @@ struct lb_env {
        unsigned int            loop_max;
 
        enum fbq_type           fbq_type;
+       struct list_head        tasks;
 };
 
-/*
- * move_task - move a task from one runqueue to another runqueue.
- * Both runqueues must be locked.
- */
-static void move_task(struct task_struct *p, struct lb_env *env)
-{
-       deactivate_task(env->src_rq, p, 0);
-       set_task_cpu(p, env->dst_cpu);
-       activate_task(env->dst_rq, p, 0);
-       check_preempt_curr(env->dst_rq, p, 0);
-}
-
 /*
  * Is this task likely cache-hot:
  */
-static int
-task_hot(struct task_struct *p, u64 now)
+static int task_hot(struct task_struct *p, struct lb_env *env)
 {
        s64 delta;
 
+       lockdep_assert_held(&env->src_rq->lock);
+
        if (p->sched_class != &fair_sched_class)
                return 0;
 
@@ -5108,7 +5653,7 @@ task_hot(struct task_struct *p, u64 now)
        /*
         * Buddy candidates are cache hot:
         */
-       if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
+       if (sched_feat(CACHE_HOT_BUDDY) && env->dst_rq->nr_running &&
                        (&p->se == cfs_rq_of(&p->se)->next ||
                         &p->se == cfs_rq_of(&p->se)->last))
                return 1;
@@ -5118,19 +5663,24 @@ task_hot(struct task_struct *p, u64 now)
        if (sysctl_sched_migration_cost == 0)
                return 0;
 
-       delta = now - p->se.exec_start;
+       delta = rq_clock_task(env->src_rq) - p->se.exec_start;
 
        return delta < (s64)sysctl_sched_migration_cost;
 }
 
 #ifdef CONFIG_NUMA_BALANCING
-/* Returns true if the destination node has incurred more faults */
+/*
+ * Returns true if the destination node is the preferred node.
+ * Needs to match fbq_classify_rq(): if there is a runnable task
+ * that is not on its preferred node, we should identify it.
+ */
 static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env)
 {
        struct numa_group *numa_group = rcu_dereference(p->numa_group);
+       unsigned long src_faults, dst_faults;
        int src_nid, dst_nid;
 
-       if (!sched_feat(NUMA_FAVOUR_HIGHER) || !p->numa_faults_memory ||
+       if (!sched_feat(NUMA_FAVOUR_HIGHER) || !p->numa_faults ||
            !(env->sd->flags & SD_NUMA)) {
                return false;
        }
@@ -5141,35 +5691,36 @@ static bool migrate_improves_locality(struct task_struct *p, struct lb_env *env)
        if (src_nid == dst_nid)
                return false;
 
-       if (numa_group) {
-               /* Task is already in the group's interleave set. */
-               if (node_isset(src_nid, numa_group->active_nodes))
-                       return false;
-
-               /* Task is moving into the group's interleave set. */
-               if (node_isset(dst_nid, numa_group->active_nodes))
-                       return true;
-
-               return group_faults(p, dst_nid) > group_faults(p, src_nid);
-       }
-
        /* Encourage migration to the preferred node. */
        if (dst_nid == p->numa_preferred_nid)
                return true;
 
-       return task_faults(p, dst_nid) > task_faults(p, src_nid);
+       /* Migrating away from the preferred node is bad. */
+       if (src_nid == p->numa_preferred_nid)
+               return false;
+
+       if (numa_group) {
+               src_faults = group_faults(p, src_nid);
+               dst_faults = group_faults(p, dst_nid);
+       } else {
+               src_faults = task_faults(p, src_nid);
+               dst_faults = task_faults(p, dst_nid);
+       }
+
+       return dst_faults > src_faults;
 }
 
 
 static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
 {
        struct numa_group *numa_group = rcu_dereference(p->numa_group);
+       unsigned long src_faults, dst_faults;
        int src_nid, dst_nid;
 
        if (!sched_feat(NUMA) || !sched_feat(NUMA_RESIST_LOWER))
                return false;
 
-       if (!p->numa_faults_memory || !(env->sd->flags & SD_NUMA))
+       if (!p->numa_faults || !(env->sd->flags & SD_NUMA))
                return false;
 
        src_nid = cpu_to_node(env->src_cpu);
@@ -5178,23 +5729,23 @@ static bool migrate_degrades_locality(struct task_struct *p, struct lb_env *env)
        if (src_nid == dst_nid)
                return false;
 
-       if (numa_group) {
-               /* Task is moving within/into the group's interleave set. */
-               if (node_isset(dst_nid, numa_group->active_nodes))
-                       return false;
+       /* Migrating away from the preferred node is bad. */
+       if (src_nid == p->numa_preferred_nid)
+               return true;
 
-               /* Task is moving out of the group's interleave set. */
-               if (node_isset(src_nid, numa_group->active_nodes))
-                       return true;
+       /* Encourage migration to the preferred node. */
+       if (dst_nid == p->numa_preferred_nid)
+               return false;
 
-               return group_faults(p, dst_nid) < group_faults(p, src_nid);
+       if (numa_group) {
+               src_faults = group_faults(p, src_nid);
+               dst_faults = group_faults(p, dst_nid);
+       } else {
+               src_faults = task_faults(p, src_nid);
+               dst_faults = task_faults(p, dst_nid);
        }
 
-       /* Migrating away from the preferred node is always bad. */
-       if (src_nid == p->numa_preferred_nid)
-               return true;
-
-       return task_faults(p, dst_nid) < task_faults(p, src_nid);
+       return dst_faults < src_faults;
 }
 
 #else
@@ -5218,6 +5769,9 @@ static
 int can_migrate_task(struct task_struct *p, struct lb_env *env)
 {
        int tsk_cache_hot = 0;
+
+       lockdep_assert_held(&env->src_rq->lock);
+
        /*
         * We do not migrate tasks that are:
         * 1) throttled_lb_pair, or
@@ -5272,28 +5826,16 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
         * 2) task is cache cold, or
         * 3) too many balance attempts have failed.
         */
-       tsk_cache_hot = task_hot(p, rq_clock_task(env->src_rq));
+       tsk_cache_hot = task_hot(p, env);
        if (!tsk_cache_hot)
                tsk_cache_hot = migrate_degrades_locality(p, env);
 
-       if (migrate_improves_locality(p, env)) {
-#ifdef CONFIG_SCHEDSTATS
+       if (migrate_improves_locality(p, env) || !tsk_cache_hot ||
+           env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
                if (tsk_cache_hot) {
                        schedstat_inc(env->sd, lb_hot_gained[env->idle]);
                        schedstat_inc(p, se.statistics.nr_forced_migrations);
                }
-#endif
-               return 1;
-       }
-
-       if (!tsk_cache_hot ||
-               env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
-
-               if (tsk_cache_hot) {
-                       schedstat_inc(env->sd, lb_hot_gained[env->idle]);
-                       schedstat_inc(p, se.statistics.nr_forced_migrations);
-               }
-
                return 1;
        }
 
@@ -5302,47 +5844,63 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
 }
 
 /*
- * move_one_task tries to move exactly one task from busiest to this_rq, as
+ * detach_task() -- detach the task for the migration specified in env
+ */
+static void detach_task(struct task_struct *p, struct lb_env *env)
+{
+       lockdep_assert_held(&env->src_rq->lock);
+
+       deactivate_task(env->src_rq, p, 0);
+       p->on_rq = TASK_ON_RQ_MIGRATING;
+       set_task_cpu(p, env->dst_cpu);
+}
+
+/*
+ * detach_one_task() -- tries to dequeue exactly one task from env->src_rq, as
  * part of active balancing operations within "domain".
- * Returns 1 if successful and 0 otherwise.
  *
- * Called with both runqueues locked.
+ * Returns a task if successful and NULL otherwise.
  */
-static int move_one_task(struct lb_env *env)
+static struct task_struct *detach_one_task(struct lb_env *env)
 {
        struct task_struct *p, *n;
 
+       lockdep_assert_held(&env->src_rq->lock);
+
        list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) {
                if (!can_migrate_task(p, env))
                        continue;
 
-               move_task(p, env);
+               detach_task(p, env);
+
                /*
-                * Right now, this is only the second place move_task()
-                * is called, so we can safely collect move_task()
-                * stats here rather than inside move_task().
+                * Right now, this is only the second place where
+                * lb_gained[env->idle] is updated (other is detach_tasks)
+                * so we can safely collect stats here rather than
+                * inside detach_tasks().
                 */
                schedstat_inc(env->sd, lb_gained[env->idle]);
-               return 1;
+               return p;
        }
-       return 0;
+       return NULL;
 }
 
 static const unsigned int sched_nr_migrate_break = 32;
 
 /*
- * move_tasks tries to move up to imbalance weighted load from busiest to
- * this_rq, as part of a balancing operation within domain "sd".
- * Returns 1 if successful and 0 otherwise.
+ * detach_tasks() -- tries to detach up to imbalance weighted load from
+ * busiest_rq, as part of a balancing operation within domain "sd".
  *
- * Called with both runqueues locked.
+ * Returns number of detached tasks if successful and 0 otherwise.
  */
-static int move_tasks(struct lb_env *env)
+static int detach_tasks(struct lb_env *env)
 {
        struct list_head *tasks = &env->src_rq->cfs_tasks;
        struct task_struct *p;
        unsigned long load;
-       int pulled = 0;
+       int detached = 0;
+
+       lockdep_assert_held(&env->src_rq->lock);
 
        if (env->imbalance <= 0)
                return 0;
@@ -5373,14 +5931,16 @@ static int move_tasks(struct lb_env *env)
                if ((load / 2) > env->imbalance)
                        goto next;
 
-               move_task(p, env);
-               pulled++;
+               detach_task(p, env);
+               list_add(&p->se.group_node, &env->tasks);
+
+               detached++;
                env->imbalance -= load;
 
 #ifdef CONFIG_PREEMPT
                /*
                 * NEWIDLE balancing is a source of latency, so preemptible
-                * kernels will stop after the first task is pulled to minimize
+                * kernels will stop after the first task is detached to minimize
                 * the critical section.
                 */
                if (env->idle == CPU_NEWLY_IDLE)
@@ -5400,13 +5960,58 @@ next:
        }
 
        /*
-        * Right now, this is one of only two places move_task() is called,
-        * so we can safely collect move_task() stats here rather than
-        * inside move_task().
+        * Right now, this is one of only two places we collect this stat
+        * so we can safely collect detach_one_task() stats here rather
+        * than inside detach_one_task().
         */
-       schedstat_add(env->sd, lb_gained[env->idle], pulled);
+       schedstat_add(env->sd, lb_gained[env->idle], detached);
 
-       return pulled;
+       return detached;
+}
+
+/*
+ * attach_task() -- attach the task detached by detach_task() to its new rq.
+ */
+static void attach_task(struct rq *rq, struct task_struct *p)
+{
+       lockdep_assert_held(&rq->lock);
+
+       BUG_ON(task_rq(p) != rq);
+       p->on_rq = TASK_ON_RQ_QUEUED;
+       activate_task(rq, p, 0);
+       check_preempt_curr(rq, p, 0);
+}
+
+/*
+ * attach_one_task() -- attaches the task returned from detach_one_task() to
+ * its new rq.
+ */
+static void attach_one_task(struct rq *rq, struct task_struct *p)
+{
+       raw_spin_lock(&rq->lock);
+       attach_task(rq, p);
+       raw_spin_unlock(&rq->lock);
+}
+
+/*
+ * attach_tasks() -- attaches all tasks detached by detach_tasks() to their
+ * new rq.
+ */
+static void attach_tasks(struct lb_env *env)
+{
+       struct list_head *tasks = &env->tasks;
+       struct task_struct *p;
+
+       raw_spin_lock(&env->dst_rq->lock);
+
+       while (!list_empty(tasks)) {
+               p = list_first_entry(tasks, struct task_struct, se.group_node);
+               list_del_init(&p->se.group_node);
+
+               attach_task(env->dst_rq, p);
+       }
+
+       raw_spin_unlock(&env->dst_rq->lock);
 }
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
@@ -5525,6 +6130,13 @@ static unsigned long task_h_load(struct task_struct *p)
 #endif
 
 /********** 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
  */
@@ -5534,12 +6146,12 @@ struct sg_lb_stats {
        unsigned long sum_weighted_load; /* Weighted load of group's tasks */
        unsigned long load_per_task;
        unsigned long group_capacity;
+       unsigned long group_usage; /* Total usage of the group */
        unsigned int sum_nr_running; /* Nr tasks running in the group */
-       unsigned int group_capacity_factor;
        unsigned int idle_cpus;
        unsigned int group_weight;
-       int group_imb; /* Is there an imbalance in the group ? */
-       int group_has_free_capacity;
+       enum group_type group_type;
+       int group_no_capacity;
 #ifdef CONFIG_NUMA_BALANCING
        unsigned int nr_numa_running;
        unsigned int nr_preferred_running;
@@ -5576,6 +6188,8 @@ static inline void init_sd_lb_stats(struct sd_lb_stats *sds)
                .total_capacity = 0UL,
                .busiest_stat = {
                        .avg_load = 0UL,
+                       .sum_nr_running = 0,
+                       .group_type = group_other,
                },
        };
 }
@@ -5608,89 +6222,60 @@ static inline int get_sd_load_idx(struct sched_domain *sd,
        return load_idx;
 }
 
-static unsigned long default_scale_capacity(struct sched_domain *sd, int cpu)
+static unsigned long default_scale_cpu_capacity(struct sched_domain *sd, int cpu)
 {
-       return SCHED_CAPACITY_SCALE;
-}
+       if ((sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
+               return sd->smt_gain / sd->span_weight;
 
-unsigned long __weak arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
-{
-       return default_scale_capacity(sd, cpu);
-}
-
-static unsigned long default_scale_smt_capacity(struct sched_domain *sd, int cpu)
-{
-       unsigned long weight = sd->span_weight;
-       unsigned long smt_gain = sd->smt_gain;
-
-       smt_gain /= weight;
-
-       return smt_gain;
+       return SCHED_CAPACITY_SCALE;
 }
 
-unsigned long __weak arch_scale_smt_capacity(struct sched_domain *sd, int cpu)
+unsigned long __weak arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
 {
-       return default_scale_smt_capacity(sd, cpu);
+       return default_scale_cpu_capacity(sd, cpu);
 }
 
 static unsigned long scale_rt_capacity(int cpu)
 {
        struct rq *rq = cpu_rq(cpu);
-       u64 total, available, age_stamp, avg;
+       u64 total, used, age_stamp, avg;
        s64 delta;
 
        /*
         * Since we're reading these variables without serialization make sure
         * we read them once before doing sanity checks on them.
         */
-       age_stamp = ACCESS_ONCE(rq->age_stamp);
-       avg = ACCESS_ONCE(rq->rt_avg);
+       age_stamp = READ_ONCE(rq->age_stamp);
+       avg = READ_ONCE(rq->rt_avg);
+       delta = __rq_clock_broken(rq) - age_stamp;
 
-       delta = rq_clock(rq) - age_stamp;
        if (unlikely(delta < 0))
                delta = 0;
 
        total = sched_avg_period() + delta;
 
-       if (unlikely(total < avg)) {
-               /* Ensures that capacity won't end up being negative */
-               available = 0;
-       } else {
-               available = total - avg;
-       }
-
-       if (unlikely((s64)total < SCHED_CAPACITY_SCALE))
-               total = SCHED_CAPACITY_SCALE;
+       used = div_u64(avg, total);
 
-       total >>= SCHED_CAPACITY_SHIFT;
+       if (likely(used < SCHED_CAPACITY_SCALE))
+               return SCHED_CAPACITY_SCALE - used;
 
-       return div_u64(available, total);
+       return 1;
 }
 
 static void update_cpu_capacity(struct sched_domain *sd, int cpu)
 {
-       unsigned long weight = sd->span_weight;
        unsigned long capacity = SCHED_CAPACITY_SCALE;
        struct sched_group *sdg = sd->groups;
 
-       if ((sd->flags & SD_SHARE_CPUCAPACITY) && weight > 1) {
-               if (sched_feat(ARCH_CAPACITY))
-                       capacity *= arch_scale_smt_capacity(sd, cpu);
-               else
-                       capacity *= default_scale_smt_capacity(sd, cpu);
-
-               capacity >>= SCHED_CAPACITY_SHIFT;
-       }
-
-       sdg->sgc->capacity_orig = capacity;
-
        if (sched_feat(ARCH_CAPACITY))
-               capacity *= arch_scale_freq_capacity(sd, cpu);
+               capacity *= arch_scale_cpu_capacity(sd, cpu);
        else
-               capacity *= default_scale_capacity(sd, cpu);
+               capacity *= default_scale_cpu_capacity(sd, cpu);
 
        capacity >>= SCHED_CAPACITY_SHIFT;
 
+       cpu_rq(cpu)->cpu_capacity_orig = capacity;
+
        capacity *= scale_rt_capacity(cpu);
        capacity >>= SCHED_CAPACITY_SHIFT;
 
@@ -5705,7 +6290,7 @@ 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, capacity_orig;
+       unsigned long capacity;
        unsigned long interval;
 
        interval = msecs_to_jiffies(sd->balance_interval);
@@ -5717,7 +6302,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
                return;
        }
 
-       capacity_orig = capacity = 0;
+       capacity = 0;
 
        if (child->flags & SD_OVERLAP) {
                /*
@@ -5737,19 +6322,15 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
                         * Use capacity_of(), which is set irrespective of domains
                         * in update_cpu_capacity().
                         *
-                        * This avoids capacity/capacity_orig from being 0 and
+                        * This avoids capacity from being 0 and
                         * causing divide-by-zero issues on boot.
-                        *
-                        * Runtime updates will correct capacity_orig.
                         */
                        if (unlikely(!rq->sd)) {
-                               capacity_orig += capacity_of(cpu);
                                capacity += capacity_of(cpu);
                                continue;
                        }
 
                        sgc = rq->sd->groups->sgc;
-                       capacity_orig += sgc->capacity_orig;
                        capacity += sgc->capacity;
                }
        } else  {
@@ -5760,39 +6341,24 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
 
                group = child->groups;
                do {
-                       capacity_orig += group->sgc->capacity_orig;
                        capacity += group->sgc->capacity;
                        group = group->next;
                } while (group != child->groups);
        }
 
-       sdg->sgc->capacity_orig = capacity_orig;
        sdg->sgc->capacity = capacity;
 }
 
 /*
- * Try and fix up capacity for tiny siblings, this is needed when
- * things like SD_ASYM_PACKING need f_b_g to select another sibling
- * which on its own isn't powerful enough.
- *
- * See update_sd_pick_busiest() and check_asym_packing().
+ * Check whether the capacity of the rq has been noticeably reduced by side
+ * activity. The imbalance_pct is used for the threshold.
+ * Return true is the capacity is reduced
  */
 static inline int
-fix_small_capacity(struct sched_domain *sd, struct sched_group *group)
+check_cpu_capacity(struct rq *rq, struct sched_domain *sd)
 {
-       /*
-        * Only siblings can have significantly less than SCHED_CAPACITY_SCALE
-        */
-       if (!(sd->flags & SD_SHARE_CPUCAPACITY))
-               return 0;
-
-       /*
-        * If ~90% of the cpu_capacity is still there, we're good.
-        */
-       if (group->sgc->capacity * 32 > group->sgc->capacity_orig * 29)
-               return 1;
-
-       return 0;
+       return ((rq->cpu_capacity * sd->imbalance_pct) <
+                               (rq->cpu_capacity_orig * 100));
 }
 
 /*
@@ -5830,31 +6396,62 @@ static inline int sg_imbalanced(struct sched_group *group)
 }
 
 /*
- * Compute the group capacity factor.
- *
- * Avoid the issue where N*frac(smt_capacity) >= 1 creates 'phantom' cores by
- * first dividing out the smt factor and computing the actual number of cores
- * and limit unit capacity with that.
+ * group_has_capacity returns true if the group has spare capacity that could
+ * be used by some tasks.
+ * We consider that a group has spare capacity if the  * number of task is
+ * smaller than the number of CPUs or if the usage is lower than the available
+ * capacity for CFS tasks.
+ * For the latter, we use a threshold to stabilize the state, to take into
+ * account the variance of the tasks' load and to return true if the available
+ * capacity in meaningful for the load balancer.
+ * As an example, an available capacity of 1% can appear but it doesn't make
+ * any benefit for the load balance.
+ */
+static inline bool
+group_has_capacity(struct lb_env *env, struct sg_lb_stats *sgs)
+{
+       if (sgs->sum_nr_running < sgs->group_weight)
+               return true;
+
+       if ((sgs->group_capacity * 100) >
+                       (sgs->group_usage * env->sd->imbalance_pct))
+               return true;
+
+       return false;
+}
+
+/*
+ *  group_is_overloaded returns true if the group has more tasks than it can
+ *  handle.
+ *  group_is_overloaded is not equals to !group_has_capacity because a group
+ *  with the exact right number of tasks, has no more spare capacity but is not
+ *  overloaded so both group_has_capacity and group_is_overloaded return
+ *  false.
  */
-static inline int sg_capacity_factor(struct lb_env *env, struct sched_group *group)
+static inline bool
+group_is_overloaded(struct lb_env *env, struct sg_lb_stats *sgs)
 {
-       unsigned int capacity_factor, smt, cpus;
-       unsigned int capacity, capacity_orig;
+       if (sgs->sum_nr_running <= sgs->group_weight)
+               return false;
 
-       capacity = group->sgc->capacity;
-       capacity_orig = group->sgc->capacity_orig;
-       cpus = group->group_weight;
+       if ((sgs->group_capacity * 100) <
+                       (sgs->group_usage * env->sd->imbalance_pct))
+               return true;
 
-       /* smt := ceil(cpus / capacity), assumes: 1 < smt_capacity < 2 */
-       smt = DIV_ROUND_UP(SCHED_CAPACITY_SCALE * cpus, capacity_orig);
-       capacity_factor = cpus / smt; /* cores */
+       return false;
+}
+
+static enum group_type group_classify(struct lb_env *env,
+               struct sched_group *group,
+               struct sg_lb_stats *sgs)
+{
+       if (sgs->group_no_capacity)
+               return group_overloaded;
 
-       capacity_factor = min_t(unsigned,
-               capacity_factor, DIV_ROUND_CLOSEST(capacity, SCHED_CAPACITY_SCALE));
-       if (!capacity_factor)
-               capacity_factor = fix_small_capacity(env->sd, group);
+       if (sg_imbalanced(group))
+               return group_imbalanced;
 
-       return capacity_factor;
+       return group_other;
 }
 
 /**
@@ -5864,10 +6461,12 @@ static inline int sg_capacity_factor(struct lb_env *env, struct sched_group *gro
  * @load_idx: Load index of sched_domain of this_cpu for load calc.
  * @local_group: Does group contain this_cpu.
  * @sgs: variable to hold the statistics for this group.
+ * @overload: Indicate more than one runnable task for any CPU.
  */
 static inline void update_sg_lb_stats(struct lb_env *env,
                        struct sched_group *group, int load_idx,
-                       int local_group, struct sg_lb_stats *sgs)
+                       int local_group, struct sg_lb_stats *sgs,
+                       bool *overload)
 {
        unsigned long load;
        int i;
@@ -5884,7 +6483,12 @@ static inline void update_sg_lb_stats(struct lb_env *env,
                        load = source_load(i, load_idx);
 
                sgs->group_load += load;
-               sgs->sum_nr_running += rq->nr_running;
+               sgs->group_usage += get_cpu_usage(i);
+               sgs->sum_nr_running += rq->cfs.h_nr_running;
+
+               if (rq->nr_running > 1)
+                       *overload = true;
+
 #ifdef CONFIG_NUMA_BALANCING
                sgs->nr_numa_running += rq->nr_numa_running;
                sgs->nr_preferred_running += rq->nr_preferred_running;
@@ -5903,11 +6507,8 @@ static inline void update_sg_lb_stats(struct lb_env *env,
 
        sgs->group_weight = group->group_weight;
 
-       sgs->group_imb = sg_imbalanced(group);
-       sgs->group_capacity_factor = sg_capacity_factor(env, group);
-
-       if (sgs->group_capacity_factor > sgs->sum_nr_running)
-               sgs->group_has_free_capacity = 1;
+       sgs->group_no_capacity = group_is_overloaded(env, sgs);
+       sgs->group_type = group_classify(env, group, sgs);
 }
 
 /**
@@ -5928,13 +6529,19 @@ static bool update_sd_pick_busiest(struct lb_env *env,
                                   struct sched_group *sg,
                                   struct sg_lb_stats *sgs)
 {
-       if (sgs->avg_load <= sds->busiest_stat.avg_load)
-               return false;
+       struct sg_lb_stats *busiest = &sds->busiest_stat;
 
-       if (sgs->sum_nr_running > sgs->group_capacity_factor)
+       if (sgs->group_type > busiest->group_type)
                return true;
 
-       if (sgs->group_imb)
+       if (sgs->group_type < busiest->group_type)
+               return false;
+
+       if (sgs->avg_load <= busiest->avg_load)
+               return false;
+
+       /* This is the busiest node in its class. */
+       if (!(env->sd->flags & SD_ASYM_PACKING))
                return true;
 
        /*
@@ -5942,8 +6549,7 @@ static bool update_sd_pick_busiest(struct lb_env *env,
         * numbered CPUs in the group, therefore mark all groups
         * higher than ourself as busy.
         */
-       if ((env->sd->flags & SD_ASYM_PACKING) && sgs->sum_nr_running &&
-           env->dst_cpu < group_first_cpu(sg)) {
+       if (sgs->sum_nr_running && env->dst_cpu < group_first_cpu(sg)) {
                if (!sds->busiest)
                        return true;
 
@@ -5995,6 +6601,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
        struct sched_group *sg = env->sd->groups;
        struct sg_lb_stats tmp_sgs;
        int load_idx, prefer_sibling = 0;
+       bool overload = false;
 
        if (child && child->flags & SD_PREFER_SIBLING)
                prefer_sibling = 1;
@@ -6015,24 +6622,28 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
                                update_group_capacity(env->sd, env->dst_cpu);
                }
 
-               update_sg_lb_stats(env, sg, load_idx, local_group, sgs);
+               update_sg_lb_stats(env, sg, load_idx, local_group, sgs,
+                                               &overload);
 
                if (local_group)
                        goto next_group;
 
                /*
                 * In case the child domain prefers tasks go to siblings
-                * first, lower the sg capacity factor to one so that we'll try
+                * first, lower the sg capacity so that we'll try
                 * and move all the excess tasks away. We lower the capacity
                 * of a group only if the local group has the capacity to fit
-                * these excess tasks, i.e. nr_running < group_capacity_factor. The
-                * extra check prevents the case where you always pull from the
-                * heaviest group when it is already under-utilized (possible
-                * with a large weight task outweighs the tasks on the system).
+                * these excess tasks. The extra check prevents the case where
+                * you always pull from the heaviest group when it is already
+                * under-utilized (possible with a large weight task outweighs
+                * the tasks on the system).
                 */
                if (prefer_sibling && sds->local &&
-                   sds->local_stat.group_has_free_capacity)
-                       sgs->group_capacity_factor = min(sgs->group_capacity_factor, 1U);
+                   group_has_capacity(env, &sds->local_stat) &&
+                   (sgs->sum_nr_running > 1)) {
+                       sgs->group_no_capacity = 1;
+                       sgs->group_type = group_overloaded;
+               }
 
                if (update_sd_pick_busiest(env, sds, sg, sgs)) {
                        sds->busiest = sg;
@@ -6049,6 +6660,13 @@ next_group:
 
        if (env->sd->flags & SD_NUMA)
                env->fbq_type = fbq_classify_group(&sds->busiest_stat);
+
+       if (!env->sd->parent) {
+               /* update overload indicator if we are at root domain */
+               if (env->dst_rq->rd->overload != overload)
+                       env->dst_rq->rd->overload = overload;
+       }
+
 }
 
 /**
@@ -6179,7 +6797,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
        local = &sds->local_stat;
        busiest = &sds->busiest_stat;
 
-       if (busiest->group_imb) {
+       if (busiest->group_type == group_imbalanced) {
                /*
                 * In the group_imb case we cannot rely on group-wide averages
                 * to ensure cpu-load equilibrium, look at wider averages. XXX
@@ -6199,17 +6817,17 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
                return fix_small_imbalance(env, sds);
        }
 
-       if (!busiest->group_imb) {
-               /*
-                * Don't want to pull so many tasks that a group would go idle.
-                * Except of course for the group_imb case, since then we might
-                * have to drop below capacity to reach cpu-load equilibrium.
-                */
-               load_above_capacity =
-                       (busiest->sum_nr_running - busiest->group_capacity_factor);
-
-               load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_CAPACITY_SCALE);
-               load_above_capacity /= busiest->group_capacity;
+       /*
+        * If there aren't any idle cpus, avoid creating some.
+        */
+       if (busiest->group_type == group_overloaded &&
+           local->group_type   == group_overloaded) {
+               load_above_capacity = busiest->sum_nr_running *
+                                       SCHED_LOAD_SCALE;
+               if (load_above_capacity > busiest->group_capacity)
+                       load_above_capacity -= busiest->group_capacity;
+               else
+                       load_above_capacity = ~0UL;
        }
 
        /*
@@ -6272,6 +6890,7 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
        local = &sds.local_stat;
        busiest = &sds.busiest_stat;
 
+       /* ASYM feature bypasses nice load balance check */
        if ((env->idle == CPU_IDLE || env->idle == CPU_NEWLY_IDLE) &&
            check_asym_packing(env, &sds))
                return sds.busiest;
@@ -6288,16 +6907,16 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
         * work because they assume all things are equal, which typically
         * isn't true due to cpus_allowed constraints and the like.
         */
-       if (busiest->group_imb)
+       if (busiest->group_type == group_imbalanced)
                goto force_balance;
 
        /* SD_BALANCE_NEWIDLE trumps SMP nice when underutilized */
-       if (env->idle == CPU_NEWLY_IDLE && local->group_has_free_capacity &&
-           !busiest->group_has_free_capacity)
+       if (env->idle == CPU_NEWLY_IDLE && group_has_capacity(env, local) &&
+           busiest->group_no_capacity)
                goto force_balance;
 
        /*
-        * If the local group is more busy than the selected busiest group
+        * If the local group is busier than the selected busiest group
         * don't try and pull any tasks.
         */
        if (local->avg_load >= busiest->avg_load)
@@ -6312,13 +6931,14 @@ static struct sched_group *find_busiest_group(struct lb_env *env)
 
        if (env->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.
+                * This cpu is idle. If the busiest group is not overloaded
+                * and there is no imbalance between this and busiest group
+                * wrt idle cpus, it is balanced. The imbalance becomes
+                * significant if the diff is greater than 1 otherwise we
+                * might end up to just move the imbalance on another group
                 */
-               if ((local->idle_cpus < busiest->idle_cpus) &&
-                   busiest->sum_nr_running <= busiest->group_weight)
+               if ((busiest->group_type != group_overloaded) &&
+                               (local->idle_cpus <= (busiest->idle_cpus + 1)))
                        goto out_balanced;
        } else {
                /*
@@ -6351,7 +6971,7 @@ static struct rq *find_busiest_queue(struct lb_env *env,
        int i;
 
        for_each_cpu_and(i, sched_group_cpus(group), env->cpus) {
-               unsigned long capacity, capacity_factor, wl;
+               unsigned long capacity, wl;
                enum fbq_type rt;
 
                rq = cpu_rq(i);
@@ -6380,9 +7000,6 @@ static struct rq *find_busiest_queue(struct lb_env *env,
                        continue;
 
                capacity = capacity_of(i);
-               capacity_factor = DIV_ROUND_CLOSEST(capacity, SCHED_CAPACITY_SCALE);
-               if (!capacity_factor)
-                       capacity_factor = fix_small_capacity(env->sd, group);
 
                wl = weighted_cpuload(i);
 
@@ -6390,7 +7007,9 @@ static struct rq *find_busiest_queue(struct lb_env *env,
                 * When comparing with imbalance, use weighted_cpuload()
                 * which is not scaled with the cpu capacity.
                 */
-               if (capacity_factor && rq->nr_running == 1 && wl > env->imbalance)
+
+               if (rq->nr_running == 1 && wl > env->imbalance &&
+                   !check_cpu_capacity(rq, env->sd))
                        continue;
 
                /*
@@ -6438,6 +7057,19 @@ static int need_active_balance(struct lb_env *env)
                        return 1;
        }
 
+       /*
+        * The dst_cpu is idle and the src_cpu CPU has only 1 CFS task.
+        * It's worth migrating the task if the src_cpu's capacity is reduced
+        * because of other sched_class or IRQs if more capacity stays
+        * available on dst_cpu.
+        */
+       if ((env->idle != CPU_NOT_IDLE) &&
+           (env->src_rq->cfs.h_nr_running == 1)) {
+               if ((check_cpu_capacity(env->src_rq, sd)) &&
+                   (capacity_of(env->src_cpu)*sd->imbalance_pct < capacity_of(env->dst_cpu)*100))
+                       return 1;
+       }
+
        return unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2);
 }
 
@@ -6490,7 +7122,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
        struct sched_group *group;
        struct rq *busiest;
        unsigned long flags;
-       struct cpumask *cpus = __get_cpu_var(load_balance_mask);
+       struct cpumask *cpus = this_cpu_cpumask_var_ptr(load_balance_mask);
 
        struct lb_env env = {
                .sd             = sd,
@@ -6501,6 +7133,7 @@ static int load_balance(int this_cpu, struct rq *this_rq,
                .loop_break     = sched_nr_migrate_break,
                .cpus           = cpus,
                .fbq_type       = all,
+               .tasks          = LIST_HEAD_INIT(env.tasks),
        };
 
        /*
@@ -6536,6 +7169,9 @@ redo:
 
        schedstat_add(sd, lb_imbalance[idle], env.imbalance);
 
+       env.src_cpu = busiest->cpu;
+       env.src_rq = busiest;
+
        ld_moved = 0;
        if (busiest->nr_running > 1) {
                /*
@@ -6545,28 +7181,33 @@ redo:
                 * correctly treated as an imbalance.
                 */
                env.flags |= LBF_ALL_PINNED;
-               env.src_cpu   = busiest->cpu;
-               env.src_rq    = busiest;
                env.loop_max  = min(sysctl_sched_nr_migrate, busiest->nr_running);
 
 more_balance:
-               local_irq_save(flags);
-               double_rq_lock(env.dst_rq, busiest);
+               raw_spin_lock_irqsave(&busiest->lock, flags);
 
                /*
                 * cur_ld_moved - load moved in current iteration
                 * ld_moved     - cumulative load moved across iterations
                 */
-               cur_ld_moved = move_tasks(&env);
-               ld_moved += cur_ld_moved;
-               double_rq_unlock(env.dst_rq, busiest);
-               local_irq_restore(flags);
+               cur_ld_moved = detach_tasks(&env);
 
                /*
-                * some other cpu did the load balance for us.
+                * We've detached some tasks from busiest_rq. Every
+                * task is masked "TASK_ON_RQ_MIGRATING", so we can safely
+                * unlock busiest->lock, and we are able to be sure
+                * that nobody can manipulate the tasks in parallel.
+                * See task_rq_lock() family for the details.
                 */
-               if (cur_ld_moved && env.dst_cpu != smp_processor_id())
-                       resched_cpu(env.dst_cpu);
+
+               raw_spin_unlock(&busiest->lock);
+
+               if (cur_ld_moved) {
+                       attach_tasks(&env);
+                       ld_moved += cur_ld_moved;
+               }
+
+               local_irq_restore(flags);
 
                if (env.flags & LBF_NEED_BREAK) {
                        env.flags &= ~LBF_NEED_BREAK;
@@ -6616,10 +7257,8 @@ more_balance:
                if (sd_parent) {
                        int *group_imbalance = &sd_parent->groups->sgc->imbalance;
 
-                       if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0) {
+                       if ((env.flags & LBF_SOME_PINNED) && env.imbalance > 0)
                                *group_imbalance = 1;
-                       } else if (*group_imbalance)
-                               *group_imbalance = 0;
                }
 
                /* All tasks on this runqueue were pinned by CPU affinity */
@@ -6630,7 +7269,7 @@ more_balance:
                                env.loop_break = sched_nr_migrate_break;
                                goto redo;
                        }
-                       goto out_balanced;
+                       goto out_all_pinned;
                }
        }
 
@@ -6695,7 +7334,7 @@ more_balance:
                 * If we've begun active balancing, start to back off. This
                 * case may not be covered by the all_pinned logic if there
                 * is only 1 task on the busy runqueue (because we don't call
-                * move_tasks).
+                * detach_tasks).
                 */
                if (sd->balance_interval < sd->max_interval)
                        sd->balance_interval *= 2;
@@ -6704,6 +7343,23 @@ more_balance:
        goto out;
 
 out_balanced:
+       /*
+        * We reach balance although we may have faced some affinity
+        * constraints. Clear the imbalance flag if it was set.
+        */
+       if (sd_parent) {
+               int *group_imbalance = &sd_parent->groups->sgc->imbalance;
+
+               if (*group_imbalance)
+                       *group_imbalance = 0;
+       }
+
+out_all_pinned:
+       /*
+        * We reach balance because all tasks are pinned at this level so
+        * we can't migrate them. Let the imbalance flag set so parent level
+        * can try to migrate them.
+        */
        schedstat_inc(sd, lb_balanced[idle]);
 
        sd->nr_balance_failed = 0;
@@ -6767,7 +7423,8 @@ 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) {
+       if (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)
@@ -6777,9 +7434,6 @@ static int idle_balance(struct rq *this_rq)
                goto out;
        }
 
-       /*
-        * Drop the rq->lock, but keep IRQ/preempt disabled.
-        */
        raw_spin_unlock(&this_rq->lock);
 
        update_blocked_averages(this_cpu);
@@ -6864,6 +7518,7 @@ static int active_load_balance_cpu_stop(void *data)
        int target_cpu = busiest_rq->push_cpu;
        struct rq *target_rq = cpu_rq(target_cpu);
        struct sched_domain *sd;
+       struct task_struct *p = NULL;
 
        raw_spin_lock_irq(&busiest_rq->lock);
 
@@ -6883,9 +7538,6 @@ static int active_load_balance_cpu_stop(void *data)
         */
        BUG_ON(busiest_rq == target_rq);
 
-       /* move a task from busiest_rq to target_rq */
-       double_lock_balance(busiest_rq, target_rq);
-
        /* Search for an sd spanning us and the target CPU. */
        rcu_read_lock();
        for_each_domain(target_cpu, sd) {
@@ -6906,16 +7558,22 @@ static int active_load_balance_cpu_stop(void *data)
 
                schedstat_inc(sd, alb_count);
 
-               if (move_one_task(&env))
+               p = detach_one_task(&env);
+               if (p)
                        schedstat_inc(sd, alb_pushed);
                else
                        schedstat_inc(sd, alb_failed);
        }
        rcu_read_unlock();
-       double_unlock_balance(busiest_rq, target_rq);
 out_unlock:
        busiest_rq->active_balance = 0;
-       raw_spin_unlock_irq(&busiest_rq->lock);
+       raw_spin_unlock(&busiest_rq->lock);
+
+       if (p)
+               attach_one_task(target_rq, p);
+
+       local_irq_enable();
+
        return 0;
 }
 
@@ -7219,22 +7877,25 @@ end:
 
 /*
  * Current heuristic for kicking the idle load balancer in the presence
- * of an idle cpu is the system.
+ * of an idle cpu in the system.
  *   - This rq has more than one task.
- *   - At any scheduler domain level, this cpu's scheduler group has multiple
- *     busy cpu's exceeding the group's capacity.
+ *   - This rq has at least one CFS task and the capacity of the CPU is
+ *     significantly reduced because of RT tasks or IRQs.
+ *   - At parent of LLC scheduler domain level, this cpu's scheduler group has
+ *     multiple busy cpu.
  *   - For SD_ASYM_PACKING, if the lower numbered cpu's in the scheduler
  *     domain span are idle.
  */
-static inline int nohz_kick_needed(struct rq *rq)
+static inline bool nohz_kick_needed(struct rq *rq)
 {
        unsigned long now = jiffies;
        struct sched_domain *sd;
        struct sched_group_capacity *sgc;
        int nr_busy, cpu = rq->cpu;
+       bool kick = false;
 
        if (unlikely(rq->idle_balance))
-               return 0;
+               return false;
 
        /*
        * We may be recently in ticked or tickless idle mode. At the first
@@ -7248,38 +7909,46 @@ static inline int nohz_kick_needed(struct rq *rq)
         * balancing.
         */
        if (likely(!atomic_read(&nohz.nr_cpus)))
-               return 0;
+               return false;
 
        if (time_before(now, nohz.next_balance))
-               return 0;
+               return false;
 
        if (rq->nr_running >= 2)
-               goto need_kick;
+               return true;
 
        rcu_read_lock();
        sd = rcu_dereference(per_cpu(sd_busy, cpu));
-
        if (sd) {
                sgc = sd->groups->sgc;
                nr_busy = atomic_read(&sgc->nr_busy_cpus);
 
-               if (nr_busy > 1)
-                       goto need_kick_unlock;
+               if (nr_busy > 1) {
+                       kick = true;
+                       goto unlock;
+               }
+
        }
 
-       sd = rcu_dereference(per_cpu(sd_asym, cpu));
+       sd = rcu_dereference(rq->sd);
+       if (sd) {
+               if ((rq->cfs.h_nr_running >= 1) &&
+                               check_cpu_capacity(rq, sd)) {
+                       kick = true;
+                       goto unlock;
+               }
+       }
 
+       sd = rcu_dereference(per_cpu(sd_asym, cpu));
        if (sd && (cpumask_first_and(nohz.idle_cpus_mask,
-                                 sched_domain_span(sd)) < cpu))
-               goto need_kick_unlock;
-
-       rcu_read_unlock();
-       return 0;
+                                 sched_domain_span(sd)) < cpu)) {
+               kick = true;
+               goto unlock;
+       }
 
-need_kick_unlock:
+unlock:
        rcu_read_unlock();
-need_kick:
-       return 1;
+       return kick;
 }
 #else
 static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) { }
@@ -7295,14 +7964,16 @@ static void run_rebalance_domains(struct softirq_action *h)
        enum cpu_idle_type idle = this_rq->idle_balance ?
                                                CPU_IDLE : CPU_NOT_IDLE;
 
-       rebalance_domains(this_rq, idle);
-
        /*
         * If this cpu has a pending nohz_balance_kick, then do the
         * balancing on behalf of the other idle cpus whose ticks are
-        * stopped.
+        * stopped. Do nohz_idle_balance *before* rebalance_domains to
+        * give the idle cpus a chance to load balance. Else we may
+        * load balance only within the local sched_domain hierarchy
+        * and abort nohz_idle_balance altogether if we pull some load.
         */
        nohz_idle_balance(this_rq, idle);
+       rebalance_domains(this_rq, idle);
 }
 
 /*
@@ -7325,6 +7996,8 @@ void trigger_load_balance(struct rq *rq)
 static void rq_online_fair(struct rq *rq)
 {
        update_sysctl();
+
+       update_runtime_enabled(rq);
 }
 
 static void rq_offline_fair(struct rq *rq)
@@ -7398,7 +8071,7 @@ static void task_fork_fair(struct task_struct *p)
                 * 'current' within the tree based on its new key value.
                 */
                swap(curr->vruntime, se->vruntime);
-               resched_task(rq->curr);
+               resched_curr(rq);
        }
 
        se->vruntime -= cfs_rq->min_vruntime;
@@ -7413,7 +8086,7 @@ static void task_fork_fair(struct task_struct *p)
 static void
 prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
 {
-       if (!p->se.on_rq)
+       if (!task_on_rq_queued(p))
                return;
 
        /*
@@ -7423,7 +8096,7 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
         */
        if (rq->curr == p) {
                if (p->prio > oldprio)
-                       resched_task(rq->curr);
+                       resched_curr(rq);
        } else
                check_preempt_curr(rq, p, 0);
 }
@@ -7438,11 +8111,11 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p)
         * switched back to the fair class the enqueue_entity(.flags=0) will
         * do the right thing.
         *
-        * If it's on_rq, then the dequeue_entity(.flags=0) will already
-        * have normalized the vruntime, if it's !on_rq, then only when
+        * If it's queued, then the dequeue_entity(.flags=0) will already
+        * have normalized the vruntime, if it's !queued, then only when
         * the task is sleeping will it still have non-normalized vruntime.
         */
-       if (!p->on_rq && p->state != TASK_RUNNING) {
+       if (!task_on_rq_queued(p) && p->state != TASK_RUNNING) {
                /*
                 * Fix up our vruntime so that the current sleep doesn't
                 * cause 'unlimited' sleep bonus.
@@ -7469,15 +8142,15 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p)
  */
 static void switched_to_fair(struct rq *rq, struct task_struct *p)
 {
-       struct sched_entity *se = &p->se;
 #ifdef CONFIG_FAIR_GROUP_SCHED
+       struct sched_entity *se = &p->se;
        /*
         * Since the real-depth could have been changed (only FAIR
         * class maintain depth value), reset depth properly.
         */
        se->depth = se->parent ? se->parent->depth + 1 : 0;
 #endif
-       if (!se->on_rq)
+       if (!task_on_rq_queued(p))
                return;
 
        /*
@@ -7486,7 +8159,7 @@ static void switched_to_fair(struct rq *rq, struct task_struct *p)
         * if we can still preempt the current task.
         */
        if (rq->curr == p)
-               resched_task(rq->curr);
+               resched_curr(rq);
        else
                check_preempt_curr(rq, p, 0);
 }
@@ -7523,7 +8196,7 @@ void init_cfs_rq(struct cfs_rq *cfs_rq)
 }
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
-static void task_move_group_fair(struct task_struct *p, int on_rq)
+static void task_move_group_fair(struct task_struct *p, int queued)
 {
        struct sched_entity *se = &p->se;
        struct cfs_rq *cfs_rq;
@@ -7542,7 +8215,7 @@ static void task_move_group_fair(struct task_struct *p, int on_rq)
         * fair sleeper stuff for the first placement, but who cares.
         */
        /*
-        * When !on_rq, vruntime of the task has usually NOT been normalized.
+        * When !queued, vruntime of the task has usually NOT been normalized.
         * But there are some cases where it has already been normalized:
         *
         * - Moving a forked child which is waiting for being woken up by
@@ -7553,14 +8226,14 @@ static void task_move_group_fair(struct task_struct *p, int on_rq)
         * To prevent boost or penalty in the new cfs_rq caused by delta
         * min_vruntime between the two cfs_rqs, we skip vruntime adjustment.
         */
-       if (!on_rq && (!se->sum_exec_runtime || p->state == TASK_WAKING))
-               on_rq = 1;
+       if (!queued && (!se->sum_exec_runtime || p->state == TASK_WAKING))
+               queued = 1;
 
-       if (!on_rq)
+       if (!queued)
                se->vruntime -= cfs_rq_of(se)->min_vruntime;
        set_task_rq(p, task_cpu(p));
        se->depth = se->parent ? se->parent->depth + 1 : 0;
-       if (!on_rq) {
+       if (!queued) {
                cfs_rq = cfs_rq_of(se);
                se->vruntime += cfs_rq->min_vruntime;
 #ifdef CONFIG_SMP
@@ -7783,6 +8456,8 @@ const struct sched_class fair_sched_class = {
 
        .get_rr_interval        = get_rr_interval_fair,
 
+       .update_curr            = update_curr_fair,
+
 #ifdef CONFIG_FAIR_GROUP_SCHED
        .task_move_group        = task_move_group_fair,
 #endif
@@ -7798,7 +8473,27 @@ void print_cfs_stats(struct seq_file *m, int cpu)
                print_cfs_rq(m, cpu, cfs_rq);
        rcu_read_unlock();
 }
-#endif
+
+#ifdef CONFIG_NUMA_BALANCING
+void show_numa_stats(struct task_struct *p, struct seq_file *m)
+{
+       int node;
+       unsigned long tsf = 0, tpf = 0, gsf = 0, gpf = 0;
+
+       for_each_online_node(node) {
+               if (p->numa_faults) {
+                       tsf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 0)];
+                       tpf = p->numa_faults[task_faults_idx(NUMA_MEM, node, 1)];
+               }
+               if (p->numa_group) {
+                       gsf = p->numa_group->faults[task_faults_idx(NUMA_MEM, node, 0)],
+                       gpf = p->numa_group->faults[task_faults_idx(NUMA_MEM, node, 1)];
+               }
+               print_numa_stats(m, node, tsf, tpf, gsf, gpf);
+       }
+}
+#endif /* CONFIG_NUMA_BALANCING */
+#endif /* CONFIG_SCHED_DEBUG */
 
 __init void init_sched_fair_class(void)
 {