Merge tag 'please-pull-sys_bpf' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2a1e6ac..b78280c 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -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>
@@ -1817,10 +1818,6 @@ 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) *
@@ -1959,7 +1956,7 @@ 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))
                        continue;
 
                /*
@@ -4419,20 +4416,46 @@ 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 {
+                       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;
 }
 
 /*
@@ -5292,24 +5315,12 @@ int can_migrate_task(struct task_struct *p, struct lb_env *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;
        }
 
@@ -6425,13 +6436,14 @@ 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 {
                /*
@@ -6689,12 +6701,6 @@ more_balance:
 
                local_irq_restore(flags);
 
-               /*
-                * some other cpu did the load balance for us.
-                */
-               if (cur_ld_moved && env.dst_cpu != smp_processor_id())
-                       resched_cpu(env.dst_cpu);
-
                if (env.flags & LBF_NEED_BREAK) {
                        env.flags &= ~LBF_NEED_BREAK;
                        goto more_balance;