Merge android-4.4-p.195 (4af3204) into msm-4.4

[sagit-ice-cold/kernel_xiaomi_msm8998.git] / kernel / sched / fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c759c6a..f01eb27 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1901,6 +1901,10 @@ static u64 numa_get_avg_runtime(struct task_struct *p, u64 *period)
        if (p->last_task_numa_placement) {
                delta = runtime - p->last_sum_exec_runtime;
                *period = now - p->last_task_numa_placement;
+
+               /* Avoid time going backwards, prevent potential divide error: */
+               if (unlikely((s64)*period < 0))
+                       *period = 0;
        } else {
                delta = p->se.avg.load_sum / p->se.load.weight;
                *period = LOAD_AVG_MAX;
@@ -2229,13 +2233,23 @@ no_join:
        return;
 }
 
-void task_numa_free(struct task_struct *p)
+/*
+ * Get rid of NUMA staticstics associated with a task (either current or dead).
+ * If @final is set, the task is dead and has reached refcount zero, so we can
+ * safely free all relevant data structures. Otherwise, there might be
+ * concurrent reads from places like load balancing and procfs, and we should
+ * reset the data back to default state without freeing ->numa_faults.
+ */
+void task_numa_free(struct task_struct *p, bool final)
 {
        struct numa_group *grp = p->numa_group;
-       void *numa_faults = p->numa_faults;
+       unsigned long *numa_faults = p->numa_faults;
        unsigned long flags;
        int i;
 
+       if (!numa_faults)
+               return;
+
        if (grp) {
                spin_lock_irqsave(&grp->lock, flags);
                for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
@@ -2248,8 +2262,14 @@ void task_numa_free(struct task_struct *p)
                put_numa_group(grp);
        }
 
-       p->numa_faults = NULL;
-       kfree(numa_faults);
+       if (final) {
+               p->numa_faults = NULL;
+               kfree(numa_faults);
+       } else {
+               p->total_numa_faults = 0;
+               for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
+                       numa_faults[i] = 0;
+       }
 }
 
 /*
@@ -10709,9 +10729,10 @@ no_move:
 out_balanced:
        /*
         * We reach balance although we may have faced some affinity
-        * constraints. Clear the imbalance flag if it was set.
+        * constraints. Clear the imbalance flag only if other tasks got
+        * a chance to move and fix the imbalance.
         */
-       if (sd_parent) {
+       if (sd_parent && !(env.flags & LBF_ALL_PINNED)) {
                int *group_imbalance = &sd_parent->groups->sgc->imbalance;
 
                if (*group_imbalance)