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-rw-r--r--kernel/sched/fair.c35
1 files changed, 30 insertions, 5 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0b069bf3e70..ef2b104b254 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -726,6 +726,11 @@ 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)
{
@@ -828,11 +833,12 @@ 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 = ACCESS_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);
@@ -1164,9 +1170,26 @@ static void task_numa_compare(struct task_numa_env *env,
long moveimp = imp;
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
@@ -1520,7 +1543,7 @@ 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;
}
@@ -7938,6 +7961,8 @@ 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