The commit is pushed to "branch-rh7-3.10.0-229.7.2-ovz" and will appear at
https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.6.5
------>
commit 315dcacbe9e305082a46c9d2ea585d83576efae9
Author: Kirill Tkhai <ktk...@odin.com>
Date: Tue Sep 1 17:08:03 2015 +0400
ve/sched: Fix double put_prev_task_fair() because of
trigger_cpulimit_balance()
The scheduller code is written with the assumption, that rq->curr task can't
be already put. For example, in sched_move_task() we check for
running = task_current(rq, tsk);
and call put_prev_task() if "running" is true.
When we're unlocking rq->lock in trigger_cpulimit_balance(), the task has
already been put, so concurrent cpu_cgroup_attach_task()->sched_move_task()
puts it one more time.
https://jira.sw.ru/browse/PSBM-35082
Signed-off-by: Kirill Tkhai <ktk...@odin.com>
---
kernel/sched/fair.c | 36 ++++++++++++++++++------------------
1 file changed, 18 insertions(+), 18 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 167d0f6..3092f76 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5068,18 +5068,16 @@ static inline void trigger_cpulimit_balance(struct
task_struct *p)
int this_cpu, cpu, target_cpu = -1;
struct sched_domain *sd;
- if (!p->se.on_rq)
- return;
-
this_rq = rq_of(cfs_rq_of(&p->se));
this_cpu = cpu_of(this_rq);
+ if (!p->se.on_rq || this_rq->active_balance)
+ return;
+
cfs_rq = top_cfs_rq_of(&p->se);
if (check_cpulimit_spread(cfs_rq, this_cpu) >= 0)
return;
- raw_spin_unlock(&this_rq->lock);
-
rcu_read_lock();
for_each_domain(this_cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
@@ -5096,17 +5094,14 @@ static inline void trigger_cpulimit_balance(struct
task_struct *p)
unlock:
rcu_read_unlock();
- raw_spin_lock(&this_rq->lock);
if (target_cpu >= 0) {
- if (!this_rq->active_balance) {
- this_rq->active_balance = 1;
- this_rq->push_cpu = target_cpu;
- raw_spin_unlock(&this_rq->lock);
- stop_one_cpu_nowait(this_cpu,
- cpulimit_balance_cpu_stop, this_rq,
- &this_rq->active_balance_work);
- raw_spin_lock(&this_rq->lock);
- }
+ this_rq->active_balance = 1;
+ this_rq->push_cpu = target_cpu;
+ raw_spin_unlock(&this_rq->lock);
+ stop_one_cpu_nowait(this_rq->cpu,
+ cpulimit_balance_cpu_stop, this_rq,
+ &this_rq->active_balance_work);
+ raw_spin_lock(&this_rq->lock);
}
}
#else
@@ -5127,8 +5122,6 @@ static void put_prev_task_fair(struct rq *rq, struct
task_struct *prev)
cfs_rq = cfs_rq_of(se);
put_prev_entity(cfs_rq, se);
}
-
- trigger_cpulimit_balance(prev);
}
/*
@@ -5787,7 +5780,8 @@ static int cpulimit_balance_cpu_stop(void *data)
raw_spin_lock_irq(&rq->lock);
- if (unlikely(cpu != smp_processor_id() || !rq->active_balance))
+ if (unlikely(cpu != smp_processor_id() || !rq->active_balance ||
+ !cpu_online(target_cpu)))
goto out_unlock;
if (unlikely(!rq->nr_running))
@@ -7269,6 +7263,11 @@ out_unlock:
return 0;
}
+static void pre_schedule_fair(struct rq *rq, struct task_struct *prev)
+{
+ trigger_cpulimit_balance(prev);
+}
+
#ifdef CONFIG_NO_HZ_COMMON
/*
* idle load balancing details
@@ -8171,6 +8170,7 @@ const struct sched_class fair_sched_class = {
.rq_offline = rq_offline_fair,
.task_waking = task_waking_fair,
+ .pre_schedule = pre_schedule_fair,
#endif
.set_curr_task = set_curr_task_fair,
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