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Commit a4c96ae3 authored by Peter Boonstoppel's avatar Peter Boonstoppel Committed by Ingo Molnar
Browse files

sched: Unthrottle rt runqueues in __disable_runtime() 



migrate_tasks() uses _pick_next_task_rt() to get tasks from the
real-time runqueues to be migrated. When rt_rq is throttled
_pick_next_task_rt() won't return anything, in which case
migrate_tasks() can't move all threads over and gets stuck in an
infinite loop.

Instead unthrottle rt runqueues before migrating tasks.

Additionally: move unthrottle_offline_cfs_rqs() to rq_offline_fair()

Signed-off-by: default avatarPeter Boonstoppel <pboonstoppel@nvidia.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/5FBF8E85CA34454794F0F7ECBA79798F379D3648B7@HQMAIL04.nvidia.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 749c8814

kernel/sched/core.c

+0 −3
Original line number Diff line number Diff line
@@ -5342,9 +5342,6 @@ static void migrate_tasks(unsigned int dead_cpu) 
	 */

	rq->stop = NULL;



	/* Ensure any throttled groups are reachable by pick_next_task */

	unthrottle_offline_cfs_rqs(rq);



	for ( ; ; ) {

		/*

		 * There's this thread running, bail when that's the only

kernel/sched/fair.c

+5 −2
Original line number Diff line number Diff line
@@ -2052,7 +2052,7 @@ static void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) 
	hrtimer_cancel(&cfs_b->slack_timer);

}



void unthrottle_offline_cfs_rqs(struct rq *rq)

static void unthrottle_offline_cfs_rqs(struct rq *rq)

{

	struct cfs_rq *cfs_rq;
@@ -2106,7 +2106,7 @@ 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) {}

void unthrottle_offline_cfs_rqs(struct rq *rq) {}

static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}



#endif /* CONFIG_CFS_BANDWIDTH */
@@ -4956,6 +4956,9 @@ static void rq_online_fair(struct rq *rq) 
static void rq_offline_fair(struct rq *rq)

{

	update_sysctl();



	/* Ensure any throttled groups are reachable by pick_next_task */

	unthrottle_offline_cfs_rqs(rq);

}



#endif /* CONFIG_SMP */

kernel/sched/rt.c

+1 −0
Original line number Diff line number Diff line
@@ -691,6 +691,7 @@ static void __disable_runtime(struct rq *rq) 
		 * runtime - in which case borrowing doesn't make sense.

		 */

		rt_rq->rt_runtime = RUNTIME_INF;

		rt_rq->rt_throttled = 0;

		raw_spin_unlock(&rt_rq->rt_runtime_lock);

		raw_spin_unlock(&rt_b->rt_runtime_lock);

	}

kernel/sched/sched.h

+0 −1
Original line number Diff line number Diff line
@@ -1144,7 +1144,6 @@ extern void print_rt_stats(struct seq_file *m, int cpu); 


extern void init_cfs_rq(struct cfs_rq *cfs_rq);

extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);

extern void unthrottle_offline_cfs_rqs(struct rq *rq);



extern void account_cfs_bandwidth_used(int enabled, int was_enabled);