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Commit 14dbc56a authored by Greg Kroah-Hartman's avatar Greg Kroah-Hartman
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Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Ingo writes:
  "scheduler fixes:

   Two fixes: a CFS-throttling bug fix, and an interactivity fix."

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix the min_vruntime update logic in dequeue_entity()
  sched/fair: Fix throttle_list starvation with low CFS quota
parents 9b00eb8a 9845c49c

kernel/sched/fair.c

+20 −4
Original line number Diff line number Diff line
@@ -4001,7 +4001,7 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) 
	 * put back on, and if we advance min_vruntime, we'll be placed back

	 * further than we started -- ie. we'll be penalized.

	 */

	if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)

	if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) != DEQUEUE_SAVE)

		update_min_vruntime(cfs_rq);

}
@@ -4476,9 +4476,13 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq) 


	/*

	 * Add to the _head_ of the list, so that an already-started

	 * distribute_cfs_runtime will not see us

	 * distribute_cfs_runtime will not see us. If disribute_cfs_runtime is

	 * not running add to the tail so that later runqueues don't get starved.

	 */

	if (cfs_b->distribute_running)

		list_add_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);

	else

		list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);



	/*

	 * If we're the first throttled task, make sure the bandwidth
@@ -4622,14 +4626,16 @@ static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun) 
	 * in us over-using our runtime if it is all used during this loop, but

	 * only by limited amounts in that extreme case.

	 */

	while (throttled && cfs_b->runtime > 0) {

	while (throttled && cfs_b->runtime > 0 && !cfs_b->distribute_running) {

		runtime = cfs_b->runtime;

		cfs_b->distribute_running = 1;

		raw_spin_unlock(&cfs_b->lock);

		/* we can't nest cfs_b->lock while distributing bandwidth */

		runtime = distribute_cfs_runtime(cfs_b, runtime,

						 runtime_expires);

		raw_spin_lock(&cfs_b->lock);



		cfs_b->distribute_running = 0;

		throttled = !list_empty(&cfs_b->throttled_cfs_rq);



		cfs_b->runtime -= min(runtime, cfs_b->runtime);
@@ -4740,6 +4746,11 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) 


	/* confirm we're still not at a refresh boundary */

	raw_spin_lock(&cfs_b->lock);

	if (cfs_b->distribute_running) {

		raw_spin_unlock(&cfs_b->lock);

		return;

	}



	if (runtime_refresh_within(cfs_b, min_bandwidth_expiration)) {

		raw_spin_unlock(&cfs_b->lock);

		return;
@@ -4749,6 +4760,9 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) 
		runtime = cfs_b->runtime;



	expires = cfs_b->runtime_expires;

	if (runtime)

		cfs_b->distribute_running = 1;



	raw_spin_unlock(&cfs_b->lock);



	if (!runtime)
@@ -4759,6 +4773,7 @@ static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b) 
	raw_spin_lock(&cfs_b->lock);

	if (expires == cfs_b->runtime_expires)

		cfs_b->runtime -= min(runtime, cfs_b->runtime);

	cfs_b->distribute_running = 0;

	raw_spin_unlock(&cfs_b->lock);

}
@@ -4867,6 +4882,7 @@ void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b) 
	cfs_b->period_timer.function = sched_cfs_period_timer;

	hrtimer_init(&cfs_b->slack_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	cfs_b->slack_timer.function = sched_cfs_slack_timer;

	cfs_b->distribute_running = 0;

}



static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)

kernel/sched/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -346,6 +346,8 @@ struct cfs_bandwidth { 
	int			nr_periods;

	int			nr_throttled;

	u64			throttled_time;



	bool                    distribute_running;

#endif

};