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Commit 0fb3d191 authored by Satya Durga Srinivasu Prabhala's avatar Satya Durga Srinivasu Prabhala
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sched: fair: add support to check for misfit tasks 



Introduce walt_fixup_nr_big_tasks function to check
for misfit tasks (tasks that can not be run on the CPU as
CPU capcity is not sufficient and CPU gets overloaded),
which can cause issues by running on undesired CPUs.

Change-Id: I229ffaf458a44edbf3c9f87a4e5092df84862b0d
Signed-off-by: default avatarSatya Durga Srinivasu Prabhala <satyap@codeaurora.org>
parent 5b405e62

kernel/sched/fair.c

+46 −0
Original line number Diff line number Diff line
@@ -34,6 +34,8 @@ static inline bool task_fits_max(struct task_struct *p, int cpu); 
static void walt_fixup_sched_stats_fair(struct rq *rq, struct task_struct *p,

					u16 updated_demand_scaled,

					u16 updated_pred_demand_scaled);

static void walt_fixup_nr_big_tasks(struct rq *rq, struct task_struct *p,

					int delta, bool inc);

#endif /* CONFIG_SCHED_WALT */



#if defined(CONFIG_SCHED_WALT) && defined(CONFIG_CFS_BANDWIDTH)
@@ -5254,6 +5256,9 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) 
	 */

	schedtune_enqueue_task(p, cpu_of(rq));



#ifdef CONFIG_SCHED_WALT

	p->misfit = !task_fits_max(p, rq->cpu);

#endif

	/*

	 * If in_iowait is set, the code below may not trigger any cpufreq

	 * utilization updates, so do it here explicitly with the IOWAIT flag
@@ -10763,6 +10768,10 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) 
{

	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &curr->se;

#ifdef CONFIG_SCHED_WALT

	bool old_misfit = curr->misfit;

	bool misfit;

#endif



	for_each_sched_entity(se) {

		cfs_rq = cfs_rq_of(se);
@@ -10773,6 +10782,16 @@ static void task_tick_fair(struct rq *rq, struct task_struct *curr, int queued) 
		task_tick_numa(rq, curr);



	update_misfit_status(curr, rq);



#ifdef CONFIG_SCHED_WALT

	misfit = rq->misfit_task_load;



	if (old_misfit != misfit) {

		walt_fixup_nr_big_tasks(rq, curr, 1, misfit);

		curr->misfit = misfit;

	}

#endif



	update_overutilized_status(task_rq(curr));

}
@@ -11419,6 +11438,27 @@ static void walt_fixup_sched_stats_fair(struct rq *rq, struct task_struct *p, 
	}

}



static void walt_fixup_nr_big_tasks(struct rq *rq, struct task_struct *p,

							int delta, bool inc)

{

	struct cfs_rq *cfs_rq;

	struct sched_entity *se = &p->se;



	for_each_sched_entity(se) {

		cfs_rq = cfs_rq_of(se);



		cfs_rq->walt_stats.nr_big_tasks += inc ? delta : -delta;

		BUG_ON(cfs_rq->walt_stats.nr_big_tasks < 0);



		if (cfs_rq_throttled(cfs_rq))

			break;

	}



	/* Fix up rq->walt_stats only if we didn't find any throttled cfs_rq */

	if (!se)

		walt_adjust_nr_big_tasks(rq, delta, inc);

}



/*

 * Check if task is part of a hierarchy where some cfs_rq does not have any

 * runtime left.
@@ -11456,6 +11496,12 @@ static void walt_fixup_sched_stats_fair(struct rq *rq, struct task_struct *p, 
					updated_pred_demand_scaled);

}



static void walt_fixup_nr_big_tasks(struct rq *rq, struct task_struct *p,

							int delta, bool inc)

{

	walt_adjust_nr_big_tasks(rq, delta, inc);

}



static int task_will_be_throttled(struct task_struct *p)

{

	return false;