Commit 9059393e authored by Vincent Guittot's avatar Vincent Guittot Committed by Ingo Molnar
Browse files

sched/fair: Use reweight_entity() for set_user_nice() 



Now that we directly change load_avg and propagate that change into
the sums, sys_nice() and co should do the same, otherwise its possible
to confuse load accounting when we migrate near the weight change.

Fixes-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarVincent Guittot <vincent.guittot@linaro.org>
[ Added changelog, fixed the call condition. ]
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/20170517095045.GA8420@linaro.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 840c5abc

kernel/sched/core.c

+15 −7
Original line number Diff line number Diff line
@@ -733,7 +733,7 @@ int tg_nop(struct task_group *tg, void *data) 
}

#endif



static void set_load_weight(struct task_struct *p)

static void set_load_weight(struct task_struct *p, bool update_load)

{

	int prio = p->static_prio - MAX_RT_PRIO;

	struct load_weight *load = &p->se.load;
@@ -747,9 +747,17 @@ static void set_load_weight(struct task_struct *p) 
		return;

	}



	/*

	 * SCHED_OTHER tasks have to update their load when changing their

	 * weight

	 */

	if (update_load && p->sched_class == &fair_sched_class) {

		reweight_task(p, prio);

	} else {

		load->weight = scale_load(sched_prio_to_weight[prio]);

		load->inv_weight = sched_prio_to_wmult[prio];

	}

}



static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags)

{
@@ -2358,7 +2366,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p) 
			p->static_prio = NICE_TO_PRIO(0);



		p->prio = p->normal_prio = __normal_prio(p);

		set_load_weight(p);

		set_load_weight(p, false);



		/*

		 * We don't need the reset flag anymore after the fork. It has
@@ -3805,7 +3813,7 @@ void set_user_nice(struct task_struct *p, long nice) 
		put_prev_task(rq, p);



	p->static_prio = NICE_TO_PRIO(nice);

	set_load_weight(p);

	set_load_weight(p, true);

	old_prio = p->prio;

	p->prio = effective_prio(p);

	delta = p->prio - old_prio;
@@ -3962,7 +3970,7 @@ static void __setscheduler_params(struct task_struct *p, 
	 */

	p->rt_priority = attr->sched_priority;

	p->normal_prio = normal_prio(p);

	set_load_weight(p);

	set_load_weight(p, true);

}



/* Actually do priority change: must hold pi & rq lock. */
@@ -5933,7 +5941,7 @@ void __init sched_init(void) 
		atomic_set(&rq->nr_iowait, 0);

	}



	set_load_weight(&init_task);

	set_load_weight(&init_task, false);



	/*

	 * The boot idle thread does lazy MMU switching as well:

kernel/sched/fair.c

+37 −26
Original line number Diff line number Diff line
@@ -2776,6 +2776,43 @@ static inline void 
dequeue_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) { }

#endif



static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,

			    unsigned long weight)

{

	if (se->on_rq) {

		/* commit outstanding execution time */

		if (cfs_rq->curr == se)

			update_curr(cfs_rq);

		account_entity_dequeue(cfs_rq, se);

		dequeue_runnable_load_avg(cfs_rq, se);

	}

	dequeue_load_avg(cfs_rq, se);



	update_load_set(&se->load, weight);



#ifdef CONFIG_SMP

	se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum,

				   LOAD_AVG_MAX - 1024 + se->avg.period_contrib);

#endif



	enqueue_load_avg(cfs_rq, se);

	if (se->on_rq) {

		account_entity_enqueue(cfs_rq, se);

		enqueue_runnable_load_avg(cfs_rq, se);

	}

}



void reweight_task(struct task_struct *p, int prio)

{

	struct sched_entity *se = &p->se;

	struct cfs_rq *cfs_rq = cfs_rq_of(se);

	struct load_weight *load = &se->load;

	unsigned long weight = scale_load(sched_prio_to_weight[prio]);



	reweight_entity(cfs_rq, se, weight);

	load->inv_weight = sched_prio_to_wmult[prio];

}



#ifdef CONFIG_FAIR_GROUP_SCHED

# ifdef CONFIG_SMP

/*
@@ -2878,32 +2915,6 @@ static long calc_cfs_shares(struct cfs_rq *cfs_rq) 
}

# endif /* CONFIG_SMP */



static void reweight_entity(struct cfs_rq *cfs_rq, struct sched_entity *se,

			    unsigned long weight)

{

	if (se->on_rq) {

		/* commit outstanding execution time */

		if (cfs_rq->curr == se)

			update_curr(cfs_rq);

		account_entity_dequeue(cfs_rq, se);

		dequeue_runnable_load_avg(cfs_rq, se);

	}

	dequeue_load_avg(cfs_rq, se);



	update_load_set(&se->load, weight);



#ifdef CONFIG_SMP

	se->avg.load_avg = div_u64(se_weight(se) * se->avg.load_sum,

				   LOAD_AVG_MAX - 1024 + se->avg.period_contrib);

#endif



	enqueue_load_avg(cfs_rq, se);

	if (se->on_rq) {

		account_entity_enqueue(cfs_rq, se);

		enqueue_runnable_load_avg(cfs_rq, se);

	}

}



static inline int throttled_hierarchy(struct cfs_rq *cfs_rq);



static void update_cfs_shares(struct sched_entity *se)

kernel/sched/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -1529,6 +1529,8 @@ extern void init_sched_dl_class(void); 
extern void init_sched_rt_class(void);

extern void init_sched_fair_class(void);



extern void reweight_task(struct task_struct *p, int prio);



extern void resched_curr(struct rq *rq);

extern void resched_cpu(int cpu);

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