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Commit be68a682 authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

sched/fair: Consolidate nohz CPU load update code 



Lets factorize a bit of code there. We'll even have a third user soon.
While at it, standardize the idle update function name against the
others.

Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: default avatarByungchul Park <byungchul.park@lge.com>
Cc: Chris Metcalf <cmetcalf@ezchip.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1452700891-21807-3-git-send-email-fweisbec@gmail.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7400d3bb

kernel/sched/fair.c

+25 −23
Original line number Diff line number Diff line
@@ -4542,6 +4542,25 @@ static unsigned long weighted_cpuload(const int cpu) 
}



#ifdef CONFIG_NO_HZ_COMMON

static void __update_cpu_load_nohz(struct rq *this_rq,

				   unsigned long curr_jiffies,

				   unsigned long load,

				   int active)

{

	unsigned long pending_updates;



	pending_updates = curr_jiffies - this_rq->last_load_update_tick;

	if (pending_updates) {

		this_rq->last_load_update_tick = curr_jiffies;

		/*

		 * In the regular NOHZ case, we were idle, this means load 0.

		 * In the NOHZ_FULL case, we were non-idle, we should consider

		 * its weighted load.

		 */

		__update_cpu_load(this_rq, load, pending_updates, active);

	}

}



/*

 * There is no sane way to deal with nohz on smp when using jiffies because the

 * cpu doing the jiffies update might drift wrt the cpu doing the jiffy reading
@@ -4559,22 +4578,15 @@ static unsigned long weighted_cpuload(const int cpu) 
 * Called from nohz_idle_balance() to update the load ratings before doing the

 * idle balance.

 */

static void update_idle_cpu_load(struct rq *this_rq)

static void update_cpu_load_idle(struct rq *this_rq)

{

	unsigned long curr_jiffies = READ_ONCE(jiffies);

	unsigned long load = weighted_cpuload(cpu_of(this_rq));

	unsigned long pending_updates;



	/*

	 * bail if there's load or we're actually up-to-date.

	 */

	if (load || curr_jiffies == this_rq->last_load_update_tick)

	if (weighted_cpuload(cpu_of(this_rq)))

		return;



	pending_updates = curr_jiffies - this_rq->last_load_update_tick;

	this_rq->last_load_update_tick = curr_jiffies;



	__update_cpu_load(this_rq, load, pending_updates, 0);

	__update_cpu_load_nohz(this_rq, READ_ONCE(jiffies), 0, 0);

}



/*
@@ -4585,22 +4597,12 @@ void update_cpu_load_nohz(int active) 
	struct rq *this_rq = this_rq();

	unsigned long curr_jiffies = READ_ONCE(jiffies);

	unsigned long load = active ? weighted_cpuload(cpu_of(this_rq)) : 0;

	unsigned long pending_updates;



	if (curr_jiffies == this_rq->last_load_update_tick)

		return;



	raw_spin_lock(&this_rq->lock);

	pending_updates = curr_jiffies - this_rq->last_load_update_tick;

	if (pending_updates) {

		this_rq->last_load_update_tick = curr_jiffies;

		/*

		 * In the regular NOHZ case, we were idle, this means load 0.

		 * In the NOHZ_FULL case, we were non-idle, we should consider

		 * its weighted load.

		 */

		__update_cpu_load(this_rq, load, pending_updates, active);

	}

	__update_cpu_load_nohz(this_rq, curr_jiffies, load, active);

	raw_spin_unlock(&this_rq->lock);

}

#endif /* CONFIG_NO_HZ */
@@ -4612,7 +4614,7 @@ void update_cpu_load_active(struct rq *this_rq) 
{

	unsigned long load = weighted_cpuload(cpu_of(this_rq));

	/*

	 * See the mess around update_idle_cpu_load() / update_cpu_load_nohz().

	 * See the mess around update_cpu_load_idle() / update_cpu_load_nohz().

	 */

	this_rq->last_load_update_tick = jiffies;

	__update_cpu_load(this_rq, load, 1, 1);
@@ -7906,7 +7908,7 @@ static void nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) 
		if (time_after_eq(jiffies, rq->next_balance)) {

			raw_spin_lock_irq(&rq->lock);

			update_rq_clock(rq);

			update_idle_cpu_load(rq);

			update_cpu_load_idle(rq);

			raw_spin_unlock_irq(&rq->lock);

			rebalance_domains(rq, CPU_IDLE);

		}