Commit 0ccb977f authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

sched/fair: Explicitly generate __update_load_avg() instances 



The __update_load_avg() function is an __always_inline because its
used with constant propagation to generate different variants of the
code without having to duplicate it (which would be prone to bugs).

Explicitly instantiate the 3 variants.

Note that most of this is called from rather hot paths, so reducing
branches is good.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 05b40e05

kernel/sched/fair.c

+38 −18
Original line number Diff line number Diff line
@@ -2849,7 +2849,7 @@ static u32 __compute_runnable_contrib(u64 n) 
 *            = u_0 + u_1*y + u_2*y^2 + ... [re-labeling u_i --> u_{i+1}]

 */

static __always_inline int

__update_load_avg(u64 now, int cpu, struct sched_avg *sa,

___update_load_avg(u64 now, int cpu, struct sched_avg *sa,

		  unsigned long weight, int running, struct cfs_rq *cfs_rq)

{

	u64 delta, scaled_delta, periods;
@@ -2953,6 +2953,28 @@ __update_load_avg(u64 now, int cpu, struct sched_avg *sa, 
	return decayed;

}



static int

__update_load_avg_blocked_se(u64 now, int cpu, struct sched_entity *se)

{

	return ___update_load_avg(now, cpu, &se->avg, 0, 0, NULL);

}



static int

__update_load_avg_se(u64 now, int cpu, struct cfs_rq *cfs_rq, struct sched_entity *se)

{

	return ___update_load_avg(now, cpu, &se->avg,

				  se->on_rq * scale_load_down(se->load.weight),

				  cfs_rq->curr == se, NULL);

}



static int

__update_load_avg_cfs_rq(u64 now, int cpu, struct cfs_rq *cfs_rq)

{

	return ___update_load_avg(now, cpu, &cfs_rq->avg,

			scale_load_down(cfs_rq->load.weight),

			cfs_rq->curr != NULL, cfs_rq);

}



/*

 * Signed add and clamp on underflow.

 *
@@ -3014,6 +3036,9 @@ static inline void update_tg_load_avg(struct cfs_rq *cfs_rq, int force) 
void set_task_rq_fair(struct sched_entity *se,

		      struct cfs_rq *prev, struct cfs_rq *next)

{

	u64 p_last_update_time;

	u64 n_last_update_time;



	if (!sched_feat(ATTACH_AGE_LOAD))

		return;
@@ -3024,11 +3049,11 @@ void set_task_rq_fair(struct sched_entity *se, 
	 * time. This will result in the wakee task is less decayed, but giving

	 * the wakee more load sounds not bad.

	 */

	if (se->avg.last_update_time && prev) {

		u64 p_last_update_time;

		u64 n_last_update_time;

	if (!(se->avg.last_update_time && prev))

		return;



#ifndef CONFIG_64BIT

	{

		u64 p_last_update_time_copy;

		u64 n_last_update_time_copy;
@@ -3043,15 +3068,14 @@ void set_task_rq_fair(struct sched_entity *se, 


		} while (p_last_update_time != p_last_update_time_copy ||

			 n_last_update_time != n_last_update_time_copy);

	}

#else

	p_last_update_time = prev->avg.last_update_time;

	n_last_update_time = next->avg.last_update_time;

#endif

		__update_load_avg(p_last_update_time, cpu_of(rq_of(prev)),

				  &se->avg, 0, 0, NULL);

	__update_load_avg_blocked_se(p_last_update_time, cpu_of(rq_of(prev)), se);

	se->avg.last_update_time = n_last_update_time;

}

}



/* Take into account change of utilization of a child task group */

static inline void
@@ -3295,8 +3319,7 @@ update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq, bool update_freq) 
		set_tg_cfs_propagate(cfs_rq);

	}



	decayed = __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,

		scale_load_down(cfs_rq->load.weight), cfs_rq->curr != NULL, cfs_rq);

	decayed = __update_load_avg_cfs_rq(now, cpu_of(rq_of(cfs_rq)), cfs_rq);



#ifndef CONFIG_64BIT

	smp_wmb();
@@ -3328,11 +3351,8 @@ static inline void update_load_avg(struct sched_entity *se, int flags) 
	 * Track task load average for carrying it to new CPU after migrated, and

	 * track group sched_entity load average for task_h_load calc in migration

	 */

	if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD)) {

		__update_load_avg(now, cpu, &se->avg,

			  se->on_rq * scale_load_down(se->load.weight),

			  cfs_rq->curr == se, NULL);

	}

	if (se->avg.last_update_time && !(flags & SKIP_AGE_LOAD))

		__update_load_avg_se(now, cpu, cfs_rq, se);



	decayed  = update_cfs_rq_load_avg(now, cfs_rq, true);

	decayed |= propagate_entity_load_avg(se);
@@ -3437,7 +3457,7 @@ void sync_entity_load_avg(struct sched_entity *se) 
	u64 last_update_time;



	last_update_time = cfs_rq_last_update_time(cfs_rq);

	__update_load_avg(last_update_time, cpu_of(rq_of(cfs_rq)), &se->avg, 0, 0, NULL);

	__update_load_avg_blocked_se(last_update_time, cpu_of(rq_of(cfs_rq)), se);

}



/*

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