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Commit e201c56b authored by Quentin Perret's avatar Quentin Perret
Browse files

FROMLIST: sched/fair: Clean-up update_sg_lb_stats parameters 



In preparation for the introduction of a new root domain flag which can
be set during load balance (the 'overutilized' flag), clean-up the set
of parameters passed to update_sg_lb_stats(). More specifically, the
'local_group' and 'local_idx' parameters can be removed since they can
easily be reconstructed from within the function.

While at it, transform the 'overload' parameter into a flag stored in
the 'sg_status' parameter hence facilitating the definition of new flags
when needed.

Change-Id: Ic2ccb51fdc08d7da0f8cc0442ef97cbcb4a52c86
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Suggested-by: default avatarPeter Zijlstra <peterz@infradead.org>
Suggested-by: default avatarValentin Schneider <valentin.schneider@arm.com>
Signed-off-by: default avatarQuentin Perret <quentin.perret@arm.com>
Message-Id: <20181016101513.26919-12-quentin.perret@arm.com>
Signed-off-by: default avatarQuentin Perret <quentin.perret@arm.com>
parent b78eec5f

kernel/sched/fair.c

+11 −16
Original line number Diff line number Diff line
@@ -7884,16 +7884,16 @@ static bool update_nohz_stats(struct rq *rq, bool force) 
 * update_sg_lb_stats - Update sched_group's statistics for load balancing.

 * @env: The load balancing environment.

 * @group: sched_group whose statistics are to be updated.

 * @load_idx: Load index of sched_domain of this_cpu for load calc.

 * @local_group: Does group contain this_cpu.

 * @sgs: variable to hold the statistics for this group.

 * @overload: Indicate pullable load (e.g. >1 runnable task).

 * @sg_status: Holds flag indicating the status of the sched_group

 */

static inline void update_sg_lb_stats(struct lb_env *env,

			struct sched_group *group, int load_idx,

			int local_group, struct sg_lb_stats *sgs,

			bool *overload)

				      struct sched_group *group,

				      struct sg_lb_stats *sgs,

				      int *sg_status)

{

	int local_group = cpumask_test_cpu(env->dst_cpu, sched_group_span(group));

	int load_idx = get_sd_load_idx(env->sd, env->idle);

	unsigned long load;

	int i, nr_running;
@@ -7917,7 +7917,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, 


		nr_running = rq->nr_running;

		if (nr_running > 1)

			*overload = true;

			*sg_status |= SG_OVERLOAD;



#ifdef CONFIG_NUMA_BALANCING

		sgs->nr_numa_running += rq->nr_numa_running;
@@ -7933,7 +7933,7 @@ static inline void update_sg_lb_stats(struct lb_env *env, 
		if (env->sd->flags & SD_ASYM_CPUCAPACITY &&

		    sgs->group_misfit_task_load < rq->misfit_task_load) {

			sgs->group_misfit_task_load = rq->misfit_task_load;

			*overload = 1;

			*sg_status |= SG_OVERLOAD;

		}

	}
@@ -8078,17 +8078,14 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd 
	struct sched_group *sg = env->sd->groups;

	struct sg_lb_stats *local = &sds->local_stat;

	struct sg_lb_stats tmp_sgs;

	int load_idx;

	bool overload = false;

	bool prefer_sibling = child && child->flags & SD_PREFER_SIBLING;

	int sg_status = 0;



#ifdef CONFIG_NO_HZ_COMMON

	if (env->idle == CPU_NEWLY_IDLE && READ_ONCE(nohz.has_blocked))

		env->flags |= LBF_NOHZ_STATS;

#endif



	load_idx = get_sd_load_idx(env->sd, env->idle);



	do {

		struct sg_lb_stats *sgs = &tmp_sgs;

		int local_group;
@@ -8103,8 +8100,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd 
				update_group_capacity(env->sd, env->dst_cpu);

		}



		update_sg_lb_stats(env, sg, load_idx, local_group, sgs,

						&overload);

		update_sg_lb_stats(env, sg, sgs, &sg_status);



		if (local_group)

			goto next_group;
@@ -8154,8 +8150,7 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd 


	if (!env->sd->parent) {

		/* update overload indicator if we are at root domain */

		if (READ_ONCE(env->dst_rq->rd->overload) != overload)

			WRITE_ONCE(env->dst_rq->rd->overload, overload);

		WRITE_ONCE(env->dst_rq->rd->overload, sg_status & SG_OVERLOAD);

	}

}

kernel/sched/sched.h

+3 −0
Original line number Diff line number Diff line
@@ -709,6 +709,9 @@ struct perf_domain { 
	struct rcu_head rcu;

};



/* Scheduling group status flags */

#define SG_OVERLOAD		0x1 /* More than one runnable task on a CPU. */



/*

 * We add the notion of a root-domain which will be used to define per-domain

 * variables. Each exclusive cpuset essentially defines an island domain by