sched/fair: Disambiguate existing/remaining "capacity" usage

We have "power" (which should actually become "capacity") and "capacity"
which is a scaled down "capacity factor" in terms of unitary tasks.
Let's use "capacity_factor" to make room for proper usage of "capacity"
later.

Signed-off-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linaro-kernel@lists.linaro.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/n/tip-gk1co8sqdev3763opqm6ovml@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 8993dfa2e82b9c94a2256f0b0f12b2c92a3132e5..e401e446e87cbf01538ace57e214134e7aa2fa06 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -5534,7 +5534,7 @@ struct sg_lb_stats {
        unsigned long load_per_task;
        unsigned long group_power;
        unsigned int sum_nr_running; /* Nr tasks running in the group */
-       unsigned int group_capacity;
+       unsigned int group_capacity_factor;
        unsigned int idle_cpus;
        unsigned int group_weight;
        int group_imb; /* Is there an imbalance in the group ? */
@@ -5829,15 +5829,15 @@ static inline int sg_imbalanced(struct sched_group *group)
 }
 
 /*
- * Compute the group capacity.
+ * Compute the group capacity factor.
  *
  * Avoid the issue where N*frac(smt_power) >= 1 creates 'phantom' cores by
  * first dividing out the smt factor and computing the actual number of cores
  * and limit power unit capacity with that.
  */
-static inline int sg_capacity(struct lb_env *env, struct sched_group *group)
+static inline int sg_capacity_factor(struct lb_env *env, struct sched_group *group)
 {
-       unsigned int capacity, smt, cpus;
+       unsigned int capacity_factor, smt, cpus;
        unsigned int power, power_orig;
 
        power = group->sgp->power;
@@ -5846,13 +5846,13 @@ static inline int sg_capacity(struct lb_env *env, struct sched_group *group)
 
        /* smt := ceil(cpus / power), assumes: 1 < smt_power < 2 */
        smt = DIV_ROUND_UP(SCHED_POWER_SCALE * cpus, power_orig);
-       capacity = cpus / smt; /* cores */
+       capacity_factor = cpus / smt; /* cores */
 
-       capacity = min_t(unsigned, capacity, DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE));
-       if (!capacity)
-               capacity = fix_small_capacity(env->sd, group);
+       capacity_factor = min_t(unsigned, capacity_factor, DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE));
+       if (!capacity_factor)
+               capacity_factor = fix_small_capacity(env->sd, group);
 
-       return capacity;
+       return capacity_factor;
 }
 
 /**
@@ -5902,9 +5902,9 @@ static inline void update_sg_lb_stats(struct lb_env *env,
        sgs->group_weight = group->group_weight;
 
        sgs->group_imb = sg_imbalanced(group);
-       sgs->group_capacity = sg_capacity(env, group);
+       sgs->group_capacity_factor = sg_capacity_factor(env, group);
 
-       if (sgs->group_capacity > sgs->sum_nr_running)
+       if (sgs->group_capacity_factor > sgs->sum_nr_running)
                sgs->group_has_free_capacity = 1;
 }
 
@@ -5929,7 +5929,7 @@ static bool update_sd_pick_busiest(struct lb_env *env,
        if (sgs->avg_load <= sds->busiest_stat.avg_load)
                return false;
 
-       if (sgs->sum_nr_running > sgs->group_capacity)
+       if (sgs->sum_nr_running > sgs->group_capacity_factor)
                return true;
 
        if (sgs->group_imb)
@@ -6020,17 +6020,17 @@ static inline void update_sd_lb_stats(struct lb_env *env, struct sd_lb_stats *sd
 
                /*
                 * In case the child domain prefers tasks go to siblings
-                * first, lower the sg capacity to one so that we'll try
+                * first, lower the sg capacity factor to one so that we'll try
                 * and move all the excess tasks away. We lower the capacity
                 * of a group only if the local group has the capacity to fit
-                * these excess tasks, i.e. nr_running < group_capacity. The
+                * these excess tasks, i.e. nr_running < group_capacity_factor. The
                 * extra check prevents the case where you always pull from the
                 * heaviest group when it is already under-utilized (possible
                 * with a large weight task outweighs the tasks on the system).
                 */
                if (prefer_sibling && sds->local &&
                    sds->local_stat.group_has_free_capacity)
-                       sgs->group_capacity = min(sgs->group_capacity, 1U);
+                       sgs->group_capacity_factor = min(sgs->group_capacity_factor, 1U);
 
                if (update_sd_pick_busiest(env, sds, sg, sgs)) {
                        sds->busiest = sg;
@@ -6204,7 +6204,7 @@ static inline void calculate_imbalance(struct lb_env *env, struct sd_lb_stats *s
                 * have to drop below capacity to reach cpu-load equilibrium.
                 */
                load_above_capacity =
-                       (busiest->sum_nr_running - busiest->group_capacity);
+                       (busiest->sum_nr_running - busiest->group_capacity_factor);
 
                load_above_capacity *= (SCHED_LOAD_SCALE * SCHED_POWER_SCALE);
                load_above_capacity /= busiest->group_power;
@@ -6348,7 +6348,7 @@ static struct rq *find_busiest_queue(struct lb_env *env,
        int i;
 
        for_each_cpu_and(i, sched_group_cpus(group), env->cpus) {
-               unsigned long power, capacity, wl;
+               unsigned long power, capacity_factor, wl;
                enum fbq_type rt;
 
                rq = cpu_rq(i);
@@ -6377,9 +6377,9 @@ static struct rq *find_busiest_queue(struct lb_env *env,
                        continue;
 
                power = power_of(i);
-               capacity = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
-               if (!capacity)
-                       capacity = fix_small_capacity(env->sd, group);
+               capacity_factor = DIV_ROUND_CLOSEST(power, SCHED_POWER_SCALE);
+               if (!capacity_factor)
+                       capacity_factor = fix_small_capacity(env->sd, group);
 
                wl = weighted_cpuload(i);
 
@@ -6387,7 +6387,7 @@ static struct rq *find_busiest_queue(struct lb_env *env,
                 * When comparing with imbalance, use weighted_cpuload()
                 * which is not scaled with the cpu power.
                 */
-               if (capacity && rq->nr_running == 1 && wl > env->imbalance)
+               if (capacity_factor && rq->nr_running == 1 && wl > env->imbalance)
                        continue;
 
                /*