sched/fair: Factor out the {at,de}taching of the per entity load {to,from} the runqueue

Currently we open-code the addition/subtraction of the per entity load
to/from the runqueue, factor this out into helper functions.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
[ Rewrote the changelog. ]
Signed-off-by: Peter 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: yuyang.du@intel.com
Link: http://lkml.kernel.org/r/1440069720-27038-2-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6e2e348..a72a71b 100644 (file)
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2664,8 +2664,8 @@ static inline u64 cfs_rq_clock_task(struct cfs_rq *cfs_rq);
 /* Group cfs_rq's load_avg is used for task_h_load and update_cfs_share */
 static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
 {
-       int decayed;
        struct sched_avg *sa = &cfs_rq->avg;
+       int decayed;
 
        if (atomic_long_read(&cfs_rq->removed_load_avg)) {
                long r = atomic_long_xchg(&cfs_rq->removed_load_avg, 0);
@@ -2695,33 +2695,52 @@ static inline int update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
 static inline void update_load_avg(struct sched_entity *se, int update_tg)
 {
        struct cfs_rq *cfs_rq = cfs_rq_of(se);
-       int cpu = cpu_of(rq_of(cfs_rq));
        u64 now = cfs_rq_clock_task(cfs_rq);
+       int cpu = cpu_of(rq_of(cfs_rq));
 
        /*
         * 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
         */
        __update_load_avg(now, cpu, &se->avg,
-               se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL);
+                         se->on_rq * scale_load_down(se->load.weight),
+                         cfs_rq->curr == se, NULL);
 
        if (update_cfs_rq_load_avg(now, cfs_rq) && update_tg)
                update_tg_load_avg(cfs_rq, 0);
 }
 
+static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+       se->avg.last_update_time = cfs_rq->avg.last_update_time;
+       cfs_rq->avg.load_avg += se->avg.load_avg;
+       cfs_rq->avg.load_sum += se->avg.load_sum;
+       cfs_rq->avg.util_avg += se->avg.util_avg;
+       cfs_rq->avg.util_sum += se->avg.util_sum;
+}
+
+static void detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+       __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
+                         &se->avg, se->on_rq * scale_load_down(se->load.weight),
+                         cfs_rq->curr == se, NULL);
+
+       cfs_rq->avg.load_avg = max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0);
+       cfs_rq->avg.load_sum = max_t(s64,  cfs_rq->avg.load_sum - se->avg.load_sum, 0);
+       cfs_rq->avg.util_avg = max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0);
+       cfs_rq->avg.util_sum = max_t(s32,  cfs_rq->avg.util_sum - se->avg.util_sum, 0);
+}
+
 /* Add the load generated by se into cfs_rq's load average */
 static inline void
 enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
 {
        struct sched_avg *sa = &se->avg;
        u64 now = cfs_rq_clock_task(cfs_rq);
-       int migrated = 0, decayed;
+       int migrated, decayed;
 
-       if (sa->last_update_time == 0) {
-               sa->last_update_time = now;
-               migrated = 1;
-       }
-       else {
+       migrated = !sa->last_update_time;
+       if (!migrated) {
                __update_load_avg(now, cpu_of(rq_of(cfs_rq)), sa,
                        se->on_rq * scale_load_down(se->load.weight),
                        cfs_rq->curr == se, NULL);
@@ -2732,12 +2751,8 @@ enqueue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
        cfs_rq->runnable_load_avg += sa->load_avg;
        cfs_rq->runnable_load_sum += sa->load_sum;
 
-       if (migrated) {
-               cfs_rq->avg.load_avg += sa->load_avg;
-               cfs_rq->avg.load_sum += sa->load_sum;
-               cfs_rq->avg.util_avg += sa->util_avg;
-               cfs_rq->avg.util_sum += sa->util_sum;
-       }
+       if (migrated)
+               attach_entity_load_avg(cfs_rq, se);
 
        if (decayed || migrated)
                update_tg_load_avg(cfs_rq, 0);
@@ -2752,7 +2767,7 @@ dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
        cfs_rq->runnable_load_avg =
                max_t(long, cfs_rq->runnable_load_avg - se->avg.load_avg, 0);
        cfs_rq->runnable_load_sum =
-               max_t(s64, cfs_rq->runnable_load_sum - se->avg.load_sum, 0);
+               max_t(s64,  cfs_rq->runnable_load_sum - se->avg.load_sum, 0);
 }
 
 /*
@@ -2820,6 +2835,11 @@ static inline void
 dequeue_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
 static inline void remove_entity_load_avg(struct sched_entity *se) {}
 
+static inline void
+attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+static inline void
+detach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se) {}
+
 static inline int idle_balance(struct rq *rq)
 {
        return 0;
@@ -7909,25 +7929,10 @@ static void switched_from_fair(struct rq *rq, struct task_struct *p)
                se->vruntime -= cfs_rq->min_vruntime;
        }
 
-#ifdef CONFIG_SMP
        /* Catch up with the cfs_rq and remove our load when we leave */
-       __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq), &se->avg,
-               se->on_rq * scale_load_down(se->load.weight), cfs_rq->curr == se, NULL);
-
-       cfs_rq->avg.load_avg =
-               max_t(long, cfs_rq->avg.load_avg - se->avg.load_avg, 0);
-       cfs_rq->avg.load_sum =
-               max_t(s64, cfs_rq->avg.load_sum - se->avg.load_sum, 0);
-       cfs_rq->avg.util_avg =
-               max_t(long, cfs_rq->avg.util_avg - se->avg.util_avg, 0);
-       cfs_rq->avg.util_sum =
-               max_t(s32, cfs_rq->avg.util_sum - se->avg.util_sum, 0);
-#endif
+       detach_entity_load_avg(cfs_rq, se);
 }
 
-/*
- * We switched to the sched_fair class.
- */
 static void switched_to_fair(struct rq *rq, struct task_struct *p)
 {
        struct sched_entity *se = &p->se;
@@ -8040,14 +8045,8 @@ static void task_move_group_fair(struct task_struct *p, int queued)
                cfs_rq = cfs_rq_of(se);
                se->vruntime += cfs_rq->min_vruntime;
 
-#ifdef CONFIG_SMP
                /* Virtually synchronize task with its new cfs_rq */
-               p->se.avg.last_update_time = cfs_rq->avg.last_update_time;
-               cfs_rq->avg.load_avg += p->se.avg.load_avg;
-               cfs_rq->avg.load_sum += p->se.avg.load_sum;
-               cfs_rq->avg.util_avg += p->se.avg.util_avg;
-               cfs_rq->avg.util_sum += p->se.avg.util_sum;
-#endif
+               attach_entity_load_avg(cfs_rq, se);
        }
 }