sched: Update tg->shares after cpu.shares write

Formerly sched_group_set_shares would force a rebalance by overflowing domain
share sums.  Now that per-cpu averages are maintained we can set the true value
by issuing an update_cfs_shares() following a tg->shares update.

Also initialize tg se->load to 0 for consistency since we'll now set correct
weights on enqueue.

Signed-off-by: Paul Turner <pjt@google.com?>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20101115234938.465521344@google.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 11 insertions, 31 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index e914a716e1d4..550cf3a02377 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7646,7 +7646,7 @@ static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
                 se->cfs_rq = parent->my_q;
 
         se->my_q = cfs_rq;
-        update_load_set(&se->load, tg->shares);
+        update_load_set(&se->load, 0);
         se->parent = parent;
 }
 #endif
@@ -8274,37 +8274,12 @@ void sched_move_task(struct task_struct *tsk)
 #endif /* CONFIG_CGROUP_SCHED */
 
 #ifdef CONFIG_FAIR_GROUP_SCHED
-static void __set_se_shares(struct sched_entity *se, unsigned long shares)
-{
-        struct cfs_rq *cfs_rq = se->cfs_rq;
-        int on_rq;
-
-        on_rq = se->on_rq;
-        if (on_rq)
-                dequeue_entity(cfs_rq, se, 0);
-
-        update_load_set(&se->load, shares);
-
-        if (on_rq)
-                enqueue_entity(cfs_rq, se, 0);
-}
-
-static void set_se_shares(struct sched_entity *se, unsigned long shares)
-{
-        struct cfs_rq *cfs_rq = se->cfs_rq;
-        struct rq *rq = cfs_rq->rq;
-        unsigned long flags;
-
-        raw_spin_lock_irqsave(&rq->lock, flags);
-        __set_se_shares(se, shares);
-        raw_spin_unlock_irqrestore(&rq->lock, flags);
-}
-
 static DEFINE_MUTEX(shares_mutex);
 
 int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 {
         int i;
+        unsigned long flags;
 
         /*
          * We can't change the weight of the root cgroup.
@@ -8323,10 +8298,15 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares)
 
         tg->shares = shares;
         for_each_possible_cpu(i) {
-                /*
-                 * force a rebalance
-                 */
-                set_se_shares(tg->se[i], shares);
+                struct rq *rq = cpu_rq(i);
+                struct sched_entity *se;
+
+                se = tg->se[i];
+                /* Propagate contribution to hierarchy */
+                raw_spin_lock_irqsave(&rq->lock, flags);
+                for_each_sched_entity(se)
+                        update_cfs_shares(group_cfs_rq(se), 0);
+                raw_spin_unlock_irqrestore(&rq->lock, flags);
         }
 
 done: