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sched: yield fix 

fix yield bugs due to the current-not-in-rbtree changes: the task is
not in the rbtree so rbtree-removal is a no-no.

[ From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>: build fix. ]

also, nice code size reduction:

kernel/sched.o:
   text    data     bss     dec     hex filename
  38323    3506      24   41853    a37d sched.o.before
  38236    3506      24   41766    a326 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Dmitry Adamushko 2007-10-15 17:00:12 +02:00 committed by Ingo Molnar
parent 8651a86c34
commit 2b1e315dd2
1 changed files with 5 additions and 20 deletions
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25
kernel/sched_fair.c
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@ -739,9 +739,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int sleep)
static void yield_task_fair(struct rq *rq)
{
struct cfs_rq *cfs_rq = task_cfs_rq(rq->curr);
struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
struct sched_entity *rightmost, *se = &rq->curr->se;
struct rb_node *parent;
/*
* Are we the only task in the tree?
@ -755,39 +753,26 @@ static void yield_task_fair(struct rq *rq)
* Dequeue and enqueue the task to update its
* position within the tree:
*/
dequeue_entity(cfs_rq, se, 0);
enqueue_entity(cfs_rq, se, 0);
update_curr(cfs_rq);
return;
}
/*
* Find the rightmost entry in the rbtree:
*/
do {
parent = *link;
link = &parent->rb_right;
} while (*link);
rightmost = rb_entry(parent, struct sched_entity, run_node);
rightmost = __pick_last_entity(cfs_rq);
/*
* Already in the rightmost position?
*/
if (unlikely(rightmost == se))
if (unlikely(rightmost->vruntime < se->vruntime))
return;
/*
* Minimally necessary key value to be last in the tree:
* Upon rescheduling, sched_class::put_prev_task() will place
* 'current' within the tree based on its new key value.
*/
se->vruntime = rightmost->vruntime + 1;
if (cfs_rq->rb_leftmost == &se->run_node)
cfs_rq->rb_leftmost = rb_next(&se->run_node);
/*
* Relink the task to the rightmost position:
*/
rb_erase(&se->run_node, &cfs_rq->tasks_timeline);
rb_link_node(&se->run_node, parent, link);
rb_insert_color(&se->run_node, &cfs_rq->tasks_timeline);
}
/*