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sched: Replace use of entity_key()

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"entity_key()" is only used in "__enqueue_entity()" and
its only function is to subtract a tasks vruntime by
its groups minvruntime.
Before this patch a rbtree enqueue-decision is done by
comparing two tasks in the style:

	"if (entity_key(cfs_rq, se) < entity_key(cfs_rq, entry))"

which would be

	"if (se->vruntime-cfs_rq->min_vruntime < entry->vruntime-cfs_rq->min_vruntime)"

or (if reducing cfs_rq->min_vruntime out)

	"if (se->vruntime < entry->vruntime)"

which is

	"if (entity_before(se, entry))"

So we do not need "entity_key()".
If "entity_before()" is inline we will also save one subtraction (only one,
because "entity_key(cfs_rq, se)"  was cached in "key")

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-ns12mnd2h5w8rb9agd8hnsfk@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Stephan Baerwolf 2011-07-20 14:46:59 +02:00 committed by Ingo Molnar
parent acb5a9ba3b
commit 2bd2d6f2dc
1 changed files with 1 additions and 7 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

8
kernel/sched_fair.c
View file

@ -321,11 +321,6 @@ static inline int entity_before(struct sched_entity *a,
return (s64)(a->vruntime - b->vruntime) < 0;
}
static inline s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
return se->vruntime - cfs_rq->min_vruntime;
}
static void update_min_vruntime(struct cfs_rq *cfs_rq)
{
u64 vruntime = cfs_rq->min_vruntime;
@ -359,7 +354,6 @@ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
struct rb_node *parent = NULL;
struct sched_entity *entry;
s64 key = entity_key(cfs_rq, se);
int leftmost = 1;
/*
@ -372,7 +366,7 @@ static void __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
* We dont care about collisions. Nodes with
* the same key stay together.
*/
if (key < entity_key(cfs_rq, entry)) {
if (entity_before(se, entry)) {
link = &parent->rb_left;
} else {
link = &parent->rb_right;