Commit 9014623c authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar

sched: handle vruntime 64-bit overflow

Handle vruntime overflow by centering the key space around min_vruntime.

( otherwise we could overflow 64-bit vruntime in a few days with SCHED_IDLE
 tasks - or in a few years with nice +19. )
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 94dfb5e7
...@@ -124,11 +124,18 @@ set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost) ...@@ -124,11 +124,18 @@ set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost)
cfs_rq->rb_leftmost = leftmost; cfs_rq->rb_leftmost = leftmost;
if (leftmost) { if (leftmost) {
se = rb_entry(leftmost, struct sched_entity, run_node); se = rb_entry(leftmost, struct sched_entity, run_node);
cfs_rq->min_vruntime = max(se->vruntime, if ((se->vruntime > cfs_rq->min_vruntime) ||
cfs_rq->min_vruntime); (cfs_rq->min_vruntime > (1ULL << 61) &&
se->vruntime < (1ULL << 50)))
cfs_rq->min_vruntime = se->vruntime;
} }
} }
s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
return se->fair_key - cfs_rq->min_vruntime;
}
/* /*
* Enqueue an entity into the rb-tree: * Enqueue an entity into the rb-tree:
*/ */
...@@ -138,7 +145,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) ...@@ -138,7 +145,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
struct rb_node **link = &cfs_rq->tasks_timeline.rb_node; struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
struct rb_node *parent = NULL; struct rb_node *parent = NULL;
struct sched_entity *entry; struct sched_entity *entry;
s64 key = se->fair_key; s64 key = entity_key(cfs_rq, se);
int leftmost = 1; int leftmost = 1;
/* /*
...@@ -151,7 +158,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) ...@@ -151,7 +158,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
* We dont care about collisions. Nodes with * We dont care about collisions. Nodes with
* the same key stay together. * the same key stay together.
*/ */
if (key - entry->fair_key < 0) { if (key < entity_key(cfs_rq, entry)) {
link = &parent->rb_left; link = &parent->rb_left;
} else { } else {
link = &parent->rb_right; link = &parent->rb_right;
......
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