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: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Mike Galbraith <efault@gmx.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
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@ -124,11 +124,18 @@ set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost)
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cfs_rq->rb_leftmost = leftmost;
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cfs_rq->rb_leftmost = leftmost;
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if (leftmost) {
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if (leftmost) {
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se = rb_entry(leftmost, struct sched_entity, run_node);
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se = rb_entry(leftmost, struct sched_entity, run_node);
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cfs_rq->min_vruntime = max(se->vruntime,
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if ((se->vruntime > cfs_rq->min_vruntime) ||
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cfs_rq->min_vruntime);
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(cfs_rq->min_vruntime > (1ULL << 61) &&
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se->vruntime < (1ULL << 50)))
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cfs_rq->min_vruntime = se->vruntime;
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}
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}
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}
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}
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s64 entity_key(struct cfs_rq *cfs_rq, struct sched_entity *se)
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{
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return se->fair_key - cfs_rq->min_vruntime;
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}
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/*
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/*
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* Enqueue an entity into the rb-tree:
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* Enqueue an entity into the rb-tree:
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*/
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*/
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@ -138,7 +145,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
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struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
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struct rb_node **link = &cfs_rq->tasks_timeline.rb_node;
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struct rb_node *parent = NULL;
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struct rb_node *parent = NULL;
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struct sched_entity *entry;
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struct sched_entity *entry;
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s64 key = se->fair_key;
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s64 key = entity_key(cfs_rq, se);
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int leftmost = 1;
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int leftmost = 1;
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/*
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/*
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@ -151,7 +158,7 @@ __enqueue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se)
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* We dont care about collisions. Nodes with
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* We dont care about collisions. Nodes with
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* the same key stay together.
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* the same key stay together.
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*/
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*/
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if (key - entry->fair_key < 0) {
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if (key < entity_key(cfs_rq, entry)) {
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link = &parent->rb_left;
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link = &parent->rb_left;
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} else {
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} else {
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link = &parent->rb_right;
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link = &parent->rb_right;
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