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| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2007-10-15 17:00:05 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2007-10-15 17:00:05 +0200 |
| commit | 9014623c0e3545be58a7f19f55793f6517bdc274 (patch) | |
| tree | 064267aecedeacb8154282c6475d67f4e34f41e3 /kernel/sched_fair.c | |
| parent | 94dfb5e75ef59068a8cf68fa6e18f25ebdcd20b9 (diff) | |
| download | lwn-9014623c0e3545be58a7f19f55793f6517bdc274.tar.gz lwn-9014623c0e3545be58a7f19f55793f6517bdc274.zip | |
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>
Diffstat (limited to 'kernel/sched_fair.c')
| -rw-r--r-- | kernel/sched_fair.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 86e5e8c5d101..895fef74d99a 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -124,11 +124,18 @@ set_leftmost(struct cfs_rq *cfs_rq, struct rb_node *leftmost) cfs_rq->rb_leftmost = leftmost; if (leftmost) { se = rb_entry(leftmost, struct sched_entity, run_node); - cfs_rq->min_vruntime = max(se->vruntime, - cfs_rq->min_vruntime); + if ((se->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: */ @@ -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 *parent = NULL; struct sched_entity *entry; - s64 key = se->fair_key; + s64 key = entity_key(cfs_rq, se); int leftmost = 1; /* @@ -151,7 +158,7 @@ __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 - entry->fair_key < 0) { + if (key < entity_key(cfs_rq, entry)) { link = &parent->rb_left; } else { link = &parent->rb_right; |