Messages in this thread Patch in this message | | | From | Mark Langsdorf <> | Subject | [PATCH] Prevent immediate process rescheduling | Date | Fri, 18 Sep 2009 14:49:12 -0500 |
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Prevent the scheduler from immediately rescheduling a process that just yielded if there is another process available.
Originally suggested by Mike Galbraith (efault@gmx.de).
Signed-off-by: Mark Langsdorf <mark.langsdorf@amd.com> --- kernel/sched_fair.c | 16 +++++++++++++++- 1 files changed, 15 insertions(+), 1 deletions(-)
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 652e8bd..4fad08f 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -353,11 +353,25 @@ static void __dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se) static struct sched_entity *__pick_next_entity(struct cfs_rq *cfs_rq) { struct rb_node *left = cfs_rq->rb_leftmost; + struct sched_entity *se, *curr; if (!left) return NULL; - return rb_entry(left, struct sched_entity, run_node); + se = rb_entry(left, struct sched_entity, run_node); + curr = ¤t->se; + + /* + * Don't select the entity who just tried to schedule away + * if there's another entity available. + */ + if (unlikely(se == curr && cfs_rq->nr_running > 1)) { + struct rb_node *next_node = rb_next(&curr->run_node); + if (next_node) + se = rb_entry(next_node, struct sched_entity, run_node); + } + + return se; } static struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq) -- 1.6.0.2
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