[PATCH] Prevent immediate process rescheduling
in [Kernel]
|
Prev: perf sched: Determine the number of CPUs automatically
Next: /etc/profile: line 30: /dev/null: Permission denied
From: Mark Langsdorf on 18 Sep 2009 17:10 Prevent the scheduler from immediately rescheduling a process that just yielded if there is another process available. Originally suggested by Mike Galbraith (efault(a)gmx.de). Signed-off-by: Mark Langsdorf <mark.langsdorf(a)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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |