diff options
| author | Mike Galbraith <efault@gmx.de> | 2009-01-28 14:51:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-02-01 10:49:50 +0100 |
| commit | a9f3e2b549f83a9cdab873abf4140be27c05a3f2 (patch) | |
| tree | 756fb52736f8bd1e1f8fb0a621ac58ec8e1812d3 | |
| parent | 1596e29773eadd96b0a5fc6e736afa52394cafda (diff) | |
| download | linux-a9f3e2b549f83a9cdab873abf4140be27c05a3f2.tar.bz2 | |
sched: clear buddies more aggressively
It was noticed that a task could get re-elected past its run quota due to buddy
affinities. This could increase latency a little. Cure it by more aggresively
clearing buddy state.
We do so in two situations:
- when we force preempt
- when we select a buddy to run
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched_fair.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index fdc417504681..75248b9ff4c1 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -768,8 +768,14 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr) ideal_runtime = sched_slice(cfs_rq, curr); delta_exec = curr->sum_exec_runtime - curr->prev_sum_exec_runtime; - if (delta_exec > ideal_runtime) + if (delta_exec > ideal_runtime) { resched_task(rq_of(cfs_rq)->curr); + /* + * The current task ran long enough, ensure it doesn't get + * re-elected due to buddy favours. + */ + clear_buddies(cfs_rq, curr); + } } static void @@ -1445,6 +1451,11 @@ static struct task_struct *pick_next_task_fair(struct rq *rq) do { se = pick_next_entity(cfs_rq); + /* + * If se was a buddy, clear it so that it will have to earn + * the favour again. + */ + clear_buddies(cfs_rq, se); set_next_entity(cfs_rq, se); cfs_rq = group_cfs_rq(se); } while (cfs_rq); |