50 lines
1.6 KiB
Diff
50 lines
1.6 KiB
Diff
From d7b6978553d25bcbb64294834d6cc98000bad63b Mon Sep 17 00:00:00 2001
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From: Peter Zijlstra <peterz@infradead.org>
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Date: Tue, 18 Oct 2011 22:03:48 +0200
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Subject: [PATCH 015/298] sched: Do not throttle due to PI boosting
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When a runqueue has rt_runtime_us = 0 then the only way it can
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accumulate rt_time is via PI boosting. Though that causes the runqueue
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to be throttled and replenishing does not change anything due to
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rt_runtime_us = 0. So avoid that situation by clearing rt_time and
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skip the throttling alltogether.
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[ tglx: Preliminary changelog ]
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/sched_rt.c | 20 ++++++++++++++++++--
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1 file changed, 18 insertions(+), 2 deletions(-)
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diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c
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index 40d97e1..c108b9c 100644
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--- a/kernel/sched_rt.c
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+++ b/kernel/sched_rt.c
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@@ -659,8 +659,24 @@ static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
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return 0;
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if (rt_rq->rt_time > runtime) {
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- rt_rq->rt_throttled = 1;
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- printk_once(KERN_WARNING "sched: RT throttling activated\n");
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+ struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
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+
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+ /*
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+ * Don't actually throttle groups that have no runtime assigned
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+ * but accrue some time due to boosting.
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+ */
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+ if (likely(rt_b->rt_runtime)) {
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+ rt_rq->rt_throttled = 1;
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+ printk_once(KERN_WARNING "sched: RT throttling activated\n");
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+ } else {
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+ /*
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+ * In case we did anyway, make it go away,
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+ * replenishment is a joke, since it will replenish us
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+ * with exactly 0 ns.
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+ */
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+ rt_rq->rt_time = 0;
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+ }
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+
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if (rt_rq_throttled(rt_rq)) {
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sched_rt_rq_dequeue(rt_rq);
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return 1;
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