50 lines
1.3 KiB
Diff
50 lines
1.3 KiB
Diff
From: Peter Zijlstra <peterz@infradead.org>
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Date: Tue, 16 Mar 2010 14:31:44 -0700
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Subject: sched: Break out from load_balancing on rq_lock contention
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Also limit NEW_IDLE pull
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Signed-off-by: Peter Zijlstra <peterz@infradead.org>
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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kernel/sched_fair.c | 18 ++++++++++++++++++
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1 file changed, 18 insertions(+)
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Index: linux-3.2/kernel/sched_fair.c
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===================================================================
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--- linux-3.2.orig/kernel/sched_fair.c
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+++ linux-3.2/kernel/sched_fair.c
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@@ -2899,6 +2899,10 @@ balance_tasks(struct rq *this_rq, int th
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*/
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if (idle == CPU_NEWLY_IDLE)
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break;
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+
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+ if (raw_spin_is_contended(&this_rq->lock) ||
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+ raw_spin_is_contended(&busiest->lock))
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+ break;
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#endif
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/*
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@@ -3039,6 +3043,20 @@ load_balance_fair(struct rq *this_rq, in
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rem_load_move -= moved_load;
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if (rem_load_move < 0)
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break;
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+
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+#ifdef CONFIG_PREEMPT
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+ /*
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+ * NEWIDLE balancing is a source of latency, so preemptible
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+ * kernels will stop after the first task is pulled to minimize
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+ * the critical section.
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+ */
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+ if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
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+ break;
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+
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+ if (raw_spin_is_contended(&this_rq->lock) ||
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+ raw_spin_is_contended(&busiest->lock))
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+ break;
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+#endif
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}
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rcu_read_unlock();
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