linux/debian/patches-rt/0106-sched-Limit-the-number-of-task-migrations-per-batch.patch

From 377f1de1f1aa4bbd7afa40c6d4262eae1780b84b Mon Sep 17 00:00:00 2001
Message-Id: <377f1de1f1aa4bbd7afa40c6d4262eae1780b84b.1592846147.git.zanussi@kernel.org>
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References: <07cd0dbc80b976663c80755496a03f288decfe5a.1592846146.git.zanussi@kernel.org>
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 6 Jun 2011 12:12:51 +0200
Subject: [PATCH 106/330] sched: Limit the number of task migrations per batch
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.127-rt55.tar.xz

Put an upper limit on the number of tasks which are migrated per batch
to avoid large latencies.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/sched/core.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2f6b4365d070..5c23d1272429 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -44,7 +44,11 @@ const_debug unsigned int sysctl_sched_features =
  * Number of tasks to iterate in a single balance run.
  * Limited because this is done with IRQs disabled.
  */
+#ifdef CONFIG_PREEMPT_RT_FULL
+const_debug unsigned int sysctl_sched_nr_migrate = 8;
+#else
 const_debug unsigned int sysctl_sched_nr_migrate = 32;
+#endif
 
 /*
  * period over which we measure -rt task CPU usage in us.
-- 
2.17.1