From 1e9114e34389619347eecc362b72d28efdf53b1a Mon Sep 17 00:00:00 2001
Message-Id: <1e9114e34389619347eecc362b72d28efdf53b1a.1592846147.git.zanussi@kernel.org>
In-Reply-To: <07cd0dbc80b976663c80755496a03f288decfe5a.1592846146.git.zanussi@kernel.org>
References: <07cd0dbc80b976663c80755496a03f288decfe5a.1592846146.git.zanussi@kernel.org>
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon, 24 Jun 2019 18:29:13 +0200
Subject: [PATCH 269/330] rcu: Don't allow to change rcu_normal_after_boot on
 RT
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.127-rt55.tar.xz

[ Upstream commit c6c058c10577815a2491ce661876cff00a4c3b15 ]

On RT rcu_normal_after_boot is enabled by default.
Don't allow to disable it on RT because the "expedited rcu" would
introduce latency spikes.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 kernel/rcu/update.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index 16d8dba23329..ed75addd3ccd 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -69,7 +69,9 @@ module_param(rcu_expedited, int, 0);
 extern int rcu_normal; /* from sysctl */
 module_param(rcu_normal, int, 0);
 static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
+#ifndef CONFIG_PREEMPT_RT_FULL
 module_param(rcu_normal_after_boot, int, 0);
+#endif
 #endif /* #ifndef CONFIG_TINY_RCU */
 
 #ifdef CONFIG_DEBUG_LOCK_ALLOC
-- 
2.17.1

