2018-08-27 14:32:32 +00:00
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From: Julia Cartwright <julia@ni.com>
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Date: Wed, 12 Oct 2016 11:21:14 -0500
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Subject: [PATCH] rcu: enable rcu_normal_after_boot by default for RT
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2018-10-30 12:40:05 +00:00
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19-rt1.tar.xz
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2018-08-27 14:32:32 +00:00
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The forcing of an expedited grace period is an expensive and very
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RT-application unfriendly operation, as it forcibly preempts all running
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tasks on CPUs which are preventing the gp from expiring.
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By default, as a policy decision, disable the expediting of grace
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periods (after boot) on configurations which enable PREEMPT_RT_FULL.
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Suggested-by: Luiz Capitulino <lcapitulino@redhat.com>
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Signed-off-by: Julia Cartwright <julia@ni.com>
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/rcu/update.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/kernel/rcu/update.c
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+++ b/kernel/rcu/update.c
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@@ -67,7 +67,7 @@ extern int rcu_expedited; /* from sysctl
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module_param(rcu_expedited, int, 0);
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extern int rcu_normal; /* from sysctl */
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module_param(rcu_normal, int, 0);
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-static int rcu_normal_after_boot;
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+static int rcu_normal_after_boot = IS_ENABLED(CONFIG_PREEMPT_RT_FULL);
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module_param(rcu_normal_after_boot, int, 0);
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#endif /* #ifndef CONFIG_TINY_RCU */
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