0013-Make-threaded-IRQs-optionally-the-default-which-can-.patch

From df4136f6de5b3f45c2f4be7a3cc042903e983e0c Mon Sep 17 00:00:00 2001
From: Con Kolivas <kernel@kolivas.org>
Date: Wed, 7 Dec 2016 21:13:16 +1100
Subject: [PATCH 13/16] Make threaded IRQs optionally the default which can be
 disabled.

---
 kernel/irq/Kconfig  | 17 +++++++++++++++++
 kernel/irq/manage.c | 11 +++++++++++
 2 files changed, 28 insertions(+)

diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 5f3e2baefca9..de3e5740679b 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -107,6 +107,23 @@ config GENERIC_IRQ_RESERVATION_MODE
 config IRQ_FORCED_THREADING
        bool
 
+config FORCE_IRQ_THREADING
+	bool "Make IRQ threading compulsory"
+	depends on IRQ_FORCED_THREADING
+	default n
+	---help---
+
+	  Make IRQ threading mandatory for any IRQ handlers that support it
+	  instead of being optional and requiring the threadirqs kernel
+	  parameter. Instead they can be optionally disabled with the
+	  nothreadirqs kernel parameter.
+
+	  Enabling this may make some architectures not boot with runqueue
+	  sharing and MuQSS.
+
+	  Enable if you are building for a desktop or low latency system,
+	  otherwise say N.
+
 config SPARSE_IRQ
 	bool "Support sparse irq numbering" if MAY_HAVE_SPARSE_IRQ
 	---help---
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index fb86146037a7..b322b1a0caa0 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -23,9 +23,20 @@
 #include "internals.h"
 
 #ifdef CONFIG_IRQ_FORCED_THREADING
+#ifdef CONFIG_FORCE_IRQ_THREADING
+__read_mostly bool force_irqthreads = true;
+#else
 __read_mostly bool force_irqthreads;
+#endif
 EXPORT_SYMBOL_GPL(force_irqthreads);
 
+static int __init setup_noforced_irqthreads(char *arg)
+{
+	force_irqthreads = false;
+	return 0;
+}
+early_param("nothreadirqs", setup_noforced_irqthreads);
+
 static int __init setup_forced_irqthreads(char *arg)
 {
 	force_irqthreads = true;
-- 
2.17.1