From 1fd2b4425a5702c112b441e20b250ac8833a9608 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Wed, 11 Jul 2012 20:26:40 +0200
Subject: [PATCH] rcu: Userspace RCU extended QS selftest
Provide a config option that enables the userspace
RCU extended quiescent state on every CPUs by default.
This is for testing purpose.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Alessio Igor Bogani <abogani@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Kevin Hilman <khilman@ti.com>
Cc: Max Krasnyansky <maxk@qualcomm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Hemminger <shemminger@vyatta.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sven-Thorsten Dietrich <thebigcorporation@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---
init/Kconfig | 8 ++++++++
kernel/rcutree.c | 2 +-
2 files changed, 9 insertions(+), 1 deletion(-)
diff --git a/init/Kconfig b/init/Kconfig
index f6a1830165cea..c26b8a1d2b576 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -451,6 +451,14 @@ config RCU_USER_QS
excluded from the global RCU state machine and thus doesn't
to keep the timer tick on for RCU.
+config RCU_USER_QS_FORCE
+ bool "Force userspace extended QS by default"
+ depends on RCU_USER_QS
+ help
+ Set the hooks in user/kernel boundaries by default in order to
+ test this feature that treats userspace as an extended quiescent
+ state until we have a real user like a full adaptive nohz option.
+
config RCU_FANOUT
int "Tree-based hierarchical RCU fanout value"
range 2 64 if 64BIT
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index d2e74c8d4b0e5..812d04b6b3950 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -206,7 +206,7 @@ EXPORT_SYMBOL_GPL(rcu_note_context_switch);
DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
.dynticks_nesting = DYNTICK_TASK_EXIT_IDLE,
.dynticks = ATOMIC_INIT(1),
-#ifdef CONFIG_RCU_USER_QS
+#if defined(CONFIG_RCU_USER_QS) && !defined(CONFIG_RCU_USER_QS_FORCE)
.ignore_user_qs = true,
#endif
};
--
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