Commit 1fd2b442 authored Jul 11, 2012 by Frederic Weisbecker

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>

parent edf55fda

init/Kconfig

+8 −0

Original line number	Diff line number	Diff line
		@@ -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

kernel/rcutree.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -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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