[PATCH 4/5] nohz: Improve a bit the full dynticks Kconfig documentation

[Frederic Weisbecker]

Remove the "single task" statement from CONFIG_NO_HZ_FULL
title. The constraint can be invalidated when tasks from
other sched classes than SCHED_FAIR are running. Moreover
it's possible that hrtick join the party in the future.

Also add a line about the dependency on SMP.

Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Geoff Levand <geoff@xxxxxxxxxxxxx>
Cc: Gilad Ben Yossef <gilad@xxxxxxxxxxxxx>
Cc: Hakan Akkan <hakanakkan@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Kevin Hilman <khilman@xxxxxxxxxx>
Cc: Li Zhong <zhong@xxxxxxxxxxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
 kernel/time/Kconfig |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 3b68322..358d601 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -97,11 +97,13 @@ config NO_HZ_IDLE
 	  Most of the time you want to say Y here.
 
 config NO_HZ_FULL
-	bool "Full dynticks system (tickless single task)"
+	bool "Full dynticks system (tickless)"
 	# NO_HZ_COMMON dependency
 	depends on !ARCH_USES_GETTIMEOFFSET && GENERIC_CLOCKEVENTS
-	# RCU_USER_QS
-	depends on HAVE_CONTEXT_TRACKING && SMP
+	# We need at least one periodic CPU for timekeeping
+	depends on SMP
+	# RCU_USER_QS dependency
+	depends on HAVE_CONTEXT_TRACKING
 	# RCU_NOCB_CPU dependency
 	depends on TREE_RCU || TREE_PREEMPT_RCU
 	depends on VIRT_CPU_ACCOUNTING_GEN
-- 
1.7.5.4

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