From d1e43fa5f8bb25f83a86a29f11fcfb57ed4d7566 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Tue, 26 Mar 2013 23:47:24 +0100 Subject: nohz: Ensure full dynticks CPUs are RCU nocbs We need full dynticks CPU to also be RCU nocb so that we don't have to keep the tick to handle RCU callbacks. Make sure the range passed to nohz_full= boot parameter is a subset of rcu_nocbs= The CPUs that fail to meet this requirement will be excluded from the nohz_full range. This is checked early in boot time, before any CPU has the opportunity to stop its tick. Suggested-by: Steven Rostedt Reviewed-by: Paul E. McKenney Signed-off-by: Frederic Weisbecker Cc: Andrew Morton Cc: Chris Metcalf Cc: Christoph Lameter Cc: Geoff Levand Cc: Gilad Ben Yossef Cc: Hakan Akkan Cc: Ingo Molnar Cc: Kevin Hilman Cc: Li Zhong Cc: Paul E. McKenney Cc: Paul Gortmaker Cc: Peter Zijlstra Cc: Steven Rostedt Cc: Thomas Gleixner --- Documentation/kernel-parameters.txt | 2 ++ 1 file changed, 2 insertions(+) (limited to 'Documentation/kernel-parameters.txt') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 887b2970844..4865e9bfd08 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1918,6 +1918,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted. the specified list of CPUs whose tick will be stopped whenever possible. The boot CPU will be forced outside the range to maintain the timekeeping. + The CPUs in this range must also be included in the + rcu_nocbs= set. noiotrap [SH] Disables trapped I/O port accesses. -- cgit v1.2.3-70-g09d2