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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-06-02 11:26:43 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-07-24 16:00:15 -0700
commitf99bcb2cdb5843548a2b0b78157cb7a0b4c7ccac (patch)
tree5ac6ecbfcf517eca466a3c57fe1654ae9180c5ee
parent520eccdfe187591a51ea9ab4c1a024ae4d0f68d9 (diff)
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documentation: Fix relation between nohz_full and rcu_nocbs
If a CPU is specified in the nohz_full= kernel boot parameter to a kernel built with CONFIG_NO_HZ_FULL=y, then that CPU's callbacks will be offloaded, just as if that CPU had also been specified in the rcu_nocbs= kernel boot parameter. But the current documentation states that the user must keep these two boot parameters manually synchronized. This commit therefore updates the documentation to reflect reality. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt7
1 files changed, 4 insertions, 3 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index d9c171ce4190..3a99cc96b6b1 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2633,9 +2633,10 @@
In kernels built with CONFIG_NO_HZ_FULL=y, set
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.
+ the range to maintain the timekeeping. Any CPUs
+ in this list will have their RCU callbacks offloaded,
+ just as if they had also been called out in the
+ rcu_nocbs= boot parameter.
noiotrap [SH] Disables trapped I/O port accesses.
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