rcu: Add rcutorture CPU-hotplug capability
Running CPU-hotplug operations concurrently with rcutorture has
historically been a good way to find bugs in both RCU and CPU hotplug.
This commit therefore adds an rcutorture module parameter called
"onoff_interval" that causes a randomly selected CPU-hotplug operation to
be executed at the specified interval, in seconds. The default value of
"onoff_interval" is zero, which disables rcutorture-instigated CPU-hotplug
operations.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index af40929..d67068d 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -61,6 +61,14 @@
To properly exercise RCU implementations with preemptible
read-side critical sections.
+onoff_interval
+ The number of seconds between each attempt to execute a
+ randomly selected CPU-hotplug operation. Defaults to
+ zero, which disables CPU hotplugging. In HOTPLUG_CPU=n
+ kernels, rcutorture will silently refuse to do any
+ CPU-hotplug operations regardless of what value is
+ specified for onoff_interval.
+
shuffle_interval
The number of seconds to keep the test threads affinitied
to a particular subset of the CPUs, defaults to 3 seconds.