rcu: Add stall-warning checks for RCU-tasks

This commit adds a ten-minute RCU-tasks stall warning.  The actual
time is controlled by the boot/sysfs parameter rcu_task_stall_timeout,
with values less than or equal to zero disabling the stall warnings.
The default value is ten minutes, which means that the tasks that have
not yet responded will get their stacks dumped every ten minutes, until
they pass through a voluntary context switch.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 5ae8608ca9f5..e98be953d96c 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2982,6 +2982,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
         rcupdate.rcu_cpu_stall_timeout= [KNL]
                         Set timeout for RCU CPU stall warning messages.
 
+        rcupdate.rcu_task_stall_timeout= [KNL]
+                        Set timeout in jiffies for RCU task stall warning
+                        messages.  Disable with a value less than or equal
+                        to zero.
+
         rdinit=         [KNL]
                         Format: <full_path>
                         Run specified binary instead of /init from the ramdisk,