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authorPaul E. McKenney <paulmck@linux.ibm.com>2018-12-12 12:32:06 -0800
committerPaul E. McKenney <paulmck@linux.ibm.com>2019-01-25 15:29:59 -0800
commit2ccaff10f71307ad4f75ce673b815d3fe6254e3d (patch)
tree9d6d8064a44db829f879802af697a13a49868074 /Documentation/admin-guide
parent3b6505fd8eb86e3ef5ce12b34fe81e9edeb84475 (diff)
rcu: Add sysrq rcu_node-dump capability
Life is hard if RCU manages to get stuck without triggering RCU CPU stall warnings or triggering the rcu_check_gp_start_stall() checks for failing to start a grace period. This commit therefore adds a boot-time-selectable sysrq key (commandeering "y") that allows manually dumping Tree RCU state. The new rcutree.sysrq_rcu kernel boot parameter must be set for this sysrq to be available. Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'Documentation/admin-guide')
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index b799bcf67d7b..b0dbb2fa401f 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3721,6 +3721,11 @@
This wake_up() will be accompanied by a
WARN_ONCE() splat and an ftrace_dump().
+ rcutree.sysrq_rcu= [KNL]
+ Commandeer a sysrq key to dump out Tree RCU's
+ rcu_node tree with an eye towards determining
+ why a new grace period has not yet started.
+
rcuperf.gp_async= [KNL]
Measure performance of asynchronous
grace-period primitives such as call_rcu().