rcu: Print scheduling-clock information on RCU CPU stall-warning messages
There have been situations where RCU CPU stall warnings were caused by
issues in scheduling-clock timer initialization. To make it easier to
track these down, this commit causes the RCU CPU stall-warning messages
to print out the number of scheduling-clock interrupts taken in the
current grace period for each stalled CPU.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 3cc419d..d27a2aa 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -927,6 +927,20 @@
Say Y if you want to enable such checks.
+config RCU_CPU_STALL_INFO
+ bool "Print additional diagnostics on RCU CPU stall"
+ depends on (TREE_RCU || TREE_PREEMPT_RCU) && DEBUG_KERNEL
+ default n
+ help
+ For each stalled CPU that is aware of the current RCU grace
+ period, print out additional per-CPU diagnostic information
+ regarding scheduling-clock ticks, idle state, and,
+ for RCU_FAST_NO_HZ kernels, idle-entry state.
+
+ Say N if you are unsure.
+
+ Say Y if you want to enable such diagnostics.
+
config RCU_TRACE
bool "Enable tracing for RCU"
depends on DEBUG_KERNEL