[PATCH tip/core/rcu 05/14] rcu: Add state name to show_rcu_gp_kthreads() output

From: Paul E. McKenney
Date: Sun Nov 11 2018 - 14:30:03 EST


This commit adds the name of the RCU grace-period state to
the show_rcu_gp_kthreads() output in order to ease debugging.
This commit also moves gp_state_getname() up in the code so that
show_rcu_gp_kthreads() can use it.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
---
kernel/rcu/tree.c | 25 +++++++++++++------------
1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 36e30150e1e9..ea78532183ac 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -499,6 +499,16 @@ void rcu_force_quiescent_state(void)
}
EXPORT_SYMBOL_GPL(rcu_force_quiescent_state);

+/*
+ * Convert a ->gp_state value to a character string.
+ */
+static const char *gp_state_getname(short gs)
+{
+ if (gs < 0 || gs >= ARRAY_SIZE(gp_state_names))
+ return "???";
+ return gp_state_names[gs];
+}
+
/*
* Show the state of the grace-period kthreads.
*/
@@ -508,8 +518,9 @@ void show_rcu_gp_kthreads(void)
struct rcu_data *rdp;
struct rcu_node *rnp;

- pr_info("%s: wait state: %d ->state: %#lx\n", rcu_state.name,
- rcu_state.gp_state, rcu_state.gp_kthread->state);
+ pr_info("%s: wait state: %s(%d) ->state: %#lx\n", rcu_state.name,
+ gp_state_getname(rcu_state.gp_state), rcu_state.gp_state,
+ rcu_state.gp_kthread->state);
rcu_for_each_node_breadth_first(rnp) {
if (ULONG_CMP_GE(rcu_state.gp_seq, rnp->gp_seq_needed))
continue;
@@ -1142,16 +1153,6 @@ static void record_gp_stall_check_time(void)
rcu_state.n_force_qs_gpstart = READ_ONCE(rcu_state.n_force_qs);
}

-/*
- * Convert a ->gp_state value to a character string.
- */
-static const char *gp_state_getname(short gs)
-{
- if (gs < 0 || gs >= ARRAY_SIZE(gp_state_names))
- return "???";
- return gp_state_names[gs];
-}
-
/*
* Complain about starvation of grace-period kthread.
*/
--
2.17.1