rcu: Add last-CPU to GP-kthread starvation messages

This commit augments the grace-period-kthread starvation debugging
messages by adding the last CPU that ran the kthread.

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

1 files changed, 3 insertions, 2 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 51d4c3acf32d..48c6ab5ca164 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1358,12 +1358,13 @@ static void rcu_check_gp_kthread_starvation(struct rcu_state *rsp)
         j = jiffies;
         gpa = READ_ONCE(rsp->gp_activity);
         if (j - gpa > 2 * HZ) {
-                pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x %s(%d) ->state=%#lx\n",
+                pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x %s(%d) ->state=%#lx ->cpu=%d\n",
                        rsp->name, j - gpa,
                        rsp->gpnum, rsp->completed,
                        rsp->gp_flags,
                        gp_state_getname(rsp->gp_state), rsp->gp_state,
-                       rsp->gp_kthread ? rsp->gp_kthread->state : ~0);
+                       rsp->gp_kthread ? rsp->gp_kthread->state : ~0,
+                       rsp->gp_kthread ? task_cpu(rsp->gp_kthread) : -1);
                 if (rsp->gp_kthread) {
                         sched_show_task(rsp->gp_kthread);
                         wake_up_process(rsp->gp_kthread);