[PATCH tip/core/rcu 2/4] rcu: Add grace-period information to RCU CPU stall warnings

["Paul E. McKenney" <paulmck@linux.vnet.ibm.com>]

From: "Paul E. McKenney" <paul.mckenney@linaro.org>

This commit causes the last grace period started and completed to be
printed on RCU CPU stall warning messages in order to aid diagnosis.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcutree.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e785387..8f4de3a 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -947,8 +947,9 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
 	raw_spin_unlock_irqrestore(&rnp->lock, flags);
 
 	print_cpu_stall_info_end();
-	printk(KERN_CONT "(detected by %d, t=%ld jiffies)\n",
-	       smp_processor_id(), (long)(jiffies - rsp->gp_start));
+	pr_cont("(detected by %d, t=%ld jiffies, g=%lu, c=%lu)\n",
+	       smp_processor_id(), (long)(jiffies - rsp->gp_start),
+	       rsp->gpnum, rsp->completed);
 	if (ndetected == 0)
 		printk(KERN_ERR "INFO: Stall ended before state dump start\n");
 	else if (!trigger_all_cpu_backtrace())
@@ -975,7 +976,8 @@ static void print_cpu_stall(struct rcu_state *rsp)
 	print_cpu_stall_info_begin();
 	print_cpu_stall_info(rsp, smp_processor_id());
 	print_cpu_stall_info_end();
-	printk(KERN_CONT " (t=%lu jiffies)\n", jiffies - rsp->gp_start);
+	pr_cont(" (t=%lu jiffies g=%lu c=%lu)\n",
+		jiffies - rsp->gp_start, rsp->gpnum, rsp->completed);
 	if (!trigger_all_cpu_backtrace())
 		dump_stack();
 
-- 
1.7.8