From 81e701e4376232b2779f52f15e3b7413131bd8e4 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Thu, 16 Apr 2015 11:02:25 -0700 Subject: [PATCH] rcu: Add more debug info on "kthread starved" RCU CPU stall warnings This commit adds grace number and command-flags information to the "kthread starved" message that is sometimes printed out as part of RCU CPU stall warnings. This message is caused by the corresponding RCU grace-period kthread not having run for at least two seconds, and this added information can be helpful when debugging. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 7d369b829598..52f064ac7b49 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1136,8 +1136,9 @@ 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!\n", - rsp->name, j - gpa); + pr_err("%s kthread starved for %ld jiffies! g%lu c%lu f%#x\n", + rsp->name, j - gpa, + rsp->gpnum, rsp->completed, rsp->gp_flags); } /*