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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-01-22 14:32:06 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-03-11 13:22:38 -0700
commit237a0f2193c6daf9b1edd7fd15d55e680f268952 (patch)
tree7f7c0b994878808a47842138a3026620fc2c6edf /kernel/rcu
parent18c629eaebf1814ca7f0c27327f75aa93aa4a5de (diff)
rcu: Detect stalls caused by failure to propagate up rcu_node tree
If all CPUs have passed through quiescent states, then stalls might be due to starvation of the grace-period kthread or to failure to propagate the quiescent states up the rcu_node combining tree. The current stall warning messages do not differentiate, so this commit adds a printout of the root rcu_node structure's ->qsmask field. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
-rw-r--r--kernel/rcu/tree.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 98da632d1d49..3b7e4133ca99 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1196,9 +1196,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum)
} else {
j = jiffies;
gpa = ACCESS_ONCE(rsp->gp_activity);
- pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld\n",
+ pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n",
rsp->name, j - gpa, j, gpa,
- jiffies_till_next_fqs);
+ jiffies_till_next_fqs,
+ rcu_get_root(rsp)->qsmask);
/* In this case, the current CPU might be at fault. */
sched_show_task(current);
}