Commit-ID: bfcfcffc5f23e76a1b88f7412ee7efaec5107b28
Gitweb: https://git.kernel.org/tip/bfcfcffc5f23e76a1b88f7412ee7efaec5107b28
Author: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
AuthorDate: Tue, 2 Oct 2018 17:09:56 -0700
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
CommitDate: Sat, 1 Dec 2018 12:45:38 -0800
rcu: Print per-CPU callback counts for forward-progress failures
This commit prints out the non-zero per-CPU callback counts when a
forware-progress error (OOM event) occurs.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxx>
[ paulmck: Fix a pair of uninitialized locals spotted by kbuild test robot. ]
---
kernel/rcu/tree.c | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 0933d8650890..90a67c75a447 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2675,6 +2675,10 @@ rcu_check_gp_start_stall(struct rcu_node *rnp, struct rcu_data *rdp,
*/
void rcu_fwd_progress_check(unsigned long j)
{
+ unsigned long cbs;
+ int cpu;
+ unsigned long max_cbs = 0;
+ int max_cpu = -1;
struct rcu_data *rdp;
if (rcu_gp_in_progress()) {
@@ -2685,6 +2689,20 @@ void rcu_fwd_progress_check(unsigned long j)
rcu_check_gp_start_stall(rdp->mynode, rdp, j);
preempt_enable();
}
+ for_each_possible_cpu(cpu) {
+ cbs = rcu_get_n_cbs_cpu(cpu);
+ if (!cbs)
+ continue;
+ if (max_cpu < 0)
+ pr_info("%s: callbacks", __func__);
+ pr_cont(" %d: %lu", cpu, cbs);
+ if (cbs <= max_cbs)
+ continue;
+ max_cbs = cbs;
+ max_cpu = cpu;
+ }
+ if (max_cpu >= 0)
+ pr_cont("\n");
}
EXPORT_SYMBOL_GPL(rcu_fwd_progress_check);
|