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@linux.ibm.com>
[ paulmck: Fix a pair of uninitialized locals spotted by kbuild test robot. ]
This commit is contained in:
Paul E. McKenney 2018-10-02 17:09:56 -07:00
parent 903ee83d91
commit bfcfcffc5f

View file

@ -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);