From bfcfcffc5f23e76a1b88f7412ee7efaec5107b28 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Tue, 2 Oct 2018 17:09:56 -0700 Subject: 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: Fix a pair of uninitialized locals spotted by kbuild test robot. ] --- kernel/rcu/tree.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'kernel/rcu/tree.c') 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); -- cgit v1.2.3-59-g8ed1b