rcu/nocb: Print gp/cb kthread hierarchy if dump_tree

This commit causes the no-CBs grace-period/callback hierarchy to be
printed to the console when the dump_tree kernel boot parameter is set.

Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 80b27a9..0a3f868 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2135,6 +2135,7 @@ module_param(rcu_nocb_gp_stride, int, 0444);
 static void __init rcu_organize_nocb_kthreads(void)
 {
        int cpu;
+       bool firsttime = true;
        int ls = rcu_nocb_gp_stride;
        int nl = 0;  /* Next GP kthread. */
        struct rcu_data *rdp;
@@ -2160,10 +2161,15 @@ static void __init rcu_organize_nocb_kthreads(void)
                        nl = DIV_ROUND_UP(rdp->cpu + 1, ls) * ls;
                        rdp->nocb_gp_rdp = rdp;
                        rdp_gp = rdp;
+                       if (!firsttime && dump_tree)
+                               pr_cont("\n");
+                       firsttime = false;
+                       pr_alert("%s: No-CB GP kthread CPU %d:", __func__, cpu);
                } else {
                        /* Another CB kthread, link to previous GP kthread. */
                        rdp->nocb_gp_rdp = rdp_gp;
                        rdp_prev->nocb_next_cb_rdp = rdp;
+                       pr_alert(" %d", cpu);
                }
                rdp_prev = rdp;
        }