rcu: Add diagnostics for rcutorture writer stall warning

This commit adds any in-the-future ->gp_seq_needed fields to the
diagnostics for an rcutorture writer stall warning message.

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

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 7746fe1ee3fceaff616fff967bc97c539c0dd387..4915525559ace231f5ebe664d90579e56dacccb2 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -606,11 +606,32 @@ EXPORT_SYMBOL_GPL(rcu_sched_force_quiescent_state);
  */
 void show_rcu_gp_kthreads(void)
 {
+       int cpu;
+       struct rcu_data *rdp;
+       struct rcu_node *rnp;
        struct rcu_state *rsp;
 
        for_each_rcu_flavor(rsp) {
                pr_info("%s: wait state: %d ->state: %#lx\n",
                        rsp->name, rsp->gp_state, rsp->gp_kthread->state);
+               rcu_for_each_node_breadth_first(rsp, rnp) {
+                       if (ULONG_CMP_GE(rsp->gp_seq, rnp->gp_seq_needed))
+                               continue;
+                       pr_info("\trcu_node %d:%d ->gp_seq %lu ->gp_seq_needed %lu\n",
+                               rnp->grplo, rnp->grphi, rnp->gp_seq,
+                               rnp->gp_seq_needed);
+                       if (!rcu_is_leaf_node(rnp))
+                               continue;
+                       for_each_leaf_node_possible_cpu(rnp, cpu) {
+                               rdp = per_cpu_ptr(rsp->rda, cpu);
+                               if (rdp->gpwrap ||
+                                   ULONG_CMP_GE(rsp->gp_seq,
+                                                rdp->gp_seq_needed))
+                                       continue;
+                               pr_info("\tcpu %d ->gp_seq_needed %lu\n",
+                                       cpu, rdp->gp_seq_needed);
+                       }
+               }
                /* sched_show_task(rsp->gp_kthread); */
        }
 }