rcu: Add up-tree information to dump_blkd_tasks() diagnostics

This commit updates dump_blkd_tasks() to print out quiescent-state
bitmasks for the rcu_node structures further up the tree.  This
information helps debugging of interactions between CPU-hotplug
operations and RCU grace-period initialization.

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

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6b85ce9..f45ff97 100644 (file)
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -858,13 +858,15 @@ static void dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
 {
        int i;
        struct list_head *lhp;
+       struct rcu_node *rnp1;
 
        raw_lockdep_assert_held_rcu_node(rnp);
-       pr_info("%s: grp: %d-%d level: %d ->gp_seq %#lx ->completedqs %#lx\n",
+       pr_info("%s: grp: %d-%d level: %d ->gp_seq %ld ->completedqs %ld\n",
                __func__, rnp->grplo, rnp->grphi, rnp->level,
-               rnp->gp_seq, rnp->completedqs);
-       pr_info("%s: ->qsmask %#lx ->qsmaskinit %#lx ->qsmaskinitnext %#lx\n",
-               __func__, rnp->qsmask, rnp->qsmaskinit, rnp->qsmaskinitnext);
+               (long)rnp->gp_seq, (long)rnp->completedqs);
+       for (rnp1 = rnp; rnp1; rnp1 = rnp1->parent)
+               pr_info("%s: %d:%d ->qsmask %#lx ->qsmaskinit %#lx ->qsmaskinitnext %#lx\n",
+                       __func__, rnp1->grplo, rnp1->grphi, rnp1->qsmask, rnp1->qsmaskinit, rnp1->qsmaskinitnext);
        pr_info("%s: ->gp_tasks %p ->boost_tasks %p ->exp_tasks %p\n",
                __func__, rnp->gp_tasks, rnp->boost_tasks, rnp->exp_tasks);
        pr_info("%s: ->blkd_tasks", __func__);