From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Tue, 8 May 2018 19:50:14 +0000 (-0700)
Subject: rcu: Add up-tree information to dump_blkd_tasks() diagnostics
X-Git-Tag: v4.19-rc1~214^2^2~31
X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=ff3cee39088b1931a432587059d66cd505f785dc;p=linux.git

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 6b85ce936ad4..f45ff97b0d51 100644
--- 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__);