Commit b6407e86 authored Jan 04, 2010 by Paul E. McKenney Committed by Ingo Molnar Jan 13, 2010

rcu: Give different levels of the rcu_node hierarchy distinct lockdep names



Previously, each level of the rcu_node hierarchy had the same
rather unimaginative name: "&rcu_node_class[i]".  This makes
lockdep diagnostics involving these lockdep classes less helpful
than would be nice. This patch fixes this by giving each level
of the rcu_node hierarchy a distinct name: "rcu_node_level_0",
"rcu_node_level_1", and so on. This version of the patch
includes improved diagnostics suggested by Josh Triplett and
Peter Zijlstra.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <12626498421830-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent cba8244a

kernel/rcutree.c

+8 −1

Original line number	Diff line number	Diff line
		@@ -1811,11 +1811,17 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp)
		*/
		static void __init rcu_init_one(struct rcu_state *rsp)
		{
		static char *buf[] = { "rcu_node_level_0",
		"rcu_node_level_1",
		"rcu_node_level_2",
		"rcu_node_level_3" }; /* Match MAX_RCU_LVLS */
		int cpustride = 1;
		int i;
		int j;
		struct rcu_node *rnp;

		BUILD_BUG_ON(MAX_RCU_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */

		/* Initialize the level-tracking arrays. */

		for (i = 1; i < NUM_RCU_LVLS; i++)
		@@ -1829,7 +1835,8 @@ static void __init rcu_init_one(struct rcu_state *rsp)
		rnp = rsp->level[i];
		for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) {
		spin_lock_init(&rnp->lock);
		lockdep_set_class(&rnp->lock, &rcu_node_class[i]);
		lockdep_set_class_and_name(&rnp->lock,
		&rcu_node_class[i], buf[i]);
		rnp->gpnum = 0;
		rnp->qsmask = 0;
		rnp->qsmaskinit = 0;

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