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Commit b6407e86 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Ingo Molnar
Browse files

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: default avatarPaul 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: default avatarIngo 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;