From: Glauber Costa <glommer@gmail.com>
Date: Thu, 27 Jun 2013 23:52:15 +0000 (+1000)
Subject: list_lru: per-node list infrastructure fix
X-Git-Tag: next-20130628~3^2~415
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=3d862f5c3a1dbc1bbf409cafcf0497a1d435bcdd;p=karo-tx-linux.git

list_lru: per-node list infrastructure fix

After a while investigating, it seems to us that the imbalance we are
seeing are due to a multi-node race already in tree (our guess).  Although
the WARN is useful to show us the race, BUG_ON is too much, since it seems
the kernel should be fine going on after that.

Signed-off-by: Glauber Costa <glommer@openvz.org>
Cc: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/list_lru.c b/mm/list_lru.c
index f2d1d6e78eb6..1efe4ecc02b1 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -15,7 +15,7 @@ bool list_lru_add(struct list_lru *lru, struct list_head *item)
 	struct list_lru_node *nlru = &lru->node[nid];
 
 	spin_lock(&nlru->lock);
-	BUG_ON(nlru->nr_items < 0);
+	WARN_ON_ONCE(nlru->nr_items < 0);
 	if (list_empty(item)) {
 		list_add_tail(item, &nlru->list);
 		if (nlru->nr_items++ == 0)
@@ -38,7 +38,7 @@ bool list_lru_del(struct list_lru *lru, struct list_head *item)
 		list_del_init(item);
 		if (--nlru->nr_items == 0)
 			node_clear(nid, lru->active_nodes);
-		BUG_ON(nlru->nr_items < 0);
+		WARN_ON_ONCE(nlru->nr_items < 0);
 		spin_unlock(&nlru->lock);
 		return true;
 	}
@@ -56,7 +56,7 @@ unsigned long list_lru_count(struct list_lru *lru)
 		struct list_lru_node *nlru = &lru->node[nid];
 
 		spin_lock(&nlru->lock);
-		BUG_ON(nlru->nr_items < 0);
+		WARN_ON_ONCE(nlru->nr_items < 0);
 		count += nlru->nr_items;
 		spin_unlock(&nlru->lock);
 	}
@@ -91,7 +91,7 @@ restart:
 		case LRU_REMOVED:
 			if (--nlru->nr_items == 0)
 				node_clear(nid, lru->active_nodes);
-			BUG_ON(nlru->nr_items < 0);
+			WARN_ON_ONCE(nlru->nr_items < 0);
 			isolated++;
 			break;
 		case LRU_ROTATE: