From: Christoph Lameter <clameter@sgi.com>
Date: Sat, 21 Oct 2006 17:24:16 +0000 (-0700)
Subject: [PATCH] Slab: Do not fallback to nodes that have not been bootstrapped yet
X-Git-Tag: v2.6.19-rc3~21
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=aedb0eb107961a234f7c38e53da65a8f7ea992a9;p=linux-2.6-omap-h63xx.git

[PATCH] Slab: Do not fallback to nodes that have not been bootstrapped yet

The zonelist may contain zones of nodes that have not been bootstrapped and
we will oops if we try to allocate from those zones.  So check if the node
information for the slab and the node have been setup before attempting an
allocation.  If it has not been setup then skip that zone.

Usually we will not encounter this situation since the slab bootstrap code
avoids falling back before we have setup the respective nodes but we seem
to have a special needs for pppc.

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Kravetz <kravetz@us.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Will Schmidt <will_schmidt@vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/mm/slab.c b/mm/slab.c
index 266449d604b..84c631f3074 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3152,12 +3152,15 @@ void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
 	struct zone **z;
 	void *obj = NULL;
 
-	for (z = zonelist->zones; *z && !obj; z++)
+	for (z = zonelist->zones; *z && !obj; z++) {
+		int nid = zone_to_nid(*z);
+
 		if (zone_idx(*z) <= ZONE_NORMAL &&
-				cpuset_zone_allowed(*z, flags))
+				cpuset_zone_allowed(*z, flags) &&
+				cache->nodelists[nid])
 			obj = __cache_alloc_node(cache,
-					flags | __GFP_THISNODE,
-					zone_to_nid(*z));
+					flags | __GFP_THISNODE, nid);
+	}
 	return obj;
 }