Re: 2.6.24-rc3-mm2 (bugfix for memory cgroup per-zone-struct allocation.)

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Thu, 29 Nov 2007 12:23:29 +0900
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> wrote:
> I noticed CONFIG_NUMA + CONFIG_CGROUP_MEM_CONT + CONFIG_SLUB cannot boot because of my patch.
> (SLAB is ok.)
> I'll post workaround soon.
> 
==
This is a fix. tested on my ia64/NUMA box both on SLAB/SLUB.
This patch fixes kmalloc_node() is called against node-without-memory.

It's better to add memory hotplug callback for supporing possible nodes
(memory hotplug) but here just uses kmalloc().

Should be revisited later.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

 mm/memcontrol.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

Index: linux-2.6.24-rc3-mm2/mm/memcontrol.c
===================================================================
--- linux-2.6.24-rc3-mm2.orig/mm/memcontrol.c
+++ linux-2.6.24-rc3-mm2/mm/memcontrol.c
@@ -1117,8 +1117,18 @@ static int alloc_mem_cgroup_per_zone_inf
 	struct mem_cgroup_per_node *pn;
 	struct mem_cgroup_per_zone *mz;
 	int zone;
-
-	pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
+	/*
+	 * This routine is called against possible nodes.
+	 * But it's BUG to call kmalloc() against offline node.
+	 *
+	 * TODO: this routine can waste much memory for nodes which will
+	 *       never be onlined. It's better to use memory hotplug callback
+	 *       function.
+	 */
+	if (node_state(node, N_HIGH_MEMORY))
+		pn = kmalloc_node(sizeof(*pn), GFP_KERNEL, node);
+	else
+		pn = kmalloc(sizeof(*pn), GFP_KERNEL);
 	if (!pn)
 		return 1;
 

-
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