On 10/05/2015 06:59 AM, Vlastimil Babka wrote:
On 10/02/2015 12:18 PM, Konstantin Khlebnikov wrote:
When openvswitch tries allocate memory from offline numa node 0:
stats = kmem_cache_alloc_node(flow_stats_cache, GFP_KERNEL |
__GFP_ZERO, 0)
It catches VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES ||
!node_online(nid))
[ replaced with VM_WARN_ON(!node_online(nid)) recently ] in linux/gfp.h
This patch disables numa affinity in this case.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@xxxxxxxxxxxxxx>
...
diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index f2ea83ba4763..c7f74aab34b9 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -93,7 +93,8 @@ struct sw_flow *ovs_flow_alloc(void)
/* Initialize the default stat node. */
stats = kmem_cache_alloc_node(flow_stats_cache,
- GFP_KERNEL | __GFP_ZERO, 0);
+ GFP_KERNEL | __GFP_ZERO,
+ node_online(0) ? 0 : NUMA_NO_NODE);
Stupid question: can node 0 become offline between this check, and the
VM_WARN_ON? :) BTW what kind of system has node 0 offline?
Another question to ask would be is it possible for node 0 to be online,
but be a memoryless node?
I would say you are better off just making this call kmem_cache_alloc.
I don't see anything that indicates the memory has to come from node 0,
so adding the extra overhead doesn't provide any value.
- Alex
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