Re: [PATCH] ovs: do not allocate memory from offline numa node

From: Vlastimil Babka
Date: Mon Oct 05 2015 - 09:59:27 EST


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?

if (!stats)
goto err;



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