[PATCH net-next v3 5/6] vxlan: vnifilter: account per-VNI memory to memcg

[Ali Firas <alishmery18@gmail.com>]

vxlan_vni_alloc() allocates a struct vxlan_vni_node and a per-CPU stats
block for every VNI, both with plain GFP_KERNEL, so neither is charged
to the cgroup of the process that created the VNI. A netdevice's own
queues, ethtool state and NAPI config are already GFP_KERNEL_ACCOUNT in
alloc_netdev_mqs() (commit c948f51c1654 ("memcg: enable accounting for
net_device and Tx/Rx queues")), so these per-VNI allocations are the
unaccounted part of a device that a cgroup can grow one VNI at a time.

Charge both to the caller's cgroup with GFP_KERNEL_ACCOUNT in
vxlan_vni_alloc(). __GFP_ACCOUNT only charges an allocation made from a
task in a non-root memcg, so the sole caller, which already handles a
NULL return, is unaffected outside a memcg.

The charge lands in the caller's memcg: adding VNIs from inside one
moves each node into the accounted slab and raises the cgroup's per-CPU
memory, while the unaccounted slab is unchanged.

Assisted-by: LLM
Signed-off-by: Ali Firas <alishmery18@gmail.com>
---

Notes:
    v3: replaces 3/5 and 4/5. Account the per-VNI node and its per-CPU stats in vxlan_vni_alloc().

 drivers/net/vxlan/vxlan_vnifilter.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/vxlan/vxlan_vnifilter.c b/drivers/net/vxlan/vxlan_vnifilter.c
index 92ea1fc94f45..3087877ed1cb 100644
--- a/drivers/net/vxlan/vxlan_vnifilter.c
+++ b/drivers/net/vxlan/vxlan_vnifilter.c
@@ -711,10 +711,11 @@ static struct vxlan_vni_node *vxlan_vni_alloc(struct vxlan_dev *vxlan,
 {
 	struct vxlan_vni_node *vninode;
 
-	vninode = kzalloc_obj(*vninode);
+	vninode = kzalloc_obj(*vninode, GFP_KERNEL_ACCOUNT);
 	if (!vninode)
 		return NULL;
-	vninode->stats = netdev_alloc_pcpu_stats(struct vxlan_vni_stats_pcpu);
+	vninode->stats = __netdev_alloc_pcpu_stats(struct vxlan_vni_stats_pcpu,
+						   GFP_KERNEL_ACCOUNT);
 	if (!vninode->stats) {
 		kfree(vninode);
 		return NULL;
-- 
2.53.0