Macvlan always turns on offload features that have sofware
fallback (NETIF_GSO_SOFTWARE). This allows much higher guest-guest
communications over macvtap.
However, macvtap does not turn on these features for vlan tagged traffic.
As a result, depending on the HW that mactap is configured on, the
performance of guest-guest communication over a vlan is very
inconsistent. If the HW supports TSO/UFO over vlans, then the
performance will be fine. If not, the the performance will suffer
greatly since the VM may continue using TSO/UFO, and will force the host
segment the traffic and possibly overlow the macvtap queue.
This patch adds the always on offloads to vlan_features. This
makes sure that any vlan tagged traffic between 2 guest will not
be segmented needlessly.
Signed-off-by: Vladislav Yasevich <vyase...@redhat.com>
---
drivers/net/macvlan.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index b34eaaa..346ad2f 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -789,10 +789,12 @@ static int macvlan_change_mtu(struct net_device *dev, int
new_mtu)
*/
static struct lock_class_key macvlan_netdev_addr_lock_key;
-#define ALWAYS_ON_FEATURES \
- (NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE | NETIF_F_LLTX | \
+#define ALWAYS_ON_OFFLOADS \
+ (NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_GSO_SOFTWARE | \
NETIF_F_GSO_ROBUST)
+#define ALWAYS_ON_FEATURES (ALWAYS_ON_OFFLOADS | NETIF_F_LLTX)
+
#define MACVLAN_FEATURES \
(NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_HIGHDMA | NETIF_F_FRAGLIST | \
NETIF_F_GSO | NETIF_F_TSO | NETIF_F_UFO | NETIF_F_LRO | \
@@ -827,6 +829,7 @@ static int macvlan_init(struct net_device *dev)
dev->features |= ALWAYS_ON_FEATURES;
dev->hw_features |= NETIF_F_LRO;
dev->vlan_features = lowerdev->vlan_features & MACVLAN_FEATURES;
+ dev->vlan_features |= ALWAYS_ON_OFFLOADS;
dev->gso_max_size = lowerdev->gso_max_size;
dev->gso_max_segs = lowerdev->gso_max_segs;
dev->hard_header_len = lowerdev->hard_header_len;
--
2.7.4
