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macvlan: Fix performance issues with vlan tagged packets 

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 <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Vlad Yasevich 2017-05-11 11:09:52 -04:00 committed by David S. Miller
parent 66c25f6e31
commit 70957eaecc
1 changed files with 5 additions and 2 deletions
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7
drivers/net/macvlan.c
View File

@ -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;