datapath: Increase default MTU on patch ports

The default MTU on patch ports was 1500, which would cause jumbo frames
to get dropped between the ends of the patch.  It also dropped the MTU
of attached bridges to no more that 1500 bytes.  This patch increases
the default MTU to 65535.  Long term, we should eliminate MTU on patch
ports entirely.

Signed-off-by: Justin Pettit <jpettit@nicira.com>

diff --git a/datapath/vport-patch.c b/datapath/vport-patch.c
index d55a1bf2dc02f9c1f24e35f9bfafe2677b6ac89b..62fd71f796fbd2ec43ffeed194beb5c29f31fb68 100644 (file)
--- a/datapath/vport-patch.c
+++ b/datapath/vport-patch.c
@@ -136,7 +136,10 @@ static struct vport *patch_create(const char *name, const void __user *config)
        }
 
        vport_gen_rand_ether_addr(patch_vport->devconf->eth_addr);
-       patch_vport->devconf->mtu = ETH_DATA_LEN;
+
+    /* Make the default MTU fairly large so that it doesn't become the
+     * bottleneck on systems using jumbo frames. */
+       patch_vport->devconf->mtu = 65535;
 
        return vport;