On 15/02/13 09:27, Peter Lieven wrote:
> historically the kernel queues packets two times. once
> at the device and second in qdisc. this is believed to cause
> interface stalls if one of these queues overruns.
>
> setting IFF_ONE_QUEUE is the default in kernels >= 3.8. the
> flag is ignored since then. see kernel commit
> 5d097109257c03a71845729f8db6b5770c4bbedc
>
> Signed-off-by: Peter Lieven <p...@kamp.de>
> ---
> net/tap-linux.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/tap-linux.c b/net/tap-linux.c
> index a953189..2759b78 100644
> --- a/net/tap-linux.c
> +++ b/net/tap-linux.c
> @@ -49,7 +49,7 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
> return -1;
> }
> memset(&ifr, 0, sizeof(ifr));
> - ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
> + ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_ONE_QUEUE;
>
> if (*vnet_hdr) {
> unsigned int features;
Wouldn't that break macvtap?
there is
case TUNSETIFF:
/* ignore the name, just look at flags */
if (get_user(u, &ifr->ifr_flags))
return -EFAULT;
ret = 0;
if ((u & ~IFF_VNET_HDR) != (IFF_NO_PI | IFF_TAP))
ret = -EINVAL;
in drivers/net/macvtap.c
