diff options
Diffstat (limited to 'net/tap-linux.c')
| -rw-r--r-- | net/tap-linux.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/net/tap-linux.c b/net/tap-linux.c index f7aa9041b8..ff8cad0ea0 100644 --- a/net/tap-linux.c +++ b/net/tap-linux.c @@ -82,12 +82,17 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required return fd; } -/* sndbuf should be set to a value lower than the tx queue - * capacity of any destination network interface. +/* sndbuf implements a kind of flow control for tap. + * Unfortunately when it's enabled, and packets are sent + * to other guests on the same host, the receiver + * can lock up the transmitter indefinitely. + * + * To avoid packet loss, sndbuf should be set to a value lower than the tx + * queue capacity of any destination network interface. * Ethernet NICs generally have txqueuelen=1000, so 1Mb is - * a good default, given a 1500 byte MTU. + * a good value, given a 1500 byte MTU. */ -#define TAP_DEFAULT_SNDBUF 1024*1024 +#define TAP_DEFAULT_SNDBUF 0 int tap_set_sndbuf(int fd, QemuOpts *opts) { |