net: only read from tapfd when we can send

Reduce the number of packets dropped under heavy network
traffic by only reading a packet from the tapfd when a
client can actually handle it.

Signed-off-by: Mark McLoughlin <markmc@redhat.com>
This commit is contained in:
Mark McLoughlin 2009-04-29 09:50:32 +01:00
parent 2e1e064110
commit 3471b757d0

9
net.c
View file

@ -956,6 +956,13 @@ static void tap_receive(void *opaque, const uint8_t *buf, int size)
} }
} }
static int tap_can_send(void *opaque)
{
TAPState *s = opaque;
return qemu_can_send_packet(s->vc);
}
#ifdef __sun__ #ifdef __sun__
static ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen) static ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
{ {
@ -1011,7 +1018,7 @@ static TAPState *net_tap_fd_init(VLANState *vlan,
s->vc = qemu_new_vlan_client(vlan, model, name, tap_receive, s->vc = qemu_new_vlan_client(vlan, model, name, tap_receive,
NULL, tap_cleanup, s); NULL, tap_cleanup, s);
s->vc->fd_readv = tap_receive_iov; s->vc->fd_readv = tap_receive_iov;
qemu_set_fd_handler(s->fd, tap_send, NULL, s); qemu_set_fd_handler2(s->fd, tap_can_send, tap_send, NULL, s);
snprintf(s->vc->info_str, sizeof(s->vc->info_str), "fd=%d", fd); snprintf(s->vc->info_str, sizeof(s->vc->info_str), "fd=%d", fd);
return s; return s;
} }