Commit 3471b757 authored by Mark McLoughlin's avatar Mark McLoughlin
Browse files

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: default avatarMark McLoughlin <markmc@redhat.com>
parent 2e1e0641

net.c

+8 −1
Original line number Diff line number Diff line
@@ -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__

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,

                                 NULL, tap_cleanup, s);

    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);

    return s;

}