gwj / at91sam9263 · Commits

Commit 3471b757d0ca63a0e8188c4c96acd1c279a8c737

Authored by Mark McLoughlin
1 parent 2e1e0641

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>
Inline Side-by-side
Showing 1 changed file with 8 additions and 1 deletions
@@ -956,6 +956,13 @@ static void tap_receive(void *opaque, const uint8_t *buf, int size) @@ -956,6 +956,13 @@ static void tap_receive(void *opaque, const uint8_t *buf, int size)
956 } 956 }
957 } 957 }
958 958
  959 +static int tap_can_send(void *opaque)
  960 +{
  961 + TAPState *s = opaque;
  962 +
  963 + return qemu_can_send_packet(s->vc);
  964 +}
  965 +
959 #ifdef __sun__ 966 #ifdef __sun__
960 static ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen) 967 static ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)
961 { 968 {
@@ -1011,7 +1018,7 @@ static TAPState *net_tap_fd_init(VLANState *vlan, @@ -1011,7 +1018,7 @@ static TAPState *net_tap_fd_init(VLANState *vlan,
1011 s->vc = qemu_new_vlan_client(vlan, model, name, tap_receive, 1018 s->vc = qemu_new_vlan_client(vlan, model, name, tap_receive,
1012 NULL, tap_cleanup, s); 1019 NULL, tap_cleanup, s);
1013 s->vc->fd_readv = tap_receive_iov; 1020 s->vc->fd_readv = tap_receive_iov;
1014 - qemu_set_fd_handler(s->fd, tap_send, NULL, s); 1021 + qemu_set_fd_handler2(s->fd, tap_can_send, tap_send, NULL, s);
1015 snprintf(s->vc->info_str, sizeof(s->vc->info_str), "fd=%d", fd); 1022 snprintf(s->vc->info_str, sizeof(s->vc->info_str), "fd=%d", fd);
1016 return s; 1023 return s;
1017 } 1024 }