tap: fix vcpu long time io blocking on tap
[Adjusted doc comment for grammar.
--Stefan]
Signed-off-by: Wangkai <wangkai86@huawei.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/net/tap.c b/net/tap.c
index bde6b58..1fe0edf 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -189,6 +189,7 @@
{
TAPState *s = opaque;
int size;
+ int packets = 0;
while (qemu_can_send_packet(&s->nc)) {
uint8_t *buf = s->buf;
@@ -210,6 +211,17 @@
} else if (size < 0) {
break;
}
+
+ /*
+ * When the host keeps receiving more packets while tap_send() is
+ * running we can hog the QEMU global mutex. Limit the number of
+ * packets that are processed per tap_send() callback to prevent
+ * stalling the guest.
+ */
+ packets++;
+ if (packets >= 50) {
+ break;
+ }
}
}
