Commit dbf34207 authored May 02, 2012 by Jason Wang Committed by Michael S. Tsirkin May 02, 2012

vhost_net: re-poll only on EAGAIN or ENOBUFS



Currently, we restart tx polling unconditionally when sendmsg()
fails. This would cause unnecessary wakeups of vhost wokers and waste
cpu utlization when evil userspace(guest driver) is able to hit EFAULT or
EINVAL.

The polling is only needed when the socket send buffer were exceeded or not
enough memory. So fix this by restarting polling only when sendmsg() returns
EAGAIN/ENOBUFS.

Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

parent c460f057

drivers/vhost/net.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -257,6 +257,7 @@ static void handle_tx(struct vhost_net *net)
		UIO_MAXIOV;
		}
		vhost_discard_vq_desc(vq, 1);
		if (err == -EAGAIN \|\| err == -ENOBUFS)
		tx_poll_start(net, sock);
		break;
		}

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