On Thu, 2014-03-06 at 21:48 +0000, Zoltan Kiss wrote:
> @@ -557,12 +577,25 @@ void xenvif_disconnect(struct xenvif *vif)
> void xenvif_free(struct xenvif *vif)
> {
> int i, unmap_timeout = 0;
> + /* Here we want to avoid timeout messages if an skb can be legitimatly
"legitimately"
> + * stucked somewhere else. Realisticly this could be an another vif's
"stuck" and "Realistically"
> + * internal or QDisc queue. That another vif also has this
> + * rx_drain_timeout_msecs timeout, but the timer only ditches the
> + * internal queue. After that, the QDisc queue can put in worst case
> + * XEN_NETIF_RX_RING_SIZE / MAX_SKB_FRAGS skbs into that another vif's
> + * internal queue, so we need several rounds of such timeouts until we
> + * can be sure that no another vif should have skb's from us. We are
> + * not sending more skb's, so newly stucked packets are not interesting
"stuck" again.
> diff --git a/drivers/net/xen-netback/netback.c
> b/drivers/net/xen-netback/netback.c
> index 560950e..bb65c7c 100644
> --- a/drivers/net/xen-netback/netback.c
> +++ b/drivers/net/xen-netback/netback.c
> @@ -63,6 +63,13 @@ module_param(separate_tx_rx_irq, bool, 0644);
> static unsigned int fatal_skb_slots = FATAL_SKB_SLOTS_DEFAULT;
> module_param(fatal_skb_slots, uint, 0444);
>
> +/* When guest ring is filled up, qdisc queues the packets for us, but we have
> + * to timeout them, otherwise other guests' packets can get stucked there
"stuck"
Ian.
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