From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rusty Russell Subject: [PATCH 2/2] virtio_net: fix oom handling on tx Date: Sat, 3 Jul 2010 12:34:01 +1000 Message-ID: <201007031234.01937.rusty@rustcorp.com.au> References: <201007031232.56510.rusty@rustcorp.com.au> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: "Michael S. Tsirkin" , Herbert Xu To: netdev@vger.kernel.org Return-path: Received: from ozlabs.org ([203.10.76.45]:46175 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753062Ab0GCCeG (ORCPT ); Fri, 2 Jul 2010 22:34:06 -0400 In-Reply-To: <201007031232.56510.rusty@rustcorp.com.au> Sender: netdev-owner@vger.kernel.org List-ID: virtio net will never try to overflow the TX ring, so the only reason add_buf may fail is out of memory. Thus, we can not stop the device until some request completes - there's no guarantee anything at all is outstanding. Make the error message clearer as well: error here does not indicate queue full. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell (...and avoid TX_BUSY) Cc: stable@kernel.org # .34.x (s/virtqueue_/vi->svq->vq_ops->/) --- drivers/net/virtio_net.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -562,7 +562,6 @@ static netdev_tx_t start_xmit(struct sk_ struct virtnet_info *vi = netdev_priv(dev); int capacity; -again: /* Free up any pending old buffers before queueing new ones. */ free_old_xmit_skbs(vi); @@ -571,14 +570,20 @@ again: /* This can happen with OOM and indirect buffers. */ if (unlikely(capacity < 0)) { - netif_stop_queue(dev); - dev_warn(&dev->dev, "Unexpected full queue\n"); - if (unlikely(!virtqueue_enable_cb(vi->svq))) { - virtqueue_disable_cb(vi->svq); - netif_start_queue(dev); - goto again; + if (net_ratelimit()) { + if (likely(capacity == -ENOMEM)) { + dev_warn(&dev->dev, + "TX queue failure: out of memory\n"); + } else { + dev->stats.tx_fifo_errors++; + dev_warn(&dev->dev, + "Unexpected TX queue failure: %d\n", + capacity); + } } - return NETDEV_TX_BUSY; + dev->stats.tx_dropped++; + kfree_skb(skb); + return NETDEV_TX_OK; } virtqueue_kick(vi->svq);