public inbox for netdev@vger.kernel.org 
 help / color / mirror / Atom feed

From: Rusty Russell <rusty@rustcorp•com.au>
To: netdev@vger•kernel.org
Cc: "Michael S. Tsirkin" <mst@redhat•com>,
	Herbert Xu <herbert@gondor•apana.org.au>
Subject: [PATCH 2/2] virtio_net: fix oom handling on tx
Date: Sat, 3 Jul 2010 12:34:01 +1000	[thread overview]
Message-ID: <201007031234.01937.rusty@rustcorp.com.au> (raw)
In-Reply-To: <201007031232.56510.rusty@rustcorp.com.au>

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 <mst@redhat•com>
Signed-off-by: Rusty Russell <rusty@rustcorp•com.au> (...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);
 

next prev parent reply	other threads:[~2010-07-03  2:34 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-03  2:32 [PATCH 1/2] virtio_net: do not reschedule rx refill forever Rusty Russell
2010-07-03  2:34 ` Rusty Russell [this message]
2010-07-03  5:29   ` [PATCH 2/2] virtio_net: fix oom handling on tx David Miller
2010-07-03  5:29 ` [PATCH 1/2] virtio_net: do not reschedule rx refill forever David Miller

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=201007031234.01937.rusty@rustcorp.com.au \
    --to=rusty@rustcorp$(echo .)com.au \
    --cc=herbert@gondor$(echo .)apana.org.au \
    --cc=mst@redhat$(echo .)com \
    --cc=netdev@vger$(echo .)kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox