From: Rusty Russell <rusty@rustcorp•com.au>
To: Shirley Ma <mashirle@us•ibm.com>, "Michael S. Tsirkin" <mst@redhat•com>
Cc: David Miller <davem@davemloft•net>,
kvm@vger•kernel.org, netdev@vger•kernel.org
Subject: Re: [PATCH 2/2] virtio_net: remove send completion interrupts and avoid TX queue overrun through packet drop
Date: Thu, 17 Mar 2011 15:40:58 +1030 [thread overview]
Message-ID: <874o72gwm5.fsf@rustcorp.com.au> (raw)
In-Reply-To: <1300320775.3255.34.camel@localhost.localdomain>
On Wed, 16 Mar 2011 17:12:55 -0700, Shirley Ma <mashirle@us•ibm.com> wrote:
> Signed-off-by: Shirley Ma <xma@us•ibm.com>
This is fascinating... and deeply weird.
OK, what's the difference between calling xmit_skb and ignoring failure,
and this patch which figures out it's going to fail before calling
xmit_skb?
ie. what if you *just* delete this:
> @@ -605,20 +620,6 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
> skb_orphan(skb);
> nf_reset(skb);
>
> - /* Apparently nice girls don't return TX_BUSY; stop the queue
> - * before it gets out of hand. Naturally, this wastes entries. */
> - if (capacity < 2+MAX_SKB_FRAGS) {
> - netif_stop_queue(dev);
> - if (unlikely(!virtqueue_enable_cb(vi->svq))) {
> - /* More just got used, free them then recheck. */
> - capacity += free_old_xmit_skbs(vi);
> - if (capacity >= 2+MAX_SKB_FRAGS) {
> - netif_start_queue(dev);
> - virtqueue_disable_cb(vi->svq);
> - }
> - }
> - }
> -
> return NETDEV_TX_OK;
> }
Thanks!
Rusty.
next prev parent reply other threads:[~2011-03-17 11:53 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-03-17 0:12 [PATCH 2/2] virtio_net: remove send completion interrupts and avoid TX queue overrun through packet drop Shirley Ma
2011-03-17 5:02 ` Michael S. Tsirkin
2011-03-17 15:18 ` Shirley Ma
2011-03-18 3:28 ` Shirley Ma
2011-03-18 13:15 ` Michael S. Tsirkin
2011-03-18 16:54 ` Shirley Ma
2011-03-17 5:10 ` Rusty Russell [this message]
2011-03-17 15:10 ` Shirley Ma
2011-03-18 13:33 ` Herbert Xu
2011-03-19 1:41 ` Shirley Ma
2011-03-21 18:03 ` Shirley Ma
2011-03-22 11:36 ` Michael S. Tsirkin
2011-03-23 2:26 ` Shirley Ma
2011-03-24 0:30 ` Rusty Russell
2011-03-24 4:14 ` Shirley Ma
2011-03-24 14:28 ` Michael S. Tsirkin
2011-03-24 17:46 ` Shirley Ma
2011-03-24 18:10 ` Michael S. Tsirkin
2011-03-25 4:51 ` Rusty Russell
2011-03-25 4:50 ` Rusty Russell
2011-03-27 7:52 ` Michael S. Tsirkin
2011-04-04 6:13 ` Rusty Russell
2011-03-24 0:16 ` Rusty Russell
2011-03-24 6:39 ` Michael S. Tsirkin
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