| Message ID | 1475573358-32414-5-git-send-email-paul.durrant@citrix.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Oct 04, 2016 at 02:29:15AM -0700, Paul Durrant wrote: > From: David Vrabel <david.vrabel@citrix.com> > > When an skb is removed from the guest rx queue, immediately wake the > tx queue, instead of after processing them. Please, could the description explain why? > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> > [re-based] > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > --- > Cc: Wei Liu <wei.liu2@citrix.com> > --- > drivers/net/xen-netback/rx.c | 24 ++++++++---------------- > 1 file changed, 8 insertions(+), 16 deletions(-) > > diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c > index b0ce4c6..9548709 100644 > --- a/drivers/net/xen-netback/rx.c > +++ b/drivers/net/xen-netback/rx.c > @@ -92,27 +92,21 @@ static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) > spin_lock_irq(&queue->rx_queue.lock); > > skb = __skb_dequeue(&queue->rx_queue); > - if (skb) > + if (skb) { > queue->rx_queue_len -= skb->len; > + if (queue->rx_queue_len < queue->rx_queue_max) { > + struct netdev_queue *txq; > + > + txq = netdev_get_tx_queue(queue->vif->dev, queue->id); > + netif_tx_wake_queue(txq); > + } > + } > > spin_unlock_irq(&queue->rx_queue.lock); > > return skb; > } > > -static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) > -{ > - spin_lock_irq(&queue->rx_queue.lock); > - > - if (queue->rx_queue_len < queue->rx_queue_max) { > - struct net_device *dev = queue->vif->dev; > - > - netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id)); > - } > - > - spin_unlock_irq(&queue->rx_queue.lock); > -} > - > static void xenvif_rx_queue_purge(struct xenvif_queue *queue) > { > struct sk_buff *skb; > @@ -585,8 +579,6 @@ int xenvif_kthread_guest_rx(void *data) > */ > xenvif_rx_queue_drop_expired(queue); > > - xenvif_rx_queue_maybe_wake(queue); > - > cond_resched(); > } > > -- > 2.1.4 > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > https://lists.xen.org/xen-devel
> -----Original Message----- > From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > Sent: 04 October 2016 13:49 > To: Paul Durrant <Paul.Durrant@citrix.com> > Cc: netdev@vger.kernel.org; xen-devel@lists.xenproject.org; Wei Liu > <wei.liu2@citrix.com>; David Vrabel <david.vrabel@citrix.com> > Subject: Re: [Xen-devel] [PATCH v2 net-next 4/7] xen-netback: immediately > wake tx queue when guest rx queue has space > > On Tue, Oct 04, 2016 at 02:29:15AM -0700, Paul Durrant wrote: > > From: David Vrabel <david.vrabel@citrix.com> > > > > When an skb is removed from the guest rx queue, immediately wake the > > tx queue, instead of after processing them. > > Please, could the description explain why? > Is it not reasonably obvious that it improves parallelism between filling and draining the queue? I could add a comment if you think it needs spelling out. Paul > > > > Signed-off-by: David Vrabel <david.vrabel@citrix.com> [re-based] > > Signed-off-by: Paul Durrant <paul.durrant@citrix.com> > > --- > > Cc: Wei Liu <wei.liu2@citrix.com> > > --- > > drivers/net/xen-netback/rx.c | 24 ++++++++---------------- > > 1 file changed, 8 insertions(+), 16 deletions(-) > > > > diff --git a/drivers/net/xen-netback/rx.c > > b/drivers/net/xen-netback/rx.c index b0ce4c6..9548709 100644 > > --- a/drivers/net/xen-netback/rx.c > > +++ b/drivers/net/xen-netback/rx.c > > @@ -92,27 +92,21 @@ static struct sk_buff *xenvif_rx_dequeue(struct > xenvif_queue *queue) > > spin_lock_irq(&queue->rx_queue.lock); > > > > skb = __skb_dequeue(&queue->rx_queue); > > - if (skb) > > + if (skb) { > > queue->rx_queue_len -= skb->len; > > + if (queue->rx_queue_len < queue->rx_queue_max) { > > + struct netdev_queue *txq; > > + > > + txq = netdev_get_tx_queue(queue->vif->dev, > queue->id); > > + netif_tx_wake_queue(txq); > > + } > > + } > > > > spin_unlock_irq(&queue->rx_queue.lock); > > > > return skb; > > } > > > > -static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) - > { > > - spin_lock_irq(&queue->rx_queue.lock); > > - > > - if (queue->rx_queue_len < queue->rx_queue_max) { > > - struct net_device *dev = queue->vif->dev; > > - > > - netif_tx_wake_queue(netdev_get_tx_queue(dev, queue- > >id)); > > - } > > - > > - spin_unlock_irq(&queue->rx_queue.lock); > > -} > > - > > static void xenvif_rx_queue_purge(struct xenvif_queue *queue) { > > struct sk_buff *skb; > > @@ -585,8 +579,6 @@ int xenvif_kthread_guest_rx(void *data) > > */ > > xenvif_rx_queue_drop_expired(queue); > > > > - xenvif_rx_queue_maybe_wake(queue); > > - > > cond_resched(); > > } > > > > -- > > 2.1.4 > > > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@lists.xen.org > > https://lists.xen.org/xen-devel
diff --git a/drivers/net/xen-netback/rx.c b/drivers/net/xen-netback/rx.c index b0ce4c6..9548709 100644 --- a/drivers/net/xen-netback/rx.c +++ b/drivers/net/xen-netback/rx.c @@ -92,27 +92,21 @@ static struct sk_buff *xenvif_rx_dequeue(struct xenvif_queue *queue) spin_lock_irq(&queue->rx_queue.lock); skb = __skb_dequeue(&queue->rx_queue); - if (skb) + if (skb) { queue->rx_queue_len -= skb->len; + if (queue->rx_queue_len < queue->rx_queue_max) { + struct netdev_queue *txq; + + txq = netdev_get_tx_queue(queue->vif->dev, queue->id); + netif_tx_wake_queue(txq); + } + } spin_unlock_irq(&queue->rx_queue.lock); return skb; } -static void xenvif_rx_queue_maybe_wake(struct xenvif_queue *queue) -{ - spin_lock_irq(&queue->rx_queue.lock); - - if (queue->rx_queue_len < queue->rx_queue_max) { - struct net_device *dev = queue->vif->dev; - - netif_tx_wake_queue(netdev_get_tx_queue(dev, queue->id)); - } - - spin_unlock_irq(&queue->rx_queue.lock); -} - static void xenvif_rx_queue_purge(struct xenvif_queue *queue) { struct sk_buff *skb; @@ -585,8 +579,6 @@ int xenvif_kthread_guest_rx(void *data) */ xenvif_rx_queue_drop_expired(queue); - xenvif_rx_queue_maybe_wake(queue); - cond_resched(); }