From mboxrd@z Thu Jan 1 00:00:00 1970 From: annie li Subject: Re: [PATCH net-next V2 1/2] xen-netback: split event channels support for Xen backend driver Date: Wed, 22 May 2013 11:40:41 -0400 Message-ID: <519CE6F9.8080307@oracle.com> References: <1369161310-9529-1-git-send-email-wei.liu2@citrix.com> <1369161310-9529-2-git-send-email-wei.liu2@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: xen-devel@lists.xen.org, netdev@vger.kernel.org, ian.campbell@citrix.com, konrad.wilk@oracle.com, david.vrabel@citrix.com To: Wei Liu Return-path: Received: from userp1040.oracle.com ([156.151.31.81]:49774 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755409Ab3EVPk2 (ORCPT ); Wed, 22 May 2013 11:40:28 -0400 In-Reply-To: <1369161310-9529-2-git-send-email-wei.liu2@citrix.com> Sender: netdev-owner@vger.kernel.org List-ID: On 2013-5-21 14:35, Wei Liu wrote: > [....] > + > static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev) > { > struct xenvif *vif = netdev_priv(dev); > @@ -125,13 +143,15 @@ static struct net_device_stats *xenvif_get_stats(struct net_device *dev) > static void xenvif_up(struct xenvif *vif) > { > xen_netbk_add_xenvif(vif); > - enable_irq(vif->irq); > + enable_irq(vif->tx_irq); > + enable_irq(vif->rx_irq); enable_irq are called twice in one event channel situation. How about adding if condition here to differ one event channel and split event channel? > xen_netbk_check_rx_xenvif(vif); > } > > static void xenvif_down(struct xenvif *vif) > { > - disable_irq(vif->irq); > + disable_irq(vif->tx_irq); > + disable_irq(vif->rx_irq); Same as enable_irq. > del_timer_sync(&vif->credit_timeout); > xen_netbk_deschedule_xenvif(vif); > xen_netbk_remove_xenvif(vif); > @@ -308,12 +328,13 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, > } > > int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, > - unsigned long rx_ring_ref, unsigned int evtchn) > + unsigned long rx_ring_ref, unsigned int tx_evtchn, > + unsigned int rx_evtchn) > { > int err = -ENOMEM; > > /* Already connected through? */ > - if (vif->irq) > + if (vif->tx_irq) > return 0; > > __module_get(THIS_MODULE); > @@ -322,13 +343,38 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, > if (err < 0) > goto err; > > - err = bind_interdomain_evtchn_to_irqhandler( > - vif->domid, evtchn, xenvif_interrupt, 0, > - vif->dev->name, vif); > - if (err < 0) > - goto err_unmap; > - vif->irq = err; > - disable_irq(vif->irq); > + if (tx_evtchn == rx_evtchn) { > + /* feature-split-event-channels == 0 */ > + err = bind_interdomain_evtchn_to_irqhandler( > + vif->domid, tx_evtchn, xenvif_interrupt, 0, > + vif->dev->name, vif); > + if (err < 0) > + goto err_unmap; > + vif->tx_irq = vif->rx_irq = err; > + disable_irq(vif->tx_irq); > + disable_irq(vif->rx_irq); Same as above. > + } else { > + /* feature-split-event-channels == 1 */ > + snprintf(vif->tx_irq_name, sizeof(vif->tx_irq_name), > + "%s-tx", vif->dev->name); > + err = bind_interdomain_evtchn_to_irqhandler( > + vif->domid, tx_evtchn, xenvif_tx_interrupt, 0, > + vif->tx_irq_name, vif); > + if (err < 0) > + goto err_unmap; > + vif->tx_irq = err; > + disable_irq(vif->tx_irq); > + > + snprintf(vif->rx_irq_name, sizeof(vif->rx_irq_name), > + "%s-rx", vif->dev->name); > + err = bind_interdomain_evtchn_to_irqhandler( > + vif->domid, rx_evtchn, xenvif_rx_interrupt, 0, > + vif->rx_irq_name, vif); > + if (err < 0) > + goto err_tx_unbind; > + vif->rx_irq = err; > + disable_irq(vif->rx_irq); > + } > > xenvif_get(vif); > > @@ -342,6 +388,9 @@ int xenvif_connect(struct xenvif *vif, unsigned long tx_ring_ref, > rtnl_unlock(); > > return 0; > +err_tx_unbind: > + unbind_from_irqhandler(vif->tx_irq, vif); > + vif->tx_irq = 0; > err_unmap: > xen_netbk_unmap_frontend_rings(vif); > err: > @@ -375,8 +424,13 @@ void xenvif_disconnect(struct xenvif *vif) > atomic_dec(&vif->refcnt); > wait_event(vif->waiting_to_free, atomic_read(&vif->refcnt) == 0); > > - if (vif->irq) { > - unbind_from_irqhandler(vif->irq, vif); > + if (vif->tx_irq) { > + if (vif->tx_irq == vif->rx_irq) > + unbind_from_irqhandler(vif->tx_irq, vif); > + else { > + unbind_from_irqhandler(vif->tx_irq, vif); > + unbind_from_irqhandler(vif->rx_irq, vif); > + } > /* vif->irq is valid, we had a module_get in > * xenvif_connect. > */ > diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c > index 2d9477f..ccfbb74 100644 > --- a/drivers/net/xen-netback/netback.c > +++ b/drivers/net/xen-netback/netback.c > @@ -47,6 +47,13 @@ > #include > #include > > +/* Provide an option to disable split event channels at load time as > + * event channels are limited resource. Split event channels are > + * enabled by default. > + */ > +unsigned int feature_split_event_channels = 1; > +module_param(feature_split_event_channels, uint, 0644); > + > /* > * This is the maximum slots a skb can have. If a guest sends a skb > * which exceeds this limit it is considered malicious. > @@ -662,7 +669,7 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk) > { > struct xenvif *vif = NULL, *tmp; > s8 status; > - u16 irq, flags; > + u16 flags; > struct xen_netif_rx_response *resp; > struct sk_buff_head rxq; > struct sk_buff *skb; > @@ -771,7 +778,6 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk) > sco->meta_slots_used); > > RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->rx, ret); > - irq = vif->irq; > if (ret && list_empty(&vif->notify_list)) > list_add_tail(&vif->notify_list, ¬ify); > > @@ -783,7 +789,7 @@ static void xen_netbk_rx_action(struct xen_netbk *netbk) > } > > list_for_each_entry_safe(vif, tmp, ¬ify, notify_list) { > - notify_remote_via_irq(vif->irq); > + notify_remote_via_irq(vif->rx_irq); > list_del_init(&vif->notify_list); > } > > @@ -1762,7 +1768,7 @@ static void make_tx_response(struct xenvif *vif, > vif->tx.rsp_prod_pvt = ++i; > RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&vif->tx, notify); > if (notify) > - notify_remote_via_irq(vif->irq); > + notify_remote_via_irq(vif->tx_irq); > } > > static struct xen_netif_rx_response *make_rx_response(struct xenvif *vif, > diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c > index d230c14..461efc6 100644 > --- a/drivers/net/xen-netback/xenbus.c > +++ b/drivers/net/xen-netback/xenbus.c > @@ -114,6 +114,15 @@ static int netback_probe(struct xenbus_device *dev, > goto abort_transaction; > } > > + /* Split event channels support */ > + err = xenbus_printf(xbt, dev->nodename, > + "feature-split-event-channels", > + "%u", feature_split_event_channels); > + if (err) { > + message = "writing feature-split-event-channels"; > + goto abort_transaction; > + } > + > err = xenbus_transaction_end(xbt, 0); > } while (err == -EAGAIN); > > @@ -393,21 +402,36 @@ static int connect_rings(struct backend_info *be) > struct xenvif *vif = be->vif; > struct xenbus_device *dev = be->dev; > unsigned long tx_ring_ref, rx_ring_ref; > - unsigned int evtchn, rx_copy; > + unsigned int tx_evtchn, rx_evtchn, rx_copy; > int err; > int val; > > err = xenbus_gather(XBT_NIL, dev->otherend, > "tx-ring-ref", "%lu", &tx_ring_ref, > - "rx-ring-ref", "%lu", &rx_ring_ref, > - "event-channel", "%u", &evtchn, NULL); > + "rx-ring-ref", "%lu", &rx_ring_ref, NULL); > if (err) { > xenbus_dev_fatal(dev, err, > - "reading %s/ring-ref and event-channel", > + "reading %s/ring-ref", > dev->otherend); > return err; > } > > + /* Try split event channels first, then single event channel. */ > + err = xenbus_gather(XBT_NIL, dev->otherend, > + "event-channel-tx", "%u", &tx_evtchn, > + "event-channel-rx", "%u", &rx_evtchn, NULL); > + if (err) { > + err = xenbus_gather(XBT_NIL, dev->otherend, > + "event-channel", "%u", &tx_evtchn, NULL); > + if (err) { > + xenbus_dev_fatal(dev, err, > + "reading %s/event-channel(-tx/rx)", > + dev->otherend); This err really comes from reading original implementation(one event channel), right? So it is better to not use (-tx/rx) here? Or using two xenbus_dev_fatal to print log: one for reading tx/rx failure, the other for one event channel failure. Thanks Annie