diff options
| author | Wei Liu <wei.liu2@citrix.com> | 2013-05-22 10:34:45 +0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-05-24 05:40:37 +0400 |
| commit | e1f00a69ec26e3eb9847c61c665b8fb3f0c6b477 (patch) | |
| tree | 5958617283d231a3a58229e0e78a4d4623a569a5 /drivers/net/xen-netback/xenbus.c | |
| parent | 8892475386e819aa50856947948c546ccc964d96 (diff) | |
| download | linux-e1f00a69ec26e3eb9847c61c665b8fb3f0c6b477.tar.xz | |
xen-netback: split event channels support for Xen backend driver
Netback and netfront only use one event channel to do TX / RX notification,
which may cause unnecessary wake-up of processing routines. This patch adds a
new feature called feature-split-event-channels to netback, enabling it to
handle TX and RX events separately.
Netback will use tx_irq to notify guest for TX completion, rx_irq for RX
notification.
If frontend doesn't support this feature, tx_irq equals to rx_irq.
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/xen-netback/xenbus.c')
| -rw-r--r-- | drivers/net/xen-netback/xenbus.c | 41 |
1 files changed, 34 insertions, 7 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index d230c145660c..04bd860d16a9 100644 --- a/drivers/net/xen-netback/xenbus.c +++ b/drivers/net/xen-netback/xenbus.c @@ -122,6 +122,16 @@ static int netback_probe(struct xenbus_device *dev, goto fail; } + /* + * Split event channels support, this is optional so it is not + * put inside the above loop. + */ + err = xenbus_printf(XBT_NIL, dev->nodename, + "feature-split-event-channels", + "%u", separate_tx_rx_irq); + if (err) + pr_debug("Error writing feature-split-event-channels"); + err = xenbus_switch_state(dev, XenbusStateInitWait); if (err) goto fail; @@ -393,21 +403,36 @@ 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 < 0) { + err = xenbus_scanf(XBT_NIL, dev->otherend, + "event-channel", "%u", &tx_evtchn); + if (err < 0) { + xenbus_dev_fatal(dev, err, + "reading %s/event-channel(-tx/rx)", + dev->otherend); + return err; + } + rx_evtchn = tx_evtchn; + } + err = xenbus_scanf(XBT_NIL, dev->otherend, "request-rx-copy", "%u", &rx_copy); if (err == -ENOENT) { @@ -454,11 +479,13 @@ static int connect_rings(struct backend_info *be) vif->csum = !val; /* Map the shared frame, irq etc. */ - err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, evtchn); + err = xenvif_connect(vif, tx_ring_ref, rx_ring_ref, + tx_evtchn, rx_evtchn); if (err) { xenbus_dev_fatal(dev, err, - "mapping shared-frames %lu/%lu port %u", - tx_ring_ref, rx_ring_ref, evtchn); + "mapping shared-frames %lu/%lu port tx %u rx %u", + tx_ring_ref, rx_ring_ref, + tx_evtchn, rx_evtchn); return err; } return 0; |