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Date: Thu, 2 Feb 2012 16:49:21 +0000
From: Wei Liu <wei.liu2@...rix.com>
To: netdev@...r.kernel.org, xen-devel@...ts.xensource.com
CC: ian.campbell@...rix.com, konrad.wilk@...cle.com,
Wei Liu <wei.liu2@...rix.com>
Subject: [RFC PATCH V4 11/13] netback: split event channels support
Originally, netback and netfront only use one event channel to do tx /
rx notification. This may cause unnecessary wake-up of NAPI / kthread.
When guest tx is completed, netback will only notify tx_irq.
If feature-split-event-channels ==0, rx_irq = tx_irq, so
RX protocol will just work as expected.
Signed-off-by: Wei Liu <wei.liu2@...rix.com>
---
drivers/net/xen-netback/common.h | 7 ++-
drivers/net/xen-netback/interface.c | 82 +++++++++++++++++++++++++++--------
drivers/net/xen-netback/netback.c | 4 +-
drivers/net/xen-netback/xenbus.c | 51 +++++++++++++++++----
4 files changed, 111 insertions(+), 33 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 1bb16ec..a0497fc 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -85,8 +85,9 @@ struct xenvif {
u8 fe_dev_addr[6];
- /* Physical parameters of the comms window. */
- unsigned int irq;
+ /* When feature-split-event-channels = 0, tx_irq = rx_irq */
+ unsigned int tx_irq;
+ unsigned int rx_irq;
/* The shared rings and indexes. */
struct xen_netif_tx_back_ring tx;
@@ -145,7 +146,7 @@ struct xenvif *xenvif_alloc(struct device *parent,
int xenvif_connect(struct xenvif *vif,
unsigned long tx_ring_ref[], unsigned int tx_ring_order,
unsigned long rx_ring_ref[], unsigned int rx_ring_order,
- unsigned int evtchn);
+ unsigned int tx_evtchn, unsigned int rx_evtchn);
void xenvif_disconnect(struct xenvif *vif);
int xenvif_xenbus_init(void);
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index e1aa003..c6dbd50 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -51,19 +51,35 @@ static int xenvif_rx_schedulable(struct xenvif *vif)
return xenvif_schedulable(vif) && !xenvif_rx_ring_full(vif);
}
-static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
+static irqreturn_t xenvif_tx_interrupt(int irq, void *dev_id)
{
struct xenvif *vif = dev_id;
- if (xenvif_rx_schedulable(vif))
- netif_wake_queue(vif->dev);
-
if (RING_HAS_UNCONSUMED_REQUESTS(&vif->tx))
napi_schedule(&vif->napi);
return IRQ_HANDLED;
}
+static irqreturn_t xenvif_rx_interrupt(int irq, void *dev_id)
+{
+ struct xenvif *vif = dev_id;
+
+ if (xenvif_schedulable(vif) && !xenvif_rx_ring_full(vif))
+ netif_wake_queue(vif->dev);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
+{
+ xenvif_tx_interrupt(irq, dev_id);
+
+ xenvif_rx_interrupt(irq, dev_id);
+
+ return IRQ_HANDLED;
+}
+
static int xenvif_poll(struct napi_struct *napi, int budget)
{
struct xenvif *vif = container_of(napi, struct xenvif, napi);
@@ -132,14 +148,16 @@ static struct net_device_stats *xenvif_get_stats(struct net_device *dev)
static void xenvif_up(struct xenvif *vif)
{
napi_enable(&vif->napi);
- enable_irq(vif->irq);
+ enable_irq(vif->tx_irq);
+ enable_irq(vif->rx_irq);
xenvif_check_rx_xenvif(vif);
}
static void xenvif_down(struct xenvif *vif)
{
napi_disable(&vif->napi);
- disable_irq(vif->irq);
+ disable_irq(vif->tx_irq);
+ disable_irq(vif->rx_irq);
}
static int xenvif_open(struct net_device *dev)
@@ -322,7 +340,7 @@ struct xenvif *xenvif_alloc(struct device *parent, domid_t domid,
int xenvif_connect(struct xenvif *vif,
unsigned long tx_ring_ref[], unsigned int tx_ring_ref_count,
unsigned long rx_ring_ref[], unsigned int rx_ring_ref_count,
- unsigned int evtchn)
+ unsigned int tx_evtchn, unsigned int rx_evtchn)
{
int err = -ENOMEM;
void *addr;
@@ -331,7 +349,7 @@ int xenvif_connect(struct xenvif *vif,
int tmp[NETBK_MAX_RING_PAGES], i;
/* Already connected through? */
- if (vif->irq)
+ if (vif->tx_irq)
return 0;
__module_get(THIS_MODULE);
@@ -358,13 +376,34 @@ int xenvif_connect(struct xenvif *vif,
BACK_RING_INIT(&vif->rx, rxs, PAGE_SIZE * rx_ring_ref_count);
vif->nr_rx_handles = rx_ring_ref_count;
- err = bind_interdomain_evtchn_to_irqhandler(
- vif->domid, evtchn, xenvif_interrupt, 0,
- vif->dev->name, vif);
- if (err < 0)
- goto err_rx_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_rx_unmap;
+ vif->tx_irq = vif->rx_irq = err;
+ disable_irq(vif->tx_irq);
+ disable_irq(vif->rx_irq);
+ } else {
+ err = bind_interdomain_evtchn_to_irqhandler(
+ vif->domid, tx_evtchn, xenvif_tx_interrupt, 0,
+ vif->dev->name, vif);
+ if (err < 0)
+ goto err_rx_unmap;
+ vif->tx_irq = err;
+ disable_irq(vif->tx_irq);
+
+ err = bind_interdomain_evtchn_to_irqhandler(
+ vif->domid, rx_evtchn, xenvif_rx_interrupt, 0,
+ vif->dev->name, vif);
+ if (err < 0) {
+ unbind_from_irqhandler(vif->tx_irq, vif);
+ goto err_rx_unmap;
+ }
+ vif->rx_irq = err;
+ disable_irq(vif->rx_irq);
+ }
init_waitqueue_head(&vif->wq);
vif->task = kthread_create(xenvif_kthread,
@@ -389,7 +428,12 @@ int xenvif_connect(struct xenvif *vif,
return 0;
err_unbind:
- unbind_from_irqhandler(vif->irq, vif);
+ 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);
+ }
err_rx_unmap:
xenvif_unmap_frontend_ring(vif, (void *)vif->tx.sring);
err_tx_unmap:
@@ -419,10 +463,12 @@ void xenvif_disconnect(struct xenvif *vif)
del_timer_sync(&vif->credit_timeout);
- if (vif->irq) {
- unbind_from_irqhandler(vif->irq, vif);
+ if (vif->tx_irq) {
+ unbind_from_irqhandler(vif->tx_irq, vif);
need_module_put = 1;
}
+ if (vif->tx_irq != vif->rx_irq)
+ unbind_from_irqhandler(vif->rx_irq, vif);
unregister_netdev(vif->dev);
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 60c8951..957cf9d 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -622,7 +622,7 @@ void xenvif_rx_action(struct xenvif *vif)
}
if (need_to_notify)
- notify_remote_via_irq(vif->irq);
+ notify_remote_via_irq(vif->rx_irq);
if (!skb_queue_empty(&vif->rx_queue))
xenvif_kick_thread(vif);
@@ -1392,7 +1392,7 @@ 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 79499fc..3772e0c 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -131,6 +131,14 @@ static int netback_probe(struct xenbus_device *dev,
goto abort_transaction;
}
+ err = xenbus_printf(xbt, dev->nodename,
+ "feature-split-event-channels",
+ "%u", 1);
+ if (err) {
+ message = "writing feature-split-event-channels";
+ goto abort_transaction;
+ }
+
err = xenbus_transaction_end(xbt, 0);
} while (err == -EAGAIN);
@@ -408,7 +416,7 @@ static int connect_rings(struct backend_info *be)
{
struct xenvif *vif = be->vif;
struct xenbus_device *dev = be->dev;
- unsigned int evtchn, rx_copy;
+ unsigned int tx_evtchn, rx_evtchn, rx_copy;
int err;
int val;
unsigned long tx_ring_ref[NETBK_MAX_RING_PAGES];
@@ -417,12 +425,30 @@ static int connect_rings(struct backend_info *be)
unsigned int rx_ring_order;
err = xenbus_gather(XBT_NIL, dev->otherend,
- "event-channel", "%u", &evtchn, NULL);
+ "event-channel", "%u", &tx_evtchn, NULL);
if (err) {
- xenbus_dev_fatal(dev, err,
- "reading %s/event-channel",
- dev->otherend);
- return err;
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "event-channel-tx", "%u", &tx_evtchn,
+ NULL);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "reading %s/event-channel-tx",
+ dev->otherend);
+ return err;
+ }
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "event-channel-rx", "%u", &rx_evtchn,
+ NULL);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "reading %s/event-channel-rx",
+ dev->otherend);
+ return err;
+ }
+ dev_info(&dev->dev, "split event channels\n");
+ } else {
+ rx_evtchn = tx_evtchn;
+ dev_info(&dev->dev, "single event channel\n");
}
err = xenbus_scanf(XBT_NIL, dev->otherend, "tx-ring-order", "%u",
@@ -559,12 +585,17 @@ static int connect_rings(struct backend_info *be)
err = xenvif_connect(vif,
tx_ring_ref, (1U << tx_ring_order),
rx_ring_ref, (1U << rx_ring_order),
- evtchn);
+ tx_evtchn, rx_evtchn);
if (err) {
int i;
- xenbus_dev_fatal(dev, err,
- "binding port %u",
- evtchn);
+ if (tx_evtchn == rx_evtchn)
+ xenbus_dev_fatal(dev, err,
+ "binding port %u",
+ tx_evtchn);
+ else
+ xenbus_dev_fatal(dev, err,
+ "binding tx port %u, rx port %u",
+ tx_evtchn, rx_evtchn);
for (i = 0; i < (1U << tx_ring_order); i++)
xenbus_dev_fatal(dev, err,
"mapping tx ring handle: %lu",
--
1.7.2.5
--
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