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Date: Fri, 15 Feb 2013 16:00:08 +0000
From: Wei Liu <wei.liu2@...rix.com>
To: <xen-devel@...ts.xen.org>, <netdev@...r.kernel.org>,
<ian.campbell@...rix.com>, <konrad.wilk@...cle.com>,
<annie.li@...cle.com>
CC: Wei Liu <wei.liu2@...rix.com>
Subject: [PATCH 7/8] netback: split event channels support
Netback and netfront only use one event channel to do tx / rx notification.
This may cause unnecessary wake-up of process routines. This patch adds a new
feature called feautre-split-event-channel to netback, enabling it to handle
Tx and Rx event 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 = rx_irq.
Signed-off-by: Wei Liu <wei.liu2@...rix.com>
---
drivers/net/xen-netback/common.h | 10 +++--
drivers/net/xen-netback/interface.c | 78 ++++++++++++++++++++++++++++-------
drivers/net/xen-netback/netback.c | 7 ++--
drivers/net/xen-netback/xenbus.c | 44 ++++++++++++++++----
4 files changed, 109 insertions(+), 30 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index f541ba9..cc2a9f0 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -63,8 +63,11 @@ struct xenvif {
u8 fe_dev_addr[6];
- /* Physical parameters of the comms window. */
- unsigned int irq;
+ /* Physical parameters of the comms window.
+ * When feature-split-event-channels = 0, tx_irq = rx_irq.
+ */
+ unsigned int tx_irq;
+ unsigned int rx_irq;
/* List of frontends to notify after a batch of frames sent. */
struct list_head notify_list;
@@ -122,10 +125,11 @@ struct xenvif *xenvif_alloc(struct device *parent,
domid_t domid,
unsigned int handle);
+/* When feature-split-event-channels == 0, tx_evtchn == rx_evtchn */
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);
void xenvif_get(struct xenvif *vif);
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index fa4d46d..c9ebe21 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -60,7 +60,8 @@ static int xenvif_rx_schedulable(struct xenvif *vif)
return xenvif_schedulable(vif) && !xen_netbk_rx_ring_full(vif);
}
-static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
+/* Tx interrupt handler used when feature-split-event-channels == 1 */
+static irqreturn_t xenvif_tx_interrupt(int tx_irq, void *dev_id)
{
struct xenvif *vif = dev_id;
@@ -69,12 +70,31 @@ static irqreturn_t xenvif_interrupt(int irq, void *dev_id)
xen_netbk_schedule_xenvif(vif);
+ return IRQ_HANDLED;
+}
+
+/* Rx interrupt handler used when feature-split-event-channels == 1 */
+static irqreturn_t xenvif_rx_interrupt(int rx_irq, void *dev_id)
+{
+ struct xenvif *vif = dev_id;
+
+ if (vif->netbk == NULL)
+ return IRQ_NONE;
+
if (xenvif_rx_schedulable(vif))
netif_wake_queue(vif->dev);
return IRQ_HANDLED;
}
+/* Used when feature-split-event-channels == 0 */
+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_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
@@ -125,13 +145,15 @@ 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);
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);
del_timer_sync(&vif->credit_timeout);
xen_netbk_deschedule_xenvif(vif);
xen_netbk_remove_xenvif(vif);
@@ -308,7 +330,7 @@ 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;
@@ -317,7 +339,7 @@ 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);
@@ -347,13 +369,32 @@ 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 { /* feature-split-event-channels == 1 */
+ 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)
+ goto err_tx_unbind;
+ vif->rx_irq = err;
+ disable_irq(vif->rx_irq);
+ }
xenvif_get(vif);
@@ -367,6 +408,10 @@ int xenvif_connect(struct xenvif *vif,
rtnl_unlock();
return 0;
+
+err_tx_unbind:
+ unbind_from_irqhandler(vif->tx_irq, vif);
+ vif->tx_irq = 0;
err_rx_unmap:
xen_netbk_unmap_frontend_rings(vif, (void *)vif->rx.sring);
vif->nr_rx_handles = 0;
@@ -406,8 +451,13 @@ 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);
+ }
need_module_put = 1;
}
diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c
index 644c760..5ac8c35 100644
--- a/drivers/net/xen-netback/netback.c
+++ b/drivers/net/xen-netback/netback.c
@@ -639,7 +639,7 @@ 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;
@@ -750,7 +750,6 @@ 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);
@@ -762,7 +761,7 @@ 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);
}
@@ -1595,7 +1594,7 @@ 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 1791807..6822d89 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -141,6 +141,15 @@ 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", 1);
+ if (err) {
+ message = "writing feature-split-event-channels";
+ goto abort_transaction;
+ }
+
err = xenbus_transaction_end(xbt, 0);
} while (err == -EAGAIN);
@@ -419,7 +428,7 @@ 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];
@@ -428,12 +437,22 @@ 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;
+ /* try split event channels */
+ err = xenbus_gather(XBT_NIL, dev->otherend,
+ "event-channel-tx", "%u", &tx_evtchn,
+ "event-channel-rx", "%u", &rx_evtchn,
+ NULL);
+ if (err) {
+ xenbus_dev_fatal(dev, err,
+ "reading %s/event-channel(-tx/rx)",
+ dev->otherend);
+ return err;
+ }
+ } else { /* frontend doesn't support split event channels */
+ rx_evtchn = tx_evtchn;
+ dev_info(&dev->dev, "single event channel\n");
}
err = xenbus_scanf(XBT_NIL, dev->otherend, "tx-ring-order", "%u",
@@ -568,12 +587,19 @@ static int connect_rings(struct backend_info *be)
/* Map the shared frame, irq etc. */
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) {
/* construct 1 2 3 / 4 5 6 */
int i;
char txs[3 * (1U << MODPARM_netback_max_tx_ring_page_order)];
char rxs[3 * (1U << MODPARM_netback_max_rx_ring_page_order)];
+ char evtchns[20];
+
+ if (tx_evtchn == rx_evtchn)
+ snprintf(evtchns, sizeof(evtchns)-1, "%u", tx_evtchn);
+ else
+ snprintf(evtchns, sizeof(evtchns)-1, "%u/%u",
+ tx_evtchn, rx_evtchn);
txs[0] = rxs[0] = 0;
@@ -586,8 +612,8 @@ static int connect_rings(struct backend_info *be)
" %lu", rx_ring_ref[i]);
xenbus_dev_fatal(dev, err,
- "mapping shared-frames%s /%s port %u",
- txs, rxs, evtchn);
+ "mapping shared-frames%s /%s port %s",
+ txs, rxs, evtchns);
return err;
}
return 0;
--
1.7.10.4
--
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