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Message-ID: <1445423785-4654-8-git-send-email-paul.durrant@citrix.com>
Date: Wed, 21 Oct 2015 11:36:24 +0100
From: Paul Durrant <paul.durrant@...rix.com>
To: <netdev@...r.kernel.org>, <xen-devel@...ts.xenproject.org>
CC: Paul Durrant <paul.durrant@...rix.com>,
Ian Campbell <ian.campbell@...rix.com>,
Wei Liu <wei.liu2@...rix.com>
Subject: [PATCH net-next 7/8] xen-netback: add support for a multi-queue hash mapping table
Advertise the capability to handle a hash mapping specified by the
frontend (see netif.h for details).
Add an ndo_select() entry point so that, of the frontend does specify a
hash mapping, the skb hash is extracted and mapped to a queue. If no
mapping is specified then the fallback queue selection function is
called so there is no change in behaviour.
Signed-off-by: Paul Durrant <paul.durrant@...rix.com>
Cc: Ian Campbell <ian.campbell@...rix.com>
Cc: Wei Liu <wei.liu2@...rix.com>
---
drivers/net/xen-netback/common.h | 7 ++
drivers/net/xen-netback/interface.c | 14 ++++
drivers/net/xen-netback/xenbus.c | 154 ++++++++++++++++++++++++++++++------
3 files changed, 152 insertions(+), 23 deletions(-)
diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h
index 1bce5a5..23f2275 100644
--- a/drivers/net/xen-netback/common.h
+++ b/drivers/net/xen-netback/common.h
@@ -212,6 +212,8 @@ struct xenvif_mcast_addr {
#define XEN_NETBK_MCAST_MAX 64
+#define XEN_NETBK_MAX_HASH_MAPPING_SIZE 128
+
struct xenvif {
/* Unique identifier for this interface. */
domid_t domid;
@@ -244,7 +246,12 @@ struct xenvif {
unsigned int num_queues; /* active queues, resource allocated */
unsigned int stalled_queues;
+ struct {
+ unsigned int table[XEN_NETBK_MAX_HASH_MAPPING_SIZE];
+ unsigned int length;
+ } hash_mapping;
struct xenbus_watch credit_watch;
+ struct xenbus_watch hash_mapping_watch;
spinlock_t lock;
diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c
index e7bd63e..0c7da7b 100644
--- a/drivers/net/xen-netback/interface.c
+++ b/drivers/net/xen-netback/interface.c
@@ -142,6 +142,19 @@ void xenvif_wake_queue(struct xenvif_queue *queue)
netif_tx_wake_queue(netdev_get_tx_queue(dev, id));
}
+static u16 xenvif_select_queue(struct net_device *dev, struct sk_buff *skb,
+ void *accel_priv,
+ select_queue_fallback_t fallback)
+{
+ struct xenvif *vif = netdev_priv(dev);
+
+ if (vif->hash_mapping.length == 0)
+ return fallback(dev, skb) % dev->real_num_tx_queues;
+
+ return vif->hash_mapping.table[skb_get_hash_raw(skb) %
+ vif->hash_mapping.length];
+}
+
static int xenvif_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct xenvif *vif = netdev_priv(dev);
@@ -386,6 +399,7 @@ static const struct ethtool_ops xenvif_ethtool_ops = {
};
static const struct net_device_ops xenvif_netdev_ops = {
+ .ndo_select_queue = xenvif_select_queue,
.ndo_start_xmit = xenvif_start_xmit,
.ndo_get_stats = xenvif_get_stats,
.ndo_open = xenvif_open,
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index a31bcee..f5ed945 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -367,6 +367,13 @@ static int netback_probe(struct xenbus_device *dev,
if (err)
pr_debug("Error writing multi-queue-max-queues\n");
+ /* Multi-queue mapping support: This is an optional feature. */
+ err = xenbus_printf(XBT_NIL, dev->nodename,
+ "multi-queue-max-hash-mapping-length", "%u",
+ XEN_NETBK_MAX_HASH_MAPPING_SIZE);
+ if (err)
+ pr_debug("Error writing multi-queue-max-hash-mapping-length\n");
+
script = xenbus_read(XBT_NIL, dev->nodename, "script", NULL);
if (IS_ERR(script)) {
err = PTR_ERR(script);
@@ -691,38 +698,139 @@ static void xen_net_rate_changed(struct xenbus_watch *watch,
}
}
-static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
+static void xen_net_read_multi_queue_hash_mapping(struct xenvif *vif)
+{
+ struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
+ char *str, *token;
+ unsigned int *table;
+ unsigned int n, i;
+
+ str = xenbus_read(XBT_NIL, dev->otherend,
+ "multi-queue-hash-mapping", NULL);
+ if (IS_ERR(str))
+ goto fail1;
+
+ table = kcalloc(ARRAY_SIZE(vif->hash_mapping.table),
+ sizeof(unsigned int),
+ GFP_KERNEL);
+ if (!table) {
+ pr_err("%s: failed to allocate mapping table\n",
+ dev->nodename);
+ goto fail2;
+ }
+
+ n = 0;
+ while ((token = strsep(&str, ",")) != NULL) {
+ int rc;
+
+ if (n >= ARRAY_SIZE(vif->hash_mapping.table)) {
+ pr_err("%s: mapping table too big\n",
+ dev->nodename);
+ goto fail3;
+ }
+
+ rc = kstrtouint(token, 0, &table[n]);
+ if (rc < 0) {
+ pr_err("%s: invalid mapping table value (%s at index %u)\n",
+ dev->nodename, token, n);
+ goto fail3;
+ }
+
+ n++;
+ }
+
+ if (n == 0) {
+ pr_err("%s: invalid mapping table\n", dev->nodename);
+ goto fail3;
+ }
+
+ vif->hash_mapping.length = n;
+
+ for (i = 0; i < n; i++)
+ vif->hash_mapping.table[i] =
+ (table[i] < vif->num_queues) ? table[i] : 0;
+
+ kfree(table);
+ kfree(str);
+ return;
+
+fail3:
+ kfree(table);
+fail2:
+ kfree(str);
+fail1:
+ vif->hash_mapping.length = 0;
+}
+
+static void xen_hash_mapping_changed(struct xenbus_watch *watch,
+ const char **vec, unsigned int len)
+{
+ struct xenvif *vif = container_of(watch, struct xenvif,
+ hash_mapping_watch);
+
+ xen_net_read_multi_queue_hash_mapping(vif);
+}
+
+static int xenvif_register_watch(const char *prefix, const char *name,
+ void (*callback)(struct xenbus_watch *,
+ const char **vec,
+ unsigned int len),
+ struct xenbus_watch *watch)
{
- int err = 0;
+ unsigned int len;
char *node;
- unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
+ int err;
- if (vif->credit_watch.node)
+ if (watch->node)
return -EADDRINUSE;
- node = kmalloc(maxlen, GFP_KERNEL);
+ len = strlen(prefix) + 1 + strlen(name) + 1;
+
+ node = kmalloc(len, GFP_KERNEL);
if (!node)
return -ENOMEM;
- snprintf(node, maxlen, "%s/rate", dev->nodename);
- vif->credit_watch.node = node;
- vif->credit_watch.callback = xen_net_rate_changed;
- err = register_xenbus_watch(&vif->credit_watch);
+
+ snprintf(node, len, "%s/%s", prefix, name);
+ watch->node = node;
+ watch->callback = callback;
+ err = register_xenbus_watch(watch);
if (err) {
- pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
+ pr_err("Failed to set watch %s\n", node);
kfree(node);
- vif->credit_watch.node = NULL;
- vif->credit_watch.callback = NULL;
+ watch->node = NULL;
+ watch->callback = NULL;
}
return err;
}
+static void xenvif_unregister_watch(struct xenbus_watch *watch)
+{
+ if (!watch->node)
+ return;
+
+ unregister_xenbus_watch(watch);
+ kfree(watch->node);
+
+ watch->node = NULL;
+ watch->callback = NULL;
+}
+
+static void xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
+{
+ xenvif_register_watch(dev->nodename, "rate",
+ xen_net_rate_changed,
+ &vif->credit_watch);
+
+ xenvif_register_watch(dev->otherend,
+ "multi-queue-hash-mapping",
+ xen_hash_mapping_changed,
+ &vif->hash_mapping_watch);
+}
+
static void xen_unregister_watchers(struct xenvif *vif)
{
- if (vif->credit_watch.node) {
- unregister_xenbus_watch(&vif->credit_watch);
- kfree(vif->credit_watch.node);
- vif->credit_watch.node = NULL;
- }
+ xenvif_unregister_watch(&vif->hash_mapping_watch);
+ xenvif_unregister_watch(&vif->credit_watch);
}
static void unregister_hotplug_status_watch(struct backend_info *be)
@@ -782,6 +890,12 @@ static void connect(struct backend_info *be)
return;
}
+ /* Use the number of queues requested by the frontend */
+ be->vif->queues = vzalloc(requested_num_queues *
+ sizeof(struct xenvif_queue));
+ be->vif->num_queues = requested_num_queues;
+ be->vif->stalled_queues = requested_num_queues;
+
err = xen_net_read_mac(dev, be->vif->fe_dev_addr);
if (err) {
xenbus_dev_fatal(dev, err, "parsing %s/mac", dev->nodename);
@@ -793,12 +907,6 @@ static void connect(struct backend_info *be)
xen_register_watchers(dev, be->vif);
read_xenbus_vif_flags(be);
- /* Use the number of queues requested by the frontend */
- be->vif->queues = vzalloc(requested_num_queues *
- sizeof(struct xenvif_queue));
- be->vif->num_queues = requested_num_queues;
- be->vif->stalled_queues = requested_num_queues;
-
for (queue_index = 0; queue_index < requested_num_queues; ++queue_index) {
queue = &be->vif->queues[queue_index];
queue->vif = be->vif;
--
2.1.4
--
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