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authorPalik, Imre <imrep@amazon.de>2015-03-19 11:05:42 +0100
committerDavid S. Miller <davem@davemloft.net>2015-03-20 12:55:15 -0400
commitedafc132baac4f5331b7bffd99a7af371776f2b5 (patch)
treeed29dce2d9af57b59272c557552973adab466039 /drivers/net/xen-netback/xenbus.c
parent750f2f9165bafb5fc20a1ec689f46c89dac54658 (diff)
xen-netback: making the bandwidth limiter runtime settable
With the current netback, the bandwidth limiter's parameters are only settable during vif setup time. This patch register a watch on them, and thus makes them runtime changeable. When the watch fires, the timer is reset. The timer's mutex is used for fencing the change. Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: Imre Palik <imrep@amazon.de> Acked-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.c57
1 files changed, 57 insertions, 0 deletions
diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c
index 794204e34fba..3d8dbf5f2d39 100644
--- a/drivers/net/xen-netback/xenbus.c
+++ b/drivers/net/xen-netback/xenbus.c
@@ -41,6 +41,7 @@ static void connect(struct backend_info *be);
static int read_xenbus_vif_flags(struct backend_info *be);
static int backend_create_xenvif(struct backend_info *be);
static void unregister_hotplug_status_watch(struct backend_info *be);
+static void xen_unregister_watchers(struct xenvif *vif);
static void set_backend_state(struct backend_info *be,
enum xenbus_state state);
@@ -232,6 +233,7 @@ static int netback_remove(struct xenbus_device *dev)
unregister_hotplug_status_watch(be);
if (be->vif) {
kobject_uevent(&dev->dev.kobj, KOBJ_OFFLINE);
+ xen_unregister_watchers(be->vif);
xenbus_rm(XBT_NIL, dev->nodename, "hotplug-status");
xenvif_free(be->vif);
be->vif = NULL;
@@ -430,6 +432,7 @@ static int backend_create_xenvif(struct backend_info *be)
static void backend_disconnect(struct backend_info *be)
{
if (be->vif) {
+ xen_unregister_watchers(be->vif);
#ifdef CONFIG_DEBUG_FS
xenvif_debugfs_delif(be->vif);
#endif /* CONFIG_DEBUG_FS */
@@ -645,6 +648,59 @@ static int xen_net_read_mac(struct xenbus_device *dev, u8 mac[])
return 0;
}
+static void xen_net_rate_changed(struct xenbus_watch *watch,
+ const char **vec, unsigned int len)
+{
+ struct xenvif *vif = container_of(watch, struct xenvif, credit_watch);
+ struct xenbus_device *dev = xenvif_to_xenbus_device(vif);
+ unsigned long credit_bytes;
+ unsigned long credit_usec;
+ unsigned int queue_index;
+
+ xen_net_read_rate(dev, &credit_bytes, &credit_usec);
+ for (queue_index = 0; queue_index < vif->num_queues; queue_index++) {
+ struct xenvif_queue *queue = &vif->queues[queue_index];
+
+ queue->credit_bytes = credit_bytes;
+ queue->credit_usec = credit_usec;
+ if (!mod_timer_pending(&queue->credit_timeout, jiffies) &&
+ queue->remaining_credit > queue->credit_bytes) {
+ queue->remaining_credit = queue->credit_bytes;
+ }
+ }
+}
+
+static int xen_register_watchers(struct xenbus_device *dev, struct xenvif *vif)
+{
+ int err = 0;
+ char *node;
+ unsigned maxlen = strlen(dev->nodename) + sizeof("/rate");
+
+ node = kmalloc(maxlen, 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);
+ if (err) {
+ pr_err("Failed to set watcher %s\n", vif->credit_watch.node);
+ kfree(node);
+ vif->credit_watch.node = NULL;
+ vif->credit_watch.callback = NULL;
+ }
+ return err;
+}
+
+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;
+ }
+}
+
static void unregister_hotplug_status_watch(struct backend_info *be)
{
if (be->have_hotplug_status_watch) {
@@ -709,6 +765,7 @@ static void connect(struct backend_info *be)
}
xen_net_read_rate(dev, &credit_bytes, &credit_usec);
+ xen_register_watchers(dev, be->vif);
read_xenbus_vif_flags(be);
/* Use the number of queues requested by the frontend */