From edafc132baac4f5331b7bffd99a7af371776f2b5 Mon Sep 17 00:00:00 2001 From: "Palik, Imre" Date: Thu, 19 Mar 2015 11:05:42 +0100 Subject: [PATCH] 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 Signed-off-by: Imre Palik Acked-by: Wei Liu Signed-off-by: David S. Miller --- drivers/net/xen-netback/common.h | 4 +++ drivers/net/xen-netback/interface.c | 1 + drivers/net/xen-netback/netback.c | 4 +-- drivers/net/xen-netback/xenbus.c | 57 +++++++++++++++++++++++++++++++++++++ 4 files changed, 63 insertions(+), 3 deletions(-) diff --git a/drivers/net/xen-netback/common.h b/drivers/net/xen-netback/common.h index 589fa25..8a495b3 100644 --- a/drivers/net/xen-netback/common.h +++ b/drivers/net/xen-netback/common.h @@ -238,6 +238,8 @@ struct xenvif { unsigned int num_queues; /* active queues, resource allocated */ unsigned int stalled_queues; + struct xenbus_watch credit_watch; + spinlock_t lock; #ifdef CONFIG_DEBUG_FS @@ -260,6 +262,8 @@ static inline struct xenbus_device *xenvif_to_xenbus_device(struct xenvif *vif) return to_xenbus_device(vif->dev->dev.parent); } +void xenvif_tx_credit_callback(unsigned long data); + struct xenvif *xenvif_alloc(struct device *parent, domid_t domid, unsigned int handle); diff --git a/drivers/net/xen-netback/interface.c b/drivers/net/xen-netback/interface.c index d2ada7c..1a83e19 100644 --- a/drivers/net/xen-netback/interface.c +++ b/drivers/net/xen-netback/interface.c @@ -463,6 +463,7 @@ int xenvif_init_queue(struct xenvif_queue *queue) queue->credit_bytes = queue->remaining_credit = ~0UL; queue->credit_usec = 0UL; init_timer(&queue->credit_timeout); + queue->credit_timeout.function = xenvif_tx_credit_callback; queue->credit_window_start = get_jiffies_64(); queue->rx_queue_max = XENVIF_RX_QUEUE_BYTES; diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c index cab9f52..2c25e8e 100644 --- a/drivers/net/xen-netback/netback.c +++ b/drivers/net/xen-netback/netback.c @@ -641,7 +641,7 @@ static void tx_add_credit(struct xenvif_queue *queue) queue->remaining_credit = min(max_credit, max_burst); } -static void tx_credit_callback(unsigned long data) +void xenvif_tx_credit_callback(unsigned long data) { struct xenvif_queue *queue = (struct xenvif_queue *)data; tx_add_credit(queue); @@ -1169,8 +1169,6 @@ static bool tx_credit_exceeded(struct xenvif_queue *queue, unsigned size) if (size > queue->remaining_credit) { queue->credit_timeout.data = (unsigned long)queue; - queue->credit_timeout.function = - tx_credit_callback; mod_timer(&queue->credit_timeout, next_credit); queue->credit_window_start = next_credit; diff --git a/drivers/net/xen-netback/xenbus.c b/drivers/net/xen-netback/xenbus.c index 794204e..3d8dbf5 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 */ -- 2.7.4