[dpdk-dev] [RFC 0/3] Auto enable hotplug with netvsc devices

[dpdk-dev] [RFC 0/3] Auto enable hotplug with netvsc devices

[Stephen Hemminger]

In Azure, hotplug is a requirement for a working application.
Yet most applications don't enable it because DPDK hotplug support
is opt-in. 

There are three options:
  1. Blame the application (this seems to be the DPDK default)
  2. Fix the design mistake (too risky at this time)
  3. Automatically enable hotplug if necessary (that is what this
     patchset does).

Stephen Hemminger (3):
  eal/hotplug: allow monitor to be setup by multiple places
  net/vdev_netvsc: automatically enable hotplug support
  net/netvsc: automatically enable hotplug support

 drivers/net/netvsc/hn_ethdev.c        |  5 ++++-
 drivers/net/vdev_netvsc/vdev_netvsc.c |  4 ++++
 lib/librte_eal/linux/eal_dev.c        | 15 +++++++--------
 3 files changed, 15 insertions(+), 9 deletions(-)

-- 
2.20.1

[dpdk-dev] [RFC 1/3] eal/hotplug: allow monitor to be setup by multiple places

[Stephen Hemminger]

In some cases, a device or infrastructure may want to enable hotplug
but application may also try and start hotplug as well. Therefore
change the monitor_started from a boolean into a reference count.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 lib/librte_eal/linux/eal_dev.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/lib/librte_eal/linux/eal_dev.c b/lib/librte_eal/linux/eal_dev.c
index 83c9cd660754..4d1c08f4c258 100644
--- a/lib/librte_eal/linux/eal_dev.c
+++ b/lib/librte_eal/linux/eal_dev.c
@@ -23,8 +23,11 @@
 
 #include "eal_private.h"
 
-static struct rte_intr_handle intr_handle = {.fd = -1 };
-static bool monitor_started;
+static struct rte_intr_handle intr_handle = {
+	.type = RTE_INTR_HANDLE_DEV_EVENT,
+	.fd = -1,
+};
+static uint32_t monitor_refcount;
 static bool hotplug_handle;
 
 #define EAL_UEV_MSG_LEN 4096
@@ -290,7 +293,7 @@ rte_dev_event_monitor_start(void)
 {
 	int ret;
 
-	if (monitor_started)
+	if (__atomic_fetch_add(&monitor_refcount, 1, __ATOMIC_RELAXED))
 		return 0;
 
 	ret = dev_uev_socket_fd_create();
@@ -299,7 +302,6 @@ rte_dev_event_monitor_start(void)
 		return -1;
 	}
 
-	intr_handle.type = RTE_INTR_HANDLE_DEV_EVENT;
 	ret = rte_intr_callback_register(&intr_handle, dev_uev_handler, NULL);
 
 	if (ret) {
@@ -307,8 +309,6 @@ rte_dev_event_monitor_start(void)
 		return -1;
 	}
 
-	monitor_started = true;
-
 	return 0;
 }
 
@@ -317,7 +317,7 @@ rte_dev_event_monitor_stop(void)
 {
 	int ret;
 
-	if (!monitor_started)
+	if (__atomic_sub_fetch(&monitor_refcount, 1, __ATOMIC_RELAXED))
 		return 0;
 
 	ret = rte_intr_callback_unregister(&intr_handle, dev_uev_handler,
@@ -329,7 +329,6 @@ rte_dev_event_monitor_stop(void)
 
 	close(intr_handle.fd);
 	intr_handle.fd = -1;
-	monitor_started = false;
 
 	return 0;
 }
-- 
2.20.1

[dpdk-dev] [RFC 2/3] net/vdev_netvsc: automatically enable hotplug support

[Stephen Hemminger]

In Hyper-V/Azure with accelerated networking the VF device
maybe added or removed at anytime. Automatically enable hotplug
support (in case application has forgot to).

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/vdev_netvsc/vdev_netvsc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/vdev_netvsc/vdev_netvsc.c b/drivers/net/vdev_netvsc/vdev_netvsc.c
index 9ed74a1d6a2e..f99909ad800f 100644
--- a/drivers/net/vdev_netvsc/vdev_netvsc.c
+++ b/drivers/net/vdev_netvsc/vdev_netvsc.c
@@ -729,6 +729,7 @@ vdev_netvsc_vdev_probe(struct rte_vdev_device *dev)
 	if (kvargs)
 		rte_kvargs_free(kvargs);
 	++vdev_netvsc_ctx_inst;
+	rte_dev_event_monitor_start();
 	return 0;
 }
 
@@ -749,7 +750,10 @@ vdev_netvsc_vdev_remove(__rte_unused struct rte_vdev_device *dev)
 {
 	if (--vdev_netvsc_ctx_inst)
 		return 0;
+
 	rte_eal_alarm_cancel(vdev_netvsc_alarm, NULL);
+	rte_dev_event_monitor_stop();
+
 	while (!LIST_EMPTY(&vdev_netvsc_ctx_list)) {
 		struct vdev_netvsc_ctx *ctx = LIST_FIRST(&vdev_netvsc_ctx_list);
 
-- 
2.20.1

[dpdk-dev] [RFC 3/3] net/netvsc: automatically enable hotplug support

[Stephen Hemminger]

In Hyper-V/Azure with accelerated networking the VF device
maybe added or removed at anytime. Automatically enable hotplug
support (in case application has forgot to).

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 drivers/net/netvsc/hn_ethdev.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/netvsc/hn_ethdev.c b/drivers/net/netvsc/hn_ethdev.c
index 05f1a25a1abc..cf10fc24b37b 100644
--- a/drivers/net/netvsc/hn_ethdev.c
+++ b/drivers/net/netvsc/hn_ethdev.c
@@ -1074,8 +1074,10 @@ static int eth_hn_probe(struct rte_vmbus_driver *drv __rte_unused,
 	ret = eth_hn_dev_init(eth_dev);
 	if (ret)
 		eth_dev_vmbus_release(eth_dev);
-	else
+	else {
 		rte_eth_dev_probing_finish(eth_dev);
+		rte_dev_event_monitor_stop();
+	}
 
 	return ret;
 }
@@ -1096,6 +1098,7 @@ static int eth_hn_remove(struct rte_vmbus_device *dev)
 		return ret;
 
 	eth_dev_vmbus_release(eth_dev);
+	rte_dev_event_monitor_stop();
 	return 0;
 }
 
-- 
2.20.1