[dpdk-dev] rte_eal_hotplug_remove() generates error message

[Hideyuki Yamashita <yamashita.hideyuki@po.ntt-tx.co.jp>]

Subject: 

Dear Thomas and all,

I hope you all get safely back home after DPDK summit.
(When I get back Japan, it is chilling. (start of winter))

On DPDK 18.11.0, we tried to remove vhost device by using rte_eal_hotplug_remove().
However, following syslog message is printed.
“EAL: Error: Invalid memory”

At DPDK summit San Jose, we had chance to ask Thomas how to handle the error message, and he gave us following advice:
Replace “rte_eal_hotplug_add()” to “rte_dev_probe(devargs)” and
“rte_eal_hotplug_remove()” to “rte_eth_dev_close() and rte_dev_remove(rte_dev)”

We tested above changes, but the result is the same (i.e., same error message is printed).
The debug log message says:
---
[primary]
VHOST_CONFIG: vhost-user server: socket created, fd: 17
VHOST_CONFIG: bind to /tmp/sock0
EAL: Error: Invalid memory
VHOST_CONFIG: vhost-user server: socket created, fd: 17
VHOST_CONFIG: bind to /tmp/sock0

[secondary]
APP: devargs=eth_vhost0,iface=/tmp/sock0,queues=1
EAL: request: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
EAL: request: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: reply: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
rte_eth_promiscuous_disable: Function not supported
rte_eth_allmulticast_disable: Function not supported
APP: To Server: add
EAL: request: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
EAL: reply: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
APP: To Server: del
APP: devargs=eth_vhost0,iface=/tmp/sock0,queues=1
EAL: request: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
EAL: request: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: msg: bus_vdev_mp
EAL: reply: eal_dev_mp_request
EAL: msg: eal_dev_mp_request
rte_eth_promiscuous_disable: Function not supported
rte_eth_allmulticast_disable: Function not supported
APP: To Server: add
---

We would like to ask:
1)	Is the message “EAL: Error: Invalid memory” ignorable or not? There is no obstacle except this message to re-add the vhost device.
2)	Which is the better(best?) way to add/del vhost device “rte_eal_hotplug_add/remove()” or the way Thomas suggested?

Thanks in advance and have a nice day.

BR,
Hideyuki Yamashita
NTT TechnoCross