On 08/05/2025 04:50, Changliang Wu wrote:
> The ovs op hangs when performing:
> 1. Create a DPDK bridge (datapath_type=netdev) with bind-ed DPDK port
> 2. Restart OVS service (systemctl restart openvswitch)
> 3. Delete the bridge (ovs-vsctl del-br)
> 4. Recreate bridge and re-add DPDK port
>
> Root cause:
> During OVS service restart, ovs-vswitchd reloads all ports from OVSDB via:
> dpdk_init() -> dpdk_init__() -> rte_eal_init() -> ... ->
> rte_eth_dev_probing_finish()
> This leaves port in DPDK's global rte_eth_devices array with
> dev->state=RTE_ETH_DEV_ATTACHED
>
> When recreating port:
> netdev_dpdk_process_devargs() calls rte_eth_dev_is_valid_port(port_id)
> Since port_id is valid, skips rte_dev_probe() and does not set
> netdev->attached=true
>
Hi,
Do you hit an issue with this when running, or is this from review ?
rte_eal_init() will probe all devices at init (except when dpdk-extra
has -a/-b args to allow/block specific devices). Probed devices in DPDK
have rte_eth_devices[].state set as RTE_ETH_DEV_ATTACHED. Other devices
are set as RTE_ETH_DEV_UNUSED.
If a device that is not already probed is added as a port in OVS then
OVS will call probe for it. In DPDK, rte_eth_devices[].state is then set
to RTE_ETH_DEV_ATTACHED.
Note, OVS dev->attached=true is only used to track whether the device
was explicitly probed from OVS, so that when the port is deleted we can
remove the device and return it to it's previous RTE_ETH_DEV_UNUSED
state in DPDK.
OVS dev->attached is *not* a mirror of
rte_eth_devices[].state=RTE_ETH_DEV_ATTACHED and may have a different value.
The existing code looks ok to me. Your change would mean that devices
that were not explicitly probed by OVS are being removed by OVS. That's
not something we want to do, perhaps there could be some hotplug
limitations and the device cannot be reused etc.
If you are having an issue with a device probed during rte_eal_init() it
is probably something that should be reported in DPDK ml. One option is
to set dpdk-extra like below, so any device will be explicitly probed on
port add.
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-extra="-a
0000:00:00.0"
thanks,
Kevin.
> During bridge/port deletion:
> netdev_dpdk_destruct() checks if(dev->attached)
> and fail to execute cleanup logic for attached devices
> Leave a device in rte_eth_devices with RTE_ETH_DEV_ATTACHED
>
> Subsequent port addition:
> rte_eth_dev_is_valid_port() still returns true,
> critical PCI initialization (rte_dev_probe()) was skip,
> the following configurations hang due to uninitialized device state
>
> Fix implementation:
> Modify netdev_dpdk_process_devargs() to set netdev->attached=true explicitly,
> when port_id is not DPDK_ETH_PORT_ID_INVALID.
>
> Signed-off-by: Changliang Wu <changliang...@smartx.com>
> ---
> lib/netdev-dpdk.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/netdev-dpdk.c b/lib/netdev-dpdk.c
> index e2708a8a5..a551b204e 100644
> --- a/lib/netdev-dpdk.c
> +++ b/lib/netdev-dpdk.c
> @@ -2129,7 +2129,6 @@ netdev_dpdk_process_devargs(struct netdev_dpdk *dev,
> new_port_id = netdev_dpdk_get_port_by_devargs(devargs);
> if (rte_eth_dev_is_valid_port(new_port_id)) {
> /* Attach successful */
> - dev->attached = true;
> VLOG_INFO("Device '%s' attached to DPDK", devargs);
> } else {
> /* Attach unsuccessful */
> @@ -2141,6 +2140,8 @@ netdev_dpdk_process_devargs(struct netdev_dpdk *dev,
>
> if (new_port_id == DPDK_ETH_PORT_ID_INVALID) {
> VLOG_WARN_BUF(errp, "Error attaching device '%s' to DPDK", devargs);
> + } else {
> + dev->attached = true;
> }
>
> return new_port_id;
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