Re: [dpdk-stable] [dpdk-dev] [PATCH v2] app/testpmd: fix pmd_test_exit function for vdevs

[Thomas Monjalon <thomas@monjalon.net>]

21/05/2018 18:32, Ferruh Yigit:
> On 5/21/2018 11:54 AM, Thomas Monjalon wrote:
> > 19/05/2018 16:19, Thomas Monjalon:
> >> 18/05/2018 18:29, Ferruh Yigit:
> >>> On 5/18/2018 4:55 PM, Matan Azrad wrote:
> >>>> Hi all
> >>>>
> >>>> While this patch also applied I don't understand it.
> >>>> Is it mandatory for each PMD to free all its resources in dev_close()?
> >>>> Or it should be done by the rte_device remove function?
> >>>>
> >>>> If the resource cleanup should be done by the remove function I think it
> >>>> should be called for all the devices (pci, vdev, etc).
> >>>>
> >>>> Is there an exit function for EAL to clean rte_eal_init()? If no, looks like we need it...
> >>>
> >>> Hi Matan,
> >>>
> >>> I believe there is a gap in resource cleanup.
> >>> dev_close() it not for resource cleanup, it should be in PMD remove() functions,
> >>> and PMDs have it. The problem is remove path is not called in application exit.
> >>>
> >>> As far as I know there is no simple API to clean the resources, having it may
> >>> help application to do the cleanup.
> >>>
> >>> I have seen the rte_eal_cleanup() API by Harry, that can be extended to cover
> >>> PMD resource cleanup if there is enough motivation for it.
> >>
> >> Yes, EAL resources should be removed by the function rte_eal_cleanup().
> >> And ethdev ports must be removed by rte_eth_dev_close().
> > 
> > This patch is relying on rte_eth_dev_detach() to remove the EAL device.
> > It should be done in rte_eal_cleanup().
> > 
> > I am concerned that this patch is workarounding a miss in rte_eal_cleanup,
> > and takes a different action only for vdev. It is a bad example.
> 
> Indeed it does workaround, but it is needed to fix a defect in virtio-user.

The defect is still in virtio-user after this patch.
To make this workaround acceptable, you need:
	1/ add the virtio-user known issue in release notes
	2/ add a FIXME comment in testpmd code explaining the workaround
	3/ commit to work on rte_eal_cleanup() in 18.08

> And currently rte_eal_cleanup() is not complete, it is not doing any device
> related cleanup.

Yes, we need to add more code in rte_eal_cleanup().

> > And the function rte_eth_dev_detach() is fundamentally wrong and should be deprecated:
> > 	http://dpdk.org/commit/b05b444d22
> > 	http://dpdk.org/commit/b0fb266855
> > 	http://dpdk.org/commit/df3e8ad73f
> > 
> > One more concern: it seems this patch is breaking failsafe use case.
> > Note: bonding is managed as an exception in rte_eth_dev_detach().

I have sent a fix in vdev code for the failsafe issue.

No matter the vdev fix is applied or not, this workaround could target only virtio-user.