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

["Yang, Zhiyong" <zhiyong.yang@intel.com>]

Hi Thomas, 

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> Sent: Wednesday, May 23, 2018 3:49 AM
> To: Yigit, Ferruh <ferruh.yigit@intel.com>
> Cc: Yang, Zhiyong <zhiyong.yang@intel.com>; dev@dpdk.org; Matan Azrad
> <matan@mellanox.com>; Iremonger, Bernard
> <bernard.iremonger@intel.com>; Yao, Lei A <lei.a.yao@intel.com>;
> maxime.coquelin@redhat.com; Bie, Tiwei <tiwei.bie@intel.com>;
> stable@dpdk.org; Van Haaren, Harry <harry.van.haaren@intel.com>
> Subject: Re: [dpdk-dev] [PATCH v2] app/testpmd: fix pmd_test_exit function for
> vdevs
> 
> 22/05/2018 20:38, Ferruh Yigit:
> > On 5/22/2018 2:12 PM, Thomas Monjalon wrote:
> > > Any update to improve this workaround?
> > >
> > > 21/05/2018 18:38, Thomas Monjalon:
> > >> 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

I don't think it is a bug for virtio-user. Just no proper implemented API can free the virtio-user resources  allocated by probe method.
Socket file is just one example,  other resources are freed in the remove method.  Testpmd was always missing the functionality.

> > >> 	2/ add a FIXME comment in testpmd code explaining the workaround
> > >> 	3/ commit to work on rte_eal_cleanup() in 18.08
> >
> > I have submitted following patch [1], can it cover 2/ for the v18.05-rc5?
> >
> > [1]
> > https://dpdk.org/dev/patchwork/patch/40350/
> 
> Yes, it covers item 2/. Thanks
> 
> 

rte_eal_cleanup() is a proper API,  which is needed to clean up resources.

Thanks
Zhiyong