Re: [dpdk-dev] [RFC V1] examples/l3fwd-power: fix memory leak for rte_pci_device

[Thomas Monjalon <thomas@monjalon.net>]

30/09/2021 08:28, Huisong Li:
> Hi. Thomas
> 
> I've summed up our previous discussion.
> 
> Can you look at the final proposal again?
> 
> Do you think we should deal with the problem better?

I don't understand what is the final proposal.


> 在 2021/9/27 9:44, Huisong Li 写道:
> >
> > 在 2021/9/27 3:16, Thomas Monjalon 写道:
> >> 26/09/2021 14:20, Huisong Li:
> >>> 在 2021/9/18 16:46, Thomas Monjalon 写道:
> >>>> 18/09/2021 05:24, Huisong Li:
> >>>>> 在 2021/9/17 20:50, Thomas Monjalon 写道:
> >>>>>> 17/09/2021 04:13, Huisong Li:
> >>>>>>> How should PMD free it? What should we do? Any good suggestions?
> >>>>>> Check that there is no other port sharing the same PCI device,
> >>>>>> then call the PMD callback for rte_pci_remove_t.
> >>>>> For primary and secondary processes, their rte_pci_device is 
> >>>>> independent.
> >>>> Yes it requires to free on both primary and secondary.
> >>>>
> >>>>> Is this for a scenario where there are multiple representor ports 
> >>>>> under
> >>>>> the same PCI address in the same processe?
> >>>> A PCI device can have multiple physical or representor ports.
> >>> Got it.
> >>>>>>> Would it be more appropriate to do this in rte_eal_cleanup() if it
> >>>>>>> cann't be done in the API above?
> >>>>>> rte_eal_cleanup is a last cleanup for what was not done earlier.
> >>>>>> We could do that but first we should properly free devices when 
> >>>>>> closed.
> >>>>>>
> >>>>> Totally, it is appropriate that rte_eal_cleanup is responsible for
> >>>>> releasing devices under the pci bus.
> >>>> Yes, but if a device is closed while the rest of the app keep running,
> >>>> we should not wait to free it.
> >>>   From this point of view, it seems to make sense. However, 
> >>> according to
> >>> the OVS-DPDK
> >>>
> >>> usage, it calls dev_close() first, and then check whether all ports
> >>> under the PCI address are
> >>>
> >>> closed to free rte_pci_device by calling rte_dev_remove().
> >>>
> >>>
> >>> If we do not want the user to be aware of this, and we want
> >>> rte_pci_device to be freed
> >>>
> >>> in a timely manner. Can we add a code logic calculating the number of
> >>> ports under a PCI address
> >>>
> >>> and calling rte_dev_remove() to rte_eth_dev_close() to free
> >>> rte_pci_device and delete it from rte_pci_bus?
> >>>
> >>> If we do, we may need to make some extra work, otherwise some
> >>> applications, such as OVS-DPDK, will
> >>>
> >>> fail due to a second call to rte_dev_remove().
> >> I don't understand the proposal.
> >> Please could explain again the code path?
> >
> > 1. This RFC patch intended to free rte_pci_device in DPDK app by calling
> >
> > rte_dev_remove() after calling dev_close().
> >
> > 2. For the above-mentioned usage in OVS-DPDK, please see function
> >
> > netdev_dpdk_destruct() in lib/netdev-dpdk.c.
> >
> > 3. Later, you suggest that the release of rte_pci_device should be done
> >
> > in the dev_close() API, not in the rte_eal_init() which is not real-time.
> >
> > To sum up, the above proposal comes out.
> >
> >> It may deserve a separate mail thread.
> >>
> >>
> >> .
> > .
>