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

[Huisong Li <lihuisong@huawei.com>]

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.
>
>
> .