Re: [dpdk-dev] [PATCH 1/2 v4] fm10k: Free queues when close port

["Qiu, Michael" <michael.qiu@intel.com>]

On 2015/6/29 17:54, Iremonger, Bernard wrote:
>> -----Original Message-----
>> From: Qiu, Michael
>> Sent: Monday, June 29, 2015 10:21 AM
>> To: Iremonger, Bernard; dev@dpdk.org
>> Cc: Chen, Jing D; He, Shaopeng
>> Subject: Re: [PATCH 1/2 v4] fm10k: Free queues when close port
>>
>> On 6/29/2015 4:57 PM, Iremonger, Bernard wrote:
>>>> -----Original Message-----
>>>> From: Qiu, Michael
>>>> Sent: Monday, June 29, 2015 9:17 AM
>>>> To: Iremonger, Bernard; dev@dpdk.org
>>>> Cc: Chen, Jing D; He, Shaopeng
>>>> Subject: Re: [PATCH 1/2 v4] fm10k: Free queues when close port
>>>>
>>>> On 6/26/2015 7:02 PM, Iremonger, Bernard wrote:
>>>>>> -----Original Message-----
>>>>>> From: Qiu, Michael
>>>>>> Sent: Friday, June 26, 2015 9:30 AM
>>>>>> To: dev@dpdk.org
>>>>>> Cc: Chen, Jing D; He, Shaopeng; Iremonger, Bernard; Qiu, Michael
>>>>>> Subject: [PATCH 1/2 v4] fm10k: Free queues when close port
>>>>>>
>>>>>> When close a port, lots of memory should be released, such as
>>>>>> software rings, queues, etc.
>>>>>>
>>>>>> Signed-off-by: Michael Qiu <michael.qiu@intel.com>
>>>>>> ---
>>>>> Hi Michael,
>>>>>
>>>>> There are 2 comments inline
>>>>>
>>>>>>  drivers/net/fm10k/fm10k_ethdev.c | 37
>>>>>> +++++++++++++++++++++++++++++++++----
>>>>>>  1 file changed, 33 insertions(+), 4 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/net/fm10k/fm10k_ethdev.c
>>>>>> b/drivers/net/fm10k/fm10k_ethdev.c
>>>>>> index 406c350..eba7228 100644
>>>>>> --- a/drivers/net/fm10k/fm10k_ethdev.c
>>>>>> +++ b/drivers/net/fm10k/fm10k_ethdev.c
>>>>>> @@ -65,6 +65,8 @@ static void
>>>>>>  fm10k_MAC_filter_set(struct rte_eth_dev *dev, const u8 *mac, bool
>>>>>> add); static void  fm10k_MACVLAN_remove_all(struct rte_eth_dev
>>>> *dev);
>>>>>> +static void fm10k_tx_queue_release(void *queue); static void
>>>>>> +fm10k_rx_queue_release(void *queue);
>>>>>>
>>>>>>  static void
>>>>>>  fm10k_mbx_initlock(struct fm10k_hw *hw) @@ -809,11 +811,37 @@
>>>>>> fm10k_dev_stop(struct rte_eth_dev *dev)
>>>>>>
>>>>>>  	PMD_INIT_FUNC_TRACE();
>>>>>>
>>>>>> -	for (i = 0; i < dev->data->nb_tx_queues; i++)
>>>>>> -		fm10k_dev_tx_queue_stop(dev, i);
>>>>>> +	if (dev->data->tx_queues)
>>>>>> +		for (i = 0; i < dev->data->nb_tx_queues; i++)
>>>>>> +			fm10k_dev_tx_queue_stop(dev, i);
>>>>>>
>>>>>> -	for (i = 0; i < dev->data->nb_rx_queues; i++)
>>>>>> -		fm10k_dev_rx_queue_stop(dev, i);
>>>>>> +	if (dev->data->rx_queues)
>>>>>> +		for (i = 0; i < dev->data->nb_rx_queues; i++)
>>>>>> +			fm10k_dev_rx_queue_stop(dev, i); }
>>>>>> +
>>>>>> +static void
>>>>>> +fm10k_dev_queue_release(struct rte_eth_dev *dev) {
>>>>>> +	int i;
>>>>>> +
>>>>>> +	PMD_INIT_FUNC_TRACE();
>>>>>> +
>>>>>> +	if (dev->data->tx_queues) {
>>>>>> +		for (i = 0; i < dev->data->nb_tx_queues; i++)
>>>>>> +			fm10k_tx_queue_release(dev->data-
>>>>>>> tx_queues[i]);
>>>>>> +		rte_free(dev->data->tx_queues);
>>>>>> +		dev->data->tx_queues = NULL;
>>>>> The memory for dev->data->tx_queues  is not allocated in the fm10k
>>>>> PMD, so it should probably not be released here.
>>>>> I have submitted a patch today for rte_eth_dev.c  to do this.
>>>>> /dev/patchwork/patch/5829/
>>>>>
>>>>>> +		dev->data->nb_tx_queues = 0;
>>>>>> +	}
>>>>>> +
>>>>>> +	if (dev->data->rx_queues) {
>>>>>> +		for (i = 0; i < dev->data->nb_rx_queues; i++)
>>>>>> +			fm10k_rx_queue_release(dev->data-
>>>>>>> rx_queues[i]);
>>>>>> +		rte_free(dev->data->rx_queues);
>>>>>> +		dev->data->rx_queues = NULL;
>>>>> The memory for dev->data->rx_queues  is not allocated in the fm10k
>>>>> PMD, so it should probably not be released here.
>>>>> I have submitted a patch today for rte_eth_dev.c  to do this.
>>>>> /dev/patchwork/patch/5829/
>>>> Is it a good idea?  What about to close the port for twice at a time?
>>>> I think it is better to do it in rte_eth_dev_close(), I will give the
>>>> comments to you.
>>>>
>>>> Thanks,
>>>> Michael
>>> Hi Michael,
>>> Could you take a look at the comments on
>>> http://dpdk.org/dev/patchwork/patch/5829/
>> Hi, Bernard
>>
>> I have give comments on it.
>>
>>> The consensus is that memory should be freed in the component that
>> allocated it.
>>> In my pmd hotplug patches I have used a flag to ensure that dev_close is
>> not called twice.
>>> In the e1000 patch I have added a stopped flag to struct e1000_adapter.
>>> http://dpdk.org/dev/patchwork/patch/5655/
>>
>>
>> I reviewed your patch about ixgbe and fvl before. But forget e1000.
>>
>> In my logic, when dev->data->rx_queues is NULL, that means this device has
>> been closed before. What else, we even do not care about whether it has
>> been closed or not, when close() function be called, all memory should be
>> freed if exist am I right?
>>
>> So, check  dev->data->rx_queues whether it is NULL will be recommend in
>> close function, only this could avoid unsafe situations for pointer.
>>
>> Thanks,
>> Michael
> Hi Michael,
>
> In most of the pmd's memory is allocated in the dev_init()functions and released in the dev_uninit() functions. The dev_uninit() functions call dev_close(), so either way the memory is released.

Yes, but consider that, without hotplug, users just stop a port and
close it. then what happens? the memory does not released!
So that's why I recommend to release the memory on close() function, it
could be in EAL level like rte_eth_dev_close().

Maybe my understand is wrong, please point me out :)

Thanks,
Michael

> The point I am trying to make is that the rx_queue and tx_queue memory is not allocated by the pmd and so it should not be freed by the pmd (please see comments on 
> http://dpdk.org/dev/patchwork/patch/5790/)
> The memory is allocated in rte_eth_dev_rx_queue_config() and rte_eth_dev_tx_queue_config(),
> which are both called from rte_eth_dev_configure() which is called by the application (for example test_pmd). So it seems to make sense to free this memory  in rte_eth_dev_uninit().
>
> Regards,
>
> Bernard.
>
>
>