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

["Iremonger, Bernard" <bernard.iremonger@intel.com>]

> -----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.
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.