[dpdk-dev] [PATCH v2] librte_ether: release memory in uninit function.

[Iremonger, Bernard]

> -----Original Message-----
> From: Qiu, Michael
> Sent: Monday, June 29, 2015 4:22 PM
> To: Iremonger, Bernard; dev at dpdk.org
> Cc: Zhang, Helin; Ananyev, Konstantin; mukawa at igel.co.jp; Stephen
> Hemminger
> Subject: Re: [PATCH v2] librte_ether: release memory in uninit function.
> 
> On 2015/6/29 18:20, Iremonger, Bernard wrote:
> >
> >> -----Original Message-----
> >> From: Qiu, Michael
> >> Sent: Monday, June 29, 2015 9:55 AM
> >> To: Iremonger, Bernard; dev at dpdk.org
> >> Cc: Zhang, Helin; Ananyev, Konstantin; mukawa at igel.co.jp; Stephen
> >> Hemminger
> >> Subject: Re: [PATCH v2] librte_ether: release memory in uninit function.
> >>
> >> On 6/26/2015 5:32 PM, Iremonger, Bernard wrote:
> >>> Changes in v2:
> >>> do not free mac_addrs and hash_mac_addrs here.
> >>>
> >>> Signed-off-by: Bernard Iremonger <bernard.iremonger at intel.com>
> >>> ---
> >>>  lib/librte_ether/rte_ethdev.c |    6 +++++-
> >>>  1 files changed, 5 insertions(+), 1 deletions(-)
> >>>
> >>> diff --git a/lib/librte_ether/rte_ethdev.c
> >>> b/lib/librte_ether/rte_ethdev.c index e13fde5..7ae101a 100644
> >>> --- a/lib/librte_ether/rte_ethdev.c
> >>> +++ b/lib/librte_ether/rte_ethdev.c
> >>> @@ -369,8 +369,12 @@ rte_eth_dev_uninit(struct rte_pci_device
> >> *pci_dev)
> >>>  	/* free ether device */
> >>>  	rte_eth_dev_release_port(eth_dev);
> >>>
> >>> -	if (rte_eal_process_type() == RTE_PROC_PRIMARY)
> >>> +	if (rte_eal_process_type() == RTE_PROC_PRIMARY) {
> >>> +		rte_free(eth_dev->data->rx_queues);
> >>> +		rte_free(eth_dev->data->tx_queues);
> >>>  		rte_free(eth_dev->data->dev_private);
> >>> +		memset(eth_dev->data, 0, sizeof(struct
> >> rte_eth_dev_data));
> >>> +	}
> >>>
> >>>  	eth_dev->pci_dev = NULL;
> >>>  	eth_dev->driver = NULL;
> >>
> >> Actually, This could be put in rte_eth_dev_close() becasue queues
> >> should be released when closed.
> >>
> >> Also before free dev->data->rx_queues you should make sure
> >> dev->data->rx_queues[i] has been freed in PMD close() function, So
> >> dev->data->this
> >> two should be better done at the same time, ether in
> >> rte_eth_dev_close() or in PMD close() function. For hotplug in fm10k,
> >> I put it in PMD close() function.
> >>
> >> Thanks,
> >> Michael
> > Hi Michael,
> >
> > The consensus is that the rx_queue and tx_queue memory should not be
> released in the PMD as it is not allocated by the PMD. 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().
> 
> It really make sense to free memory in rte_ether level, but when close a port
> with out detached? just as stop --> close() --> quit(), the memory will not be
> released :)
> 

In the above scenario lots of memory will not be released.

This is why the detach() and the underlying dev_uninit() functions were introduced.
The dev_uninit() functions currently call dev_close()  which in turn calls dev_stop() which calls dev_clear_queues(). 
The dev_clear_queues()  function does not release the queue_memory or the queue array memory. The queue memory is now released in the dev_uninit() and the  queue array memory is released in the rte_eth_dev_uninit() function.

If the queue array memory is released in rte_eth_dev_close() then the release of the queue_memory will have to be moved to the dev_close() functions from the dev_uninit() functions. This will impact all the existing  PMD hotplug patches.   It will also change the existing dev_close() functionality.

My preference is to leave the existing dev_close() functions unchanged as far as possible and to do what needs to be done in the dev_uninit() functions.

We probably need the view of the maintainers as to whether this should be done in the close() or uninit() functions.  

Regards,

Bernard.