Re: [dpdk-dev] [PATCH] net/i40e: fix modifying the number of queues

[Jeff Guo <jia.guo@intel.com>]

hi, alvin

On 6/29/2020 11:16 AM, Zhang, AlvinX wrote:
> Hi Jia,
>
>> -----Original Message-----
>> From: Guo, Jia
>> Sent: Sunday, June 21, 2020 9:36 PM
>> To: Zhang, AlvinX <alvinx.zhang@intel.com>; dev@dpdk.org
>> Cc: stable@dpdk.org; Xing, Beilei <beilei.xing@intel.com>; Jiang, MaoX
>> <maox.jiang@intel.com>
>> Subject: Re: [PATCH] net/i40e: fix modifying the number of queues
>>
>> hi, alvin
>>
>> On 6/10/2020 8:07 PM, alvinx.zhang@intel.com wrote:
>>> From: Alvin Zhang <alvinx.zhang@intel.com>
>>>
>>> For the newly created VF, if the number of qps is greater than 4 at
>>> startup, it may fail to start. This patch updates the API
>>> `i40evf_dev_configure`.
>>
>> Could you explicit explain why it limit to 4 qps, and more detail about below
>> code change with the purpose of the patch.
> For each VF, the kernel PF driver assign 4 qps when the VF be created.


It would be better also add the detail info replace of "updates".


>>
>>> Fixes: c48eb308ed13 ("net/i40e: support VF request more queues")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Alvin Zhang <alvinx.zhang@intel.com>
>>> ---
>>>    drivers/net/i40e/i40e_ethdev_vf.c | 32 ++++++++++++++++++++++++---
>> -----
>>>    1 file changed, 24 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/net/i40e/i40e_ethdev_vf.c
>> b/drivers/net/i40e/i40e_ethdev_vf.c
>>> index bb5d28a..7500e0a 100644
>>> --- a/drivers/net/i40e/i40e_ethdev_vf.c
>>> +++ b/drivers/net/i40e/i40e_ethdev_vf.c
>>> @@ -1082,13 +1082,10 @@ static int i40evf_dev_xstats_get(struct
>> rte_eth_dev *dev,
>>>    	args.out_buffer = vf->aq_resp;
>>>    	args.out_size = I40E_AQ_BUF_SZ;
>>>
>>> -	rte_eal_alarm_cancel(i40evf_dev_alarm_handler, dev);
>>
>> Why interrupt handler is no need to cancel here and more why this change
>> is related with this patch according with the commit log?
> Here, the handler has been cancecled by the caller.


  If it related with this patch please add the fix info into the commit 
log and delete the useless statement in the begin.


>>
>>>    	err = i40evf_execute_vf_cmd(dev, &args);
>>>    	if (err)
>>>    		PMD_DRV_LOG(ERR, "fail to execute command
>> OP_REQUEST_QUEUES");
>>> -	rte_eal_alarm_set(I40EVF_ALARM_INTERVAL,
>>> -			  i40evf_dev_alarm_handler, dev);
>>>    	return err;
>>>    }
>>>
>>> @@ -1516,7 +1513,7 @@ static int i40evf_dev_xstats_get(struct
>> rte_eth_dev *dev,
>>>    	hw->bus.device = pci_dev->addr.devid;
>>>    	hw->bus.func = pci_dev->addr.function;
>>>    	hw->hw_addr = (void *)pci_dev->mem_resource[0].addr;
>>> -	hw->adapter_stopped = 0;
>>> +	hw->adapter_stopped = 1;
>>
>> Why it should be set stopped when init dev?
> The Device has not been started until the API ` i40evf_dev_start ` been called.
> Here we just initiate the device, so it should be set to 1.


make sense, and what about below "hw->adapter_closed = 0;", should it be 
after the success of the init process.


>>
>>>    	hw->adapter_closed = 0;
>>>
>>>    	/* Pass the information to the rte_eth_dev_close() that it should
>> also
>>> @@ -1612,16 +1609,35 @@ static int eth_i40evf_pci_remove(struct
>> rte_pci_device *pci_dev)
>>>    	ad->tx_vec_allowed = true;
>>>
>>>    	if (num_queue_pairs > vf->vsi_res->num_queue_pairs) {
>>> -		int ret = 0;
>>> +		struct i40e_hw *hw;
>>> +		int ret;
>>>
>>> +		hw  = I40E_DEV_PRIVATE_TO_HW(dev->data->dev_private);
>>>    		PMD_DRV_LOG(INFO, "change queue pairs from %u to %u",
>>>    			    vf->vsi_res->num_queue_pairs,
>> num_queue_pairs);
>>> +		if (hw->adapter_stopped == 0) {
>>> +			PMD_DRV_LOG(WARNING, "Device must be
>> stopped first!");
>>> +			return -EINVAL;
>>> +		}
>>> +
>>> +		rte_eal_alarm_cancel(i40evf_dev_alarm_handler, dev);
>>>    		ret = i40evf_request_queues(dev, num_queue_pairs);
>>> -		if (ret != 0)
>>> +		if (ret)
>>>    			return ret;
>>>
>>> -		ret = i40evf_dev_reset(dev);
>>> -		if (ret != 0)
>>> +		/*
>>> +		 * The device must be reinitiated after queue resources
>>> +		 * changed
>>> +		 */
>>
>> Should you check below part is reinitialize process according to exist
>> dev_close and dev_init.
> Yes, it stops and reinitializes the device , but if call the dev_close to do, some process is no needed and should report errors.


When close dev, it will stop dev and free queues, but you don't involve 
the process of free queues here,  and you check the 
"hw->adapter_stopped" before, so if it had stopped and then close, why 
it will report some errors of some useless process?


>>
>>> +		i40e_shutdown_adminq(hw);
>>> +		i40evf_disable_irq0(hw);
>>> +		rte_free(vf->vf_res);
>>> +		vf->vf_res = NULL;
>>> +		rte_free(vf->aq_resp);
>>> +		vf->aq_resp = NULL;
>>> +
>>> +		ret = i40evf_dev_init(dev);
>>> +		if (ret)
>>>    			return ret;
>>>    	}
>>>