Re: [PATCH v3] net/iavf: fix iavf query stats in intr thread

[Ferruh Yigit <ferruh.yigit@amd.com>]

On 3/27/2023 6:31 AM, Deng, KaiwenX wrote:
> 
> 
>> -----Original Message-----
>> From: Ferruh Yigit <ferruh.yigit@amd.com>
>> Sent: Thursday, March 23, 2023 11:39 PM
>> To: Deng, KaiwenX <kaiwenx.deng@intel.com>; dev@dpdk.org
>> Cc: stable@dpdk.org; Yang, Qiming <qiming.yang@intel.com>; Zhou, YidingX
>> <yidingx.zhou@intel.com>; Chas Williams <chas3@att.com>; Min Hu (Connor)
>> <humin29@huawei.com>; Wu, Jingjing <jingjing.wu@intel.com>; Xing, Beilei
>> <beilei.xing@intel.com>; Mike Pattrick <mkp@redhat.com>; Zhang, Qi Z
>> <qi.z.zhang@intel.com>; Doherty, Declan <declan.doherty@intel.com>;
>> Mrzyglod, Daniel T <daniel.t.mrzyglod@intel.com>; Dapeng Yu
>> <dapengx.yu@intel.com>
>> Subject: Re: [PATCH v3] net/iavf: fix iavf query stats in intr thread
>>
>> On 3/22/2023 7:26 AM, Kaiwen Deng wrote:
>>> When iavf send query-stats command in eal-intr-thread through virtual
>>> channel, there will be no response received from
>>> iavf_dev_virtchnl_handler for this command during block and wait.
>>> Because iavf_dev_virtchnl_handler is also registered in eal-intr-thread.
>>>
>>> When vf device is bonded as BONDING_MODE_TLB mode, the slave device
>>> update callback will registered in alarm and called by
>>> eal-intr-thread, it would also raise the above issue.
>>>
>>> This commit add to poll the response for VIRTCHNL_OP_GET_STATS when
>> it
>>> is called by eal-intr-thread to fix this issue.
>>>
>>> Fixes: 91bf37d250aa ("net/iavf: add lock for VF commands")
>>> Fixes: 22b123a36d07 ("net/avf: initialize PMD")
>>> Fixes: 7c76a747e68c ("bond: add mode 5")
>>> Fixes: 435d523112cc ("net/iavf: fix multi-process shared data")
>>> Fixes: cb5c1b91f76f ("net/iavf: add thread for event callbacks")
>>
>>
>> Hi Kaiwen,
>>
>> Above commit already seems trying to address same issue, it creates "iavf-
>> event-thread" control thread to asyncroniously handle the interrupts, in non-
>> interrupt context, why it is not working?
>>
>> Instead of adding 'rte_thread_is_intr()' checks, can't you make sure all
>> interrupts handled in control tread?
>>
>> And can you please provide a stack trace in commit log, to describe the issue
>> better?
> Hi Ferru,
> Sorry for my late reply, And thanks for your review.
>  
> The above commit does not fix this issue when we need to get the returned data.
> If we call iavf_query_stats and wait for response statistics in the intr-thread.
> iavf_handle_virtchnl_msg is also registered in the intr_thread and will not be 
> executed while waiting.
> 

Got it, since return value is required, API can't be called asyncroniously.



I think 'rte_thread_is_intr()' checks may cause more trouble for you in
long term,

- why 'iavf_query_stats()' is called in the iterrupt thread, can it be
prevented?

- does it make sense to allways poll messages from PF (for simplification)?


If answer to both are 'No', I am OK to continue with current proposal if
you are happy with it.


> This commit I changed it to polling for replies to commands executed in the interrupt thread.
> 
> main thread                                                                                                interrupt thread
>      |                                                                                                                               |
>      |                                                                                                                               |
> iavf_query_stats                                                                                                        |
> iavf_execute_vf_cmd                                                                                               |
> iavf_aq_send_msg_to_pf  and wait handle complete                                       |
>      |                                                                                                                              |
>      |-------------------------------------------------------------------------------------------->|
>      |                                                                                                                              |
>      |                                                                                                       iavf_handle_virtchnl_msg
>      |                                                                                                                             |
>      |<--------------------------------------------------------------------------------------------|
>      |                                                                                                                             |
> iavf_execute_vf_cmd get response                                                                      |
>      |                                                                                                                             |
> 
> The above is the stack trace for the normal execution of iavf_query_stats 
> in the main thread.
> 
>  interrupt thread
>      |
>      |
> iavf_query_stats
> iavf_execute_vf_cmd
> iavf_aq_send_msg_to_pf wait handle complete(1 sec)
> iavf_execute_vf_cmd timeout
>      |
>      |
> iavf_handle_virtchnl_msg
>      |
> 
> The above is the stack trace for the abnormal execution of iavf_query_stats 
> in the interrupt thread.
>>
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Kaiwen Deng <kaiwenx.deng@intel.com>
>>> ---
>>> Changes since v2:
>>> - Add to poll the response for VIRTCHNL_OP_GET_STATS.
>>>
>>> Changes since v1:
>>> - Add lock to avoid race condition.
>>> ---
>>> ---
>>>  drivers/net/bonding/rte_eth_bond_pmd.c |  7 ++-
>>>  drivers/net/iavf/iavf_ethdev.c         |  5 +-
>>>  drivers/net/iavf/iavf_vchnl.c          | 71 ++++++++++++++++++--------
>>>  3 files changed, 58 insertions(+), 25 deletions(-)
>>>
>>> diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c
>>> b/drivers/net/bonding/rte_eth_bond_pmd.c
>>> index f0c4f7d26b..edce621496 100644
>>> --- a/drivers/net/bonding/rte_eth_bond_pmd.c
>>> +++ b/drivers/net/bonding/rte_eth_bond_pmd.c
>>> @@ -894,6 +894,7 @@ bond_ethdev_update_tlb_slave_cb(void *arg)
>>>  	uint8_t update_stats = 0;
>>>  	uint16_t slave_id;
>>>  	uint16_t i;
>>> +	int ret;
>>>
>>>  	internals->slave_update_idx++;
>>>
>>> @@ -903,7 +904,10 @@ bond_ethdev_update_tlb_slave_cb(void *arg)
>>>
>>>  	for (i = 0; i < internals->active_slave_count; i++) {
>>>  		slave_id = internals->active_slaves[i];
>>> -		rte_eth_stats_get(slave_id, &slave_stats);
>>> +		ret = rte_eth_stats_get(slave_id, &slave_stats);
>>> +		if (ret)
>>> +			goto OUT;
>>> +
>>>  		tx_bytes = slave_stats.obytes - tlb_last_obytets[slave_id];
>>>  		bandwidth_left(slave_id, tx_bytes,
>>>  				internals->slave_update_idx, &bwg_array[i]);
>> @@ -922,6 +926,7 @@
>>> bond_ethdev_update_tlb_slave_cb(void *arg)
>>>  	for (i = 0; i < slave_count; i++)
>>>  		internals->tlb_slaves_order[i] = bwg_array[i].slave;
>>>
>>> +OUT:
>>>  	rte_eal_alarm_set(REORDER_PERIOD_MS * 1000,
>> bond_ethdev_update_tlb_slave_cb,
>>>  			(struct bond_dev_private *)internals);  } diff --git
>>> a/drivers/net/iavf/iavf_ethdev.c b/drivers/net/iavf/iavf_ethdev.c
>>> index 3196210f2c..d6e1f1a7f4 100644
>>> --- a/drivers/net/iavf/iavf_ethdev.c
>>> +++ b/drivers/net/iavf/iavf_ethdev.c
>>> @@ -2607,6 +2607,9 @@ iavf_dev_init(struct rte_eth_dev *eth_dev)
>>>  	adapter->dev_data = eth_dev->data;
>>>  	adapter->stopped = 1;
>>>
>>> +	if (iavf_dev_event_handler_init())
>>> +		goto init_vf_err;
>>> +
>>>  	if (iavf_init_vf(eth_dev) != 0) {
>>>  		PMD_INIT_LOG(ERR, "Init vf failed");
>>>  		return -1;
>>> @@ -2634,8 +2637,6 @@ iavf_dev_init(struct rte_eth_dev *eth_dev)
>>>  	rte_ether_addr_copy((struct rte_ether_addr *)hw->mac.addr,
>>>  			&eth_dev->data->mac_addrs[0]);
>>>
>>> -	if (iavf_dev_event_handler_init())
>>> -		goto init_vf_err;
>>>
>>>  	if (vf->vf_res->vf_cap_flags & VIRTCHNL_VF_OFFLOAD_WB_ON_ITR)
>> {
>>>  		/* register callback func to eal lib */ diff --git
>>> a/drivers/net/iavf/iavf_vchnl.c b/drivers/net/iavf/iavf_vchnl.c index
>>> 9adaadb173..aeffb07cca 100644
>>> --- a/drivers/net/iavf/iavf_vchnl.c
>>> +++ b/drivers/net/iavf/iavf_vchnl.c
>>> @@ -256,6 +256,7 @@ iavf_read_msg_from_pf(struct iavf_adapter
>> *adapter, uint16_t buf_len,
>>>  				vf->link_speed =
>> iavf_convert_link_speed(speed);
>>>  			}
>>>  			iavf_dev_link_update(vf->eth_dev, 0);
>>> +			iavf_dev_event_post(vf->eth_dev,
>> RTE_ETH_EVENT_INTR_LSC, NULL, 0);
>>>  			PMD_DRV_LOG(INFO, "Link status update:%s",
>>>  					vf->link_up ? "up" : "down");
>>>  			break;
>>> @@ -368,28 +369,48 @@ iavf_execute_vf_cmd(struct iavf_adapter
>> *adapter, struct iavf_cmd_info *args,
>>>  		_clear_cmd(vf);
>>>  		break;
>>>  	default:
>>> -		/* For other virtchnl ops in running time,
>>> -		 * wait for the cmd done flag.
>>> -		 */
>>> -		do {
>>> -			if (vf->pend_cmd == VIRTCHNL_OP_UNKNOWN)
>>> -				break;
>>> -			iavf_msec_delay(ASQ_DELAY_MS);
>>> -			/* If don't read msg or read sys event, continue */
>>> -		} while (i++ < MAX_TRY_TIMES);
>>> -
>>> -		if (i >= MAX_TRY_TIMES) {
>>> -			PMD_DRV_LOG(ERR, "No response for cmd %d",
>> args->ops);
>>> +		if (rte_thread_is_intr()) {
>>> +			/* For virtchnl ops were executed in eal_intr_thread,
>>> +			 * need to poll the response.
>>> +			 */
>>> +			do {
>>> +				result = iavf_read_msg_from_pf(adapter,
>> args->out_size,
>>> +							args->out_buffer);
>>> +				if (result == IAVF_MSG_CMD)
>>> +					break;
>>> +				iavf_msec_delay(ASQ_DELAY_MS);
>>> +			} while (i++ < MAX_TRY_TIMES);
>>> +			if (i >= MAX_TRY_TIMES ||
>>> +				vf->cmd_retval !=
>> VIRTCHNL_STATUS_SUCCESS) {
>>> +				err = -1;
>>> +				PMD_DRV_LOG(ERR, "No response or return
>> failure (%d)"
>>> +						" for cmd %d", vf-
>>> cmd_retval, args->ops);
>>> +			}
>>>  			_clear_cmd(vf);
>>> -			err = -EIO;
>>> -		} else if (vf->cmd_retval ==
>>> -			   VIRTCHNL_STATUS_ERR_NOT_SUPPORTED) {
>>> -			PMD_DRV_LOG(ERR, "Cmd %d not supported", args-
>>> ops);
>>> -			err = -ENOTSUP;
>>> -		} else if (vf->cmd_retval != VIRTCHNL_STATUS_SUCCESS) {
>>> -			PMD_DRV_LOG(ERR, "Return failure %d for cmd %d",
>>> -				    vf->cmd_retval, args->ops);
>>> -			err = -EINVAL;
>>> +		} else {
>>> +			/* For other virtchnl ops in running time,
>>> +			 * wait for the cmd done flag.
>>> +			 */
>>> +			do {
>>> +				if (vf->pend_cmd ==
>> VIRTCHNL_OP_UNKNOWN)
>>> +					break;
>>> +				iavf_msec_delay(ASQ_DELAY_MS);
>>> +				/* If don't read msg or read sys event,
>> continue */
>>> +			} while (i++ < MAX_TRY_TIMES);
>>> +
>>> +			if (i >= MAX_TRY_TIMES) {
>>> +				PMD_DRV_LOG(ERR, "No response for
>> cmd %d", args->ops);
>>> +				_clear_cmd(vf);
>>> +				err = -EIO;
>>> +			} else if (vf->cmd_retval ==
>>> +				VIRTCHNL_STATUS_ERR_NOT_SUPPORTED) {
>>> +				PMD_DRV_LOG(ERR, "Cmd %d not
>> supported", args->ops);
>>> +				err = -ENOTSUP;
>>> +			} else if (vf->cmd_retval !=
>> VIRTCHNL_STATUS_SUCCESS) {
>>> +				PMD_DRV_LOG(ERR, "Return failure %d for
>> cmd %d",
>>> +						vf->cmd_retval, args->ops);
>>> +				err = -EINVAL;
>>> +			}
>>>  		}
>>>  		break;
>>>  	}
>>> @@ -403,8 +424,14 @@ iavf_execute_vf_cmd_safe(struct iavf_adapter
>>> *adapter,  {
>>>  	struct iavf_info *vf = IAVF_DEV_PRIVATE_TO_VF(adapter);
>>>  	int ret;
>>> +	int is_intr_thread = rte_thread_is_intr();
>>>
>>> -	rte_spinlock_lock(&vf->aq_lock);
>>> +	if (is_intr_thread) {
>>> +		if (!rte_spinlock_trylock(&vf->aq_lock))
>>> +			return -EIO;
>>> +	} else {
>>> +		rte_spinlock_lock(&vf->aq_lock);
>>> +	}
>>>  	ret = iavf_execute_vf_cmd(adapter, args, async);
>>>  	rte_spinlock_unlock(&vf->aq_lock);
>>>
>