[dpdk-dev] [PATCH 1/6] ether: enhancement for VMDQ support

[Chen, Jing D]

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon at 6wind.com]
> Sent: Tuesday, October 14, 2014 10:10 PM
> To: Chen, Jing D
> Cc: dev at dpdk.org
> Subject: Re: [dpdk-dev] [PATCH 1/6] ether: enhancement for VMDQ support
> 
> 2014-09-23 21:14, Chen Jing D:
> > The change includes several parts:
> > 1. Clear pool bitmap when trying to remove specific MAC.
> > 2. Define RSS, DCB and VMDQ flags to combine rx_mq_mode.
> > 3. Use 'struct' to replace 'union', which to expand the rx_adv_conf
> >    arguments to better support RSS, DCB and VMDQ.
> > 4. Fix bug in rte_eth_dev_config_restore function, which will restore
> >    all MAC address to default pool.
> > 5. Define additional 3 arguments for better VMDQ support.
> >
> > Signed-off-by: Chen Jing D(Mark) <jing.d.chen at intel.com>
> > Acked-by: Konstantin Ananyev <konstantin.ananyev at intel.com>
> > Acked-by: Jingjing Wu <jingjing.wu at intel.com>
> > Acked-by: Jijiang Liu <jijiang.liu at intel.com>
> > Acked-by: Huawei Xie <huawei.xie at intel.com>
> 
> Whaou, there were a lot of reviewers!
> The patch should be really clean. Let's see :)

First time I saw you are so humorous. :)

> 
> > --- a/lib/librte_ether/rte_ethdev.c
> > +++ b/lib/librte_ether/rte_ethdev.c
> >  		/* add address to the hardware */
> > -		if  (*dev->dev_ops->mac_addr_add)
> > +		if  (*dev->dev_ops->mac_addr_add &&
> > +			dev->data->mac_pool_sel[i] & (1ULL << pool))
> >  			(*dev->dev_ops->mac_addr_add)(dev, &addr, i,
> pool);
> 
> > +	/* Update pool bitmap in NIC data structure */
> > +	dev->data->mac_pool_sel[index] = 0;
> 
> Reset is a better word than "Update" in this case.
> But do we really need a comment for that?

Accept.

> 
> > +#define ETH_MQ_RX_RSS_FLAG  0x1
> > +#define ETH_MQ_RX_DCB_FLAG  0x2
> > +#define ETH_MQ_RX_VMDQ_FLAG 0x4
> 
> Need a comment to know where these flags can be used.

Accept.

> 
> >  enum rte_eth_rx_mq_mode {
> > -	ETH_MQ_RX_NONE = 0,  /**< None of DCB,RSS or VMDQ mode */
> > -
> > -	ETH_MQ_RX_RSS,       /**< For RX side, only RSS is on */
> > -	ETH_MQ_RX_DCB,       /**< For RX side,only DCB is on. */
> > -	ETH_MQ_RX_DCB_RSS,   /**< Both DCB and RSS enable */
> > -
> > -	ETH_MQ_RX_VMDQ_ONLY, /**< Only VMDQ, no RSS nor DCB */
> > -	ETH_MQ_RX_VMDQ_RSS,  /**< RSS mode with VMDQ */
> > -	ETH_MQ_RX_VMDQ_DCB,  /**< Use VMDQ+DCB to route traffic to
> queues */
> > -	ETH_MQ_RX_VMDQ_DCB_RSS, /**< Enable both VMDQ and DCB in
> VMDq */
> > +	/**< None of DCB,RSS or VMDQ mode */
> > +	ETH_MQ_RX_NONE = 0,
> > +
> > +	/**< For RX side, only RSS is on */
> > +	ETH_MQ_RX_RSS = ETH_MQ_RX_RSS_FLAG,
> > +	/**< For RX side,only DCB is on. */
> > +	ETH_MQ_RX_DCB = ETH_MQ_RX_DCB_FLAG,
> > +	/**< Both DCB and RSS enable */
> > +	ETH_MQ_RX_DCB_RSS = ETH_MQ_RX_RSS_FLAG |
> ETH_MQ_RX_DCB_FLAG,
> > +
> > +	/**< Only VMDQ, no RSS nor DCB */
> > +	ETH_MQ_RX_VMDQ_ONLY = ETH_MQ_RX_VMDQ_FLAG,
> > +	/**< RSS mode with VMDQ */
> > +	ETH_MQ_RX_VMDQ_RSS = ETH_MQ_RX_RSS_FLAG |
> ETH_MQ_RX_VMDQ_FLAG,
> > +	/**< Use VMDQ+DCB to route traffic to queues */
> > +	ETH_MQ_RX_VMDQ_DCB = ETH_MQ_RX_VMDQ_FLAG |
> ETH_MQ_RX_DCB_FLAG,
> > +	/**< Enable both VMDQ and DCB in VMDq */
> > +	ETH_MQ_RX_VMDQ_DCB_RSS = ETH_MQ_RX_RSS_FLAG |
> ETH_MQ_RX_DCB_FLAG |
> > +				 ETH_MQ_RX_VMDQ_FLAG,
> >  };
> 
> Why not simply remove all these combinations and keep only flags?
> Please keep it simple.

One reason is back-compatibility. 
Another reason is not all NIC driver support all the combined modes, only limited sets
driver supported. Under this condition, it's better to use the combination definition 
(VMDQ_DCB, DCB_RSS, etc) to let driver check whether it supports.
	
> 
> > +	/**< Specify the queue range belongs to VMDQ pools if VMDQ
> applicable */
> > +	uint16_t vmdq_queue_base;
> > +	uint16_t vmdq_queue_num;
> 
> If comment is before, it should be /** not /**<.

Accept.

> 
> > +	uint16_t vmdq_pool_base; /** < Specify the start pool ID of VMDQ
> pools */
> 
> There is a typo with the space --^
> Please, when writing comments, ask yourself if each word is required
> and how it can be shorter.
> Example here: /**< first ID of VMDQ pools */
> 
> Conclusion: NACK
> There are only few typos and minor things but it would help to have more
> careful reviews. Having a list of people at the beginning of the patch
> didn't help in this case.

I listed all the code reviewers out to reduce their workload to reply the email,
not mean to make it easier to be applied.

> 
> Thanks for your attention
> --
> Thomas