Hi Olivier,


On Monday 25 September 2017 10:52 PM, santosh wrote:

Hi Olivier,


On Monday 25 September 2017 08:37 AM, Olivier MATZ wrote:

quoted

quoted

+{
+	struct rte_eth_dev *dev;
+	const char *tmp;
+
+	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
+
+	if (pool == NULL)
+		return -EINVAL;
+
+	dev = &rte_eth_devices[port_id];
+
+	if (*dev->dev_ops->pools_ops_supported == NULL) {
+		tmp = rte_eal_mbuf_default_mempool_ops();
+		if (!strcmp(tmp, pool))
+			return 0;
+		else
+			return -ENOTSUP;

I don't understand why we are comparing with
rte_eal_mbuf_default_mempool_ops().

It means that the result of the function would be influenced
by the parameter given by the user.

But that will be only for ops not supported case and in that case,
function _must_ make sure that if inputted param is _default_ops_name
then function should return ops supported correct info (whether 
returning '0' : Best ops or '1': ops does support 
, this part is arguable.. meaning One can say that default_ops ='handle-name' is best possible handle Or 
one of handle which platform supports).

quoted

I think that a PMD that does not implement ->pools_ops_supported
should always return 1 (mempool is supported).

Return 1 says: PMD support this ops.. 

So if ops is not supported and func returns with 1, then which ops application will use?
If that ops is default_ops.. then How application will distinguish when to use default ops or
param ops?.. as because in both cases func will return with value 1.

The approach in the patch takes care of that condition and func will return -ENOTSUP 
if (ops not support || inputted param not matching with default ops) otherwise will return
0 or 1.

At application side; 
For error case: In case of -ENOTSUP, its upto application to use _default_ops or exit.
For good case: 0 or 1 case, func gaurantee that handle is either best handle for pool or pool supports
that handle.. However in your suggestion if ops not supported case returns 1 then application is not 
sure which ops to use.. default_ops Or input ops given to func.

make sense? 

Ping? Are you fine with said explanation if not then would you
share your thought in case if ops not supported returns simply
1 if then how application differentiate whether to use
default_ops Or inputted param ops.. as return value 1 holds true
for both cases, so how application will pick and choose which ops
to use?

Can we pl. close on this? need to send v5 for -rc1 release.

Thanks.