On Fri, Sep 29, 2017 at 11:16:20AM +0100, santosh wrote:
> Hi Olivier,
>
>
> On Friday 29 September 2017 09:32 AM, Olivier MATZ wrote:
> > On Mon, Sep 25, 2017 at 10:52:31PM +0100, santosh wrote:
> >> Hi Olivier,
> >>
> >>
> >> On Monday 25 September 2017 08:37 AM, Olivier MATZ wrote:
> >>
> >>>> +{
> >>>> + 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).
> >>
> >>> I think that a PMD that does not implement ->pools_ops_supported
> >>> should always return 1 (mempool is supported).
> > I don't agree.
> > The result of this API (mempool ops supported or not by a PMD)
> > should not depend on what user asks for.
> >
> >> 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?
> > My proposition is:
> >
> > - what a PMD returns does not depend on used parameter:
> > - 0: best support
> > - 1: support
> > - -ENOTSUP: not supported
> >
> > - if a PMD does not implement the _ops_supported() API, assume all pools
> > are supported (returns 1)
>
> If API returns 1 for PMD does not implement _ops_supported() case,
> then do we really need -ENOTSUP?
When the PMD explicitly does not support a mempool ops.
Not implementing the API means, like today: "I don't care what
the mempool ops is, so I a priori support all the ones available,
without preference".
