Re: [dpdk-dev] [RFC] ethdev: introduce sample action for rte flow

[Thomas Monjalon <thomas@monjalon.net>]

24/06/2020 20:09, Stephen Hemminger:
> > > +/**
> > > + * @warning
> > > + * @b EXPERIMENTAL: this structure may change without prior notice
> > > + *
> > > + * RTE_FLOW_ACTION_TYPE_SAMPLE
> > > + *
> > > + * Adds a sample action to a matched flow.
> > > + *
> > > + * The matching packets will be duplicated to a special queue or vport
> > > + * in the predefined probabiilty, All the packets continues processing
> > > + * on the default flow path.
> > > + *
> > > + * When the sample ratio is set to 1 then the packets will be 100% mirrored.
> > > + * Additional action list be supported to add for sampled or mirrored packets.
> > > + */
> > > +struct rte_flow_action_sample {
> > > +	/* packets sampled equals to '1/ratio' */
> > > +	const uint32_t ratio;
> > > +	/* sub-action list specific for the sampling hit cases */
> > > +	const struct rte_flow_action *actions;
> > > +};
> 
> Putting const on the ratio value is not necessary.
> Other flow_actions don't do that.
> 
> Note: rte_flow action structures seem to have lots of holes.
> The value of those holes is undefined. You may want to swap the fields.

Why is it a problem to have holes with undefined value?
If swapping, the hole will be at the end, right?