From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Monjalon <thomas@monjalon.net>
Subject: Re: [PATCH v2 1/2] ethdev: stop overriding rx_nombuf by
	rte_eth_stats_get
Date: Wed, 23 Aug 2017 23:35:17 +0200
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References: <20170823011937.37579-1-dharton@cisco.com> <3459676.trPQTB1ucG@xps>
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To: "David Harton (dharton)" <dharton@cisco.com>
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23/08/2017 23:27, David Harton (dharton):
> From: Thomas Monjalon [mailto:thomas@monjalon.net]
> > 23/08/2017 14:18, David Harton (dharton):
> > > From: Thomas Monjalon [mailto:thomas@monjalon.net]
> > > > 23/08/2017 04:55, David Harton:
> > > > > rte_eth_stats_get() unconditonally would set rx_nombuf even if the
> > > > > device was setting the value.  A check has been added in
> > > > > rte_eth_stats_get() to leave the device value in-tact when non-zero.
> > > >
> > > > If we get this counter from stats->rx_nombuf, why keeping
> > > > dev->data->rx_mbuf_alloc_failed ?
> > > > We could rework other PMDs to not use this global variable.
> > > > It is inconsistent to use it for some PMDs but not all.
> > > > And it seems not used outside of PMDs.
> > >
> > > Are you also asking to remove dev->data->rx_mbuf_alloc_failed as well
> > since we will have an ABI breakage anyway?
> > 
> > Not asking, just giving my thought :)
> 
> I did some more digging.  For this count it looks like some devices:
> - have their own internal version
> - have a count shared with the pf
> - rely on this field to maintain the count
> - don't count this failure at all :(
> 
> With that said I'd like to keep with the requested changes.
> 
> Thoughts?

I don't see how it is a problem for removing dev->data->rx_mbuf_alloc_failed.
If this field is used, we just have to replace it by a PMD internal variable.
Isn't it?