Re: [Xen-devel] [v4][PATCH 11/19] tools: introduce some new parameters to set rdm policy

["Chen, Tiejun" <tiejun.chen@xxxxxxxxx>]

On 2015/7/2 18:28, George Dunlap wrote:
> On 07/02/2015 11:01 AM, Chen, Tiejun wrote:
> > > 1. After spending yet another half hour doing research, I haven't found
> > > any discussion that concluded we should have the global policy override
> > > the local policy
> > I also took some time to go back checking this point and indeed this is
> > not in that public design. And as I mentioned in another email which is
> > following this, I also had a talk to Kevin about this issue, and looks
> > this is just concluded from our internal discussion and he didn't post
> > this in v2 design again because as you know, that design is about
> > something in high level. And as I recall, these discussions can't cover
> > everything at that moment because they thought we'd better post a
> > preliminary patches to further discuss something since this is really a
> > complicated case. So afterwards I sent out two RFC revisions to help all
> > guys finalize a good solution. And I can confirm current policy is
> > always same from the first RFC, but we didn't see any opposite advice
> > until now.
> Probably because the reviewers all assumed that the design draft had
> been followed, and you didn't make it clear that you'd changed it.
Shouldn't the patch head description already clarify this point? And I 
also comment this point in the code. After all, we already had several 
rounds of technical reviews so its a little hard to believe it was not 
obvious to be missed.
> > > 2. The only discussion I *did* find has *you yourself* saying that the
> > > per-device setting should override the global setting, not once, but
> > > twice; and nobody contradicting you.
> > >
> > > Maybe there is somewhere else a discussion somewhere where this was
> > > changed; but I've already spent half an hour this morning looking at
> > > where you said it was (v2 design discussion), and found the opposite --
> > > just as I remembered.  I'm not going to look anymore.
> > >
> > > You have now caused me to waste an awful lot of time on this series that
> > > could profitably have been used elsewhere.
> > Sorry to this but I just think we already have 2 RFC revisions and 4
> > revisions without RFC, and some patches are already Acked, we really
> > should overturn this policy right now?
> First of all, I think it's easy to change.
I agree but what I'm saying is this is involving our policy. It 
shouldn't change this sort of thing if not all associated maintainers 
are in the agreement with you.
> Even if it weren't, I already said that I'd be OK with accepting the
> patch series with the existing "override" semantics, and without the
> "default" semantics, *if* it were renamed to make it clear what was
> going on.
>
> But, for future reference, I am not going to approve an interface I
> think is misleading or wrong -- particularly one like the xl interface
> which we want to avoid changing if possible -- just because time is
> short.  One of my own features, HVM USB pass-through, has narrowly
> missed two releases (including the current one) because we wanted to be
> careful to get the interface right.
I admit I should concern everything carefully like you.

> > > > Again, I didn't walk into v2 design. So here I don't want to bring any
> > > > confusion to you just with my reply.
> > > This is your feature, so it is your responsibility to understand and
> > > explain why you are doing what you are doing, if only to say "Jan wanted
> > Maybe you remember I just posted v1 but looks that was not a better
> > design to show this implementation according to some feedback, so Kevin
> > issued v2 revision and had a wider discussion with you guys. Since then
> > I just follow this version. So I mean I don't further hold these things
> > in high level since I just think both policy is fine to me because IMO,
> > these two approaches are optional.
> >
> > > X to happen because of Y [see $ref]."
> > So this is why I said you'd better ask this to Kevin or Jan since I
> > can't decide what's next at this point.
> Let me say that again: I don't care whether anyone "pulled rank" and
> ordered you to do something a certain way.  YOU are the one submitting
> this patch.  That means YOU responsible for understanding why they want
> it that way, and YOU are responsible for justifying it to other people.
>   If you don't understand it at all, it's YOUR responsibility to get them
> to explain it, not mine to chase them down.
As I said above I thought initially they're optional, and just about 
which one is a preference. So I picked up these patch descriptions 
reviewed in public to say this is our expectation. But looks this is not 
satisfied to you, so I don't think I can further explain this kind of 
thing appropriately, and then I ask you to ping Jan or Kevin to get a 
formal answer. Is this procedure not reasonable?
Thanks
Tiejun


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