RE: [PATCH] [linux-2.6.39.x for xen] tmem: self-ballooning and frontswap-selfshrinking

[Dan Magenheimer <dan.magenheimer@oracle.com>]

> From: Ian Campbell [mailto:Ian.Campbell@eu.citrix.com]
> >
> > Although you're right, as I am fresh off a 2-1/2 year odyssey of
> > upstreaming cleancache, AND since this is almost certainly Xen
> > specific AND since there will likely be some changes over time
> > which could conceivably make this unnecessary, I would be content
> > with carrying this in a Xen-only tree for the foreseeable future.
> 
> As someone who is fresh of a 5+ year odyssey of upstreaming a Xen-only
> tree into mainline I must strongly object to this approach.
> 
> We have had a long uphill battle to get ourselves to the state we are in
> today and the approach you are suggesting is absolutely counter to the
> philosophy we have built up whilst doing that and accepting this undoes
> all of the good work up until now.
> 
> Getting stuff into a Xen tree is not an aim in and of itself but merely
> a conduit towards upstream. Nothing should be going into the Xen stable
> trees with the explicit aim of staying there for the foreseeable future.
> 
> If you want to run a tmem-only tree with stuff you don't intend to send
> upstream yet in it then that is your prerogative, please don't ask the
> rest of us to carry that burden.

Well that's a bit harsh.  Perhaps I should clarify: By "for the
foreseeable future", I meant I don't expect it to be a candidate
for 3.1 or probably even 3.2.  I didn't mean to imply that
I wasn't going to try, just that I wasn't going to try for 3.1.

I see Konrad's tree as kind of a linux-next specific to Xen where
Xen-ish functionality/fixes can be exposed "officially" to Xen users
before the upstreaming battle is fought.  I've had many requests
for tmem over the last couple of years but haven't had a good
foundation for delivery.  Are you saying nothing should go in
Konrad's tree unless it is immediately upstreamable?

Related, there's a really good article* in lwn.net of James Bottomley's
talk about the Android fork (subscribers only as of now) that
I think nicely summarizes our frustration with upstreaming battles.

Dan

* http://lwn.net/Articles/446297/ ... This may not be public for
a week or two.