We've recently decided to give Xen another shot, and love the direction of the XCP-ng project.
I've been searching various xen sites and sources for memory overcommitment, since that's a feature we need.
I came across a presentation by Huawei in 2018, showing some impressive usage and stats on this topic:
I'm wondering if any of this has made it back to Xen sources, or if it is still a Huawei only feature.
I'm not aware of such feature available upstream. I will ask around.
What is your use case for that? I mean, this is the first time someone asking for it.
@olivierlambert strictly a density thing. it's a main vmware feature, and one of the things other virtualization environments lack. I got excited seeing huawei has actually worked on it, then couldn't find any other references to it other than that presentation.
@olivierlambert If Huawei developers implemented this feature in Huawei Cloud as an open source derivative, would they not be required to provide their source code back to the upstream project?
Okay I asked Xen upstream and nobody saw any commit related to that ended in the Xen code.
Also, the question you asked is very interesting. In GPLv2 (Xen license), you are forced to redistribute your modifications (here, modified Xen code) if you distribute the software.
But in the Cloud era (ie SaaS), since you are not distributing the software anymore (but hosting it), it's a loophole in the GPLv2. Guess why AWS never contributed to Xen in the first place?
That's fixed by aGPLv3 (the license we use for XO): regardless the fact you redistribute the code or not, every modification must be publicly available.
Also, publishing the code is one thing. But maintaining it or upstream it is another one. I'm a strong believer of "upstream first" philosophy (meaning you'll do all the efforts to get your code in the upstream): because then, it will be maintained by everyone (ideally).
To go back to your case, you might dig to see if you can find Huawei code, and then see why it never ended upstream.
@olivierlambert very interesting. I'll bet we never see this, such a shame. They have an open source release center here:
however the link to cloud goes to not found.
I'll try some emails, and see if I can get anywhere. The developer who did the presentation never responded to the email address posted in the presentation.
No result found on searching "Xen" in the link you posted.
I found the guy on LinkedIn, he's still working at Huawei. Trying to connect with him, but I have thin chances to get an answer too…
@olivierlambert is this something that can be turned in as an issue to an open source enforcement group of some kind? Any recommendations of one to ask?
You might ask Xen project upstream directly (on appropriate mailing list), see https://xenproject.org/help/mailing-list/
However, if there's nobody interesting to do this, it means no money. If your company is interesting in it, we can try to see the amount of work needed (IMHO: not trivial at all) and get a rough price estimate.