It's not so that Google is creating new code which is adopted into The Mainline Kernel (Linux)... its moreso that Linux is becoming more -droidish and Android becoming less -droidish.

All the performance boosts in software we've seen from the iterations are simply [linux] available code that entered into the Android Kernel.

I think Android will ALWAYS be separated from the mainline kernel. But they are getting more shared features, and eventually the AMP (Android Mainlining Project) will be complete.

So that certain devices (eg Nexus) can have the AOSP-kernel removed and replaced with a hybrid-kernel (Linux with crucial aosp differences) so that it can run *some linux code without prior modification. Or perhaps the opposite, so an (old?) x86 device that's used for nix (ubuntu/rh/osuse) can get its kernel stripped and replaced with AMP so that android can be compatible within the build--I'm not talking about ssh environments either, talking about native running code.