[PATCH 0/3] UserfaultFD: Extension for non cooperative uffd usage

Hi,

On the recent LSF Andrea presented his userfault-fd patches and
I had shown some issues that appear in usage scenarios when the
monitor task and mm task do not cooperate to each other on VM
changes (and fork()-s).

Here's the implementation of the extended uffd API that would help 
us to address those issues.

As proof of concept I've implemented only fix for fork() case, but
I also plan to add the mremap() and exit() notifications, both are
also required for such non-cooperative usage.

More details about the extension itself is in patch #2 and the fork()
notification description is in patch #3.

Comments and suggestion are warmly welcome :)


Andrea, what's the best way to go on with the patches -- would you
prefer to include them in your git tree or should I instead continue
with them on my own, re-sending them when required? Either way would
be OK for me.

Thanks,
Pavel