Hi Michal, thanks for your replay and suggestions.

Yes the memory consumption is going to increase but the question is
whether this is something that is a real problem. Is it really common to
have many vmas with a dedicated policy?

Yes, it does not a realy problem.

What I am arguing here is that there are essentially 2 ways forward.
Either we continue to build up on top of the existing and arguably very
fragile code and make it even more subtle or follow a general pattern of
a proper reference counting (with usual tricks to reduce cache line
bouncing and similar issues). I do not really see why memory policies
should be any different and require very special treatment.

I got it. It is rather subtle and easy to get wrong if we push forward
with the existing way and it is a good opportunity to get from the
existing subtle model. I will try that on next version.

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Best Regards,
Zhongkun