One thing I was considering is to check agains ref counte overflo (a deep process chain with many vmas could grow really high. ref_count interface doesn't provide any easy way to check for overflows as far as I could see from a quick glance so I gave up there but the logic would be really straightforward. We just create a new anon_vma_name with the same content and use it when duplicating if the usage grow really (arbitrarily) high. -- Michal Hocko SUSE Labs
