Hi! Commit c0b124054f9e42eb6da545a10fe9122a7d7c3f72 has very nice commit message, explaining what HMM_MIRROR is and when it is needed. Unfortunately, it did not make it into Kconfig help: CONFIG_HMM_MIRROR: Select HMM_MIRROR if you want to mirror range of the CPU page table of a process into a device page table. Here, mirror means "keep synchronized". Prerequisites: the device must provide the ability to write-protect its page tables (at PAGE_SIZE granularity), and must be able to recover from the resulting potential page faults. Could that be fixed? This is key information for me: # This is a heterogeneous memory management (HMM) process address space # mirroring. # This is useful for NVidia GPU >= Pascal, Mellanox IB >= mlx5 and more # hardware in the future. Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html