https://bugs.freedesktop.org/show_bug.cgi?id=92775
--- Comment #3 from Christian König deathsimple@vodafone.de --- Actually it doesn't need to be so complicated. Just take a look at amdgpu|radeon_move_vram_ram().
Instead of trying to reallocate and binding everything at once we just need to bind the already allocate new_mem pages page by page and copy page by page.