On Mon, 15 Jul 2019 17:38:04 -0700 Ralph Campbell <rcampbell@xxxxxxxxxx> wrote: > I'm not surprised at the confusion. It took me quite awhile to > understand how migrate_vma() works with ZONE_DEVICE private memory. > > ... > > I see Christoph Hellwig got confused by this too [1]. While making such discoveries, please prepare a patch which adds comments which will help the next poor soul!