On Mon 22-02-21 14:22:37, David Hildenbrand wrote: > > > Exactly. But for hugetlbfs/shmem ("!RAM-backed files") this is not what we > > > want. > > > > OK, then I must have misread your requirements. Maybe I just got lost in > > all the combinations you have listed. > > Another special case could be dax/pmem I think. You might want to fault it > in readable/writable but not perform an actual read/write unless really > required. > > QEMU phrases this as "don't cause wear on the storage backing". Sorry for being dense here but I still do not follow. If you do not want to read then what do you want to populate from? Only map if it is in the page cache? -- Michal Hocko SUSE Labs