On Sun, 11 Sep 2016 10:31:35 -0700 Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > As evidenced by this bug report [1], userspace libraries are interested > in whether a mapping is DAX mapped, i.e. no intervening page cache. > Rather than using the ambiguous VM_MIXEDMAP flag in smaps, provide an > explicit "is dax" indication as a new flag in the page vector populated > by mincore. Can you cc linux-arch when adding new syscalls (or other such things that need arch enablement). I wonder if the changelog for a new syscall should have a bit more grandeur. Without seeing patch 2, you might not know this was a new syscall just by reading the subject and changelog. mincore() defines other bits to be reserved, but I guess it probably breaks things if you suddenly started using them. It's a bit sad to introduce a new syscall for this and immediately use up all bits that can be returned. Would it be a serious problem to return a larger mask per page? Thanks, Nick -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>