> currently, once a page is first faulted and the pmap-level mapping is created,
> it can be modified again indefinitely without the kernel knowing and thus
> without mtime being updated.  if this is a problem, then we could change
> things so that making a clean page dirty again will cause another fault
> to give us a chance to update mtime again.  we'll need that same refault-
> on-redirty logic to do the fsync() optimizations that were discussed
> some time back, so once we have that then we could also call back into
> the fs to update mtime if we want.
> 
> -Chuck

have you decided to do fsync optimization in the way which needs
refault-on-redirty?

an alternative is not to care much about pages dirtied via mmap
as it isn't required by any standards afaik.

YAMAMOTO Takashi