What new system calls do you want in BSD?

[Malaclypse the Elder]

In article <12067 at smoke.BRL.MIL>, gwyn at smoke.BRL.MIL (Doug Gwyn) writes:
> In article <2863 at auspex.auspex.com> guy at auspex.auspex.com (Guy Harris) writes:
> >>	vm_offset_t	*addr;		/* Where to map to (page aligned) */
> >Yes, and so do SunOS 4.x and System V Release 4.  What's more, both of
> >them implement "mmap", which bears a startling resemblance to "map_fd". 
> 
> For a user-mode function, I strongly dislike the page-alignment constraint.
> Does mmap have a similar requirement?

yes mmap has a similar requirement.  this is because the page is
the unit of mapping that the hardware supports.  the alternative
is some HUGE overhead of faulting on any reference to a page that
has an address that is not page aligned and doing any copying necessary
to update that page.

i'm not sure, but doesn't mmap return the address that something was
actually attached to?  the *addr above is just a hint to the system
about where to attach?  so user level code doesn't have to know?

danny chen
att!hocus!dwc