Re: [PATCH 4/4] Add a monotonic time device

[Samuel Thibault]

Pino Toscano, le Thu 17 Nov 2011 23:10:16 +0100, a écrit :
> Alle sabato 27 agosto 2011, Samuel Thibault ha scritto:
> > Roland McGrath, le Sat 27 Aug 2011 10:03:24 -0700, a écrit :
> > > > Pino Toscano, le Fri 26 Aug 2011 20:29:43 +0200, a écrit :
> > > > > +extern vm_offset_t monotonicmmap();
> > > > > +#define      monotonicname           "monotonic"
> > > > 
> > > > Ah, I was rather thinking about appending the new clock to the
> > > > existing mappable clock.  I don't think it is useful to separate
> > > > them.
> > > 
> > > It does seem good to consolidate on the one page, no reason to have
> > > two pages.  But how exactly will the user tell that he has a new
> > > kernel that has both? It could be by some magic number on the page
> > > or something.
> > 
> > It could simply be the field being non-zero?
> 
> Won't that be problematic when running a newer glibc with a older 
> gnumach that does not zero the page?

Older gnumach does zero the page, see mapable_time_init().

Samuel