Date: Thu, 13 Feb 2003 17:02:44 -0800 From: Marcel Moolenaar <marcel@xcllnt.net> To: Arun Sharma <arun.sharma@intel.com> Cc: freebsd-ia64@FreeBSD.ORG Subject: Re: Maxmem should be bytes ? Message-ID: <20030214010244.GA1344@athlon.pn.xcllnt.net> In-Reply-To: <uvfzn1yev.fsf@unix-os.sc.intel.com> References: <200302080111.h181Bkr26574@unix-os.sc.intel.com> <u1y2b3eb7.fsf@unix-os.sc.intel.com> <20030214002346.GA1267@athlon.pn.xcllnt.net> <uvfzn1yev.fsf@unix-os.sc.intel.com>
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On Thu, Feb 13, 2003 at 04:47:04PM -0800, Arun Sharma wrote:
> Marcel Moolenaar <marcel@xcllnt.net> writes:
> > On Thu, Feb 13, 2003 at 04:18:20PM -0800, Arun Sharma wrote:
> > > Arun Sharma <arun.sharma@intel.com> writes:
> > >
> > > > I found that my VHPT size was limited to 2**15 no matter how much
> > > > memory I had. I tracked this down to the code in machdep.c:598.
> > > >
> > > > physmem is in units of pages and Maxmem is the number of bytes. This
> > > > incorrect assignment results in a small VHPT size.
> > >
> > > I didn't see a response to this message. While VHPT < 2**15 isn't a
> > > huge issue, this bug could result in other correctness problems.
> >
> > Such as?
>
> New code that tries to use ia64_ptob(Maxmem) for something other than
> VHPT sizing would be broken.
Like machdep.c:164?
printf("real memory = %ld (%ld MB)\n", ia64_ptob(Maxmem),
ia64_ptob(Maxmem) / 1048576);
As for the fact that Maxmem is in bytes and physmem isn't: we define
Maxmem to be equal to physmem (machdep.c:598). So they are in fact
equal.
> And of course, it doesn't hurt to have a
> bigger VHPT on large memory machines :)
Agreed. However, I'd like us to first get things to work without VHPT
(especially SMP) and then focus on getting a good VHPT implementation.
I think this way we'll have the best infrastructure. I have it planned
after EPC (I'm working on that right now).
--
Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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