On Wed, Dec 17, 2008 at 07:34:07PM +0100, Markus Hennecke wrote:
> Raimo Niskanen schrieb:
> >[config description]
> 
> >But how to find a bigmem parameter I do not know, I have
> >no amd64 system. Try 'help' in the config editor.
> >
> >And, as pointed out before:
> >
> >    If you search the archives, you'll find the clue you need to enable it
> >    on your own system.
> >
> >See also:
> >    config(8)
> >    options(4)
> >    boot_config(8)
> >    boot_i386(8)
> >    boot(8)
> 
> So I read all that before and now I have to out me as plain stupid. I 
> still have no clue how to set bigmem to 1 using config(8). And as you 
> can see in this thread, it looks like I am not alone. Either I read over 
> it on more than one occasion, or there is no documentation describing it.

Sorry about that. I could only give you some pointers on how to use
UCK(config(8)) and have no amd64 system myself, so I deemed it probably
futile for me to try to find the bigmem parameter.

Then I assumed the rest of the clues _would_ be in the archives
but did not search myself. They still might be in the archives
but a later post in this thread suggests you can not do this with
config(8). You probably will have to compile a kernel.

I have searched the 4.4 kernel source tree and found:
$ find sys -type f | xargs grep -i bigmem
sys/arch/amd64/amd64/machdep.c:int bigmem = 1;
sys/arch/amd64/amd64/machdep.c: if (bigmem)
sys/arch/amd64/amd64/machdep.c:         printf("Bigmem = %d\n", bigmem);
sys/arch/amd64/amd64/machdep.c:         if (!bigmem && (e1 >= (1UL<<32))) {
sys/arch/amd64/amd64/machdep.c:         } else if (bigmem && (e1 >= (1UL<<32))) 
{

The revision of the file is 1.81 so that was just
before the release. In the cvsweb
http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/amd64/amd64/machdep.c
it says bigmem was set to 0 for the release of 4.4, and it still is
(revision 1.85).

I can also not find a documented way to tweak it from config(8)
as it is stated on the comment line before "int bigmem = 0;".
It is probably daft simple or untrue. But changing the line to
"int bigmem = 1;" in the source code will certainly do the trick.


> 
> Kind regards,
>   Markus

-- 

/ Raimo Niskanen, Erlang/OTP, Ericsson AB

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