Re: i686 SMP systems with more then 12 GB ram with 2.4.x kernel ?

Marvin Justice (mjustice@austin.rr.com)
Sun, 6 Jan 2002 12:59:12 -0600


Is this what your looking for? Just below the definition of PAGE_OFFSET in
page.h:

/*
* This much address space is reserved for vmalloc() and iomap()
* as well as fixmap mappings.
*/
#define __VMALLOC_RESERVE (128 << 20)

On Sunday 06 January 2002 12:39 pm, Daniel Freedman wrote:
> On Jan 01 2002, H. Peter Anvin (hpa@zytor.com) wrote:
> > By author: Alan Cox <alan@lxorguk.ukuu.org.uk>
> >
> > > > 2. Isn't the boundary at 2^30 really irrelevant and the three
> > > > "correct" zones are (0 - 2^24-1), (2^24 - 2^32-1) and (2^32 -
> > > > 2^36-1)?
> > >
> > > Nope. The limit for directly mapped memory is 2^30.
> >
> > 2^30-2^27 to be exact (assuming a 3:1 split and 128MB vmalloc zone.)
> >
> > -hpa
>
> For my better understanding, where's the 128MB vmalloc zone assumption
> defined, please?
>
> I'm pretty sure I understand that the 3:1 split you refer to is
> defined by PAGE_OFFSET in asm-i386/page.h
>
> But when I tried to find the answer in the source for the vmalloc
> zone, I looked in linux/mm.h, linux/mmzone.h, linux/vmalloc.h, and
> mm/vmalloc.c, but couldn't find anything there or in O'Reilly's kernel
> book that I could follow/understand.
>
> Thanks for any pointers.
>
> Take care,
>
> Daniel
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