On Thu, 3 Apr 2008, Fernando Apesteguía wrote:
> On 4/3/08, Robert P. J. Day <rpjday@xxxxxxxxxxxxxx> wrote:
> >
> > given that i'm determined to nail down how linux MM works, i'm
> > perusing the code and some docs from the beginning and, since a lot of
> > those docs annoyingly disagree with each other in some fundamental
> > places, i'm going to be asking some annoyingly trivial questions. get
> > used to it. :-)
> >
> > to start, the standard definition of high memory on a 32-bit x86
> > system is memory above 896M.
> >
> > * where is that exact boundary defined?
>
> in arch/<architecture>/mm/init.c, e.g:
>
> arch/i386/mm/init.c in function zone_size_init
i'm guessing you're looking at an older version of the source tree
as that arch directory doesn't even exist anymore -- both 32 and 64
bit versions have been amalgamated under arch/x86 and, as the previous
poster pointed out, the limit is now in arch/x86/mm/init_32.c, which
does answer my question. more questions coming shortly.
rday
p.s. i'm wondering what would happen if you deliberately decided to
change the defining macro:
unsigned int __VMALLOC_RESERVE = 128 << 20;
--
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Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry:
Have classroom, will lecture.
http://crashcourse.ca Waterloo, Ontario, CANADA
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