Re: no-arch-specific-mem_map-init

[Matthew Wilcox <matthew@wil.cx>]

On Wed, Mar 09, 2005 at 10:58:33PM -0800, Andrew Morton wrote:
> Everyone OK with this?

Since I don't understand VM and he's touching everything except my port,
no ;-P

> From: Dave Hansen <haveblue@us.ibm.com>
> The following patch does what my first one did (don't pass mem_map into the
> init functions), incorporates Jesse Barnes' ia64 fixes on top of that, and
> gets rid of all but one of the global mem_map initializations (parisc is
> weird).  It also magically removes more code than it adds.  It could be
> smaller, but I shamelessly added some comments.  

I'm not quite sure why parisc is 'weird'.  Here's the code block in question:

void __init mem_init(void)
{
        high_memory = __va((max_pfn << PAGE_SHIFT));

#ifndef CONFIG_DISCONTIGMEM
        max_mapnr = page_to_pfn(virt_to_page(high_memory - 1)) + 1;
        mem_map = zone_table[ZONE_DMA]->zone_mem_map;
        totalram_pages += free_all_bootmem();
#else
        {
                int i;

                for (i = 0; i < npmem_ranges; i++)
                        totalram_pages += free_all_bootmem_node(NODE_DATA(i));
        }
#endif

Something that may not be intuitively obvious to someone with i386 biases
is that on PA-RISC (at least in the case of CONFIG_DISCONTIGMEM=n), all
memory is in ZONE_DMA.  Does that help divine what the right answer is
for parisc?

Randolph, you touched this code last ... can you help Dave understand it?

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