Re: HIGH MEMORY access

From: Manfred Spraul (manfreds@colorfullife.com)
Date: Wed Mar 08 2000 - 04:31:20 EST


Ingo Molnar wrote:
>
> On Fri, 3 Mar 2000, Manfred Spraul wrote:
>
> > Now I'm confused: I thought that ioremap() should be used for reserved
> > memory, and kmap() for normal memory (e820: ram) with
> > page->virtual==NULL.
>
> well you can use kmap() for anything, not just high memory. I suggested
> kmap() because ioremap() relies on a working allocator and other
> higher-level structures - kmap() certainly works better for smaller
> structures such as the MP-table.

Have you ever tried to do that?
kmap() is a nop if your kernel is not compiled for CONFIG_HIGHMEM, and
kmap_atomic() doesn't even exist.

It seems we should add a vremap_boot() for the boot process.
Btw, can the MP tables cross page boundaries? kmap() would make parsing
such tables extremely difficult.

--
	Manfred

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