Re: reg adjust_total_lowmem

Kumar Gala wrote:

On Fri, 26 Oct 2007, Scott Wood wrote:

quoted

Scott Wood wrote:

quoted

On Fri, Oct 26, 2007 at 10:04:19AM -0500, Kumar Gala wrote:

quoted

The reason you have 192M is that lowmem is the total amount of memory
that can be covered by up to three CAM entries.  In the case of  setting
mem=252M that max that three CAM entries can cover is 192M (64 +64+64).
You should be able to access the other 60M via HIGHMEM.

Why doesn't it just use a 256M mapping, and not access the last 4M?

This has some possibility, not sure what the threshold should be.  Do we
just always map 768M of lowmem regardless of how much memory we have?

That's probably the simplest way.  We'll need to fix VMALLOC_START as well.

quoted

Not to mention, why highmem and not just normal TLB0 mappings for the extra
pages?

Because we do not handle recursive misses in the TLB handlers.  We expect
any load/store that occurs in the TLB handlers to not have a TLB fault
associated with (and thus all of lowmem must be pinned).

OK.  I guess that means no page debugging... :-P

-Scott