Re: [PATCH 0/4] Atari kernel-in-FastRAM patches, take three

schmitz
2014-04-01T07:40:11Z

Hi Geert
> Hi Michael,
>
> On Mon, Mar 31, 2014 at 11:24 PM, Michael Schmitz <schmitzmic@gmail.com> wrote:
>
>> do we know the size of the first memory chunk early enough in head.S?
>> Maybe it's time to increase INIT_MAPPED_SIZE at least in cases where
>> we know that there's more than 4 MB in the first memchunk ...
>>
>
> "get_bi_record BI_MEMCHUNK" will return a pointer to the first mem_info
> struct.
>

Yep, that's as far as I got - if I read bootinfo.h right, this will need
to have an offset of 12 bytes added to get to the size member, correct?

> If the first chunk is at least 8 MiB it should be not that intrusive.
> If it isn't, and you have to use multiple chunks, it becomes more complicated.
>

My reasoning exactly - if the first chunk is the smaller one, the page
tables shouldn't get too big anyway. If it's the larger one, multiple
chunks are not possible anyway (at least on Atari) due to the
discontigmem constraint. Either way, 8 MB should be safe if present.

What size FastRAM did precipitate that bug for you, Andreas?

Cheers,

Michael