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

schmitz
2014-04-01T07:45:45Z

Hi Geert,
>
>>>> 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 ...
>>>>
>>> How do you know? You would have to reimplement the check paging_init
>>> does.
>>>
>> I see - as a heuristic, we can probably assume that the first memchunk is
>> the relevant one, and especially in the case of FastRAM, also the larger
>> one.
>> Does this hold for Amiga/Mac/VME as well?
>>
>
> People want to run the kernel in the fastest memory chunk, which is typically
> also the largest (slow Amiga mainboard memory may be 2 - 16 MiB for
> Linux-capable machines, accelerator memory may be larger).
>

And the chunk the kernel runs from would always be the first chunk
listed in bootinfo, since that's the one mapped at virtual address zero?

> Don't know about Mac, but I have some memories of interleaved banks
> and such...
>

Not sure I've ever seen accelerators or memory upgrades on the Macs that
I hacked on. 4 MB was sort of plenty in those days.

Cheers,

Michael