Re: kexec reboot code buffer

["Martin J. Bligh" <mbligh@aracnet.com>]

>> The problem is that I have not figured out how to tell the memory
>> allocator just what I need, 
> <snip>
>> I guess I would make the standard zones something like:
>> /*
>>  * ZONE_DMA	  < 16 MB	ISA DMA capable memory
>>  * ZONE_NORMAL  16-896 MB	direct mapped by the kernel
>>  * ZONE_PHYSMEM 896-4096 MB	memory that is accessible with the
>>                               MMU disabled.
>>  * ZONE_HIGHMEM > 4096MB      only page cache and user processes
>>  */
> 
> I think this might be overkill.  ZONE_NORMAL gives you what you want,
> and I don't think it's worth it to introduce a new one just for the
> relatively short timespan where you have the new kernel loaded, but
> haven't actually shut down.  I think a little comment next to the
> allocation explaining this will be more than enough.
> 
> Martin, any ideas?

We talked about creating a new zone specifically for DMA32 (ie <4Gb)
for other reasons, but it's not there as yet. As Dave mentioned,
ZONE_NORMAL should be sufficient, though if you need it physically
contiguous, that might be a problem.

How much memory do you need? If it's only 2Mb or so, why don't we
statically reserve it at boot time and keep it set aside?

M.