PATCH: enable use of memory beyond kseg0

[Neel Natu]

Hi JC,

On Fri, Mar 19, 2010 at 5:18 AM, C. Jayachandran
<c.jayachandran at gmail.com> wrote:
> On Tue, Mar 16, 2010 at 7:05 AM, Neel Natu <neelnatu at gmail.com> wrote:
>> This patch enables use of physical memory that is beyond the direct
>> mapped kseg0 region.
>>
>> The basic idea is to use KVA from the kseg2 region for mapping page
>> table pages that lie beyond the direct mapped region.
>>
>> The TLB miss handler can now recursively fault into the TLB invalid
>> handler if it dereferences a kseg2 page table page address that is not
>> in the TLB. The TLB invalid handler had to be extensively modified but
>> in the end came out much cleaner.
>>
>> I have tested this on a uni and multi-processor Sibyte with 1GB of
>> memory. It would be useful if this patch had some independent testing
>> as well.
>>
>> Please review.
>>
>> http://people.freebsd.org/~neel/mips_beyond_kseg.diff
>
> This fixes the crash I was seeing during 'make -j16 buildworld' on
> XLR. The buildworld completed after running about 6 hours over NFS
> mounted src and obj dir, so the patch looks good. I haven't done any
> performance comparisons yet.
>

Thanks a lot for taking the time and effort to test this - much appreciated.

best
Neel

> JC.
>