Port-mips archive
[
Date Prev][
Date Next][
Thread Prev][
Thread Next][
Date Index][
Thread Index][
Old Index]
RFC: two-level page tables for 16KB pages on LP64 kernels
Normally, MIPS uses a 3 level page table for a 64-bit kernel which gives 1TB
(40 [12+10+9+9] bits) of user address space when using 4KB pages. A 3 level
page table using 16KB pages can address 256TB (48 [14+12+11+11] bits) while a 2
level page table using 16KB pages can address 128GB (37 [14+12+11] bits) of
address space.
Thinking about it, 128GB seems to more than enough on the GDIUM or other
Loongson2 base platforms but it is significantly less the 16TB that it could
use. I have to think the smaller (but adequate) address space using a simple 2
level page table might result in a small performance boost.
I figure this could be a config file option. Maybe even defining
VM_MAX_USER_ADDRESS in an option file and letting the kernel figure out how
many levels are needed to accomodate that maximum.
Home |
Main Index |
Thread Index |
Old Index