On Fri, Aug 29, 2003 at 02:59:49PM -0700, Steve Madsen wrote: > Is it possible to use more than 256 MB of system memory with the Broadcom > SB1250 in 32-bit mode? The memory map I'm looking at shows me that the > second 256 MB of memory is at physical address 0x80000000. I suspect that > due to the 2G/2G split in the kernel, I can't use memory this high without > moving to the 64-bit kernel. Steve Finney's answer was correct; I'd like to add a few details though. The explanation you gave isn't exactly right. A 2GB/2GB split would normally support 2GB of low memory. We don't on MIPS due to the very inconvenient and unchangable mappings of KSEG0/KSEG1 - something that may have been sweet in '85 when the address map was designed but not today when 32-bit address spaces are beginning to be fairly tight. Highmem works ok in 2.4 as long as you have a reasonably low ratio of highmem to lowmem. For typical loads that means going beyond 4:1 isn't sensible but the actual number may vary much based on exact system configuration or workload. Ralf
