Once upon a time, the global max_pfn value was set up as part of bootmem_init(), but this seems to have been dropped in favor of establishing max_low_pfn, I suppose to be clear that it's the max non-highmem PFN. However, the global max_pfn gets used in the MIPS APRP support code, and also in places like block/blk-settings.c. Is the use of max_pfn supposed to be deprecated, such that we consider blk-settings.c to be broken and change arch/mips/kernel/vpe.c to use max_low_pfn, or ought we assign max_pfn = max_low_pfn in bootmem_init()? I'm going to try the later for my own experimental purposes, but won't propose a patch until I have a better understanding of why things changed. Regards, Kevin K.