To avoid any duplication of efforts, I'm starting work on getting the various "kmem" command options working again for RHEL5-alpha x86_64 kernels, into which CONFIG_SPARSEMEM was recently introduced, and CONFIG_NUMA is also configured. So that particular kernel uses node_online_map and node_data. There are going to be some variances among the different architectures in this area, but we have to start somewhere. Expect fairly frequent version updates so that we can all be on the same page... Note that the first thing I ran into was a problem with the SPARSEMEM support patch that I accepted into 4.0-2.22 -- which requires this fix: --- memory.c 2006-08-22 14:27:51.000000000 -0400 +++ ../next/memory.c 2006-08-24 14:51:25.000000000 -0400 @@ -11374,13 +11374,16 @@ ulong pfn_to_map(ulong pfn) { ulong section, page_offset; + ulong section_nr; - section = pfn_to_section_nr(pfn); + section_nr = pfn_to_section_nr(pfn); + if (!(section = valid_section_nr(section_nr))) + return 0; if (section_has_mem_map(section)) { - page_offset = pfn - section_nr_to_pfn(section); + page_offset = pfn - section_nr_to_pfn(section_nr); return (section_mem_map_addr(section) + - (page_offset * PAGESIZE())); + (page_offset * SIZE(page))); } return 0; This SPARSEMEM-only primitive could never have worked since it was passing a section number into a function expecting a section address (and even it did work, the page address calculation was incorrect). So it always returned 0, and therefore all of its consumers fail. Dave