Make sure not to count on a pgdat's mem_map being contiguous. Use a (theoretically) slower pfn_to_page() call and do the math with pfns instead of pointer arithmetic on node_mem_map[] when that assumption can't be satisfied. Signed-off-by: Dave Hansen --- memhotplug-dave/include/linux/mmzone.h | 4 ++++ 1 files changed, 4 insertions(+) diff -puN include/linux/mmzone.h~B-sparse-154-sparse-no-node_mem_map include/linux/mmzone.h --- memhotplug/include/linux/mmzone.h~B-sparse-154-sparse-no-node_mem_map 2005-04-13 14:20:12.000000000 -0700 +++ memhotplug-dave/include/linux/mmzone.h 2005-04-13 14:20:12.000000000 -0700 @@ -269,7 +269,11 @@ typedef struct pglist_data { #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) #define node_spanned_pages(nid) (NODE_DATA(nid)->node_spanned_pages) +#ifdef CONFIG_FLAT_NODE_MEM_MAP #define pgdat_page_nr(pgdat, pagenr) ((pgdat)->node_mem_map + (pagenr)) +#else +#define pgdat_page_nr(pgdat, pagenr) pfn_to_page((pgdat)->node_start_pfn + (pagenr)) +#endif #define nid_page_nr(nid, pagenr) pgdat_page_nr(NODE_DATA(nid),(pagenr)) extern struct pglist_data *pgdat_list; _