There is some confusion that arose when working on SPARSEMEM patch between what is needed for DISCONTIG vs. NUMA.
Multiple pg_data_t's are needed for DISCONTIGMEM or NUMA, independently. All of the current NUMA implementations require an implementation of DISCONTIG. Because of this, quite a lot of code which is really needed for NUMA is actually under DISCONTIG #ifdefs. For SPARSEMEM, we changed some of these #ifdefs to CONFIG_NUMA, but that broke the DISCONTIG=y and NUMA=n case. Introducing this new NEED_MULTIPLE_NODES config option allows code that is needed for both NUMA or DISCONTIG to be separated out from code that is specific to DISCONTIG. One great advantage of this approach is that it doesn't require every architecture to be converted over. All of the current implementations should "just work", only the ones implementing SPARSEMEM will have to be fixed up. Signed-off-by: Dave Hansen <[EMAIL PROTECTED]> --- memhotplug-dave/include/linux/mmzone.h | 6 +++--- memhotplug-dave/mm/page_alloc.c | 6 +++--- 2 files changed, 6 insertions(+), 6 deletions(-) diff -puN include/linux/mmzone.h~B-sparse-140-separate-NUMA-DISCONTIG include/linux/mmzone.h --- memhotplug/include/linux/mmzone.h~B-sparse-140-separate-NUMA-DISCONTIG 2005-03-25 08:08:25.000000000 -0800 +++ memhotplug-dave/include/linux/mmzone.h 2005-03-25 08:08:25.000000000 -0800 @@ -385,7 +385,7 @@ int lowmem_reserve_ratio_sysctl_handler( /* Returns the number of the current Node. */ #define numa_node_id() (cpu_to_node(_smp_processor_id())) -#ifndef CONFIG_DISCONTIGMEM +#ifndef CONFIG_NEED_MULTIPLE_NODES extern struct pglist_data contig_page_data; #define NODE_DATA(nid) (&contig_page_data) @@ -393,11 +393,11 @@ extern struct pglist_data contig_page_da #define MAX_NODES_SHIFT 1 #define pfn_to_nid(pfn) (0) -#else /* CONFIG_DISCONTIGMEM */ +#else /* CONFIG_NEED_MULTIPLE_NODES */ #include <asm/mmzone.h> -#endif /* !CONFIG_DISCONTIGMEM */ +#endif /* !CONFIG_NEED_MULTIPLE_NODES */ #if BITS_PER_LONG == 32 || defined(ARCH_HAS_ATOMIC_UNSIGNED) /* diff -puN mm/page_alloc.c~B-sparse-140-separate-NUMA-DISCONTIG mm/page_alloc.c --- memhotplug/mm/page_alloc.c~B-sparse-140-separate-NUMA-DISCONTIG 2005-03-25 08:08:25.000000000 -0800 +++ memhotplug-dave/mm/page_alloc.c 2005-03-25 08:08:25.000000000 -0800 @@ -1765,18 +1765,18 @@ void __init free_area_init_node(int nid, free_area_init_core(pgdat, zones_size, zholes_size); } -#ifndef CONFIG_DISCONTIGMEM +#ifndef CONFIG_NEED_MULTIPLE_NODES static bootmem_data_t contig_bootmem_data; struct pglist_data contig_page_data = { .bdata = &contig_bootmem_data }; EXPORT_SYMBOL(contig_page_data); +#endif void __init free_area_init(unsigned long *zones_size) { - free_area_init_node(0, &contig_page_data, zones_size, + free_area_init_node(0, NODE_DATA(0), zones_size, __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL); } -#endif #ifdef CONFIG_PROC_FS _ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/