So, this patch started out with me trying to keep from passing contiguous, node-specific mem_map into free_area_init_node() and cousins. Instead, I relied on some calls to pfn_to_page(). This works fine and dandy when all you need is the pgdat->node_mem_map to do pfn_to_page(). However, the non-NUMA/DISCONTIG architectures use the real, global mem_map[] instead of a node_mem_map in the pfn_to_page() calculation. So, I ended up effectively trying to initialize mem_map from itself, when it was NULL. That was bad, and caused some very pretty colors on someone's screen when he tested it. So, I had to make sure to initialize the global mem_map[] before calling into free_area_init_node(). Then, I realized how many architectures do this on their own, and have comments like this: /* XXX: MRB-remove - this doesn't seem sane, should this be done somewhere else ?*/ mem_map = NODE_DATA(0)->node_mem_map; The following patch does what my first one did (don't pass mem_map into the init functions), incorporates Jesse Barnes' ia64 fixes on top of that, and gets rid of all but one of the global mem_map initializations (parisc is weird). It also magically removes more code than it adds. It could be smaller, but I shamelessly added some comments. Boot-tested on ppc64, i386 (NUMAQ, plain SMP, laptop), UML (i386). Signed-off-by: Dave Hansen --- memhotplug-dave/arch/arm/mm/init.c | 4 ---- memhotplug-dave/arch/arm26/mm/init.c | 2 -- memhotplug-dave/arch/cris/arch-v10/mm/init.c | 1 - memhotplug-dave/arch/ia64/mm/contig.c | 2 +- memhotplug-dave/arch/m32r/mm/init.c | 2 -- memhotplug-dave/arch/ppc64/mm/init.c | 1 - memhotplug-dave/arch/sh/mm/init.c | 2 -- memhotplug-dave/arch/sh64/mm/init.c | 3 --- memhotplug-dave/arch/sparc/mm/srmmu.c | 1 - memhotplug-dave/arch/sparc/mm/sun4c.c | 1 - memhotplug-dave/arch/sparc64/mm/init.c | 1 - memhotplug-dave/arch/um/kernel/physmem.c | 1 - memhotplug-dave/arch/v850/kernel/setup.c | 1 - memhotplug-dave/mm/page_alloc.c | 22 ++++++++++++++++------ 14 files changed, 17 insertions(+), 27 deletions(-) diff -puN arch/arm/mm/init.c~A6-no_arch_mem_map_init arch/arm/mm/init.c --- memhotplug/arch/arm/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/arm/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -501,10 +501,6 @@ void __init paging_init(struct meminfo * bdata->node_boot_start >> PAGE_SHIFT, zhole_size); } -#ifndef CONFIG_DISCONTIGMEM - mem_map = contig_page_data.node_mem_map; -#endif - /* * finish off the bad pages once * the mem_map is initialised diff -puN arch/arm26/mm/init.c~A6-no_arch_mem_map_init arch/arm26/mm/init.c --- memhotplug/arch/arm26/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/arm26/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -309,8 +309,6 @@ void __init paging_init(struct meminfo * free_area_init_node(0, pgdat, zone_size, bdata->node_boot_start >> PAGE_SHIFT, zhole_size); - mem_map = NODE_DATA(0)->node_mem_map; - /* * finish off the bad pages once * the mem_map is initialised diff -puN arch/cris/arch-v10/mm/init.c~A6-no_arch_mem_map_init arch/cris/arch-v10/mm/init.c --- memhotplug/arch/cris/arch-v10/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/cris/arch-v10/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -184,7 +184,6 @@ paging_init(void) */ free_area_init_node(0, &contig_page_data, zones_size, PAGE_OFFSET >> PAGE_SHIFT, 0); - mem_map = contig_page_data.node_mem_map; } /* Initialize remaps of some I/O-ports. It is important that this diff -puN arch/i386/mm/discontig.c~A6-no_arch_mem_map_init arch/i386/mm/discontig.c diff -puN arch/ia64/mm/contig.c~A6-no_arch_mem_map_init arch/ia64/mm/contig.c --- memhotplug/arch/ia64/mm/contig.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/ia64/mm/contig.c 2005-03-04 09:16:41.000000000 -0800 @@ -280,7 +280,7 @@ paging_init (void) vmem_map = (struct page *) vmalloc_end; efi_memmap_walk(create_mem_map_page_table, NULL); - mem_map = contig_page_data.node_mem_map = vmem_map; + NODE_DATA(0)->node_mem_map = vmem_map; free_area_init_node(0, &contig_page_data, zones_size, 0, zholes_size); diff -puN arch/ppc64/mm/init.c~A6-no_arch_mem_map_init arch/ppc64/mm/init.c --- memhotplug/arch/ppc64/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/ppc64/mm/init.c 2005-03-04 13:41:28.000000000 -0800 @@ -658,7 +658,6 @@ void __init paging_init(void) free_area_init_node(0, &contig_page_data, zones_size, __pa(PAGE_OFFSET) >> PAGE_SHIFT, zholes_size); - mem_map = contig_page_data.node_mem_map; } #endif /* CONFIG_DISCONTIGMEM */ diff -puN arch/sh/mm/init.c~A6-no_arch_mem_map_init arch/sh/mm/init.c --- memhotplug/arch/sh/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/sh/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -216,8 +216,6 @@ void __init paging_init(void) #endif NODE_DATA(0)->node_mem_map = NULL; free_area_init_node(0, NODE_DATA(0), zones_size, __MEMORY_START >> PAGE_SHIFT, 0); - /* XXX: MRB-remove - this doesn't seem sane, should this be done somewhere else ?*/ - mem_map = NODE_DATA(0)->node_mem_map; #ifdef CONFIG_DISCONTIGMEM /* diff -puN arch/sh64/mm/init.c~A6-no_arch_mem_map_init arch/sh64/mm/init.c --- memhotplug/arch/sh64/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/sh64/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -124,9 +124,6 @@ void __init paging_init(void) zones_size[ZONE_DMA] = MAX_LOW_PFN - START_PFN; NODE_DATA(0)->node_mem_map = NULL; free_area_init_node(0, NODE_DATA(0), zones_size, __MEMORY_START >> PAGE_SHIFT, 0); - - /* XXX: MRB-remove - this doesn't seem sane, should this be done somewhere else ?*/ - mem_map = NODE_DATA(0)->node_mem_map; } void __init mem_init(void) diff -puN arch/sparc/mm/srmmu.c~A6-no_arch_mem_map_init arch/sparc/mm/srmmu.c --- memhotplug/arch/sparc/mm/srmmu.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/sparc/mm/srmmu.c 2005-03-04 09:16:41.000000000 -0800 @@ -1344,7 +1344,6 @@ void __init srmmu_paging_init(void) free_area_init_node(0, &contig_page_data, zones_size, pfn_base, zholes_size); - mem_map = contig_page_data.node_mem_map; } } diff -puN arch/sparc/mm/sun4c.c~A6-no_arch_mem_map_init arch/sparc/mm/sun4c.c --- memhotplug/arch/sparc/mm/sun4c.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/sparc/mm/sun4c.c 2005-03-04 09:16:41.000000000 -0800 @@ -2117,7 +2117,6 @@ void __init sun4c_paging_init(void) free_area_init_node(0, &contig_page_data, zones_size, pfn_base, zholes_size); - mem_map = contig_page_data.node_mem_map; } cnt = 0; diff -puN arch/sparc64/mm/init.c~A6-no_arch_mem_map_init arch/sparc64/mm/init.c --- memhotplug/arch/sparc64/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/sparc64/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -1512,7 +1512,6 @@ void __init paging_init(void) free_area_init_node(0, &contig_page_data, zones_size, phys_base >> PAGE_SHIFT, zholes_size); - mem_map = contig_page_data.node_mem_map; } device_scan(); diff -puN arch/v850/kernel/setup.c~A6-no_arch_mem_map_init arch/v850/kernel/setup.c --- memhotplug/arch/v850/kernel/setup.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/v850/kernel/setup.c 2005-03-04 09:16:41.000000000 -0800 @@ -283,5 +283,4 @@ init_mem_alloc (unsigned long ram_start, NODE_DATA(0)->node_mem_map = NULL; free_area_init_node (0, NODE_DATA(0), zones_size, ADDR_TO_PAGE (PAGE_OFFSET), 0); - mem_map = NODE_DATA(0)->node_mem_map; } diff -puN mm/page_alloc.c~A6-no_arch_mem_map_init mm/page_alloc.c --- memhotplug/mm/page_alloc.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/mm/page_alloc.c 2005-03-04 13:41:29.000000000 -0800 @@ -1730,14 +1730,25 @@ static void __init free_area_init_core(s } } -void __init node_alloc_mem_map(struct pglist_data *pgdat) +static void __init alloc_node_mem_map(struct pglist_data *pgdat) { unsigned long size; - size = (pgdat->node_spanned_pages + 1) * sizeof(struct page); - pgdat->node_mem_map = alloc_bootmem_node(pgdat, size); + /* Skip empty nodes */ + if (!pgdat->node_spanned_pages) + return; + + /* ia64 gets its own node_mem_map, before this, without bootmem */ + if (!pgdat->node_mem_map) { + size = (pgdat->node_spanned_pages + 1) * sizeof(struct page); + pgdat->node_mem_map = alloc_bootmem_node(pgdat, size); + } #ifndef CONFIG_DISCONTIGMEM - mem_map = contig_page_data.node_mem_map; + /* + * With no DISCONTIG, the global mem_map is just set as node 0's + */ + if (pgdat == NODE_DATA(0)) + mem_map = NODE_DATA(0)->node_mem_map; #endif } @@ -1749,8 +1760,7 @@ void __init free_area_init_node(int nid, pgdat->node_start_pfn = node_start_pfn; calculate_zone_totalpages(pgdat, zones_size, zholes_size); - if (!pfn_to_page(node_start_pfn)) - node_alloc_mem_map(pgdat); + alloc_node_mem_map(pgdat); free_area_init_core(pgdat, zones_size, zholes_size); } diff -puN arch/i386/kernel/mpparse.c~A6-no_arch_mem_map_init arch/i386/kernel/mpparse.c diff -puN arch/i386/kernel/setup.c~A6-no_arch_mem_map_init arch/i386/kernel/setup.c diff -puN arch/m32r/mm/init.c~A6-no_arch_mem_map_init arch/m32r/mm/init.c --- memhotplug/arch/m32r/mm/init.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/m32r/mm/init.c 2005-03-04 09:16:41.000000000 -0800 @@ -121,8 +121,6 @@ unsigned long __init zone_sizes_init(voi free_area_init_node(0, NODE_DATA(0), zones_size, start_pfn, 0); - mem_map = contig_page_data.node_mem_map; - return 0; } #else /* CONFIG_DISCONTIGMEM */ diff -puN arch/um/kernel/physmem.c~A6-no_arch_mem_map_init arch/um/kernel/physmem.c --- memhotplug/arch/um/kernel/physmem.c~A6-no_arch_mem_map_init 2005-03-04 09:16:41.000000000 -0800 +++ memhotplug-dave/arch/um/kernel/physmem.c 2005-03-04 09:16:41.000000000 -0800 @@ -294,7 +294,6 @@ int init_maps(unsigned long physmem, uns INIT_LIST_HEAD(&p->lru); } - mem_map = map; max_mapnr = total_pages; return(0); } _