From: Yasunori Goto This is to refresh node_data[] array for ia64. As I mentioned previous patches, ia64 has copies of information of pgdat address array on each node as per node data. At v2 of node_add, this function used stop_machine_run() to update them. (I wished that they were copied safety as much as possible.) But, in this patch, this arrays are just copied simply, and set node_online_map bit after completion of pgdat initialization. So, kernel must touch NODE_DATA() macro after checking node_online_map(). (Current code has already done it.) This is more simple way for just hot-add..... Note : It will be problem when hot-remove will occur, because, even if online_map bit is set, kernel may touch NODE_DATA() due to race condition. :-( Signed-off-by: Yasunori Goto Cc: "Luck, Tony" Signed-off-by: Andrew Morton --- arch/ia64/mm/discontig.c | 24 +++++++++++++++++++----- include/asm-ia64/nodedata.h | 12 ++++++++++++ include/linux/memory_hotplug.h | 4 +--- 3 files changed, 32 insertions(+), 8 deletions(-) diff -puN arch/ia64/mm/discontig.c~pgdat-allocation-and-update-for-ia64-of-memory-hotplug-update-pgdat-address-array arch/ia64/mm/discontig.c --- devel/arch/ia64/mm/discontig.c~pgdat-allocation-and-update-for-ia64-of-memory-hotplug-update-pgdat-address-array 2006-05-11 15:18:44.000000000 -0700 +++ devel-akpm/arch/ia64/mm/discontig.c 2006-05-11 15:18:44.000000000 -0700 @@ -308,6 +308,17 @@ static void __init reserve_pernode_space } } +static void __meminit scatter_node_data(void) +{ + pg_data_t **dst; + int node; + + for_each_online_node(node) { + dst = LOCAL_DATA_ADDR(pgdat_list[node])->pg_data_ptrs; + memcpy(dst, pgdat_list, sizeof(pgdat_list)); + } +} + /** * initialize_pernode_data - fixup per-cpu & per-node pointers * @@ -320,11 +331,8 @@ static void __init initialize_pernode_da { int cpu, node; - /* Copy the pg_data_t list to each node and init the node field */ - for_each_online_node(node) { - memcpy(mem_data[node].node_data->pg_data_ptrs, pgdat_list, - sizeof(pgdat_list)); - } + scatter_node_data(); + #ifdef CONFIG_SMP /* Set the node_data pointer for each per-cpu struct */ for (cpu = 0; cpu < NR_CPUS; cpu++) { @@ -783,3 +791,9 @@ void __init paging_init(void) zero_page_memmap_ptr = virt_to_page(ia64_imva(empty_zero_page)); } + +void arch_refresh_nodedata(int update_node, pg_data_t *update_pgdat) +{ + pgdat_list[update_node] = update_pgdat; + scatter_node_data(); +} diff -puN include/asm-ia64/nodedata.h~pgdat-allocation-and-update-for-ia64-of-memory-hotplug-update-pgdat-address-array include/asm-ia64/nodedata.h --- devel/include/asm-ia64/nodedata.h~pgdat-allocation-and-update-for-ia64-of-memory-hotplug-update-pgdat-address-array 2006-05-11 15:18:44.000000000 -0700 +++ devel-akpm/include/asm-ia64/nodedata.h 2006-05-11 15:18:44.000000000 -0700 @@ -46,6 +46,18 @@ struct ia64_node_data { */ #define NODE_DATA(nid) (local_node_data->pg_data_ptrs[nid]) +/* + * LOCAL_DATA_ADDR - This is to calculate the address of other node's + * "local_node_data" at hot-plug phase. The local_node_data + * is pointed by per_cpu_page. Kernel usually use it for + * just executing cpu. However, when new node is hot-added, + * the addresses of local data for other nodes are necessary + * to update all of them. + */ +#define LOCAL_DATA_ADDR(pgdat) \ + ((struct ia64_node_data *)((u64)(pgdat) + \ + L1_CACHE_ALIGN(sizeof(struct pglist_data)))) + #endif /* CONFIG_NUMA */ #endif /* _ASM_IA64_NODEDATA_H */ diff -puN include/linux/memory_hotplug.h~pgdat-allocation-and-update-for-ia64-of-memory-hotplug-update-pgdat-address-array include/linux/memory_hotplug.h --- devel/include/linux/memory_hotplug.h~pgdat-allocation-and-update-for-ia64-of-memory-hotplug-update-pgdat-address-array 2006-05-11 15:18:44.000000000 -0700 +++ devel-akpm/include/linux/memory_hotplug.h 2006-05-11 15:18:44.000000000 -0700 @@ -91,9 +91,7 @@ static inline pg_data_t *arch_alloc_node static inline void arch_free_nodedata(pg_data_t *pgdat) { } -static inline void arch_refresh_nodedata(int nid, pg_data_t *pgdat) -{ -} +extern void arch_refresh_nodedata(int nid, pg_data_t *pgdat); #else /* CONFIG_HAVE_ARCH_NODEDATA_EXTENSION */ _