From dd8041f16b117f63f40fb844d6cdebe8b03514d2 Mon Sep 17 00:00:00 2001 From: Yasunori Goto Date: Tue, 4 Jul 2006 02:57:51 -0700 Subject: [PATCH] [PATCH] Fix copying of pgdat array on each node for ia64 memory hotplug I found a bug in memory hot-add code for ia64. IA64's code has copies of pgdat's array on each node to reduce memory access over crossing node. This array is used by NODE_DATA() macro. When new node is hot-added, this pgdat's array should be updated and copied on new node too. However, I used for_each_online_node() in scatter_node_data() to copy it. This meant its array is not copied on new node. Because initialization of structures for new node was halfway, so online_node_map couldn't be set at this time. To copy arrays on new node, I changed it to check value of pgdat_list[] which is source array of copies. I tested this patch with my Memory Hotadd emulation on Tiger4. This patch is for 2.6.17-git20. Signed-off-by: Yasunori Goto Cc: "Luck, Tony" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/ia64/mm/discontig.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c index 525b082eb661..99bd9e30db96 100644 --- a/arch/ia64/mm/discontig.c +++ b/arch/ia64/mm/discontig.c @@ -313,9 +313,19 @@ 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)); + /* + * for_each_online_node() can't be used at here. + * node_online_map is not set for hot-added nodes at this time, + * because we are halfway through initialization of the new node's + * structures. If for_each_online_node() is used, a new node's + * pg_data_ptrs will be not initialized. Insted of using it, + * pgdat_list[] is checked. + */ + for_each_node(node) { + if (pgdat_list[node]) { + dst = LOCAL_DATA_ADDR(pgdat_list[node])->pg_data_ptrs; + memcpy(dst, pgdat_list, sizeof(pgdat_list)); + } } } -- 2.20.1