From: Yasunori Goto Date: Tue, 4 Jul 2006 09:57:51 +0000 (-0700) Subject: [PATCH] Fix copying of pgdat array on each node for ia64 memory hotplug X-Git-Tag: v2.6.18-rc1~15 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=dd8041f16b117f63f40fb844d6cdebe8b03514d2;p=platform%2Fkernel%2Flinux-exynos.git [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 --- diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c index 525b082..99bd9e3 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)); + } } }