Commit dd8041f1 authored by Yasunori Goto's avatar Yasunori Goto Committed by Linus Torvalds
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[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: default avatarYasunori Goto <>
Cc: "Luck, Tony" <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent 31304c90
...@@ -313,10 +313,20 @@ static void __meminit scatter_node_data(void) ...@@ -313,10 +313,20 @@ static void __meminit scatter_node_data(void)
pg_data_t **dst; pg_data_t **dst;
int node; int node;
for_each_online_node(node) { /*
* 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; dst = LOCAL_DATA_ADDR(pgdat_list[node])->pg_data_ptrs;
memcpy(dst, pgdat_list, sizeof(pgdat_list)); memcpy(dst, pgdat_list, sizeof(pgdat_list));
} }
} }
/** /**
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