[PATCH] pgdat allocation and update for ia64 of memory hotplug: update pgdat address array
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 <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/asm-ia64/nodedata.h b/include/asm-ia64/nodedata.h
index a140310..2fb337b 100644
--- a/include/asm-ia64/nodedata.h
+++ b/include/asm-ia64/nodedata.h
@@ -46,6 +46,18 @@
*/
#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 */