[PATCH] pgdat allocation for new node add (call pgdat allocation)

Add node-hot-add support to add_memory().

node hotadd uses this sequence.
1. allocate pgdat.
2. refresh NODE_DATA()
3. call free_area_init_node() to initialize
4. create sysfs entry
5. add memory (old add_memory())
6. set node online
7. run kswapd for new node.
(8). update zonelist after pages are onlined. (This is already merged in -mm
   due to update phase is difference.)

Note:
  To make common function as much as possible,
  there is 2 changes from v2.
    - The old add_memory(), which is defiend by each archs,
      is renamed to arch_add_memory(). New add_memory becomes
      caller of arch dependent function as a common code.

    - This patch changes add_memory()'s interface
        From: add_memory(start, end)
        TO  : add_memory(nid, start, end).
      It was cause of similar code that finding node id from
      physical address is inside of old add_memory() on each arch.

      In addition, acpi memory hotplug driver can find node id easier.
      In v2, it must walk DSDT'S _CRS by matching physical address to
      get the handle of its memory device, then get _PXM and node id.
      Because input is just physical address.
      However, in v3, the acpi driver can use handle to get _PXM and node id
      for the new memory device. It can pass just node id to add_memory().

Fix interface of arch_add_memory() is in next patche.

Signed-off-by: Yasunori Goto     <y-goto@jp.fujitsu.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: "Brown, Len" <len.brown@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 6cdeabe..83d37a4 100644 (file)
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -164,13 +164,65 @@ int online_pages(unsigned long pfn, unsigned long nr_pages)
        return 0;
 }
 
+static pg_data_t *hotadd_new_pgdat(int nid, u64 start)
+{
+       struct pglist_data *pgdat;
+       unsigned long zones_size[MAX_NR_ZONES] = {0};
+       unsigned long zholes_size[MAX_NR_ZONES] = {0};
+       unsigned long start_pfn = start >> PAGE_SHIFT;
+
+       pgdat = arch_alloc_nodedata(nid);
+       if (!pgdat)
+               return NULL;
+
+       arch_refresh_nodedata(nid, pgdat);
+
+       /* we can use NODE_DATA(nid) from here */
+
+       /* init node's zones as empty zones, we don't have any present pages.*/
+       free_area_init_node(nid, pgdat, zones_size, start_pfn, zholes_size);
+
+       return pgdat;
+}
+
+static void rollback_node_hotadd(int nid, pg_data_t *pgdat)
+{
+       arch_refresh_nodedata(nid, NULL);
+       arch_free_nodedata(pgdat);
+       return;
+}
+
 int add_memory(int nid, u64 start, u64 size)
 {
+       pg_data_t *pgdat = NULL;
+       int new_pgdat = 0;
        int ret;
 
+       if (!node_online(nid)) {
+               pgdat = hotadd_new_pgdat(nid, start);
+               if (!pgdat)
+                       return -ENOMEM;
+               new_pgdat = 1;
+               ret = kswapd_run(nid);
+               if (ret)
+                       goto error;
+       }
+
        /* call arch's memory hotadd */
        ret = arch_add_memory(nid, start, size);
 
+       if (ret < 0)
+               goto error;
+
+       /* we online node here. we have no error path from here. */
+       node_set_online(nid);
+
+       return ret;
+error:
+       /* rollback pgdat allocation and others */
+       if (new_pgdat)
+               rollback_node_hotadd(nid, pgdat);
+
        return ret;
 }
 EXPORT_SYMBOL_GPL(add_memory);