[Patch: 006/006] pgdat allocation for new node add (call pgdat allocation)

Yasunori Goto
2006-04-20T10:11:49Z

This patch adds 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>

mm/memory_hotplug.c | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 52 insertions(+)

Index: pgdat11/mm/memory_hotplug.c
===================================================================
--- pgdat11.orig/mm/memory_hotplug.c 2006-04-20 16:36:38.000000000 +0900
+++ pgdat11/mm/memory_hotplug.c 2006-04-20 17:09:39.000000000 +0900
@@ -160,12 +160,64 @@ int online_pages(unsigned long pfn, unsi
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;