From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Subject: memory-hotplug: add hot-added memory ranges to memblock before allocate node_data for a node.
f9126ab9241f66562de ("memory-hotplug: fix wrong edge when hot add a new
node") hot-added memory range to memblock, after creating pgdat for new
node.
But there is a problem:
add_memory()
|--> hotadd_new_pgdat()
|--> free_area_init_node()
|--> get_pfn_range_for_nid()
|--> find start_pfn and end_pfn in memblock
|--> ......
|--> memblock_add_node(start, size, nid) -------- Here, just too late.
get_pfn_range_for_nid() will find that start_pfn and end_pfn are both 0.
As a result, when adding memory, dmesg will give the following wrong message.
[ 2007.577000] Initmem setup node 5 [mem 0x0000000000000000-0xffffffffffffffff]
[ 2007.584000] On node 5 totalpages: 0
[ 2007.585000] Built 5 zonelists in Node order, mobility grouping on. Total pages: 32588823
[ 2007.594000] Policy zone: Normal
[ 2007.598000] init_memory_mapping: [mem 0x60000000000-0x607ffffffff]
The solution is simple, just add the memory range to memblock a little
earlier, before hotadd_new_pgdat().
[akpm@xxxxxxxxxxxxxxxxxxxx: coding-style fixes]
Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Taku Izumi <izumi.taku@xxxxxxxxxxxxxx>
Cc: Gu Zheng <guz.fnst@xxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> [4.2.x]
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff -puN mm/memory_hotplug.c~memhp-add-hot-added-memory-ranges-to-memblock-before-allocate-node_data-for-a-node mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~memhp-add-hot-added-memory-ranges-to-memblock-before-allocate-node_data-for-a-node
+++ a/mm/memory_hotplug.c
@@ -1248,6 +1248,14 @@ int __ref add_memory(int nid, u64 start,
mem_hotplug_begin();
+ /*
+ * Add new range to memblock so that when hotadd_new_pgdat() is called
+ * to allocate new pgdat, get_pfn_range_for_nid() will be able to find
+ * this new range and calculate total pages correctly. The range will
+ * be removed at hot-remove time.
+ */
+ memblock_add_node(start, size, nid);
+
new_node = !node_online(nid);
if (new_node) {
pgdat = hotadd_new_pgdat(nid, start);
@@ -1277,7 +1285,6 @@ int __ref add_memory(int nid, u64 start,
/* create new memmap entry */
firmware_map_add_hotplug(start, start + size, "System RAM");
- memblock_add_node(start, size, nid);
goto out;
@@ -1286,6 +1293,7 @@ error:
if (new_pgdat)
rollback_node_hotadd(nid, pgdat);
release_memory_resource(res);
+ memblock_remove(start, size);
out:
mem_hotplug_done();
_
--
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