When hot adding the same memory after hot removing a memory,
the following messages are shown:
WARNING: CPU: 20 PID: 6 at mm/page_alloc.c:4968 free_area_init_node+0x3fe/0x426()
...
Call Trace:
[<...>] dump_stack+0x46/0x58
[<...>] warn_slowpath_common+0x81/0xa0
[<...>] warn_slowpath_null+0x1a/0x20
[<...>] free_area_init_node+0x3fe/0x426
[<...>] ? up+0x32/0x50
[<...>] hotadd_new_pgdat+0x90/0x110
[<...>] add_memory+0xd4/0x200
[<...>] acpi_memory_device_add+0x1aa/0x289
[<...>] acpi_bus_attach+0xfd/0x204
[<...>] ? device_register+0x1e/0x30
[<...>] acpi_bus_attach+0x178/0x204
[<...>] acpi_bus_scan+0x6a/0x90
[<...>] ? acpi_bus_get_status+0x2d/0x5f
[<...>] acpi_device_hotplug+0xe8/0x418
[<...>] acpi_hotplug_work_fn+0x1f/0x2b
[<...>] process_one_work+0x14e/0x3f0
[<...>] worker_thread+0x11b/0x510
[<...>] ? rescuer_thread+0x350/0x350
[<...>] kthread+0xe1/0x100
[<...>] ? kthread_create_on_node+0x1b0/0x1b0
[<...>] ret_from_fork+0x7c/0xb0
[<...>] ? kthread_create_on_node+0x1b0/0x1b0
The detaled explanation is as follows:
When hot removing memory, pgdat is set to 0 in try_offline_node().
But if the pgdat is allocated by bootmem allocator, the clearing
step is skipped. And when hot adding the same memory, the uninitialized
pgdat is reused. But free_area_init_node() checks wether pgdat is set
to zero. As a result, free_area_init_node() hits WARN_ON().
This patch clears pgdat which is allocated by bootmem allocator
in try_offline_node().
Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
CC: Zhang Zhen <zhenzhang.zhang@xxxxxxxxxx>
CC: Wang Nan <wangnan0@xxxxxxxxxx>
CC: Tang Chen <tangchen@xxxxxxxxxxxxxx>
CC: Toshi Kani <toshi.kani@xxxxxx>
CC: Dave Hansen <dave.hansen@xxxxxxxxx>
CC: David Rientjes <rientjes@xxxxxxxxxx>
---
v2: remove check of pgdat_page
mm/memory_hotplug.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 29d8693..252e1db 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1912,7 +1912,6 @@ void try_offline_node(int nid)
unsigned long start_pfn = pgdat->node_start_pfn;
unsigned long end_pfn = start_pfn + pgdat->node_spanned_pages;
unsigned long pfn;
- struct page *pgdat_page = virt_to_page(pgdat);
int i;
for (pfn = start_pfn; pfn < end_pfn; pfn += PAGES_PER_SECTION) {
@@ -1941,10 +1940,6 @@ void try_offline_node(int nid)
node_set_offline(nid);
unregister_one_node(nid);
- if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
- /* node data is allocated from boot memory */
- return;
-
/* free waittable in each zone */
for (i = 0; i < MAX_NR_ZONES; i++) {
struct zone *zone = pgdat->node_zones + i;
--
1.8.3.1
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