The patch titled
Subject: memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
has been added to the -mm tree. Its filename is
memory-hotplug-clear-pgdat-which-is-allocated-by-bootmem-in-try_offline_node.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/memory-hotplug-clear-pgdat-which-is-allocated-by-bootmem-in-try_offline_node.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/memory-hotplug-clear-pgdat-which-is-allocated-by-bootmem-in-try_offline_node.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/SubmitChecklist when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Subject: memory-hotplug: clear pgdat which is allocated by bootmem in try_offline_node()
When hot adding the same memory after hot removal, 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() chacks 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>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff -puN mm/memory_hotplug.c~memory-hotplug-clear-pgdat-which-is-allocated-by-bootmem-in-try_offline_node mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~memory-hotplug-clear-pgdat-which-is-allocated-by-bootmem-in-try_offline_node
+++ a/mm/memory_hotplug.c
@@ -1943,7 +1943,7 @@ void try_offline_node(int nid)
if (!PageSlab(pgdat_page) && !PageCompound(pgdat_page))
/* node data is allocated from boot memory */
- return;
+ goto out;
/* free waittable in each zone */
for (i = 0; i < MAX_NR_ZONES; i++) {
@@ -1957,6 +1957,7 @@ void try_offline_node(int nid)
vfree(zone->wait_table);
}
+out:
/*
* Since there is no way to guarentee the address of pgdat/zone is not
* on stack of any kernel threads or used by other kernel objects
_
Patches currently in -mm which might be from isimatu.yasuaki@xxxxxxxxxxxxxx are
memory-hotplug-clear-pgdat-which-is-allocated-by-bootmem-in-try_offline_node.patch
mm-introduce-single-zone-pcplists-drain.patch
mm-page_isolation-drain-single-zone-pcplists.patch
mm-cma-drain-single-zone-pcplists.patch
mm-memory_hotplug-failure-drain-single-zone-pcplists.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
