On Mon, 2014-10-20 at 19:05 +0900, Yasuaki Ishimatsu wrote:
:
> 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
s/chacks/checks
> 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>
>
> ---
> mm/memory_hotplug.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 29d8693..7649f7c 100644
> --- a/mm/memory_hotplug.c
> +++ b/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;
Do we still need this if-statement? That is, do we have to skip the
for-loop below even though it checks with is_vmalloc_addr()?
Thanks,
-Toshi
> /* 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
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