> Yes. thank you. This is helpful. From this, page_cgroup->page pointer is NULL.
> And page_zid() or some kicks it..
> 
> Then, it seems problem is in page_cgroup.c::page_cgroup_init() or
> page_cgroup()->page is cleared..Hmm..
> 
> could you show /var/log/dmesg ?
> It may includes following kinds of line
> 
> = (this is x86-64)
> sizeof(struct page) = 96
> Zone PFN ranges:
>   DMA      0x00000000 -> 0x00001000
>   DMA32    0x00001000 -> 0x00100000
>   Normal   0x00100000 -> 0x00a40000
> Movable zone start PFN for each node
> early_node_map[4] active PFN ranges
>     0: 0x00000000 -> 0x0000009e
>     0: 0x00000100 -> 0x000bfee0
>     0: 0x000bff00 -> 0x000bff80
>     0: 0x00100000 -> 0x00a40000
> On node 0 totalpages: 10485502
>   DMA zone: 96 pages used for memmap
>   DMA zone: 102 pages reserved
>   DMA zone: 3800 pages, LIFO batch:0
>   DMA32 zone: 24480 pages used for memmap
>   DMA32 zone: 757696 pages, LIFO batch:31
>   Normal zone: 227328 pages used for memmap
>   Normal zone: 9472000 pages, LIFO batch:31
>   Movable zone: 0 pages used for memmap
> .....
> 

dmesg is attached.