On 12/13/2018 11:08 AM, Wei Yang wrote:
> On Thu, Dec 13, 2018 at 10:26:41AM +0800, Rong Chen wrote:
>>
>> On 12/09/2018 08:03 PM, Wei Yang wrote:
>>> On Sat, Dec 08, 2018 at 09:42:29AM +0800, kbuild test robot wrote:
>>>> Hi Wei,
>>>>
>>>> Thank you for the patch! Perhaps something to improve:
>>>>
>>>> [auto build test WARNING on linus/master]
>>>> [also build test WARNING on v4.20-rc5 next-20181207]
>>>> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>>>>
>>>> url:    https://github.com/0day-ci/linux/commits/Wei-Yang/mm-pageblock-make-sure-pageblock-won-t-exceed-mem_sectioin/20181207-030601
>>>> config: powerpc-allmodconfig (attached as .config)
>>>> compiler: powerpc64-linux-gnu-gcc (Debian 7.2.0-11) 7.2.0
>>>> reproduce:
>>>>          wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>>>>          chmod +x ~/bin/make.cross
>>>>          # save the attached .config to linux build tree
>>>>          GCC_VERSION=7.2.0 make.cross ARCH=powerpc
>>>>
>>>> All warnings (new ones prefixed by >>):
>>>>
>>>>     In file included from include/linux/gfp.h:6:0,
>>>>                      from include/linux/xarray.h:14,
>>>>                      from include/linux/radix-tree.h:31,
>>>>                      from include/linux/fs.h:15,
>>>>                      from include/linux/compat.h:17,
>>>>                      from arch/powerpc/kernel/asm-offsets.c:16:
>>>>>> include/linux/mmzone.h:1088:6: warning: "pageblock_order" is not defined, evaluates to 0 [-Wundef]
>>>>      #if (pageblock_order + PAGE_SHIFT) > SECTION_SIZE_BITS
>>>>           ^~~~~~~~~~~~~~~
>>>> --
>>>>     In file included from include/linux/gfp.h:6:0,
>>>>                      from include/linux/mm.h:10,
>>>>                      from mm//swap.c:16:
>>>>>> include/linux/mmzone.h:1088:6: warning: "pageblock_order" is not defined, evaluates to 0 [-Wundef]
>>>>      #if (pageblock_order + PAGE_SHIFT) > SECTION_SIZE_BITS
>>>>           ^~~~~~~~~~~~~~~
>>>>     In file included from include/linux/gfp.h:6:0,
>>>>                      from include/linux/mm.h:10,
>>>>                      from mm//swap.c:16:
>>>>>> include/linux/mmzone.h:1088:6: warning: "pageblock_order" is not defined, evaluates to 0 [-Wundef]
>>>>      #if (pageblock_order + PAGE_SHIFT) > SECTION_SIZE_BITS
>>>>           ^~~~~~~~~~~~~~~
>>>>
>>>> vim +/pageblock_order +1088 include/linux/mmzone.h
>>>>
>>>>    1087	
>>>>> 1088	#if (pageblock_order + PAGE_SHIFT) > SECTION_SIZE_BITS
>>>>    1089	#error Allocator pageblock_order exceeds SECTION_SIZE
>>>>    1090	#endif
>>>>    1091	
>>>>
>>> I took a look at the latest code, at line 1082 of the same file uses
>>> pageblock_order. And I apply this patch on top of v4.20-rc5, the build
>>> looks good to me.
>>>
>>> Confused why this introduce an compile error.
>> Hi Wei,
>>
>> we could reproduce the warnings with using make.cross.
>>
> That's interesting.
>
> Do you see this file already use pageblock_order in line 1081?
>
> Is this one report warning?
>

both questions is yes.

Best Regards,
Rong Chen