Re: [PATCH 1/2] mm, pageblock: make sure pageblock won't exceed mem_sectioin

[Rong Chen <rong.a.chen@xxxxxxxxx>]

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