Re: [PATCH v4] mm: Add CONFIG_PAGE_BLOCK_ORDER to select page block order

[Juan Yescas <jyescas@google.com>]

On Tue, May 13, 2025 at 9:52 AM Zi Yan <ziy@nvidia.com> wrote:
>
> On 13 May 2025, at 12:47, Zi Yan wrote:
>
> > On 13 May 2025, at 12:41, Juan Yescas wrote:
> >
> >> On Tue, May 13, 2025 at 8:08 AM Zi Yan <ziy@nvidia.com> wrote:
> >>>
> >>> On 10 May 2025, at 13:16, kernel test robot wrote:
> >>>
> >>>> Hi Juan,
> >>>>
> >>>> kernel test robot noticed the following build errors:
> >>>>
> >>>> [auto build test ERROR on linus/master]
> >>>> [also build test ERROR on v6.15-rc5]
> >>>> [cannot apply to akpm-mm/mm-everything next-20250509]
> >>>> [If your patch is applied to the wrong git tree, kindly drop us a note.
> >>>> And when submitting patch, we suggest to use '--base' as documented in
> >>>> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> >>>>
> >>>> url:    https://github.com/intel-lab-lkp/linux/commits/Juan-Yescas/mm-Add-CONFIG_PAGE_BLOCK_ORDER-to-select-page-block-order/20250510-090501
> >>>> base:   linus/master
> >>>> patch link:    https://lore.kernel.org/r/20250510010338.3978696-1-jyescas%40google.com
> >>>> patch subject: [PATCH v4] mm: Add CONFIG_PAGE_BLOCK_ORDER to select page block order
> >>>> config: powerpc-allmodconfig (https://download.01.org/0day-ci/archive/20250511/202505110035.wtOWnL8o-lkp@intel.com/config)
> >>>> compiler: powerpc64-linux-gcc (GCC) 14.2.0
> >>>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250511/202505110035.wtOWnL8o-lkp@intel.com/reproduce)
> >>>>
> >>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> >>>> the same patch/commit), kindly add following tags
> >>>> | Reported-by: kernel test robot <lkp@intel.com>
> >>>> | Closes: https://lore.kernel.org/oe-kbuild-all/202505110035.wtOWnL8o-lkp@intel.com/
> >>>>
> >>>> All errors (new ones prefixed by >>):
> >>>>
> >>>>    In file included from include/linux/gfp.h:7,
> >>>>                     from include/linux/xarray.h:16,
> >>>>                     from include/linux/list_lru.h:14,
> >>>>                     from include/linux/fs.h:14,
> >>>>                     from include/linux/compat.h:17,
> >>>>                     from arch/powerpc/kernel/asm-offsets.c:12:
> >>>>>> include/linux/mmzone.h:53:2: error: #error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER
> >>>>       53 | #error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER
> >>>>          |  ^~~~~
> >>>>    make[3]: *** [scripts/Makefile.build:98: arch/powerpc/kernel/asm-offsets.s] Error 1
> >>>
> >>> In this config, CONFIG_ARCH_FORCE_MAX_ORDER is set to 8, lower than
> >>> the default PAGE_BLOCK_ORDER value, 10. I wonder if the error should
> >>> be changed to ignore CONFIG_PAGE_BLOCK_ORDER when MAX_PAGE_ORDER is
> >>> set by CONFIG_ARCH_FORCE_MAX_ORDER and give a warning instead.
> >>
> >> In ARMv8, MAX_PAGE_ORDER is set up by CONFIG_ARCH_FORCE_MAX_ORDER
> >> and CONFIG_PAGE_BLOCK_ORDER is also set up, so we need to take into account
> >> CONFIG_PAGE_BLOCK_ORDER. For other architectures, the default will be:
> >> CONFIG_ARCH_FORCE_MAX_ORDER = CONFIG_PAGE_BLOCK_ORDER.
> >
> > It seems that the Kconfig “range 1 ARCH_FORCE_MAX_ORDER if ARCH_FORCE_MAX_ORDER”
> > is not working. The above powerpc-allmodconfig has CONFIG_ARCH_FORCE_MAX_ORDER
> > set to 8 and CONFIG_PAGE_BLOCK_ORDER is set to 10, leading to the compilation
> > error.
>
> You can get the same config by running “ARCH=powerpc make allmodconfig”.
>

Thanks, that works!

> >
> >>
> >> Is there any valid case where the MAX_PAGE_ORDER needs to be smaller than
> >> the page block order?
> >
> > I am not aware of any.
> >
> >>
> >> Thanks
> >> Juan
> >>>
> >>>>    make[3]: Target 'prepare' not remade because of errors.
> >>>>    make[2]: *** [Makefile:1275: prepare0] Error 2
> >>>>    make[2]: Target 'prepare' not remade because of errors.
> >>>>    make[1]: *** [Makefile:248: __sub-make] Error 2
> >>>>    make[1]: Target 'prepare' not remade because of errors.
> >>>>    make: *** [Makefile:248: __sub-make] Error 2
> >>>>    make: Target 'prepare' not remade because of errors.
> >>>>
> >>>>
> >>>> vim +53 include/linux/mmzone.h
> >>>>
> >>>>     46
> >>>>     47        /*
> >>>>     48         * The MAX_PAGE_ORDER, which defines the max order of pages to be allocated
> >>>>     49         * by the buddy allocator, has to be larger or equal to the PAGE_BLOCK_ORDER,
> >>>>     50         * which defines the order for the number of pages that can have a migrate type
> >>>>     51         */
> >>>>     52        #if (PAGE_BLOCK_ORDER > MAX_PAGE_ORDER)
> >>>>   > 53        #error MAX_PAGE_ORDER must be >= PAGE_BLOCK_ORDER
> >>>>     54        #endif
> >>>>     55
> >>>>
> >>>> --
> >>>> 0-DAY CI Kernel Test Service
> >>>> https://github.com/intel/lkp-tests/wiki
> >>>
> >>>
> >>> Best Regards,
> >>> Yan, Zi
> >
> >
> > Best Regards,
> > Yan, Zi
>
>
> Best Regards,
> Yan, Zi