Re: [PATCH 10/10] mm, treewide: Redefine MAX_ORDER sanely

From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: kernel test robot <lkp@intel.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
	David Hildenbrand <david@redhat.com>,
	oe-kbuild-all@lists.linux.dev,
	Linux Memory Management List <linux-mm@kvack.org>,
	linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 10/10] mm, treewide: Redefine MAX_ORDER sanely
Date: Wed, 15 Mar 2023 18:26:36 +0300	[thread overview]
Message-ID: <20230315152636.smn34f3c6a5jzpn3@box> (raw)
In-Reply-To: <202303152251.0kYjWIXW-lkp@intel.com>

On Wed, Mar 15, 2023 at 11:06:21PM +0800, kernel test robot wrote:
> Hi Kirill,
> 
> Thank you for the patch! Yet something to improve:
> 
> [auto build test ERROR on akpm-mm/mm-everything]
> [also build test ERROR on powerpc/next powerpc/fixes linus/master v6.3-rc2 next-20230315]
> [cannot apply to davem-sparc/master]
> [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/Kirill-A-Shutemov/sparc-mm-Fix-MAX_ORDER-usage-in-tsb_grow/20230315-193254
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/20230315113133.11326-11-kirill.shutemov%40linux.intel.com
> patch subject: [PATCH 10/10] mm, treewide: Redefine MAX_ORDER sanely
> config: mips-randconfig-r015-20230313 (https://download.01.org/0day-ci/archive/20230315/202303152251.0kYjWIXW-lkp@intel.com/config)
> compiler: mips64el-linux-gcc (GCC) 12.1.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://github.com/intel-lab-lkp/linux/commit/ccefb5df94c3c6c966f6f583d60c9d9c832b7a34
>         git remote add linux-review https://github.com/intel-lab-lkp/linux
>         git fetch --no-tags linux-review Kirill-A-Shutemov/sparc-mm-Fix-MAX_ORDER-usage-in-tsb_grow/20230315-193254
>         git checkout ccefb5df94c3c6c966f6f583d60c9d9c832b7a34
>         # save the config file
>         mkdir build_dir && cp config build_dir/.config
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips olddefconfig
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips prepare
> 
> If you fix the issue, kindly add following tag where applicable
> | Reported-by: kernel test robot <lkp@intel.com>
> | Link: https://lore.kernel.org/oe-kbuild-all/202303152251.0kYjWIXW-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from include/linux/gfp.h:7,
>                     from include/linux/xarray.h:15,
>                     from include/linux/list_lru.h:14,
>                     from include/linux/fs.h:13,
>                     from include/linux/compat.h:17,
>                     from arch/mips/kernel/asm-offsets.c:12:
> >> include/linux/mmzone.h:1749:2: error: #error Allocator MAX_ORDER exceeds SECTION_SIZE
>     1749 | #error Allocator MAX_ORDER exceeds SECTION_SIZE
>          |  ^~~~~

It is not regression. MIPS Kconfig allows for excessively large
ARCH_FORCE_MAX_ORDER. The patch changes nothing with regarards to this.
But it changes meaning of ARCH_FORCE_MAX_ORDER and old configs are now
breaks.

Thomas, could you help with formulating more sensible upper limit for the
config option, so it won't collide with SECTION_SIZE?

-- 
  Kiryl Shutsemau / Kirill A. Shutemov