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

Message ID 20230315113133.11326-11-kirill.shutemov@linux.intel.com
State New
Headers
Series Fix confusion around MAX_ORDER |

Commit Message

Kirill A. Shutemov March 15, 2023, 11:31 a.m. UTC
  MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.

This definition is counter-intuitive and lead to number of bugs all over
the kernel.

Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
 .../admin-guide/kdump/vmcoreinfo.rst          |  2 +-
 .../admin-guide/kernel-parameters.txt         |  2 +-
 arch/arc/Kconfig                              |  4 +-
 arch/arm/Kconfig                              |  9 ++---
 arch/arm/configs/imx_v6_v7_defconfig          |  2 +-
 arch/arm/configs/milbeaut_m10v_defconfig      |  2 +-
 arch/arm/configs/oxnas_v6_defconfig           |  2 +-
 arch/arm/configs/pxa_defconfig                |  2 +-
 arch/arm/configs/sama7_defconfig              |  2 +-
 arch/arm/configs/sp7021_defconfig             |  2 +-
 arch/arm64/Kconfig                            | 27 ++++++-------
 arch/arm64/include/asm/sparsemem.h            |  2 +-
 arch/arm64/kvm/hyp/include/nvhe/gfp.h         |  2 +-
 arch/arm64/kvm/hyp/nvhe/page_alloc.c          | 10 ++---
 arch/csky/Kconfig                             |  2 +-
 arch/ia64/Kconfig                             |  8 ++--
 arch/ia64/include/asm/sparsemem.h             |  4 +-
 arch/ia64/mm/hugetlbpage.c                    |  2 +-
 arch/loongarch/Kconfig                        | 15 +++-----
 arch/m68k/Kconfig.cpu                         |  5 +--
 arch/mips/Kconfig                             | 19 ++++------
 arch/nios2/Kconfig                            |  7 +---
 arch/powerpc/Kconfig                          | 27 ++++++-------
 arch/powerpc/configs/85xx/ge_imp3a_defconfig  |  2 +-
 arch/powerpc/configs/fsl-emb-nonhw.config     |  2 +-
 arch/powerpc/mm/book3s64/iommu_api.c          |  2 +-
 arch/powerpc/mm/hugetlbpage.c                 |  2 +-
 arch/powerpc/platforms/powernv/pci-ioda.c     |  2 +-
 arch/sh/configs/ecovec24_defconfig            |  2 +-
 arch/sh/mm/Kconfig                            | 17 ++++-----
 arch/sparc/Kconfig                            |  5 +--
 arch/sparc/kernel/pci_sun4v.c                 |  2 +-
 arch/sparc/kernel/traps_64.c                  |  2 +-
 arch/sparc/mm/tsb.c                           |  4 +-
 arch/um/kernel/um_arch.c                      |  4 +-
 arch/xtensa/Kconfig                           |  5 +--
 drivers/base/regmap/regmap-debugfs.c          |  8 ++--
 drivers/block/floppy.c                        |  2 +-
 drivers/crypto/ccp/sev-dev.c                  |  2 +-
 drivers/crypto/hisilicon/sgl.c                |  6 +--
 drivers/gpu/drm/i915/gem/i915_gem_internal.c  |  2 +-
 .../gpu/drm/i915/gem/selftests/huge_pages.c   |  2 +-
 drivers/gpu/drm/ttm/ttm_pool.c                | 22 +++++------
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  2 +-
 drivers/iommu/dma-iommu.c                     |  2 +-
 drivers/irqchip/irq-gic-v3-its.c              |  4 +-
 drivers/md/dm-bufio.c                         |  2 +-
 drivers/misc/genwqe/card_dev.c                |  2 +-
 drivers/misc/genwqe/card_utils.c              |  4 +-
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |  2 +-
 drivers/net/ethernet/ibm/ibmvnic.h            |  2 +-
 drivers/video/fbdev/hyperv_fb.c               |  4 +-
 drivers/video/fbdev/vermilion/vermilion.c     |  2 +-
 drivers/virtio/virtio_balloon.c               |  2 +-
 drivers/virtio/virtio_mem.c                   | 12 +++---
 fs/ramfs/file-nommu.c                         |  2 +-
 include/drm/ttm/ttm_pool.h                    |  2 +-
 include/linux/hugetlb.h                       |  2 +-
 include/linux/mmzone.h                        | 10 ++---
 include/linux/pageblock-flags.h               |  4 +-
 include/linux/slab.h                          |  6 +--
 kernel/crash_core.c                           |  2 +-
 kernel/dma/pool.c                             |  6 +--
 kernel/events/ring_buffer.c                   |  4 +-
 mm/Kconfig                                    |  6 +--
 mm/compaction.c                               |  8 ++--
 mm/debug_vm_pgtable.c                         |  4 +-
 mm/huge_memory.c                              |  2 +-
 mm/hugetlb.c                                  |  4 +-
 mm/kmsan/init.c                               |  6 +--
 mm/memblock.c                                 |  2 +-
 mm/memory_hotplug.c                           |  4 +-
 mm/page_alloc.c                               | 38 +++++++++----------
 mm/page_isolation.c                           | 12 +++---
 mm/page_owner.c                               |  6 +--
 mm/page_reporting.c                           |  6 +--
 mm/shuffle.h                                  |  2 +-
 mm/slab.c                                     |  2 +-
 mm/slub.c                                     |  6 +--
 mm/vmscan.c                                   |  2 +-
 mm/vmstat.c                                   | 14 +++----
 net/smc/smc_ib.c                              |  2 +-
 security/integrity/ima/ima_crypto.c           |  2 +-
 tools/testing/memblock/linux/mmzone.h         |  6 +--
 84 files changed, 218 insertions(+), 248 deletions(-)
  

Comments

kernel test robot March 15, 2023, 3:06 p.m. UTC | #1
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
         |  ^~~~~
   arch/mips/kernel/asm-offsets.c:26:6: warning: no previous prototype for 'output_ptreg_defines' [-Wmissing-prototypes]
      26 | void output_ptreg_defines(void)
         |      ^~~~~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:78:6: warning: no previous prototype for 'output_task_defines' [-Wmissing-prototypes]
      78 | void output_task_defines(void)
         |      ^~~~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:92:6: warning: no previous prototype for 'output_thread_info_defines' [-Wmissing-prototypes]
      92 | void output_thread_info_defines(void)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:108:6: warning: no previous prototype for 'output_thread_defines' [-Wmissing-prototypes]
     108 | void output_thread_defines(void)
         |      ^~~~~~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:136:6: warning: no previous prototype for 'output_thread_fpu_defines' [-Wmissing-prototypes]
     136 | void output_thread_fpu_defines(void)
         |      ^~~~~~~~~~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:179:6: warning: no previous prototype for 'output_mm_defines' [-Wmissing-prototypes]
     179 | void output_mm_defines(void)
         |      ^~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:235:6: warning: no previous prototype for 'output_sc_defines' [-Wmissing-prototypes]
     235 | void output_sc_defines(void)
         |      ^~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:248:6: warning: no previous prototype for 'output_signal_defined' [-Wmissing-prototypes]
     248 | void output_signal_defined(void)
         |      ^~~~~~~~~~~~~~~~~~~~~
   arch/mips/kernel/asm-offsets.c:341:6: warning: no previous prototype for 'output_kvm_defines' [-Wmissing-prototypes]
     341 | void output_kvm_defines(void)
         |      ^~~~~~~~~~~~~~~~~~
   make[2]: *** [scripts/Makefile.build:114: arch/mips/kernel/asm-offsets.s] Error 1
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:1287: prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:226: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +1749 include/linux/mmzone.h

d41dee369bff3b Andy Whitcroft     2005-06-23  1744  
835c134ec4dd75 Mel Gorman         2007-10-16  1745  #define SECTION_BLOCKFLAGS_BITS \
d9c2340052278d Mel Gorman         2007-10-16  1746  	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
835c134ec4dd75 Mel Gorman         2007-10-16  1747  
ccefb5df94c3c6 Kirill A. Shutemov 2023-03-15  1748  #if (MAX_ORDER + PAGE_SHIFT) > SECTION_SIZE_BITS
d41dee369bff3b Andy Whitcroft     2005-06-23 @1749  #error Allocator MAX_ORDER exceeds SECTION_SIZE
d41dee369bff3b Andy Whitcroft     2005-06-23  1750  #endif
d41dee369bff3b Andy Whitcroft     2005-06-23  1751
  
Kirill A. Shutemov March 15, 2023, 3:26 p.m. UTC | #2
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?
  
kernel test robot March 15, 2023, 3:26 p.m. UTC | #3
Hi Kirill,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on powerpc/next powerpc/fixes linus/master v6.3-rc2 next-20230315]
[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: arm-randconfig-r033-20230313 (https://download.01.org/0day-ci/archive/20230315/202303152343.D93IbJmn-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
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
        # install arm cross compiling tool for clang build
        # apt-get install binutils-arm-linux-gnueabi
        # 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=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash

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/202303152343.D93IbJmn-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> mm/memblock.c:2046:11: warning: comparison of distinct pointer types ('typeof (11) *' (aka 'int *') and 'typeof (__ffs(start)) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
                   order = min(MAX_ORDER, __ffs(start));
                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:67:19: note: expanded from macro 'min'
   #define min(x, y)       __careful_cmp(x, y, <)
                           ^~~~~~~~~~~~~~~~~~~~~~
   include/linux/minmax.h:36:24: note: expanded from macro '__careful_cmp'
           __builtin_choose_expr(__safe_cmp(x, y), \
                                 ^~~~~~~~~~~~~~~~
   include/linux/minmax.h:26:4: note: expanded from macro '__safe_cmp'
                   (__typecheck(x, y) && __no_side_effects(x, y))
                    ^~~~~~~~~~~~~~~~~
   include/linux/minmax.h:20:28: note: expanded from macro '__typecheck'
           (!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
                      ~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~
   1 warning generated.


vim +2046 mm/memblock.c

  2040	
  2041	static void __init __free_pages_memory(unsigned long start, unsigned long end)
  2042	{
  2043		int order;
  2044	
  2045		while (start < end) {
> 2046			order = min(MAX_ORDER, __ffs(start));
  2047	
  2048			while (start + (1UL << order) > end)
  2049				order--;
  2050	
  2051			memblock_free_pages(pfn_to_page(start), start, order);
  2052	
  2053			start += (1UL << order);
  2054		}
  2055	}
  2056
  
Kirill A. Shutemov March 15, 2023, 3:38 p.m. UTC | #4
On Wed, Mar 15, 2023 at 11:26:51PM +0800, kernel test robot wrote:
> Hi Kirill,
> 
> Thank you for the patch! Perhaps something to improve:
> 
> [auto build test WARNING on akpm-mm/mm-everything]
> [also build test WARNING on powerpc/next powerpc/fixes linus/master v6.3-rc2 next-20230315]
> [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: arm-randconfig-r033-20230313 (https://download.01.org/0day-ci/archive/20230315/202303152343.D93IbJmn-lkp@intel.com/config)
> compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project 67409911353323ca5edf2049ef0df54132fa1ca7)
> 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
>         # install arm cross compiling tool for clang build
>         # apt-get install binutils-arm-linux-gnueabi
>         # 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=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm olddefconfig
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash
> 
> 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/202303152343.D93IbJmn-lkp@intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
> >> mm/memblock.c:2046:11: warning: comparison of distinct pointer types ('typeof (11) *' (aka 'int *') and 'typeof (__ffs(start)) *' (aka 'unsigned long *')) [-Wcompare-distinct-pointer-types]
>                    order = min(MAX_ORDER, __ffs(start));

The fixup:

diff --git a/mm/memblock.c b/mm/memblock.c
index 338b8cb0793e..7911224b1ed3 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2043,7 +2043,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
 	int order;
 
 	while (start < end) {
-		order = min(MAX_ORDER, __ffs(start));
+		order = min_t(int, MAX_ORDER, __ffs(start));
 
 		while (start + (1UL << order) > end)
 			order--;
  
Zi Yan March 16, 2023, 5:09 p.m. UTC | #5
On 15 Mar 2023, at 7:31, Kirill A. Shutemov wrote:

> MAX_ORDER currently defined as number of orders page allocator supports:
> user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
>
> This definition is counter-intuitive and lead to number of bugs all over
> the kernel.
>
> Change the definition of MAX_ORDER to be inclusive: the range of orders
> user can ask from buddy allocator is 0..MAX_ORDER now.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  .../admin-guide/kdump/vmcoreinfo.rst          |  2 +-
>  .../admin-guide/kernel-parameters.txt         |  2 +-
>  arch/arc/Kconfig                              |  4 +-
>  arch/arm/Kconfig                              |  9 ++---
>  arch/arm/configs/imx_v6_v7_defconfig          |  2 +-
>  arch/arm/configs/milbeaut_m10v_defconfig      |  2 +-
>  arch/arm/configs/oxnas_v6_defconfig           |  2 +-
>  arch/arm/configs/pxa_defconfig                |  2 +-
>  arch/arm/configs/sama7_defconfig              |  2 +-
>  arch/arm/configs/sp7021_defconfig             |  2 +-
>  arch/arm64/Kconfig                            | 27 ++++++-------
>  arch/arm64/include/asm/sparsemem.h            |  2 +-
>  arch/arm64/kvm/hyp/include/nvhe/gfp.h         |  2 +-
>  arch/arm64/kvm/hyp/nvhe/page_alloc.c          | 10 ++---
>  arch/csky/Kconfig                             |  2 +-
>  arch/ia64/Kconfig                             |  8 ++--
>  arch/ia64/include/asm/sparsemem.h             |  4 +-
>  arch/ia64/mm/hugetlbpage.c                    |  2 +-
>  arch/loongarch/Kconfig                        | 15 +++-----
>  arch/m68k/Kconfig.cpu                         |  5 +--
>  arch/mips/Kconfig                             | 19 ++++------
>  arch/nios2/Kconfig                            |  7 +---
>  arch/powerpc/Kconfig                          | 27 ++++++-------
>  arch/powerpc/configs/85xx/ge_imp3a_defconfig  |  2 +-
>  arch/powerpc/configs/fsl-emb-nonhw.config     |  2 +-
>  arch/powerpc/mm/book3s64/iommu_api.c          |  2 +-
>  arch/powerpc/mm/hugetlbpage.c                 |  2 +-
>  arch/powerpc/platforms/powernv/pci-ioda.c     |  2 +-
>  arch/sh/configs/ecovec24_defconfig            |  2 +-
>  arch/sh/mm/Kconfig                            | 17 ++++-----
>  arch/sparc/Kconfig                            |  5 +--
>  arch/sparc/kernel/pci_sun4v.c                 |  2 +-
>  arch/sparc/kernel/traps_64.c                  |  2 +-
>  arch/sparc/mm/tsb.c                           |  4 +-
>  arch/um/kernel/um_arch.c                      |  4 +-
>  arch/xtensa/Kconfig                           |  5 +--
>  drivers/base/regmap/regmap-debugfs.c          |  8 ++--
>  drivers/block/floppy.c                        |  2 +-
>  drivers/crypto/ccp/sev-dev.c                  |  2 +-
>  drivers/crypto/hisilicon/sgl.c                |  6 +--
>  drivers/gpu/drm/i915/gem/i915_gem_internal.c  |  2 +-
>  .../gpu/drm/i915/gem/selftests/huge_pages.c   |  2 +-
>  drivers/gpu/drm/ttm/ttm_pool.c                | 22 +++++------
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h   |  2 +-
>  drivers/iommu/dma-iommu.c                     |  2 +-
>  drivers/irqchip/irq-gic-v3-its.c              |  4 +-
>  drivers/md/dm-bufio.c                         |  2 +-
>  drivers/misc/genwqe/card_dev.c                |  2 +-
>  drivers/misc/genwqe/card_utils.c              |  4 +-
>  .../net/ethernet/hisilicon/hns3/hns3_enet.c   |  2 +-
>  drivers/net/ethernet/ibm/ibmvnic.h            |  2 +-
>  drivers/video/fbdev/hyperv_fb.c               |  4 +-
>  drivers/video/fbdev/vermilion/vermilion.c     |  2 +-
>  drivers/virtio/virtio_balloon.c               |  2 +-
>  drivers/virtio/virtio_mem.c                   | 12 +++---
>  fs/ramfs/file-nommu.c                         |  2 +-
>  include/drm/ttm/ttm_pool.h                    |  2 +-
>  include/linux/hugetlb.h                       |  2 +-
>  include/linux/mmzone.h                        | 10 ++---
>  include/linux/pageblock-flags.h               |  4 +-
>  include/linux/slab.h                          |  6 +--
>  kernel/crash_core.c                           |  2 +-
>  kernel/dma/pool.c                             |  6 +--
>  kernel/events/ring_buffer.c                   |  4 +-
>  mm/Kconfig                                    |  6 +--
>  mm/compaction.c                               |  8 ++--
>  mm/debug_vm_pgtable.c                         |  4 +-
>  mm/huge_memory.c                              |  2 +-
>  mm/hugetlb.c                                  |  4 +-
>  mm/kmsan/init.c                               |  6 +--
>  mm/memblock.c                                 |  2 +-
>  mm/memory_hotplug.c                           |  4 +-
>  mm/page_alloc.c                               | 38 +++++++++----------
>  mm/page_isolation.c                           | 12 +++---
>  mm/page_owner.c                               |  6 +--
>  mm/page_reporting.c                           |  6 +--
>  mm/shuffle.h                                  |  2 +-
>  mm/slab.c                                     |  2 +-
>  mm/slub.c                                     |  6 +--
>  mm/vmscan.c                                   |  2 +-
>  mm/vmstat.c                                   | 14 +++----
>  net/smc/smc_ib.c                              |  2 +-
>  security/integrity/ima/ima_crypto.c           |  2 +-
>  tools/testing/memblock/linux/mmzone.h         |  6 +--
>  84 files changed, 218 insertions(+), 248 deletions(-)
>
> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> index 86fd88492870..c267b8c61e97 100644
> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
> +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> @@ -172,7 +172,7 @@ variables.
>  Offset of the free_list's member. This value is used to compute the number
>  of free pages.
>
> -Each zone has a free_area structure array called free_area[MAX_ORDER].
> +Each zone has a free_area structure array called free_area[MAX_ORDER + 1].
>  The free_list represents a linked list of free page blocks.
>
>  (list_head, next|prev)

In vmcoreinfo.rst, line 192:

- (zone.free_area, MAX_ORDER)
+ (zone.free_area, MAX_ORDER + 1)



> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 6221a1d057dd..50da4f26fad5 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -3969,7 +3969,7 @@
>  			[KNL] Minimal page reporting order
>  			Format: <integer>
>  			Adjust the minimal page reporting order. The page
> -			reporting is disabled when it exceeds (MAX_ORDER-1).
> +			reporting is disabled when it exceeds MAX_ORDER.
>
>  	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
>  			timeout > 0: seconds before rebooting

line 942:
-		    possible value is MAX_ORDER/2.  Setting this parameter
+			possible value is (MAX_ORDER + 1)/2.  Setting this parameter

> diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
> index d9a13ccf89a3..ab6d701365bb 100644
> --- a/arch/arc/Kconfig
> +++ b/arch/arc/Kconfig
> @@ -556,7 +556,7 @@ endmenu	 # "ARC Architecture Configuration"
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	default "12" if ARC_HUGEPAGE_16M
> -	default "11"
> +	default "11" if ARC_HUGEPAGE_16M
> +	default "10"
>
>  source "kernel/power/Kconfig"
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index e24a9820e12f..929e646e84b9 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -1355,9 +1355,9 @@ config ARM_MODULE_PLTS
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	default "12" if SOC_AM33XX
> -	default "9" if SA1111
> -	default "11"
> +	default "11" if SOC_AM33XX
> +	default "8" if SA1111
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -1366,9 +1366,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  config ALIGNMENT_TRAP
>  	def_bool CPU_CP15_MMU
>  	select HAVE_PROC_CPU if PROC_FS
> diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig
> index 6dc6fed12af8..345a67e67dbd 100644
> --- a/arch/arm/configs/imx_v6_v7_defconfig
> +++ b/arch/arm/configs/imx_v6_v7_defconfig
> @@ -31,7 +31,7 @@ CONFIG_SOC_VF610=y
>  CONFIG_SMP=y
>  CONFIG_ARM_PSCI=y
>  CONFIG_HIGHMEM=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=14
> +CONFIG_ARCH_FORCE_MAX_ORDER=13
>  CONFIG_CMDLINE="noinitrd console=ttymxc0,115200"
>  CONFIG_KEXEC=y
>  CONFIG_CPU_FREQ=y
> diff --git a/arch/arm/configs/milbeaut_m10v_defconfig b/arch/arm/configs/milbeaut_m10v_defconfig
> index bd29e5012cb0..385ad0f391a8 100644
> --- a/arch/arm/configs/milbeaut_m10v_defconfig
> +++ b/arch/arm/configs/milbeaut_m10v_defconfig
> @@ -26,7 +26,7 @@ CONFIG_THUMB2_KERNEL=y
>  # CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11 is not set
>  # CONFIG_ARM_PATCH_IDIV is not set
>  CONFIG_HIGHMEM=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=12
> +CONFIG_ARCH_FORCE_MAX_ORDER=11
>  CONFIG_SECCOMP=y
>  CONFIG_KEXEC=y
>  CONFIG_EFI=y
> diff --git a/arch/arm/configs/oxnas_v6_defconfig b/arch/arm/configs/oxnas_v6_defconfig
> index 70a67b3fc91b..90779812c6dd 100644
> --- a/arch/arm/configs/oxnas_v6_defconfig
> +++ b/arch/arm/configs/oxnas_v6_defconfig
> @@ -12,7 +12,7 @@ CONFIG_ARCH_OXNAS=y
>  CONFIG_MACH_OX820=y
>  CONFIG_SMP=y
>  CONFIG_NR_CPUS=16
> -CONFIG_ARCH_FORCE_MAX_ORDER=12
> +CONFIG_ARCH_FORCE_MAX_ORDER=11
>  CONFIG_SECCOMP=y
>  CONFIG_ARM_APPENDED_DTB=y
>  CONFIG_ARM_ATAG_DTB_COMPAT=y
> diff --git a/arch/arm/configs/pxa_defconfig b/arch/arm/configs/pxa_defconfig
> index e656d3af2266..b46e39369dbb 100644
> --- a/arch/arm/configs/pxa_defconfig
> +++ b/arch/arm/configs/pxa_defconfig
> @@ -20,7 +20,7 @@ CONFIG_PXA_SHARPSL=y
>  CONFIG_MACH_AKITA=y
>  CONFIG_MACH_BORZOI=y
>  CONFIG_AEABI=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=9
> +CONFIG_ARCH_FORCE_MAX_ORDER=8
>  CONFIG_CMDLINE="root=/dev/ram0 ro"
>  CONFIG_KEXEC=y
>  CONFIG_CPU_FREQ=y
> diff --git a/arch/arm/configs/sama7_defconfig b/arch/arm/configs/sama7_defconfig
> index 0d964c613d71..954112041403 100644
> --- a/arch/arm/configs/sama7_defconfig
> +++ b/arch/arm/configs/sama7_defconfig
> @@ -19,7 +19,7 @@ CONFIG_ATMEL_CLOCKSOURCE_TCB=y
>  # CONFIG_CACHE_L2X0 is not set
>  # CONFIG_ARM_PATCH_IDIV is not set
>  # CONFIG_CPU_SW_DOMAIN_PAN is not set
> -CONFIG_ARCH_FORCE_MAX_ORDER=15
> +CONFIG_ARCH_FORCE_MAX_ORDER=14
>  CONFIG_UACCESS_WITH_MEMCPY=y
>  # CONFIG_ATAGS is not set
>  CONFIG_CMDLINE="console=ttyS0,115200 earlyprintk ignore_loglevel"
> diff --git a/arch/arm/configs/sp7021_defconfig b/arch/arm/configs/sp7021_defconfig
> index 5bca2eb59b86..c6448ac860b6 100644
> --- a/arch/arm/configs/sp7021_defconfig
> +++ b/arch/arm/configs/sp7021_defconfig
> @@ -17,7 +17,7 @@ CONFIG_ARCH_SUNPLUS=y
>  # CONFIG_VDSO is not set
>  CONFIG_SMP=y
>  CONFIG_THUMB2_KERNEL=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=12
> +CONFIG_ARCH_FORCE_MAX_ORDER=11
>  CONFIG_VFP=y
>  CONFIG_NEON=y
>  CONFIG_MODULES=y
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 1023e896d46b..cb5c6aa3254e 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1476,22 +1476,22 @@ config XEN
>
>  # include/linux/mmzone.h requires the following to be true:
>  #
> -#   MAX_ORDER - 1 + PAGE_SHIFT <= SECTION_SIZE_BITS
> +#   MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
>  #
> -# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS + 1 - PAGE_SHIFT:
> +# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT:
>  #
>  #     | SECTION_SIZE_BITS |  PAGE_SHIFT  |  max MAX_ORDER  |  default MAX_ORDER |
>  # ----+-------------------+--------------+-----------------+--------------------+
> -# 4K  |       27          |      12      |       16        |         11         |
> -# 16K |       27          |      14      |       14        |         12         |
> -# 64K |       29          |      16      |       14        |         14         |
> +# 4K  |       27          |      12      |       15        |         10         |
> +# 16K |       27          |      14      |       13        |         11         |
> +# 64K |       29          |      16      |       13        |         13         |
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES
> -	default "14" if ARM64_64K_PAGES
> -	range 12 14 if ARM64_16K_PAGES
> -	default "12" if ARM64_16K_PAGES
> -	range 11 16 if ARM64_4K_PAGES
> -	default "11"
> +	default "13" if ARM64_64K_PAGES
> +	range 11 13 if ARM64_16K_PAGES
> +	default "11" if ARM64_16K_PAGES
> +	range 10 15 if ARM64_4K_PAGES
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -1500,14 +1500,11 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  	  We make sure that we can allocate up to a HugePage size for each configuration.
>  	  Hence we have :
> -		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
> +		MAX_ORDER = PMD_SHIFT - PAGE_SHIFT  => PAGE_SHIFT - 3
>
> -	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
> +	  However for 4K, we choose a higher default value, 10 as opposed to 9, giving us
>  	  4M allocations matching the default size used by generic code.
>
>  config UNMAP_KERNEL_AT_EL0
> diff --git a/arch/arm64/include/asm/sparsemem.h b/arch/arm64/include/asm/sparsemem.h
> index 4b73463423c3..5f5437621029 100644
> --- a/arch/arm64/include/asm/sparsemem.h
> +++ b/arch/arm64/include/asm/sparsemem.h
> @@ -10,7 +10,7 @@
>  /*
>   * Section size must be at least 512MB for 64K base
>   * page size config. Otherwise it will be less than
> - * (MAX_ORDER - 1) and the build process will fail.
> + * MAX_ORDER and the build process will fail.
>   */
>  #ifdef CONFIG_ARM64_64K_PAGES
>  #define SECTION_SIZE_BITS 29
> diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
> index 0a048dc06a7d..fe5472a184a3 100644
> --- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
> +++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
> @@ -16,7 +16,7 @@ struct hyp_pool {
>  	 * API at EL2.
>  	 */
>  	hyp_spinlock_t lock;
> -	struct list_head free_area[MAX_ORDER];
> +	struct list_head free_area[MAX_ORDER + 1];
>  	phys_addr_t range_start;
>  	phys_addr_t range_end;
>  	unsigned short max_order;
> diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
> index 803ba3222e75..b1e392186a0f 100644
> --- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
> +++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
> @@ -110,7 +110,7 @@ static void __hyp_attach_page(struct hyp_pool *pool,
>  	 * after coalescing, so make sure to mark it HYP_NO_ORDER proactively.
>  	 */
>  	p->order = HYP_NO_ORDER;
> -	for (; (order + 1) < pool->max_order; order++) {
> +	for (; (order + 1) <= pool->max_order; order++) {
>  		buddy = __find_buddy_avail(pool, p, order);
>  		if (!buddy)
>  			break;
> @@ -203,9 +203,9 @@ void *hyp_alloc_pages(struct hyp_pool *pool, unsigned short order)
>  	hyp_spin_lock(&pool->lock);
>
>  	/* Look for a high-enough-order page */
> -	while (i < pool->max_order && list_empty(&pool->free_area[i]))
> +	while (i <= pool->max_order && list_empty(&pool->free_area[i]))
>  		i++;
> -	if (i >= pool->max_order) {
> +	if (i > pool->max_order) {
>  		hyp_spin_unlock(&pool->lock);
>  		return NULL;
>  	}
> @@ -228,8 +228,8 @@ int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages,
>  	int i;
>
>  	hyp_spin_lock_init(&pool->lock);
> -	pool->max_order = min(MAX_ORDER, get_order((nr_pages + 1) << PAGE_SHIFT));
> -	for (i = 0; i < pool->max_order; i++)
> +	pool->max_order = min(MAX_ORDER, get_order(nr_pages << PAGE_SHIFT));
> +	for (i = 0; i <= pool->max_order; i++)
>  		INIT_LIST_HEAD(&pool->free_area[i]);
>  	pool->range_start = phys;
>  	pool->range_end = phys + (nr_pages << PAGE_SHIFT);
> diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
> index dba02da6fa34..c694fac43bed 100644
> --- a/arch/csky/Kconfig
> +++ b/arch/csky/Kconfig
> @@ -334,7 +334,7 @@ config HIGHMEM
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	default "11"
> +	default "10"
>
>  config DRAM_BASE
>  	hex "DRAM start addr (the same with memory-section in dts)"
> diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
> index d7e4a24e8644..0d2f41fa56ee 100644
> --- a/arch/ia64/Kconfig
> +++ b/arch/ia64/Kconfig
> @@ -202,10 +202,10 @@ config IA64_CYCLONE
>  	  If you're unsure, answer N.
>
>  config ARCH_FORCE_MAX_ORDER
> -	int "MAX_ORDER (11 - 17)"  if !HUGETLB_PAGE
> -	range 11 17  if !HUGETLB_PAGE
> -	default "17" if HUGETLB_PAGE
> -	default "11"
> +	int "MAX_ORDER (10 - 16)"  if !HUGETLB_PAGE
> +	range 10 16  if !HUGETLB_PAGE
> +	default "16" if HUGETLB_PAGE
> +	default "10"
>
>  config SMP
>  	bool "Symmetric multi-processing support"
> diff --git a/arch/ia64/include/asm/sparsemem.h b/arch/ia64/include/asm/sparsemem.h
> index 84e8ce387b69..a58f8b466d96 100644
> --- a/arch/ia64/include/asm/sparsemem.h
> +++ b/arch/ia64/include/asm/sparsemem.h
> @@ -12,9 +12,9 @@
>  #define SECTION_SIZE_BITS	(30)
>  #define MAX_PHYSMEM_BITS	(50)
>  #ifdef CONFIG_ARCH_FORCE_MAX_ORDER
> -#if ((CONFIG_ARCH_FORCE_MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS)
> +#if (CONFIG_ARCH_FORCE_MAX_ORDER + PAGE_SHIFT > SECTION_SIZE_BITS)
>  #undef SECTION_SIZE_BITS
> -#define SECTION_SIZE_BITS (CONFIG_ARCH_FORCE_MAX_ORDER - 1 + PAGE_SHIFT)
> +#define SECTION_SIZE_BITS (CONFIG_ARCH_FORCE_MAX_ORDER + PAGE_SHIFT)
>  #endif
>  #endif
>
> diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
> index 380d2f3966c9..e8dd4323fb86 100644
> --- a/arch/ia64/mm/hugetlbpage.c
> +++ b/arch/ia64/mm/hugetlbpage.c
> @@ -170,7 +170,7 @@ static int __init hugetlb_setup_sz(char *str)
>  	size = memparse(str, &str);
>  	if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
>  		size <= PAGE_SIZE ||
> -		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
> +		size > (1UL << PAGE_SHIFT << MAX_ORDER)) {
>  		printk(KERN_WARNING "Invalid huge page size specified\n");
>  		return 1;
>  	}
> diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
> index 7fd51257e0ed..272a3a12c98d 100644
> --- a/arch/loongarch/Kconfig
> +++ b/arch/loongarch/Kconfig
> @@ -420,12 +420,12 @@ config NODES_SHIFT
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	range 14 64 if PAGE_SIZE_64KB
> -	default "14" if PAGE_SIZE_64KB
> -	range 12 64 if PAGE_SIZE_16KB
> -	default "12" if PAGE_SIZE_16KB
> -	range 11 64
> -	default "11"
> +	range 13 63 if PAGE_SIZE_64KB
> +	default "13" if PAGE_SIZE_64KB
> +	range 11 63 if PAGE_SIZE_16KB
> +	default "11" if PAGE_SIZE_16KB
> +	range 10 63
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -434,9 +434,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  	  The page size is not necessarily 4KB.  Keep this in mind
>  	  when choosing a value for this option.
>
> diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
> index 9380f6e3bb66..c9df6572133f 100644
> --- a/arch/m68k/Kconfig.cpu
> +++ b/arch/m68k/Kconfig.cpu
> @@ -400,7 +400,7 @@ config SINGLE_MEMORY_CHUNK
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order" if ADVANCED
>  	depends on !SINGLE_MEMORY_CHUNK
> -	default "11"
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -413,9 +413,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  value also defines the minimal size of the hole that allows
>  	  freeing unused memory map.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  config 060_WRITETHROUGH
>  	bool "Use write-through caching for 68060 supervisor accesses"
>  	depends on ADVANCED && M68060
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index e2f3ca73f40d..3e8b765b8c7b 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -2137,14 +2137,14 @@ endchoice
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	range 14 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
> -	default "14" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
> -	range 13 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
> -	default "13" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
> -	range 12 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
> -	default "12" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
> -	range 0 64
> -	default "11"
> +	range 13 63 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
> +	default "13" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
> +	range 12 63 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
> +	default "12" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
> +	range 11 63 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
> +	default "11" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
> +	range 0 63
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -2153,9 +2153,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  	  The page size is not necessarily 4KB.  Keep this in mind
>  	  when choosing a value for this option.
>
> diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
> index a582f72104f3..89708b95978c 100644
> --- a/arch/nios2/Kconfig
> +++ b/arch/nios2/Kconfig
> @@ -46,8 +46,8 @@ source "kernel/Kconfig.hz"
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	range 9 20
> -	default "11"
> +	range 8 19
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -56,9 +56,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  endmenu
>
>  source "arch/nios2/platform/Kconfig.platform"
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index a6c4407d3ec8..90bc0c7f2728 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -896,18 +896,18 @@ config DATA_SHIFT
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	range 8 9 if PPC64 && PPC_64K_PAGES
> -	default "9" if PPC64 && PPC_64K_PAGES
> -	range 13 13 if PPC64 && !PPC_64K_PAGES
> -	default "13" if PPC64 && !PPC_64K_PAGES
> -	range 9 64 if PPC32 && PPC_16K_PAGES
> -	default "9" if PPC32 && PPC_16K_PAGES
> -	range 7 64 if PPC32 && PPC_64K_PAGES
> -	default "7" if PPC32 && PPC_64K_PAGES
> -	range 5 64 if PPC32 && PPC_256K_PAGES
> -	default "5" if PPC32 && PPC_256K_PAGES
> -	range 11 64
> -	default "11"
> +	range 7 8 if PPC64 && PPC_64K_PAGES
> +	default "8" if PPC64 && PPC_64K_PAGES
> +	range 12 12 if PPC64 && !PPC_64K_PAGES
> +	default "12" if PPC64 && !PPC_64K_PAGES
> +	range 8 63 if PPC32 && PPC_16K_PAGES
> +	default "8" if PPC32 && PPC_16K_PAGES
> +	range 6 63 if PPC32 && PPC_64K_PAGES
> +	default "6" if PPC32 && PPC_64K_PAGES
> +	range 4 63 if PPC32 && PPC_256K_PAGES
> +	default "4" if PPC32 && PPC_256K_PAGES
> +	range 10 63
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -916,9 +916,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  	  The page size is not necessarily 4KB.  For example, on 64-bit
>  	  systems, 64KB pages can be enabled via CONFIG_PPC_64K_PAGES.  Keep
>  	  this in mind when choosing a value for this option.
> diff --git a/arch/powerpc/configs/85xx/ge_imp3a_defconfig b/arch/powerpc/configs/85xx/ge_imp3a_defconfig
> index ea719898b581..6cb7e90d52c1 100644
> --- a/arch/powerpc/configs/85xx/ge_imp3a_defconfig
> +++ b/arch/powerpc/configs/85xx/ge_imp3a_defconfig
> @@ -30,7 +30,7 @@ CONFIG_PREEMPT=y
>  # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
>  CONFIG_BINFMT_MISC=m
>  CONFIG_MATH_EMULATION=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=17
> +CONFIG_ARCH_FORCE_MAX_ORDER=16
>  CONFIG_PCI=y
>  CONFIG_PCIEPORTBUS=y
>  CONFIG_PCI_MSI=y
> diff --git a/arch/powerpc/configs/fsl-emb-nonhw.config b/arch/powerpc/configs/fsl-emb-nonhw.config
> index ab8a8c4530d9..3009b0efaf34 100644
> --- a/arch/powerpc/configs/fsl-emb-nonhw.config
> +++ b/arch/powerpc/configs/fsl-emb-nonhw.config
> @@ -41,7 +41,7 @@ CONFIG_FIXED_PHY=y
>  CONFIG_FONT_8x16=y
>  CONFIG_FONT_8x8=y
>  CONFIG_FONTS=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=13
> +CONFIG_ARCH_FORCE_MAX_ORDER=12
>  CONFIG_FRAMEBUFFER_CONSOLE=y
>  CONFIG_FRAME_WARN=1024
>  CONFIG_FTL=y
> diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c
> index 7fcfba162e0d..81d7185e2ae8 100644
> --- a/arch/powerpc/mm/book3s64/iommu_api.c
> +++ b/arch/powerpc/mm/book3s64/iommu_api.c
> @@ -97,7 +97,7 @@ static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua,
>  	}
>
>  	mmap_read_lock(mm);
> -	chunk = (1UL << (PAGE_SHIFT + MAX_ORDER - 1)) /
> +	chunk = (1UL << (PAGE_SHIFT + MAX_ORDER)) /
>  			sizeof(struct vm_area_struct *);
>  	chunk = min(chunk, entries);
>  	for (entry = 0; entry < entries; entry += chunk) {
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index f1ba8d1e8c1a..b900933507da 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -615,7 +615,7 @@ void __init gigantic_hugetlb_cma_reserve(void)
>  		order = mmu_psize_to_shift(MMU_PAGE_16G) - PAGE_SHIFT;
>
>  	if (order) {
> -		VM_WARN_ON(order < MAX_ORDER);
> +		VM_WARN_ON(order <= MAX_ORDER);
>  		hugetlb_cma_reserve(order);
>  	}
>  }
> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
> index 4f6e20a35aa1..5a81f106068e 100644
> --- a/arch/powerpc/platforms/powernv/pci-ioda.c
> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c
> @@ -1740,7 +1740,7 @@ static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
>  	 * DMA window can be larger than available memory, which will
>  	 * cause errors later.
>  	 */
> -	const u64 maxblock = 1UL << (PAGE_SHIFT + MAX_ORDER - 1);
> +	const u64 maxblock = 1UL << (PAGE_SHIFT + MAX_ORDER);
>
>  	/*
>  	 * We create the default window as big as we can. The constraint is
> diff --git a/arch/sh/configs/ecovec24_defconfig b/arch/sh/configs/ecovec24_defconfig
> index b52e14ccb450..4d655e8d4d74 100644
> --- a/arch/sh/configs/ecovec24_defconfig
> +++ b/arch/sh/configs/ecovec24_defconfig
> @@ -8,7 +8,7 @@ CONFIG_MODULES=y
>  CONFIG_MODULE_UNLOAD=y
>  # CONFIG_BLK_DEV_BSG is not set
>  CONFIG_CPU_SUBTYPE_SH7724=y
> -CONFIG_ARCH_FORCE_MAX_ORDER=12
> +CONFIG_ARCH_FORCE_MAX_ORDER=11
>  CONFIG_MEMORY_SIZE=0x10000000
>  CONFIG_FLATMEM_MANUAL=y
>  CONFIG_SH_ECOVEC=y
> diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
> index 411fdc0901f7..40271090bd7d 100644
> --- a/arch/sh/mm/Kconfig
> +++ b/arch/sh/mm/Kconfig
> @@ -20,13 +20,13 @@ config PAGE_OFFSET
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	range 9 64 if PAGE_SIZE_16KB
> -	default "9" if PAGE_SIZE_16KB
> -	range 7 64 if PAGE_SIZE_64KB
> -	default "7" if PAGE_SIZE_64KB
> -	range 11 64
> -	default "14" if !MMU
> -	default "11"
> +	range 8 63 if PAGE_SIZE_16KB
> +	default "8" if PAGE_SIZE_16KB
> +	range 6 63 if PAGE_SIZE_64KB
> +	default "6" if PAGE_SIZE_64KB
> +	range 10 63
> +	default "13" if !MMU
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -35,9 +35,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  	  The page size is not necessarily 4KB. Keep this in mind when
>  	  choosing a value for this option.
>
> diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
> index 84437a4c6545..e3242bf5a8df 100644
> --- a/arch/sparc/Kconfig
> +++ b/arch/sparc/Kconfig
> @@ -271,7 +271,7 @@ config ARCH_SPARSEMEM_DEFAULT
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	default "13"
> +	default "12"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -280,9 +280,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 13 means that the largest free memory block is 2^12 pages.
> -
>  if SPARC64 || COMPILE_TEST
>  source "kernel/power/Kconfig"
>  endif
> diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
> index 384480971805..7d91ca6aa675 100644
> --- a/arch/sparc/kernel/pci_sun4v.c
> +++ b/arch/sparc/kernel/pci_sun4v.c
> @@ -193,7 +193,7 @@ static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
>
>  	size = IO_PAGE_ALIGN(size);
>  	order = get_order(size);
> -	if (unlikely(order >= MAX_ORDER))
> +	if (unlikely(order > MAX_ORDER))
>  		return NULL;
>
>  	npages = size >> IO_PAGE_SHIFT;
> diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
> index 5b4de4a89dec..08ffd17d5ec3 100644
> --- a/arch/sparc/kernel/traps_64.c
> +++ b/arch/sparc/kernel/traps_64.c
> @@ -897,7 +897,7 @@ void __init cheetah_ecache_flush_init(void)
>
>  	/* Now allocate error trap reporting scoreboard. */
>  	sz = NR_CPUS * (2 * sizeof(struct cheetah_err_info));
> -	for (order = 0; order < MAX_ORDER; order++) {
> +	for (order = 0; order <= MAX_ORDER; order++) {
>  		if ((PAGE_SIZE << order) >= sz)
>  			break;
>  	}
> diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
> index dba8dffe2113..5e2931a18409 100644
> --- a/arch/sparc/mm/tsb.c
> +++ b/arch/sparc/mm/tsb.c
> @@ -402,8 +402,8 @@ void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
>  	unsigned long new_rss_limit;
>  	gfp_t gfp_flags;
>
> -	if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
> -		max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
> +	if (max_tsb_size > PAGE_SIZE << MAX_ORDER)
> +		max_tsb_size = PAGE_SIZE << MAX_ORDER;
>
>  	new_cache_index = 0;
>  	for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
> diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
> index 5e5a9c8e0e5d..8dcda617b8bf 100644
> --- a/arch/um/kernel/um_arch.c
> +++ b/arch/um/kernel/um_arch.c
> @@ -368,10 +368,10 @@ int __init linux_main(int argc, char **argv)
>  	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
>
>  	/*
> -	 * Zones have to begin on a 1 << MAX_ORDER-1 page boundary,
> +	 * Zones have to begin on a 1 << MAX_ORDER page boundary,
>  	 * so this makes sure that's true for highmem
>  	 */
> -	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER - 1)) - 1);
> +	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
>  	if (physmem_size + iomem_size > max_physmem) {
>  		highmem = physmem_size + iomem_size - max_physmem;
>  		physmem_size -= highmem;
> diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
> index bcb0c5d2abc2..3eee334ba873 100644
> --- a/arch/xtensa/Kconfig
> +++ b/arch/xtensa/Kconfig
> @@ -773,7 +773,7 @@ config HIGHMEM
>
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	default "11"
> +	default "10"
>  	help
>  	  The kernel memory allocator divides physically contiguous memory
>  	  blocks into "zones", where each zone is a power of two number of
> @@ -782,9 +782,6 @@ config ARCH_FORCE_MAX_ORDER
>  	  blocks of physically contiguous memory, then you may need to
>  	  increase this value.
>
> -	  This config option is actually maximum order plus one. For example,
> -	  a value of 11 means that the largest free memory block is 2^10 pages.
> -
>  endmenu
>
>  menu "Power management options"
> diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
> index 817eda2075aa..c491fabe3617 100644
> --- a/drivers/base/regmap/regmap-debugfs.c
> +++ b/drivers/base/regmap/regmap-debugfs.c
> @@ -226,8 +226,8 @@ static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
>  	if (*ppos < 0 || !count)
>  		return -EINVAL;
>
> -	if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
> -		count = PAGE_SIZE << (MAX_ORDER - 1);
> +	if (count > (PAGE_SIZE << MAX_ORDER))
> +		count = PAGE_SIZE << MAX_ORDER;
>
>  	buf = kmalloc(count, GFP_KERNEL);
>  	if (!buf)
> @@ -373,8 +373,8 @@ static ssize_t regmap_reg_ranges_read_file(struct file *file,
>  	if (*ppos < 0 || !count)
>  		return -EINVAL;
>
> -	if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
> -		count = PAGE_SIZE << (MAX_ORDER - 1);
> +	if (count > (PAGE_SIZE << MAX_ORDER))
> +		count = PAGE_SIZE << MAX_ORDER;
>
>  	buf = kmalloc(count, GFP_KERNEL);
>  	if (!buf)
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> index 90d2dfb6448e..cec2c20f5e59 100644
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -3079,7 +3079,7 @@ static void raw_cmd_free(struct floppy_raw_cmd **ptr)
>  	}
>  }
>
> -#define MAX_LEN (1UL << (MAX_ORDER - 1) << PAGE_SHIFT)
> +#define MAX_LEN (1UL << MAX_ORDER << PAGE_SHIFT)
>
>  static int raw_cmd_copyin(int cmd, void __user *param,
>  				 struct floppy_raw_cmd **rcmd)
> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
> index e2f25926eb51..bf095baca244 100644
> --- a/drivers/crypto/ccp/sev-dev.c
> +++ b/drivers/crypto/ccp/sev-dev.c
> @@ -886,7 +886,7 @@ static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp)
>  		/*
>  		 * The length of the ID shouldn't be assumed by software since
>  		 * it may change in the future.  The allocation size is limited
> -		 * to 1 << (PAGE_SHIFT + MAX_ORDER - 1) by the page allocator.
> +		 * to 1 << (PAGE_SHIFT + MAX_ORDER) by the page allocator.
>  		 * If the allocation fails, simply return ENOMEM rather than
>  		 * warning in the kernel log.
>  		 */
> diff --git a/drivers/crypto/hisilicon/sgl.c b/drivers/crypto/hisilicon/sgl.c
> index 09586a837b1e..3df7a256e919 100644
> --- a/drivers/crypto/hisilicon/sgl.c
> +++ b/drivers/crypto/hisilicon/sgl.c
> @@ -70,11 +70,11 @@ struct hisi_acc_sgl_pool *hisi_acc_create_sgl_pool(struct device *dev,
>  			 HISI_ACC_SGL_ALIGN_SIZE);
>
>  	/*
> -	 * the pool may allocate a block of memory of size PAGE_SIZE * 2^(MAX_ORDER - 1),
> +	 * the pool may allocate a block of memory of size PAGE_SIZE * 2^MAX_ORDER,
>  	 * block size may exceed 2^31 on ia64, so the max of block size is 2^31
>  	 */
> -	block_size = 1 << (PAGE_SHIFT + MAX_ORDER <= 32 ?
> -			   PAGE_SHIFT + MAX_ORDER - 1 : 31);
> +	block_size = 1 << (PAGE_SHIFT + MAX_ORDER < 32 ?
> +			   PAGE_SHIFT + MAX_ORDER : 31);
>  	sgl_num_per_block = block_size / sgl_size;
>  	block_num = count / sgl_num_per_block;
>  	remain_sgl = count % sgl_num_per_block;
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
> index eae9e9f6d3bf..6bc26b4b06b8 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
> @@ -36,7 +36,7 @@ static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
>  	struct sg_table *st;
>  	struct scatterlist *sg;
>  	unsigned int npages; /* restricted by sg_alloc_table */
> -	int max_order = MAX_ORDER - 1;
> +	int max_order = MAX_ORDER;
>  	unsigned int max_segment;
>  	gfp_t gfp;
>
> diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> index defece0bcb81..99f39a5feca1 100644
> --- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> +++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
> @@ -115,7 +115,7 @@ static int get_huge_pages(struct drm_i915_gem_object *obj)
>  		do {
>  			struct page *page;
>
> -			GEM_BUG_ON(order >= MAX_ORDER);
> +			GEM_BUG_ON(order > MAX_ORDER);
>  			page = alloc_pages(GFP | __GFP_ZERO, order);
>  			if (!page)
>  				goto err;
> diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
> index aa116a7bbae3..6c8585abe08d 100644
> --- a/drivers/gpu/drm/ttm/ttm_pool.c
> +++ b/drivers/gpu/drm/ttm/ttm_pool.c
> @@ -65,11 +65,11 @@ module_param(page_pool_size, ulong, 0644);
>
>  static atomic_long_t allocated_pages;
>
> -static struct ttm_pool_type global_write_combined[MAX_ORDER];
> -static struct ttm_pool_type global_uncached[MAX_ORDER];
> +static struct ttm_pool_type global_write_combined[MAX_ORDER + 1];
> +static struct ttm_pool_type global_uncached[MAX_ORDER + 1];
>
> -static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER];
> -static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
> +static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER + 1];
> +static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1];
>
>  static spinlock_t shrinker_lock;
>  static struct list_head shrinker_list;
> @@ -405,7 +405,7 @@ int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
>  	else
>  		gfp_flags |= GFP_HIGHUSER;
>
> -	for (order = min_t(unsigned int, MAX_ORDER - 1, __fls(num_pages));
> +	for (order = min_t(unsigned int, MAX_ORDER, __fls(num_pages));
>  	     num_pages;
>  	     order = min_t(unsigned int, order, __fls(num_pages))) {
>  		struct ttm_pool_type *pt;
> @@ -542,7 +542,7 @@ void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
>
>  	if (use_dma_alloc) {
>  		for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
> -			for (j = 0; j < MAX_ORDER; ++j)
> +			for (j = 0; j <= MAX_ORDER; ++j)
>  				ttm_pool_type_init(&pool->caching[i].orders[j],
>  						   pool, i, j);
>  	}
> @@ -562,7 +562,7 @@ void ttm_pool_fini(struct ttm_pool *pool)
>
>  	if (pool->use_dma_alloc) {
>  		for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
> -			for (j = 0; j < MAX_ORDER; ++j)
> +			for (j = 0; j <= MAX_ORDER; ++j)
>  				ttm_pool_type_fini(&pool->caching[i].orders[j]);
>  	}
>
> @@ -616,7 +616,7 @@ static void ttm_pool_debugfs_header(struct seq_file *m)
>  	unsigned int i;
>
>  	seq_puts(m, "\t ");
> -	for (i = 0; i < MAX_ORDER; ++i)
> +	for (i = 0; i <= MAX_ORDER; ++i)
>  		seq_printf(m, " ---%2u---", i);
>  	seq_puts(m, "\n");
>  }
> @@ -627,7 +627,7 @@ static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
>  {
>  	unsigned int i;
>
> -	for (i = 0; i < MAX_ORDER; ++i)
> +	for (i = 0; i <= MAX_ORDER; ++i)
>  		seq_printf(m, " %8u", ttm_pool_type_count(&pt[i]));
>  	seq_puts(m, "\n");
>  }
> @@ -736,7 +736,7 @@ int ttm_pool_mgr_init(unsigned long num_pages)
>  	spin_lock_init(&shrinker_lock);
>  	INIT_LIST_HEAD(&shrinker_list);
>
> -	for (i = 0; i < MAX_ORDER; ++i) {
> +	for (i = 0; i <= MAX_ORDER; ++i) {
>  		ttm_pool_type_init(&global_write_combined[i], NULL,
>  				   ttm_write_combined, i);
>  		ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
> @@ -769,7 +769,7 @@ void ttm_pool_mgr_fini(void)
>  {
>  	unsigned int i;
>
> -	for (i = 0; i < MAX_ORDER; ++i) {
> +	for (i = 0; i <= MAX_ORDER; ++i) {
>  		ttm_pool_type_fini(&global_write_combined[i]);
>  		ttm_pool_type_fini(&global_uncached[i]);
>
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> index 8d772ea8a583..b574c58a3487 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
> @@ -182,7 +182,7 @@
>  #ifdef CONFIG_CMA_ALIGNMENT
>  #define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + CONFIG_CMA_ALIGNMENT)
>  #else
> -#define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + MAX_ORDER - 1)
> +#define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + MAX_ORDER)
>  #endif
>
>  /*
> diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
> index ac996fd6bd9c..7a9f0b0bddbd 100644
> --- a/drivers/iommu/dma-iommu.c
> +++ b/drivers/iommu/dma-iommu.c
> @@ -736,7 +736,7 @@ static struct page **__iommu_dma_alloc_pages(struct device *dev,
>  	struct page **pages;
>  	unsigned int i = 0, nid = dev_to_node(dev);
>
> -	order_mask &= GENMASK(MAX_ORDER - 1, 0);
> +	order_mask &= GENMASK(MAX_ORDER, 0);
>  	if (!order_mask)
>  		return NULL;
>
> diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
> index 586271b8aa39..85790b870877 100644
> --- a/drivers/irqchip/irq-gic-v3-its.c
> +++ b/drivers/irqchip/irq-gic-v3-its.c
> @@ -2440,8 +2440,8 @@ static bool its_parse_indirect_baser(struct its_node *its,
>  	 * feature is not supported by hardware.
>  	 */
>  	new_order = max_t(u32, get_order(esz << ids), new_order);
> -	if (new_order >= MAX_ORDER) {
> -		new_order = MAX_ORDER - 1;
> +	if (new_order > MAX_ORDER) {
> +		new_order = MAX_ORDER;
>  		ids = ilog2(PAGE_ORDER_TO_SIZE(new_order) / (int)esz);
>  		pr_warn("ITS@%pa: %s Table too large, reduce ids %llu->%u\n",
>  			&its->phys_base, its_base_type_string[type],
> diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
> index cf077f9b30c3..733053c2eaa0 100644
> --- a/drivers/md/dm-bufio.c
> +++ b/drivers/md/dm-bufio.c
> @@ -408,7 +408,7 @@ static void __cache_size_refresh(void)
>   * If the allocation may fail we use __get_free_pages. Memory fragmentation
>   * won't have a fatal effect here, but it just causes flushes of some other
>   * buffers and more I/O will be performed. Don't use __get_free_pages if it
> - * always fails (i.e. order >= MAX_ORDER).
> + * always fails (i.e. order > MAX_ORDER).
>   *
>   * If the allocation shouldn't fail we use __vmalloc. This is only for the
>   * initial reserve allocation, so there's no risk of wasting all vmalloc
> diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
> index d0e27438a73c..55fc5b80e649 100644
> --- a/drivers/misc/genwqe/card_dev.c
> +++ b/drivers/misc/genwqe/card_dev.c
> @@ -443,7 +443,7 @@ static int genwqe_mmap(struct file *filp, struct vm_area_struct *vma)
>  	if (vsize == 0)
>  		return -EINVAL;
>
> -	if (get_order(vsize) >= MAX_ORDER)
> +	if (get_order(vsize) > MAX_ORDER)
>  		return -ENOMEM;
>
>  	dma_map = kzalloc(sizeof(struct dma_mapping), GFP_KERNEL);
> diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
> index ac29698d085a..1c798d6b2dfb 100644
> --- a/drivers/misc/genwqe/card_utils.c
> +++ b/drivers/misc/genwqe/card_utils.c
> @@ -210,7 +210,7 @@ u32 genwqe_crc32(u8 *buff, size_t len, u32 init)
>  void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,
>  			       dma_addr_t *dma_handle)
>  {
> -	if (get_order(size) >= MAX_ORDER)
> +	if (get_order(size) > MAX_ORDER)
>  		return NULL;
>
>  	return dma_alloc_coherent(&cd->pci_dev->dev, size, dma_handle,
> @@ -308,7 +308,7 @@ int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
>  	sgl->write = write;
>  	sgl->sgl_size = genwqe_sgl_size(sgl->nr_pages);
>
> -	if (get_order(sgl->sgl_size) >= MAX_ORDER) {
> +	if (get_order(sgl->sgl_size) > MAX_ORDER) {
>  		dev_err(&pci_dev->dev,
>  			"[%s] err: too much memory requested!\n", __func__);
>  		return ret;
> diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> index 25be7f8ac7cd..3973ca6adf4c 100644
> --- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> +++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
> @@ -1041,7 +1041,7 @@ static void hns3_init_tx_spare_buffer(struct hns3_enet_ring *ring)
>  		return;
>
>  	order = get_order(alloc_size);
> -	if (order >= MAX_ORDER) {
> +	if (order > MAX_ORDER) {
>  		if (net_ratelimit())
>  			dev_warn(ring_to_dev(ring), "failed to allocate tx spare buffer, exceed to max order\n");
>  		return;
> diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
> index b35c9b6f913b..4e18b4cefa97 100644
> --- a/drivers/net/ethernet/ibm/ibmvnic.h
> +++ b/drivers/net/ethernet/ibm/ibmvnic.h
> @@ -75,7 +75,7 @@
>   * pool for the 4MB. Thus the 16 Rx and Tx queues require 32 * 5 = 160
>   * plus 16 for the TSO pools for a total of 176 LTB mappings per VNIC.
>   */
> -#define IBMVNIC_ONE_LTB_MAX	((u32)((1 << (MAX_ORDER - 1)) * PAGE_SIZE))
> +#define IBMVNIC_ONE_LTB_MAX	((u32)((1 << MAX_ORDER) * PAGE_SIZE))
>  #define IBMVNIC_ONE_LTB_SIZE	min((u32)(8 << 20), IBMVNIC_ONE_LTB_MAX)
>  #define IBMVNIC_LTB_SET_SIZE	(38 << 20)
>
> diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
> index ec3f6cf05f8c..34781dec3856 100644
> --- a/drivers/video/fbdev/hyperv_fb.c
> +++ b/drivers/video/fbdev/hyperv_fb.c
> @@ -946,7 +946,7 @@ static phys_addr_t hvfb_get_phymem(struct hv_device *hdev,
>  	if (request_size == 0)
>  		return -1;
>
> -	if (order < MAX_ORDER) {
> +	if (order <= MAX_ORDER) {
>  		/* Call alloc_pages if the size is less than 2^MAX_ORDER */
>  		page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
>  		if (!page)
> @@ -977,7 +977,7 @@ static void hvfb_release_phymem(struct hv_device *hdev,
>  {
>  	unsigned int order = get_order(size);
>
> -	if (order < MAX_ORDER)
> +	if (order <= MAX_ORDER)
>  		__free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order);
>  	else
>  		dma_free_coherent(&hdev->device,
> diff --git a/drivers/video/fbdev/vermilion/vermilion.c b/drivers/video/fbdev/vermilion/vermilion.c
> index 0374ee6b6d03..32e74e02a02f 100644
> --- a/drivers/video/fbdev/vermilion/vermilion.c
> +++ b/drivers/video/fbdev/vermilion/vermilion.c
> @@ -197,7 +197,7 @@ static int vmlfb_alloc_vram(struct vml_info *vinfo,
>  		va = &vinfo->vram[i];
>  		order = 0;
>
> -		while (requested > (PAGE_SIZE << order) && order < MAX_ORDER)
> +		while (requested > (PAGE_SIZE << order) && order <= MAX_ORDER)
>  			order++;
>
>  		err = vmlfb_alloc_vram_area(va, order, 0);
> diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
> index 3f78a3a1eb75..5b15936a5214 100644
> --- a/drivers/virtio/virtio_balloon.c
> +++ b/drivers/virtio/virtio_balloon.c
> @@ -33,7 +33,7 @@
>  #define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN | \
>  					     __GFP_NOMEMALLOC)
>  /* The order of free page blocks to report to host */
> -#define VIRTIO_BALLOON_HINT_BLOCK_ORDER (MAX_ORDER - 1)
> +#define VIRTIO_BALLOON_HINT_BLOCK_ORDER MAX_ORDER
>  /* The size of a free page block in bytes */
>  #define VIRTIO_BALLOON_HINT_BLOCK_BYTES \
>  	(1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT))
> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
> index 0c2892ec6817..835f6cc2fb66 100644
> --- a/drivers/virtio/virtio_mem.c
> +++ b/drivers/virtio/virtio_mem.c
> @@ -1120,13 +1120,13 @@ static void virtio_mem_clear_fake_offline(unsigned long pfn,
>   */
>  static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pages)
>  {
> -	unsigned long order = MAX_ORDER - 1;
> +	unsigned long order = MAX_ORDER;
>  	unsigned long i;
>
>  	/*
>  	 * We might get called for ranges that don't cover properly aligned
> -	 * MAX_ORDER - 1 pages; however, we can only online properly aligned
> -	 * pages with an order of MAX_ORDER - 1 at maximum.
> +	 * MAX_ORDER pages; however, we can only online properly aligned
> +	 * pages with an order of MAX_ORDER at maximum.
>  	 */
>  	while (!IS_ALIGNED(pfn | nr_pages, 1 << order))
>  		order--;
> @@ -1237,9 +1237,9 @@ static void virtio_mem_online_page(struct virtio_mem *vm,
>  	bool do_online;
>
>  	/*
> -	 * We can get called with any order up to MAX_ORDER - 1. If our
> -	 * subblock size is smaller than that and we have a mixture of plugged
> -	 * and unplugged subblocks within such a page, we have to process in
> +	 * We can get called with any order up to MAX_ORDER. If our subblock
> +	 * size is smaller than that and we have a mixture of plugged and
> +	 * unplugged subblocks within such a page, we have to process in
>  	 * smaller granularity. In that case we'll adjust the order exactly once
>  	 * within the loop.
>  	 */
> diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
> index 2f67516bb9bf..9fbb9b5256f7 100644
> --- a/fs/ramfs/file-nommu.c
> +++ b/fs/ramfs/file-nommu.c
> @@ -70,7 +70,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
>
>  	/* make various checks */
>  	order = get_order(newsize);
> -	if (unlikely(order >= MAX_ORDER))
> +	if (unlikely(order > MAX_ORDER))
>  		return -EFBIG;
>
>  	ret = inode_newsize_ok(inode, newsize);
> diff --git a/include/drm/ttm/ttm_pool.h b/include/drm/ttm/ttm_pool.h
> index ef09b23d29e3..8ce14f9d202a 100644
> --- a/include/drm/ttm/ttm_pool.h
> +++ b/include/drm/ttm/ttm_pool.h
> @@ -72,7 +72,7 @@ struct ttm_pool {
>  	bool use_dma32;
>
>  	struct {
> -		struct ttm_pool_type orders[MAX_ORDER];
> +		struct ttm_pool_type orders[MAX_ORDER + 1];
>  	} caching[TTM_NUM_CACHING_TYPES];
>  };
>
> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> index 7c977d234aba..8fb7d91cd0b1 100644
> --- a/include/linux/hugetlb.h
> +++ b/include/linux/hugetlb.h
> @@ -818,7 +818,7 @@ static inline unsigned huge_page_shift(struct hstate *h)
>
>  static inline bool hstate_is_gigantic(struct hstate *h)
>  {
> -	return huge_page_order(h) >= MAX_ORDER;
> +	return huge_page_order(h) > MAX_ORDER;
>  }
>
>  static inline unsigned int pages_per_huge_page(const struct hstate *h)
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 9fb1b03b83b2..54a07b8862b9 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -26,11 +26,11 @@
>
>  /* Free memory management - zoned buddy allocator.  */
>  #ifndef CONFIG_ARCH_FORCE_MAX_ORDER
> -#define MAX_ORDER 11
> +#define MAX_ORDER 10
>  #else
>  #define MAX_ORDER CONFIG_ARCH_FORCE_MAX_ORDER
>  #endif
> -#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
> +#define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
>
>  /*
>   * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
> @@ -93,7 +93,7 @@ static inline bool migratetype_is_mergeable(int mt)
>  }
>
>  #define for_each_migratetype_order(order, type) \
> -	for (order = 0; order < MAX_ORDER; order++) \
> +	for (order = 0; order <= MAX_ORDER; order++) \
>  		for (type = 0; type < MIGRATE_TYPES; type++)
>
>  extern int page_group_by_mobility_disabled;
> @@ -922,7 +922,7 @@ struct zone {
>  	CACHELINE_PADDING(_pad1_);
>
>  	/* free areas of different sizes */
> -	struct free_area	free_area[MAX_ORDER];
> +	struct free_area	free_area[MAX_ORDER + 1];
>
>  	/* zone flags, see below */
>  	unsigned long		flags;
> @@ -1745,7 +1745,7 @@ static inline bool movable_only_nodes(nodemask_t *nodes)
>  #define SECTION_BLOCKFLAGS_BITS \
>  	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
>
> -#if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
> +#if (MAX_ORDER + PAGE_SHIFT) > SECTION_SIZE_BITS
>  #error Allocator MAX_ORDER exceeds SECTION_SIZE
>  #endif
>
> diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
> index 5f1ae07d724b..e83c4c095041 100644
> --- a/include/linux/pageblock-flags.h
> +++ b/include/linux/pageblock-flags.h
> @@ -41,14 +41,14 @@ extern unsigned int pageblock_order;
>   * Huge pages are a constant size, but don't exceed the maximum allocation
>   * granularity.
>   */
> -#define pageblock_order		min_t(unsigned int, HUGETLB_PAGE_ORDER, MAX_ORDER - 1)
> +#define pageblock_order		min_t(unsigned int, HUGETLB_PAGE_ORDER, MAX_ORDER)
>
>  #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
>
>  #else /* CONFIG_HUGETLB_PAGE */
>
>  /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
> -#define pageblock_order		(MAX_ORDER-1)
> +#define pageblock_order		MAX_ORDER
>
>  #endif /* CONFIG_HUGETLB_PAGE */
>
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index 45af70315a94..aa4575ef2965 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -284,7 +284,7 @@ static inline unsigned int arch_slab_minalign(void)
>   * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
>   */
>  #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
> -#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
> +#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
>  #ifndef KMALLOC_SHIFT_LOW
>  #define KMALLOC_SHIFT_LOW	5
>  #endif
> @@ -292,7 +292,7 @@ static inline unsigned int arch_slab_minalign(void)
>
>  #ifdef CONFIG_SLUB
>  #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
> -#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
> +#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
>  #ifndef KMALLOC_SHIFT_LOW
>  #define KMALLOC_SHIFT_LOW	3
>  #endif
> @@ -305,7 +305,7 @@ static inline unsigned int arch_slab_minalign(void)
>   * be allocated from the same page.
>   */
>  #define KMALLOC_SHIFT_HIGH	PAGE_SHIFT
> -#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
> +#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
>  #ifndef KMALLOC_SHIFT_LOW
>  #define KMALLOC_SHIFT_LOW	3
>  #endif
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 755f5f08ab38..90ce1dfd591c 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -474,7 +474,7 @@ static int __init crash_save_vmcoreinfo_init(void)
>  	VMCOREINFO_OFFSET(list_head, prev);
>  	VMCOREINFO_OFFSET(vmap_area, va_start);
>  	VMCOREINFO_OFFSET(vmap_area, list);
> -	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
> +	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
>  	log_buf_vmcoreinfo_setup();
>  	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
>  	VMCOREINFO_NUMBER(NR_FREE_PAGES);
> diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
> index 4d40dcce7604..1acec2e22827 100644
> --- a/kernel/dma/pool.c
> +++ b/kernel/dma/pool.c
> @@ -84,8 +84,8 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
>  	void *addr;
>  	int ret = -ENOMEM;
>
> -	/* Cannot allocate larger than MAX_ORDER-1 */
> -	order = min(get_order(pool_size), MAX_ORDER-1);
> +	/* Cannot allocate larger than MAX_ORDER */
> +	order = min(get_order(pool_size), MAX_ORDER);
>
>  	do {
>  		pool_size = 1 << (PAGE_SHIFT + order);
> @@ -190,7 +190,7 @@ static int __init dma_atomic_pool_init(void)
>
>  	/*
>  	 * If coherent_pool was not used on the command line, default the pool
> -	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
> +	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER.
>  	 */
>  	if (!atomic_pool_size) {
>  		unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
> diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
> index d6bbdb7830b2..273a0fe7910a 100644
> --- a/kernel/events/ring_buffer.c
> +++ b/kernel/events/ring_buffer.c
> @@ -609,8 +609,8 @@ static struct page *rb_alloc_aux_page(int node, int order)
>  {
>  	struct page *page;
>
> -	if (order >= MAX_ORDER)
> -		order = MAX_ORDER - 1;
> +	if (order > MAX_ORDER)
> +		order = MAX_ORDER;
>
>  	do {
>  		page = alloc_pages_node(node, PERF_AUX_GFP, order);

line 817:

-	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
+	if (order_base_2(size) > PAGE_SHIFT+MAX_ORDER)

> diff --git a/mm/Kconfig b/mm/Kconfig
> index 4751031f3f05..fc059969d7ba 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -346,9 +346,9 @@ config SHUFFLE_PAGE_ALLOCATOR
>  	  the presence of a memory-side-cache. There are also incidental
>  	  security benefits as it reduces the predictability of page
>  	  allocations to compliment SLAB_FREELIST_RANDOM, but the
> -	  default granularity of shuffling on the "MAX_ORDER - 1" i.e,
> -	  10th order of pages is selected based on cache utilization
> -	  benefits on x86.
> +	  default granularity of shuffling on the MAX_ORDER i.e, 10th
> +	  order of pages is selected based on cache utilization benefits
> +	  on x86.
>
>  	  While the randomization improves cache utilization it may
>  	  negatively impact workloads on platforms without a cache. For

line 669:

-	  Note that the pageblock_order cannot exceed MAX_ORDER - 1 and will be
-	  clamped down to MAX_ORDER - 1.
+	  Note that the pageblock_order cannot exceed MAX_ORDER and will be
+	  clamped down to MAX_ORDER.




> diff --git a/mm/compaction.c b/mm/compaction.c
> index 5a9501e0ae01..709136556b9e 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -583,7 +583,7 @@ static unsigned long isolate_freepages_block(struct compact_control *cc,
>  		if (PageCompound(page)) {
>  			const unsigned int order = compound_order(page);
>
> -			if (likely(order < MAX_ORDER)) {
> +			if (likely(order <= MAX_ORDER)) {
>  				blockpfn += (1UL << order) - 1;
>  				cursor += (1UL << order) - 1;
>  			}
> @@ -938,7 +938,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
>  			 * a valid page order. Consider only values in the
>  			 * valid order range to prevent low_pfn overflow.
>  			 */
> -			if (freepage_order > 0 && freepage_order < MAX_ORDER)
> +			if (freepage_order > 0 && freepage_order <= MAX_ORDER)
>  				low_pfn += (1UL << freepage_order) - 1;
>  			continue;
>  		}
> @@ -954,7 +954,7 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
>  		if (PageCompound(page) && !cc->alloc_contig) {
>  			const unsigned int order = compound_order(page);
>
> -			if (likely(order < MAX_ORDER))
> +			if (likely(order <= MAX_ORDER))
>  				low_pfn += (1UL << order) - 1;
>  			goto isolate_fail;
>  		}
> @@ -2124,7 +2124,7 @@ static enum compact_result __compact_finished(struct compact_control *cc)
>
>  	/* Direct compactor: Is a suitable page free? */
>  	ret = COMPACT_NO_SUITABLE_PAGE;
> -	for (order = cc->order; order < MAX_ORDER; order++) {
> +	for (order = cc->order; order <= MAX_ORDER; order++) {
>  		struct free_area *area = &cc->zone->free_area[order];
>  		bool can_steal;
>
> diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
> index af59cc7bd307..c9eb007fedcc 100644
> --- a/mm/debug_vm_pgtable.c
> +++ b/mm/debug_vm_pgtable.c
> @@ -1086,7 +1086,7 @@ debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)
>  	struct page *page = NULL;
>
>  #ifdef CONFIG_CONTIG_ALLOC
> -	if (order >= MAX_ORDER) {
> +	if (order > MAX_ORDER) {
>  		page = alloc_contig_pages((1 << order), GFP_KERNEL,
>  					  first_online_node, NULL);
>  		if (page) {
> @@ -1096,7 +1096,7 @@ debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)
>  	}
>  #endif
>
> -	if (order < MAX_ORDER)
> +	if (order <= MAX_ORDER)
>  		page = alloc_pages(GFP_KERNEL, order);
>
>  	return page;
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index 4fc43859e59a..1c03cab29d22 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -471,7 +471,7 @@ static int __init hugepage_init(void)
>  	/*
>  	 * hugepages can't be allocated by the buddy allocator
>  	 */
> -	MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER);
> +	MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER);
>  	/*
>  	 * we use page->mapping and page->index in second tail page
>  	 * as list_head: assuming THP order >= 2
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 07abcb6eb203..9525bced1e82 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -2090,7 +2090,7 @@ pgoff_t hugetlb_basepage_index(struct page *page)
>  	pgoff_t index = page_index(page_head);
>  	unsigned long compound_idx;
>
> -	if (compound_order(page_head) >= MAX_ORDER)
> +	if (compound_order(page_head) > MAX_ORDER)
>  		compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
>  	else
>  		compound_idx = page - page_head;
> @@ -4497,7 +4497,7 @@ static int __init default_hugepagesz_setup(char *s)
>  	 * The number of default huge pages (for this size) could have been
>  	 * specified as the first hugetlb parameter: hugepages=X.  If so,
>  	 * then default_hstate_max_huge_pages is set.  If the default huge
> -	 * page size is gigantic (>= MAX_ORDER), then the pages must be
> +	 * page size is gigantic (> MAX_ORDER), then the pages must be
>  	 * allocated here from bootmem allocator.
>  	 */
>  	if (default_hstate_max_huge_pages) {
> diff --git a/mm/kmsan/init.c b/mm/kmsan/init.c
> index 7fb794242fad..ffedf4dbc49d 100644
> --- a/mm/kmsan/init.c
> +++ b/mm/kmsan/init.c
> @@ -96,7 +96,7 @@ void __init kmsan_init_shadow(void)
>  struct metadata_page_pair {
>  	struct page *shadow, *origin;
>  };
> -static struct metadata_page_pair held_back[MAX_ORDER] __initdata;
> +static struct metadata_page_pair held_back[MAX_ORDER + 1] __initdata;
>
>  /*
>   * Eager metadata allocation. When the memblock allocator is freeing pages to

line 144: this one I am not sure if the original code is wrong or not.

-	.order = MAX_ORDER,
+	.order = MAX_ORDER + 1,


> @@ -211,8 +211,8 @@ static void kmsan_memblock_discard(void)
>  	 *    order=N-1,
>  	 *  - repeat.
>  	 */
> -	collect.order = MAX_ORDER - 1;
> -	for (int i = MAX_ORDER - 1; i >= 0; i--) {
> +	collect.order = MAX_ORDER;
> +	for (int i = MAX_ORDER; i >= 0; i--) {
>  		if (held_back[i].shadow)
>  			smallstack_push(&collect, held_back[i].shadow);
>  		if (held_back[i].origin)
> diff --git a/mm/memblock.c b/mm/memblock.c
> index 25fd0626a9e7..338b8cb0793e 100644
> --- a/mm/memblock.c
> +++ b/mm/memblock.c
> @@ -2043,7 +2043,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
>  	int order;
>
>  	while (start < end) {
> -		order = min(MAX_ORDER - 1UL, __ffs(start));
> +		order = min(MAX_ORDER, __ffs(start));

while you are here, maybe using min_t is better.

order = min_t(unsigned long, MAX_ORDER, __ffs(start));

>
>  		while (start + (1UL << order) > end)
>  			order--;
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index db3b270254f1..86291c79a764 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -596,7 +596,7 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
>  	unsigned long pfn;
>
>  	/*
> -	 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
> +	 * Online the pages in MAX_ORDER aligned chunks. The callback might
>  	 * decide to not expose all pages to the buddy (e.g., expose them
>  	 * later). We account all pages as being online and belonging to this
>  	 * zone ("present").
> @@ -605,7 +605,7 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
>  	 * this and the first chunk to online will be pageblock_nr_pages.
>  	 */
>  	for (pfn = start_pfn; pfn < end_pfn;) {
> -		int order = min(MAX_ORDER - 1UL, __ffs(pfn));
> +		int order = min(MAX_ORDER, __ffs(pfn));

ditto

int order = min_t(unsigned long, MAX_ORDER, __ffs(pfn));

>
>  		(*online_page_callback)(pfn_to_page(pfn), order);
>  		pfn += (1UL << order);
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index ac1fc986af44..66700f27b4c6 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c

line 842: it might make a difference when MAX_ORDER is odd.

-	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
+	if (kstrtoul(buf, 10, &res) < 0 ||  res > (MAX_ORDER + 1) / 2) {

> @@ -1059,7 +1059,7 @@ buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
>  	unsigned long higher_page_pfn;
>  	struct page *higher_page;
>
> -	if (order >= MAX_ORDER - 2)
> +	if (order >= MAX_ORDER - 1)
>  		return false;
>
>  	higher_page_pfn = buddy_pfn & pfn;
> @@ -1114,7 +1114,7 @@ static inline void __free_one_page(struct page *page,
>  	VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
>  	VM_BUG_ON_PAGE(bad_range(zone, page), page);
>
> -	while (order < MAX_ORDER - 1) {
> +	while (order < MAX_ORDER) {
>  		if (compaction_capture(capc, page, order, migratetype)) {
>  			__mod_zone_freepage_state(zone, -(1 << order),
>  								migratetype);
> @@ -2579,7 +2579,7 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
>  	struct page *page;
>
>  	/* Find a page of the appropriate size in the preferred list */
> -	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
> +	for (current_order = order; current_order <= MAX_ORDER; ++current_order) {
>  		area = &(zone->free_area[current_order]);
>  		page = get_page_from_free_area(area, migratetype);
>  		if (!page)
> @@ -2951,7 +2951,7 @@ static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
>  			continue;
>
>  		spin_lock_irqsave(&zone->lock, flags);
> -		for (order = 0; order < MAX_ORDER; order++) {
> +		for (order = 0; order <= MAX_ORDER; order++) {
>  			struct free_area *area = &(zone->free_area[order]);
>
>  			page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
> @@ -3035,7 +3035,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
>  	 * approximates finding the pageblock with the most free pages, which
>  	 * would be too costly to do exactly.
>  	 */
> -	for (current_order = MAX_ORDER - 1; current_order >= min_order;
> +	for (current_order = MAX_ORDER; current_order >= min_order;
>  				--current_order) {
>  		area = &(zone->free_area[current_order]);
>  		fallback_mt = find_suitable_fallback(area, current_order,
> @@ -3061,7 +3061,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
>  	return false;
>
>  find_smallest:
> -	for (current_order = order; current_order < MAX_ORDER;
> +	for (current_order = order; current_order <= MAX_ORDER;
>  							current_order++) {
>  		area = &(zone->free_area[current_order]);
>  		fallback_mt = find_suitable_fallback(area, current_order,
> @@ -3074,7 +3074,7 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
>  	 * This should not happen - we already found a suitable fallback
>  	 * when looking for the largest page.
>  	 */
> -	VM_BUG_ON(current_order == MAX_ORDER);
> +	VM_BUG_ON(current_order > MAX_ORDER);
>
>  do_steal:
>  	page = get_page_from_free_area(area, fallback_mt);
> @@ -4044,7 +4044,7 @@ bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
>  		return true;
>
>  	/* For a high-order request, check at least one suitable page is free */
> -	for (o = order; o < MAX_ORDER; o++) {
> +	for (o = order; o <= MAX_ORDER; o++) {
>  		struct free_area *area = &z->free_area[o];
>  		int mt;
>
> @@ -5564,7 +5564,7 @@ struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
>  	 * There are several places where we assume that the order value is sane
>  	 * so bail out early if the request is out of bound.
>  	 */
> -	if (WARN_ON_ONCE_GFP(order >= MAX_ORDER, gfp))
> +	if (WARN_ON_ONCE_GFP(order > MAX_ORDER, gfp))
>  		return NULL;
>
>  	gfp &= gfp_allowed_mask;
> @@ -6294,8 +6294,8 @@ void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_i
>
>  	for_each_populated_zone(zone) {
>  		unsigned int order;
> -		unsigned long nr[MAX_ORDER], flags, total = 0;
> -		unsigned char types[MAX_ORDER];
> +		unsigned long nr[MAX_ORDER + 1], flags, total = 0;
> +		unsigned char types[MAX_ORDER + 1];
>
>  		if (zone_idx(zone) > max_zone_idx)
>  			continue;
> @@ -6305,7 +6305,7 @@ void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_i
>  		printk(KERN_CONT "%s: ", zone->name);
>
>  		spin_lock_irqsave(&zone->lock, flags);
> -		for (order = 0; order < MAX_ORDER; order++) {
> +		for (order = 0; order <= MAX_ORDER; order++) {
>  			struct free_area *area = &zone->free_area[order];
>  			int type;
>
> @@ -6319,7 +6319,7 @@ void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_i
>  			}
>  		}
>  		spin_unlock_irqrestore(&zone->lock, flags);
> -		for (order = 0; order < MAX_ORDER; order++) {
> +		for (order = 0; order <= MAX_ORDER; order++) {
>  			printk(KERN_CONT "%lu*%lukB ",
>  			       nr[order], K(1UL) << order);
>  			if (nr[order])
> @@ -7670,7 +7670,7 @@ static inline void setup_usemap(struct zone *zone) {}
>  /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
>  void __init set_pageblock_order(void)
>  {
> -	unsigned int order = MAX_ORDER - 1;
> +	unsigned int order = MAX_ORDER;
>
>  	/* Check that pageblock_nr_pages has not already been setup */
>  	if (pageblock_order)
> @@ -9165,7 +9165,7 @@ void *__init alloc_large_system_hash(const char *tablename,
>  			else
>  				table = memblock_alloc_raw(size,
>  							   SMP_CACHE_BYTES);
> -		} else if (get_order(size) >= MAX_ORDER || hashdist) {
> +		} else if (get_order(size) > MAX_ORDER || hashdist) {
>  			table = vmalloc_huge(size, gfp_flags);
>  			virt = true;
>  			if (table)
> @@ -9379,7 +9379,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
>  	order = 0;
>  	outer_start = start;
>  	while (!PageBuddy(pfn_to_page(outer_start))) {
> -		if (++order >= MAX_ORDER) {
> +		if (++order > MAX_ORDER) {
>  			outer_start = start;
>  			break;
>  		}
> @@ -9629,7 +9629,7 @@ bool is_free_buddy_page(struct page *page)
>  	unsigned long pfn = page_to_pfn(page);
>  	unsigned int order;
>
> -	for (order = 0; order < MAX_ORDER; order++) {
> +	for (order = 0; order <= MAX_ORDER; order++) {
>  		struct page *page_head = page - (pfn & ((1 << order) - 1));
>
>  		if (PageBuddy(page_head) &&
> @@ -9637,7 +9637,7 @@ bool is_free_buddy_page(struct page *page)
>  			break;
>  	}
>
> -	return order < MAX_ORDER;
> +	return order <= MAX_ORDER;
>  }
>  EXPORT_SYMBOL(is_free_buddy_page);
>
> @@ -9688,7 +9688,7 @@ bool take_page_off_buddy(struct page *page)
>  	bool ret = false;
>
>  	spin_lock_irqsave(&zone->lock, flags);
> -	for (order = 0; order < MAX_ORDER; order++) {
> +	for (order = 0; order <= MAX_ORDER; order++) {
>  		struct page *page_head = page - (pfn & ((1 << order) - 1));
>  		int page_order = buddy_order(page_head);
>
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index 47fbc1696466..c6f3605e37ab 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -226,7 +226,7 @@ static void unset_migratetype_isolate(struct page *page, int migratetype)
>  	 */
>  	if (PageBuddy(page)) {
>  		order = buddy_order(page);
> -		if (order >= pageblock_order && order < MAX_ORDER - 1) {
> +		if (order >= pageblock_order && order < MAX_ORDER) {
>  			buddy = find_buddy_page_pfn(page, page_to_pfn(page),
>  						    order, NULL);
>  			if (buddy && !is_migrate_isolate_page(buddy)) {
> @@ -290,11 +290,11 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
>   *			isolate_single_pageblock()
>   * @migratetype:	migrate type to set in error recovery.
>   *
> - * Free and in-use pages can be as big as MAX_ORDER-1 and contain more than one
> + * Free and in-use pages can be as big as MAX_ORDER and contain more than one
>   * pageblock. When not all pageblocks within a page are isolated at the same
>   * time, free page accounting can go wrong. For example, in the case of
> - * MAX_ORDER-1 = pageblock_order + 1, a MAX_ORDER-1 page has two pagelbocks.
> - * [         MAX_ORDER-1         ]
> + * MAX_ORDER = pageblock_order + 1, a MAX_ORDER page has two pagelbocks.
> + * [         MAX_ORDER           ]
>   * [  pageblock0  |  pageblock1  ]
>   * When either pageblock is isolated, if it is a free page, the page is not
>   * split into separate migratetype lists, which is supposed to; if it is an
> @@ -451,7 +451,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
>  				 * the free page to the right migratetype list.
>  				 *
>  				 * head_pfn is not used here as a hugetlb page order
> -				 * can be bigger than MAX_ORDER-1, but after it is
> +				 * can be bigger than MAX_ORDER, but after it is
>  				 * freed, the free page order is not. Use pfn within
>  				 * the range to find the head of the free page.
>  				 */
> @@ -459,7 +459,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
>  				outer_pfn = pfn;
>  				while (!PageBuddy(pfn_to_page(outer_pfn))) {
>  					/* stop if we cannot find the free page */
> -					if (++order >= MAX_ORDER)
> +					if (++order > MAX_ORDER)
>  						goto failed;
>  					outer_pfn &= ~0UL << order;
>  				}
> diff --git a/mm/page_owner.c b/mm/page_owner.c
> index 220cdeddc295..31169b3e7f06 100644
> --- a/mm/page_owner.c
> +++ b/mm/page_owner.c
> @@ -315,7 +315,7 @@ void pagetypeinfo_showmixedcount_print(struct seq_file *m,
>  				unsigned long freepage_order;
>
>  				freepage_order = buddy_order_unsafe(page);
> -				if (freepage_order < MAX_ORDER)
> +				if (freepage_order <= MAX_ORDER)
>  					pfn += (1UL << freepage_order) - 1;
>  				continue;
>  			}
> @@ -549,7 +549,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
>  		if (PageBuddy(page)) {
>  			unsigned long freepage_order = buddy_order_unsafe(page);
>
> -			if (freepage_order < MAX_ORDER)
> +			if (freepage_order <= MAX_ORDER)
>  				pfn += (1UL << freepage_order) - 1;
>  			continue;
>  		}
> @@ -657,7 +657,7 @@ static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
>  			if (PageBuddy(page)) {
>  				unsigned long order = buddy_order_unsafe(page);
>
> -				if (order > 0 && order < MAX_ORDER)
> +				if (order > 0 && order <= MAX_ORDER)
>  					pfn += (1UL << order) - 1;
>  				continue;
>  			}
> diff --git a/mm/page_reporting.c b/mm/page_reporting.c
> index 275b466de37b..b021f482a4cb 100644
> --- a/mm/page_reporting.c
> +++ b/mm/page_reporting.c
> @@ -20,7 +20,7 @@ static int page_order_update_notify(const char *val, const struct kernel_param *
>  	 * If param is set beyond this limit, order is set to default
>  	 * pageblock_order value
>  	 */
> -	return  param_set_uint_minmax(val, kp, 0, MAX_ORDER-1);
> +	return  param_set_uint_minmax(val, kp, 0, MAX_ORDER);
>  }
>
>  static const struct kernel_param_ops page_reporting_param_ops = {
> @@ -276,7 +276,7 @@ page_reporting_process_zone(struct page_reporting_dev_info *prdev,
>  		return err;
>
>  	/* Process each free list starting from lowest order/mt */
> -	for (order = page_reporting_order; order < MAX_ORDER; order++) {
> +	for (order = page_reporting_order; order <= MAX_ORDER; order++) {
>  		for (mt = 0; mt < MIGRATE_TYPES; mt++) {
>  			/* We do not pull pages from the isolate free list */
>  			if (is_migrate_isolate(mt))
> @@ -370,7 +370,7 @@ int page_reporting_register(struct page_reporting_dev_info *prdev)
>  	 */
>
>  	if (page_reporting_order == -1) {
> -		if (prdev->order > 0 && prdev->order < MAX_ORDER)
> +		if (prdev->order > 0 && prdev->order <= MAX_ORDER)
>  			page_reporting_order = prdev->order;
>  		else
>  			page_reporting_order = pageblock_order;
> diff --git a/mm/shuffle.h b/mm/shuffle.h
> index cec62984f7d3..a6bdf54f96f1 100644
> --- a/mm/shuffle.h
> +++ b/mm/shuffle.h
> @@ -4,7 +4,7 @@
>  #define _MM_SHUFFLE_H
>  #include <linux/jump_label.h>
>
> -#define SHUFFLE_ORDER (MAX_ORDER-1)
> +#define SHUFFLE_ORDER MAX_ORDER
>
>  #ifdef CONFIG_SHUFFLE_PAGE_ALLOCATOR
>  DECLARE_STATIC_KEY_FALSE(page_alloc_shuffle_key);
> diff --git a/mm/slab.c b/mm/slab.c
> index dabc2a671fc6..dea1d580a053 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -465,7 +465,7 @@ static int __init slab_max_order_setup(char *str)
>  {
>  	get_option(&str, &slab_max_order);
>  	slab_max_order = slab_max_order < 0 ? 0 :
> -				min(slab_max_order, MAX_ORDER - 1);
> +				min(slab_max_order, MAX_ORDER);
>  	slab_max_order_set = true;
>
>  	return 1;
> diff --git a/mm/slub.c b/mm/slub.c
> index 32eb6b50fe18..0e19c0d647e6 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4171,8 +4171,8 @@ static inline int calculate_order(unsigned int size)
>  	/*
>  	 * Doh this slab cannot be placed using slub_max_order.
>  	 */
> -	order = calc_slab_order(size, 1, MAX_ORDER - 1, 1);
> -	if (order < MAX_ORDER)
> +	order = calc_slab_order(size, 1, MAX_ORDER, 1);
> +	if (order <= MAX_ORDER)
>  		return order;
>  	return -ENOSYS;
>  }
> @@ -4697,7 +4697,7 @@ __setup("slub_min_order=", setup_slub_min_order);
>  static int __init setup_slub_max_order(char *str)
>  {
>  	get_option(&str, (int *)&slub_max_order);
> -	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
> +	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER);

maybe min_t is better?

slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);

>
>  	return 1;
>  }
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 9c1c5e8b24b8..0b611d4c16f1 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -6990,7 +6990,7 @@ unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
>  	 * scan_control uses s8 fields for order, priority, and reclaim_idx.
>  	 * Confirm they are large enough for max values.
>  	 */
> -	BUILD_BUG_ON(MAX_ORDER > S8_MAX);
> +	BUILD_BUG_ON(MAX_ORDER >= S8_MAX);
>  	BUILD_BUG_ON(DEF_PRIORITY > S8_MAX);
>  	BUILD_BUG_ON(MAX_NR_ZONES > S8_MAX);
>
> diff --git a/mm/vmstat.c b/mm/vmstat.c
> index 1ea6a5ce1c41..b7307627772d 100644
> --- a/mm/vmstat.c
> +++ b/mm/vmstat.c
> @@ -1055,7 +1055,7 @@ static void fill_contig_page_info(struct zone *zone,
>  	info->free_blocks_total = 0;
>  	info->free_blocks_suitable = 0;
>
> -	for (order = 0; order < MAX_ORDER; order++) {
> +	for (order = 0; order <= MAX_ORDER; order++) {
>  		unsigned long blocks;
>
>  		/*
> @@ -1088,7 +1088,7 @@ static int __fragmentation_index(unsigned int order, struct contig_page_info *in
>  {
>  	unsigned long requested = 1UL << order;
>
> -	if (WARN_ON_ONCE(order >= MAX_ORDER))
> +	if (WARN_ON_ONCE(order > MAX_ORDER))
>  		return 0;
>
>  	if (!info->free_blocks_total)
> @@ -1462,7 +1462,7 @@ static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
>  	int order;
>
>  	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
> -	for (order = 0; order < MAX_ORDER; ++order)
> +	for (order = 0; order <= MAX_ORDER; ++order)
>  		/*
>  		 * Access to nr_free is lockless as nr_free is used only for
>  		 * printing purposes. Use data_race to avoid KCSAN warning.
> @@ -1491,7 +1491,7 @@ static void pagetypeinfo_showfree_print(struct seq_file *m,
>  					pgdat->node_id,
>  					zone->name,
>  					migratetype_names[mtype]);
> -		for (order = 0; order < MAX_ORDER; ++order) {
> +		for (order = 0; order <= MAX_ORDER; ++order) {
>  			unsigned long freecount = 0;
>  			struct free_area *area;
>  			struct list_head *curr;
> @@ -1531,7 +1531,7 @@ static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
>
>  	/* Print header */
>  	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
> -	for (order = 0; order < MAX_ORDER; ++order)
> +	for (order = 0; order <= MAX_ORDER; ++order)
>  		seq_printf(m, "%6d ", order);
>  	seq_putc(m, '\n');
>
> @@ -2153,7 +2153,7 @@ static void unusable_show_print(struct seq_file *m,
>  	seq_printf(m, "Node %d, zone %8s ",
>  				pgdat->node_id,
>  				zone->name);
> -	for (order = 0; order < MAX_ORDER; ++order) {
> +	for (order = 0; order <= MAX_ORDER; ++order) {
>  		fill_contig_page_info(zone, order, &info);
>  		index = unusable_free_index(order, &info);
>  		seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
> @@ -2205,7 +2205,7 @@ static void extfrag_show_print(struct seq_file *m,
>  	seq_printf(m, "Node %d, zone %8s ",
>  				pgdat->node_id,
>  				zone->name);
> -	for (order = 0; order < MAX_ORDER; ++order) {
> +	for (order = 0; order <= MAX_ORDER; ++order) {
>  		fill_contig_page_info(zone, order, &info);
>  		index = __fragmentation_index(order, &info);
>  		seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
> diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
> index 854772dd52fd..9b66d6aeeb1a 100644
> --- a/net/smc/smc_ib.c
> +++ b/net/smc/smc_ib.c
> @@ -843,7 +843,7 @@ long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
>  		goto out;
>  	/* the calculated number of cq entries fits to mlx5 cq allocation */
>  	cqe_size_order = cache_line_size() == 128 ? 7 : 6;
> -	smc_order = MAX_ORDER - cqe_size_order - 1;
> +	smc_order = MAX_ORDER - cqe_size_order;
>  	if (SMC_MAX_CQE + 2 > (0x00000001 << smc_order) * PAGE_SIZE)
>  		cqattr.cqe = (0x00000001 << smc_order) * PAGE_SIZE - 2;
>  	smcibdev->roce_cq_send = ib_create_cq(smcibdev->ibdev,
> diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
> index 64499056648a..51ad29940f05 100644
> --- a/security/integrity/ima/ima_crypto.c
> +++ b/security/integrity/ima/ima_crypto.c
> @@ -38,7 +38,7 @@ static int param_set_bufsize(const char *val, const struct kernel_param *kp)
>
>  	size = memparse(val, NULL);
>  	order = get_order(size);
> -	if (order >= MAX_ORDER)
> +	if (order > MAX_ORDER)
>  		return -EINVAL;
>  	ima_maxorder = order;
>  	ima_bufsize = PAGE_SIZE << order;
> diff --git a/tools/testing/memblock/linux/mmzone.h b/tools/testing/memblock/linux/mmzone.h
> index e65f89b12f1c..134f8eab0768 100644
> --- a/tools/testing/memblock/linux/mmzone.h
> +++ b/tools/testing/memblock/linux/mmzone.h
> @@ -17,10 +17,10 @@ enum zone_type {
>  };
>
>  #define MAX_NR_ZONES __MAX_NR_ZONES
> -#define MAX_ORDER 11
> -#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
> +#define MAX_ORDER 10
> +#define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
>
> -#define pageblock_order		(MAX_ORDER - 1)
> +#define pageblock_order		MAX_ORDER
>  #define pageblock_nr_pages	BIT(pageblock_order)
>  #define pageblock_align(pfn)	ALIGN((pfn), pageblock_nr_pages)
>  #define pageblock_start_pfn(pfn)	ALIGN_DOWN((pfn), pageblock_nr_pages)
> -- 
> 2.39.2

The changes look good to me. I added some missing changes inline, although the line
number might not be exact. Feel free to add Reviewed-by: Zi Yan <ziy@nvidia.com>.

Do you think it is worth adding a MAX_ORDER check in checkpatch.pl to warn people
the meaning of MAX_ORDER has changed? Something like:

# check for MAX_ORDER uses as its semantics has changed.
# MAX_ORDER now really means the max order of a page that can come out of
# kernel buddy allocator
        if ($line =~ /MAX_ORDER/) {
            WARN("MAX_ORDER",
                 "MAX_ORDER has changed its semantics. The max order of a page that can be allocated from buddy allocator is MAX_ORDER instead of MAX_ORDER - 1.")
        }

Thanks.


--
Best Regards,
Yan, Zi
  
Mike Kravetz March 16, 2023, 6:15 p.m. UTC | #6
On 03/15/23 14:31, Kirill A. Shutemov wrote:
> MAX_ORDER currently defined as number of orders page allocator supports:
> user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
> 
> This definition is counter-intuitive and lead to number of bugs all over
> the kernel.
> 
> Change the definition of MAX_ORDER to be inclusive: the range of orders
> user can ask from buddy allocator is 0..MAX_ORDER now.
> 
> --- a/arch/arc/Kconfig
> +++ b/arch/arc/Kconfig
> @@ -556,7 +556,7 @@ endmenu	 # "ARC Architecture Configuration"
>  
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order"
> -	default "12" if ARC_HUGEPAGE_16M
> -	default "11"
> +	default "11" if ARC_HUGEPAGE_16M
> +	default "10"

Is this Kconfig file wrong (off by 1) today?  It seems like it wants MAX_ORDER
to be sufficiently large to allocate 16M if ARC_HUGEPAGE_16M.  So, seems like
it should be 13 today?
  
Mike Kravetz March 16, 2023, 11 p.m. UTC | #7
On 03/16/23 11:15, Mike Kravetz wrote:
> On 03/15/23 14:31, Kirill A. Shutemov wrote:
> > MAX_ORDER currently defined as number of orders page allocator supports:
> > user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
> > 
> > This definition is counter-intuitive and lead to number of bugs all over
> > the kernel.
> > 
> > Change the definition of MAX_ORDER to be inclusive: the range of orders
> > user can ask from buddy allocator is 0..MAX_ORDER now.
> > 
> > --- a/arch/arc/Kconfig
> > +++ b/arch/arc/Kconfig
> > @@ -556,7 +556,7 @@ endmenu	 # "ARC Architecture Configuration"
> >  
> >  config ARCH_FORCE_MAX_ORDER
> >  	int "Maximum zone order"
> > -	default "12" if ARC_HUGEPAGE_16M
> > -	default "11"
> > +	default "11" if ARC_HUGEPAGE_16M
> > +	default "10"
> 
> Is this Kconfig file wrong (off by 1) today?  It seems like it wants MAX_ORDER
> to be sufficiently large to allocate 16M if ARC_HUGEPAGE_16M.  So, seems like
> it should be 13 today?

Nevermind, PAGE_SIZE seems to be 8K by default although it appears to be
configurable.  Not exactly sure how the hard coded values above work if
PAGE_SIZE is configurable.  Too confusing for me to make an intelligent
comment.  Sorry for the noise.
  
Kirill A. Shutemov March 16, 2023, 11:21 p.m. UTC | #8
On Thu, Mar 16, 2023 at 01:09:30PM -0400, Zi Yan wrote:
> > diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> > index 86fd88492870..c267b8c61e97 100644
> > --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
> > +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> > @@ -172,7 +172,7 @@ variables.
> >  Offset of the free_list's member. This value is used to compute the number
> >  of free pages.
> >
> > -Each zone has a free_area structure array called free_area[MAX_ORDER].
> > +Each zone has a free_area structure array called free_area[MAX_ORDER + 1].
> >  The free_list represents a linked list of free page blocks.
> >
> >  (list_head, next|prev)
> 
> In vmcoreinfo.rst, line 192:
> 
> - (zone.free_area, MAX_ORDER)
> + (zone.free_area, MAX_ORDER + 1)

Okay.

> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 6221a1d057dd..50da4f26fad5 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -3969,7 +3969,7 @@
> >  			[KNL] Minimal page reporting order
> >  			Format: <integer>
> >  			Adjust the minimal page reporting order. The page
> > -			reporting is disabled when it exceeds (MAX_ORDER-1).
> > +			reporting is disabled when it exceeds MAX_ORDER.
> >
> >  	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
> >  			timeout > 0: seconds before rebooting
> 
> line 942:
> -		    possible value is MAX_ORDER/2.  Setting this parameter
> +			possible value is (MAX_ORDER + 1)/2.  Setting this parameter
> 

I don't think it worth it. See below, on the relevant code change.

> > diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
> > index d6bbdb7830b2..273a0fe7910a 100644
> > --- a/kernel/events/ring_buffer.c
> > +++ b/kernel/events/ring_buffer.c
> > @@ -609,8 +609,8 @@ static struct page *rb_alloc_aux_page(int node, int order)
> >  {
> >  	struct page *page;
> >
> > -	if (order >= MAX_ORDER)
> > -		order = MAX_ORDER - 1;
> > +	if (order > MAX_ORDER)
> > +		order = MAX_ORDER;
> >
> >  	do {
> >  		page = alloc_pages_node(node, PERF_AUX_GFP, order);
> 
> line 817:
> 
> -	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
> +	if (order_base_2(size) > PAGE_SHIFT+MAX_ORDER)

Right.

> > diff --git a/mm/Kconfig b/mm/Kconfig
> > index 4751031f3f05..fc059969d7ba 100644
> > --- a/mm/Kconfig
> > +++ b/mm/Kconfig
> > @@ -346,9 +346,9 @@ config SHUFFLE_PAGE_ALLOCATOR
> >  	  the presence of a memory-side-cache. There are also incidental
> >  	  security benefits as it reduces the predictability of page
> >  	  allocations to compliment SLAB_FREELIST_RANDOM, but the
> > -	  default granularity of shuffling on the "MAX_ORDER - 1" i.e,
> > -	  10th order of pages is selected based on cache utilization
> > -	  benefits on x86.
> > +	  default granularity of shuffling on the MAX_ORDER i.e, 10th
> > +	  order of pages is selected based on cache utilization benefits
> > +	  on x86.
> >
> >  	  While the randomization improves cache utilization it may
> >  	  negatively impact workloads on platforms without a cache. For
> 
> line 669:
> 
> -	  Note that the pageblock_order cannot exceed MAX_ORDER - 1 and will be
> -	  clamped down to MAX_ORDER - 1.
> +	  Note that the pageblock_order cannot exceed MAX_ORDER and will be
> +	  clamped down to MAX_ORDER.
> 

Okay. Missed that.

> > diff --git a/mm/kmsan/init.c b/mm/kmsan/init.c
> > index 7fb794242fad..ffedf4dbc49d 100644
> > --- a/mm/kmsan/init.c
> > +++ b/mm/kmsan/init.c
> > @@ -96,7 +96,7 @@ void __init kmsan_init_shadow(void)
> >  struct metadata_page_pair {
> >  	struct page *shadow, *origin;
> >  };
> > -static struct metadata_page_pair held_back[MAX_ORDER] __initdata;
> > +static struct metadata_page_pair held_back[MAX_ORDER + 1] __initdata;
> >
> >  /*
> >   * Eager metadata allocation. When the memblock allocator is freeing pages to
> 
> line 144: this one I am not sure if the original code is wrong or not.
> 
> -	.order = MAX_ORDER,
> +	.order = MAX_ORDER + 1,

I think the original code is wrong, but the initialization seems unused:
it got overridden in kmsan_memblock_discard() before the first use.

> > @@ -211,8 +211,8 @@ static void kmsan_memblock_discard(void)
> >  	 *    order=N-1,
> >  	 *  - repeat.
> >  	 */
> > -	collect.order = MAX_ORDER - 1;
> > -	for (int i = MAX_ORDER - 1; i >= 0; i--) {
> > +	collect.order = MAX_ORDER;
> > +	for (int i = MAX_ORDER; i >= 0; i--) {
> >  		if (held_back[i].shadow)
> >  			smallstack_push(&collect, held_back[i].shadow);
> >  		if (held_back[i].origin)
> > diff --git a/mm/memblock.c b/mm/memblock.c
> > index 25fd0626a9e7..338b8cb0793e 100644
> > --- a/mm/memblock.c
> > +++ b/mm/memblock.c
> > @@ -2043,7 +2043,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
> >  	int order;
> >
> >  	while (start < end) {
> > -		order = min(MAX_ORDER - 1UL, __ffs(start));
> > +		order = min(MAX_ORDER, __ffs(start));
> 
> while you are here, maybe using min_t is better.
> 
> order = min_t(unsigned long, MAX_ORDER, __ffs(start));

Already addressed by fixup.

> >
> >  		while (start + (1UL << order) > end)
> >  			order--;
> > diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> > index db3b270254f1..86291c79a764 100644
> > --- a/mm/memory_hotplug.c
> > +++ b/mm/memory_hotplug.c
> > @@ -596,7 +596,7 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
> >  	unsigned long pfn;
> >
> >  	/*
> > -	 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
> > +	 * Online the pages in MAX_ORDER aligned chunks. The callback might
> >  	 * decide to not expose all pages to the buddy (e.g., expose them
> >  	 * later). We account all pages as being online and belonging to this
> >  	 * zone ("present").
> > @@ -605,7 +605,7 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
> >  	 * this and the first chunk to online will be pageblock_nr_pages.
> >  	 */
> >  	for (pfn = start_pfn; pfn < end_pfn;) {
> > -		int order = min(MAX_ORDER - 1UL, __ffs(pfn));
> > +		int order = min(MAX_ORDER, __ffs(pfn));
> 
> ditto
> 
> int order = min_t(unsigned long, MAX_ORDER, __ffs(pfn));

Ditto.

> >
> >  		(*online_page_callback)(pfn_to_page(pfn), order);
> >  		pfn += (1UL << order);
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index ac1fc986af44..66700f27b4c6 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> 
> line 842: it might make a difference when MAX_ORDER is odd.
> 
> -	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
> +	if (kstrtoul(buf, 10, &res) < 0 ||  res > (MAX_ORDER + 1) / 2) {

I don't think it worth the complication: the upper limit here is pretty
arbitrary and +1 doesn't really make a difference. I would rather keep it
simple.

> > diff --git a/mm/slub.c b/mm/slub.c
> > index 32eb6b50fe18..0e19c0d647e6 100644
> > --- a/mm/slub.c
> > +++ b/mm/slub.c
> > @@ -4171,8 +4171,8 @@ static inline int calculate_order(unsigned int size)
> >  	/*
> >  	 * Doh this slab cannot be placed using slub_max_order.
> >  	 */
> > -	order = calc_slab_order(size, 1, MAX_ORDER - 1, 1);
> > -	if (order < MAX_ORDER)
> > +	order = calc_slab_order(size, 1, MAX_ORDER, 1);
> > +	if (order <= MAX_ORDER)
> >  		return order;
> >  	return -ENOSYS;
> >  }
> > @@ -4697,7 +4697,7 @@ __setup("slub_min_order=", setup_slub_min_order);
> >  static int __init setup_slub_max_order(char *str)
> >  {
> >  	get_option(&str, (int *)&slub_max_order);
> > -	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
> > +	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER);
> 
> maybe min_t is better?
> 
> slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);

Fair enough.

...

> The changes look good to me. I added some missing changes inline, although the line
> number might not be exact. Feel free to add Reviewed-by: Zi Yan <ziy@nvidia.com>.
> 
> Do you think it is worth adding a MAX_ORDER check in checkpatch.pl to warn people
> the meaning of MAX_ORDER has changed? Something like:
> 
> # check for MAX_ORDER uses as its semantics has changed.
> # MAX_ORDER now really means the max order of a page that can come out of
> # kernel buddy allocator
>         if ($line =~ /MAX_ORDER/) {
>             WARN("MAX_ORDER",
>                  "MAX_ORDER has changed its semantics. The max order of a page that can be allocated from buddy allocator is MAX_ORDER instead of MAX_ORDER - 1.")
>         }
> 

We can add, if you think it is helpful. I don't feel strongly about this.

Below is fixup I made based on your feedback:

diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index c267b8c61e97..e488bb4e13c4 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -189,7 +189,7 @@ Offsets of the vmap_area's members. They carry vmalloc-specific
 information. Makedumpfile gets the start address of the vmalloc region
 from this.
 
-(zone.free_area, MAX_ORDER)
+(zone.free_area, MAX_ORDER + 1)
 ---------------------------
 
 Free areas descriptor. User-space tools use this value to iterate the
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index 273a0fe7910a..a0433f37b024 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -814,7 +814,7 @@ struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
 	size = sizeof(struct perf_buffer);
 	size += nr_pages * sizeof(void *);
 
-	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
+	if (order_base_2(size) > PAGE_SHIFT+MAX_ORDER)
 		goto fail;
 
 	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
diff --git a/mm/Kconfig b/mm/Kconfig
index 467844de48e5..6ee3b48ed298 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -666,8 +666,8 @@ config HUGETLB_PAGE_SIZE_VARIABLE
 	  HUGETLB_PAGE_ORDER when there are multiple HugeTLB page sizes available
 	  on a platform.
 
-	  Note that the pageblock_order cannot exceed MAX_ORDER - 1 and will be
-	  clamped down to MAX_ORDER - 1.
+	  Note that the pageblock_order cannot exceed MAX_ORDER and will be
+	  clamped down to MAX_ORDER.
 
 config CONTIG_ALLOC
 	def_bool (MEMORY_ISOLATION && COMPACTION) || CMA
diff --git a/mm/slub.c b/mm/slub.c
index 0e19c0d647e6..f49d669ff604 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4697,7 +4697,7 @@ __setup("slub_min_order=", setup_slub_min_order);
 static int __init setup_slub_max_order(char *str)
 {
 	get_option(&str, (int *)&slub_max_order);
-	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER);
+	slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);
 
 	return 1;
 }
  
Kirill A. Shutemov March 16, 2023, 11:30 p.m. UTC | #9
On Thu, Mar 16, 2023 at 11:15:47AM -0700, Mike Kravetz wrote:
> On 03/15/23 14:31, Kirill A. Shutemov wrote:
> > MAX_ORDER currently defined as number of orders page allocator supports:
> > user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
> > 
> > This definition is counter-intuitive and lead to number of bugs all over
> > the kernel.
> > 
> > Change the definition of MAX_ORDER to be inclusive: the range of orders
> > user can ask from buddy allocator is 0..MAX_ORDER now.
> > 
> > --- a/arch/arc/Kconfig
> > +++ b/arch/arc/Kconfig
> > @@ -556,7 +556,7 @@ endmenu	 # "ARC Architecture Configuration"
> >  
> >  config ARCH_FORCE_MAX_ORDER
> >  	int "Maximum zone order"
> > -	default "12" if ARC_HUGEPAGE_16M
> > -	default "11"
> > +	default "11" if ARC_HUGEPAGE_16M
> > +	default "10"
> 
> Is this Kconfig file wrong (off by 1) today?  It seems like it wants MAX_ORDER
> to be sufficiently large to allocate 16M if ARC_HUGEPAGE_16M.  So, seems like
> it should be 13 today?

+Vineet.

Hm. I think it is okay as long as CONFIG_ARC_PAGE_SIZE_8K=y which is
default, but breaks for other PAGE_SIZE.

Looks like ARCH_FORCE_MAX_ORDER calculation should involve selected page
size.
  
Vineet Gupta March 17, 2023, 1:57 a.m. UTC | #10
On 3/16/23 16:30, Kirill A. Shutemov wrote:
> On Thu, Mar 16, 2023 at 11:15:47AM -0700, Mike Kravetz wrote:
>> On 03/15/23 14:31, Kirill A. Shutemov wrote:
>>> MAX_ORDER currently defined as number of orders page allocator supports:
>>> user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
>>>
>>> This definition is counter-intuitive and lead to number of bugs all over
>>> the kernel.
>>>
>>> Change the definition of MAX_ORDER to be inclusive: the range of orders
>>> user can ask from buddy allocator is 0..MAX_ORDER now.
>>>
>>> --- a/arch/arc/Kconfig
>>> +++ b/arch/arc/Kconfig
>>> @@ -556,7 +556,7 @@ endmenu	 # "ARC Architecture Configuration"
>>>   
>>>   config ARCH_FORCE_MAX_ORDER
>>>   	int "Maximum zone order"
>>> -	default "12" if ARC_HUGEPAGE_16M
>>> -	default "11"
>>> +	default "11" if ARC_HUGEPAGE_16M
>>> +	default "10"
>> Is this Kconfig file wrong (off by 1) today?  It seems like it wants MAX_ORDER
>> to be sufficiently large to allocate 16M if ARC_HUGEPAGE_16M.  So, seems like
>> it should be 13 today?
> +Vineet.
>
> Hm. I think it is okay as long as CONFIG_ARC_PAGE_SIZE_8K=y which is
> default, but breaks for other PAGE_SIZE.
>
> Looks like ARCH_FORCE_MAX_ORDER calculation should involve selected page
> size.

Thats right 8K is default for ARC.

-Vineet
  
Zi Yan March 17, 2023, 1:17 p.m. UTC | #11
On 16 Mar 2023, at 19:21, Kirill A. Shutemov wrote:

> On Thu, Mar 16, 2023 at 01:09:30PM -0400, Zi Yan wrote:
>>> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
>>> index 86fd88492870..c267b8c61e97 100644
>>> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
>>> +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
>>> @@ -172,7 +172,7 @@ variables.
>>>  Offset of the free_list's member. This value is used to compute the number
>>>  of free pages.
>>>
>>> -Each zone has a free_area structure array called free_area[MAX_ORDER].
>>> +Each zone has a free_area structure array called free_area[MAX_ORDER + 1].
>>>  The free_list represents a linked list of free page blocks.
>>>
>>>  (list_head, next|prev)
>>
>> In vmcoreinfo.rst, line 192:
>>
>> - (zone.free_area, MAX_ORDER)
>> + (zone.free_area, MAX_ORDER + 1)
>
> Okay.
>
>>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>>> index 6221a1d057dd..50da4f26fad5 100644
>>> --- a/Documentation/admin-guide/kernel-parameters.txt
>>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>>> @@ -3969,7 +3969,7 @@
>>>  			[KNL] Minimal page reporting order
>>>  			Format: <integer>
>>>  			Adjust the minimal page reporting order. The page
>>> -			reporting is disabled when it exceeds (MAX_ORDER-1).
>>> +			reporting is disabled when it exceeds MAX_ORDER.
>>>
>>>  	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
>>>  			timeout > 0: seconds before rebooting
>>
>> line 942:
>> -		    possible value is MAX_ORDER/2.  Setting this parameter
>> +			possible value is (MAX_ORDER + 1)/2.  Setting this parameter
>>
>
> I don't think it worth it. See below, on the relevant code change.
>
>>> diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
>>> index d6bbdb7830b2..273a0fe7910a 100644
>>> --- a/kernel/events/ring_buffer.c
>>> +++ b/kernel/events/ring_buffer.c
>>> @@ -609,8 +609,8 @@ static struct page *rb_alloc_aux_page(int node, int order)
>>>  {
>>>  	struct page *page;
>>>
>>> -	if (order >= MAX_ORDER)
>>> -		order = MAX_ORDER - 1;
>>> +	if (order > MAX_ORDER)
>>> +		order = MAX_ORDER;
>>>
>>>  	do {
>>>  		page = alloc_pages_node(node, PERF_AUX_GFP, order);
>>
>> line 817:
>>
>> -	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
>> +	if (order_base_2(size) > PAGE_SHIFT+MAX_ORDER)
>
> Right.
>
>>> diff --git a/mm/Kconfig b/mm/Kconfig
>>> index 4751031f3f05..fc059969d7ba 100644
>>> --- a/mm/Kconfig
>>> +++ b/mm/Kconfig
>>> @@ -346,9 +346,9 @@ config SHUFFLE_PAGE_ALLOCATOR
>>>  	  the presence of a memory-side-cache. There are also incidental
>>>  	  security benefits as it reduces the predictability of page
>>>  	  allocations to compliment SLAB_FREELIST_RANDOM, but the
>>> -	  default granularity of shuffling on the "MAX_ORDER - 1" i.e,
>>> -	  10th order of pages is selected based on cache utilization
>>> -	  benefits on x86.
>>> +	  default granularity of shuffling on the MAX_ORDER i.e, 10th
>>> +	  order of pages is selected based on cache utilization benefits
>>> +	  on x86.
>>>
>>>  	  While the randomization improves cache utilization it may
>>>  	  negatively impact workloads on platforms without a cache. For
>>
>> line 669:
>>
>> -	  Note that the pageblock_order cannot exceed MAX_ORDER - 1 and will be
>> -	  clamped down to MAX_ORDER - 1.
>> +	  Note that the pageblock_order cannot exceed MAX_ORDER and will be
>> +	  clamped down to MAX_ORDER.
>>
>
> Okay. Missed that.
>
>>> diff --git a/mm/kmsan/init.c b/mm/kmsan/init.c
>>> index 7fb794242fad..ffedf4dbc49d 100644
>>> --- a/mm/kmsan/init.c
>>> +++ b/mm/kmsan/init.c
>>> @@ -96,7 +96,7 @@ void __init kmsan_init_shadow(void)
>>>  struct metadata_page_pair {
>>>  	struct page *shadow, *origin;
>>>  };
>>> -static struct metadata_page_pair held_back[MAX_ORDER] __initdata;
>>> +static struct metadata_page_pair held_back[MAX_ORDER + 1] __initdata;
>>>
>>>  /*
>>>   * Eager metadata allocation. When the memblock allocator is freeing pages to
>>
>> line 144: this one I am not sure if the original code is wrong or not.
>>
>> -	.order = MAX_ORDER,
>> +	.order = MAX_ORDER + 1,
>
> I think the original code is wrong, but the initialization seems unused:
> it got overridden in kmsan_memblock_discard() before the first use.
>
>>> @@ -211,8 +211,8 @@ static void kmsan_memblock_discard(void)
>>>  	 *    order=N-1,
>>>  	 *  - repeat.
>>>  	 */
>>> -	collect.order = MAX_ORDER - 1;
>>> -	for (int i = MAX_ORDER - 1; i >= 0; i--) {
>>> +	collect.order = MAX_ORDER;
>>> +	for (int i = MAX_ORDER; i >= 0; i--) {
>>>  		if (held_back[i].shadow)
>>>  			smallstack_push(&collect, held_back[i].shadow);
>>>  		if (held_back[i].origin)
>>> diff --git a/mm/memblock.c b/mm/memblock.c
>>> index 25fd0626a9e7..338b8cb0793e 100644
>>> --- a/mm/memblock.c
>>> +++ b/mm/memblock.c
>>> @@ -2043,7 +2043,7 @@ static void __init __free_pages_memory(unsigned long start, unsigned long end)
>>>  	int order;
>>>
>>>  	while (start < end) {
>>> -		order = min(MAX_ORDER - 1UL, __ffs(start));
>>> +		order = min(MAX_ORDER, __ffs(start));
>>
>> while you are here, maybe using min_t is better.
>>
>> order = min_t(unsigned long, MAX_ORDER, __ffs(start));
>
> Already addressed by fixup.
>
>>>
>>>  		while (start + (1UL << order) > end)
>>>  			order--;
>>> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>>> index db3b270254f1..86291c79a764 100644
>>> --- a/mm/memory_hotplug.c
>>> +++ b/mm/memory_hotplug.c
>>> @@ -596,7 +596,7 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
>>>  	unsigned long pfn;
>>>
>>>  	/*
>>> -	 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
>>> +	 * Online the pages in MAX_ORDER aligned chunks. The callback might
>>>  	 * decide to not expose all pages to the buddy (e.g., expose them
>>>  	 * later). We account all pages as being online and belonging to this
>>>  	 * zone ("present").
>>> @@ -605,7 +605,7 @@ static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
>>>  	 * this and the first chunk to online will be pageblock_nr_pages.
>>>  	 */
>>>  	for (pfn = start_pfn; pfn < end_pfn;) {
>>> -		int order = min(MAX_ORDER - 1UL, __ffs(pfn));
>>> +		int order = min(MAX_ORDER, __ffs(pfn));
>>
>> ditto
>>
>> int order = min_t(unsigned long, MAX_ORDER, __ffs(pfn));
>
> Ditto.
>
>>>
>>>  		(*online_page_callback)(pfn_to_page(pfn), order);
>>>  		pfn += (1UL << order);
>>> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
>>> index ac1fc986af44..66700f27b4c6 100644
>>> --- a/mm/page_alloc.c
>>> +++ b/mm/page_alloc.c
>>
>> line 842: it might make a difference when MAX_ORDER is odd.
>>
>> -	if (kstrtoul(buf, 10, &res) < 0 ||  res > MAX_ORDER / 2) {
>> +	if (kstrtoul(buf, 10, &res) < 0 ||  res > (MAX_ORDER + 1) / 2) {
>
> I don't think it worth the complication: the upper limit here is pretty
> arbitrary and +1 doesn't really make a difference. I would rather keep it
> simple.
>
>>> diff --git a/mm/slub.c b/mm/slub.c
>>> index 32eb6b50fe18..0e19c0d647e6 100644
>>> --- a/mm/slub.c
>>> +++ b/mm/slub.c
>>> @@ -4171,8 +4171,8 @@ static inline int calculate_order(unsigned int size)
>>>  	/*
>>>  	 * Doh this slab cannot be placed using slub_max_order.
>>>  	 */
>>> -	order = calc_slab_order(size, 1, MAX_ORDER - 1, 1);
>>> -	if (order < MAX_ORDER)
>>> +	order = calc_slab_order(size, 1, MAX_ORDER, 1);
>>> +	if (order <= MAX_ORDER)
>>>  		return order;
>>>  	return -ENOSYS;
>>>  }
>>> @@ -4697,7 +4697,7 @@ __setup("slub_min_order=", setup_slub_min_order);
>>>  static int __init setup_slub_max_order(char *str)
>>>  {
>>>  	get_option(&str, (int *)&slub_max_order);
>>> -	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
>>> +	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER);
>>
>> maybe min_t is better?
>>
>> slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);
>
> Fair enough.
>
> ...
>
>> The changes look good to me. I added some missing changes inline, although the line
>> number might not be exact. Feel free to add Reviewed-by: Zi Yan <ziy@nvidia.com>.
>>
>> Do you think it is worth adding a MAX_ORDER check in checkpatch.pl to warn people
>> the meaning of MAX_ORDER has changed? Something like:
>>
>> # check for MAX_ORDER uses as its semantics has changed.
>> # MAX_ORDER now really means the max order of a page that can come out of
>> # kernel buddy allocator
>>         if ($line =~ /MAX_ORDER/) {
>>             WARN("MAX_ORDER",
>>                  "MAX_ORDER has changed its semantics. The max order of a page that can be allocated from buddy allocator is MAX_ORDER instead of MAX_ORDER - 1.")
>>         }
>>
>
> We can add, if you think it is helpful. I don't feel strongly about this.
>
> Below is fixup I made based on your feedback:
>
> diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> index c267b8c61e97..e488bb4e13c4 100644
> --- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
> +++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
> @@ -189,7 +189,7 @@ Offsets of the vmap_area's members. They carry vmalloc-specific
>  information. Makedumpfile gets the start address of the vmalloc region
>  from this.
>
> -(zone.free_area, MAX_ORDER)
> +(zone.free_area, MAX_ORDER + 1)
>  ---------------------------
>
>  Free areas descriptor. User-space tools use this value to iterate the
> diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
> index 273a0fe7910a..a0433f37b024 100644
> --- a/kernel/events/ring_buffer.c
> +++ b/kernel/events/ring_buffer.c
> @@ -814,7 +814,7 @@ struct perf_buffer *rb_alloc(int nr_pages, long watermark, int cpu, int flags)
>  	size = sizeof(struct perf_buffer);
>  	size += nr_pages * sizeof(void *);
>
> -	if (order_base_2(size) >= PAGE_SHIFT+MAX_ORDER)
> +	if (order_base_2(size) > PAGE_SHIFT+MAX_ORDER)
>  		goto fail;
>
>  	node = (cpu == -1) ? cpu : cpu_to_node(cpu);
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 467844de48e5..6ee3b48ed298 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -666,8 +666,8 @@ config HUGETLB_PAGE_SIZE_VARIABLE
>  	  HUGETLB_PAGE_ORDER when there are multiple HugeTLB page sizes available
>  	  on a platform.
>
> -	  Note that the pageblock_order cannot exceed MAX_ORDER - 1 and will be
> -	  clamped down to MAX_ORDER - 1.
> +	  Note that the pageblock_order cannot exceed MAX_ORDER and will be
> +	  clamped down to MAX_ORDER.
>
>  config CONTIG_ALLOC
>  	def_bool (MEMORY_ISOLATION && COMPACTION) || CMA
> diff --git a/mm/slub.c b/mm/slub.c
> index 0e19c0d647e6..f49d669ff604 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4697,7 +4697,7 @@ __setup("slub_min_order=", setup_slub_min_order);
>  static int __init setup_slub_max_order(char *str)
>  {
>  	get_option(&str, (int *)&slub_max_order);
> -	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER);
> +	slub_max_order = min_t(unsigned int, slub_max_order, MAX_ORDER);
>
>  	return 1;
>  }
> -- 
>   Kiryl Shutsemau / Kirill A. Shutemov

LGTM. Thanks. Reviewed-by: Zi Yan <ziy@nvidia.com>

--
Best Regards,
Yan, Zi
  
Vlastimil Babka March 21, 2023, 11:22 a.m. UTC | #12
On 3/15/23 12:31, Kirill A. Shutemov wrote:
> MAX_ORDER currently defined as number of orders page allocator supports:
> user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
> 
> This definition is counter-intuitive and lead to number of bugs all over
> the kernel.
> 
> Change the definition of MAX_ORDER to be inclusive: the range of orders
> user can ask from buddy allocator is 0..MAX_ORDER now.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

With the fixups:
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
  
Michael Ellerman March 22, 2023, 3:26 a.m. UTC | #13
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> writes:
> MAX_ORDER currently defined as number of orders page allocator supports:
> user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
>
> This definition is counter-intuitive and lead to number of bugs all over
> the kernel.
>
> Change the definition of MAX_ORDER to be inclusive: the range of orders
> user can ask from buddy allocator is 0..MAX_ORDER now.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
...
>  arch/powerpc/Kconfig                          | 27 ++++++-------
>  arch/powerpc/configs/85xx/ge_imp3a_defconfig  |  2 +-
>  arch/powerpc/configs/fsl-emb-nonhw.config     |  2 +-
>  arch/powerpc/mm/book3s64/iommu_api.c          |  2 +-
>  arch/powerpc/mm/hugetlbpage.c                 |  2 +-
>  arch/powerpc/platforms/powernv/pci-ioda.c     |  2 +-

Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)

cheers
  

Patch

diff --git a/Documentation/admin-guide/kdump/vmcoreinfo.rst b/Documentation/admin-guide/kdump/vmcoreinfo.rst
index 86fd88492870..c267b8c61e97 100644
--- a/Documentation/admin-guide/kdump/vmcoreinfo.rst
+++ b/Documentation/admin-guide/kdump/vmcoreinfo.rst
@@ -172,7 +172,7 @@  variables.
 Offset of the free_list's member. This value is used to compute the number
 of free pages.
 
-Each zone has a free_area structure array called free_area[MAX_ORDER].
+Each zone has a free_area structure array called free_area[MAX_ORDER + 1].
 The free_list represents a linked list of free page blocks.
 
 (list_head, next|prev)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 6221a1d057dd..50da4f26fad5 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3969,7 +3969,7 @@ 
 			[KNL] Minimal page reporting order
 			Format: <integer>
 			Adjust the minimal page reporting order. The page
-			reporting is disabled when it exceeds (MAX_ORDER-1).
+			reporting is disabled when it exceeds MAX_ORDER.
 
 	panic=		[KNL] Kernel behaviour on panic: delay <timeout>
 			timeout > 0: seconds before rebooting
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index d9a13ccf89a3..ab6d701365bb 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -556,7 +556,7 @@  endmenu	 # "ARC Architecture Configuration"
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	default "12" if ARC_HUGEPAGE_16M
-	default "11"
+	default "11" if ARC_HUGEPAGE_16M
+	default "10"
 
 source "kernel/power/Kconfig"
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e24a9820e12f..929e646e84b9 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1355,9 +1355,9 @@  config ARM_MODULE_PLTS
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	default "12" if SOC_AM33XX
-	default "9" if SA1111
-	default "11"
+	default "11" if SOC_AM33XX
+	default "8" if SA1111
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -1366,9 +1366,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 config ALIGNMENT_TRAP
 	def_bool CPU_CP15_MMU
 	select HAVE_PROC_CPU if PROC_FS
diff --git a/arch/arm/configs/imx_v6_v7_defconfig b/arch/arm/configs/imx_v6_v7_defconfig
index 6dc6fed12af8..345a67e67dbd 100644
--- a/arch/arm/configs/imx_v6_v7_defconfig
+++ b/arch/arm/configs/imx_v6_v7_defconfig
@@ -31,7 +31,7 @@  CONFIG_SOC_VF610=y
 CONFIG_SMP=y
 CONFIG_ARM_PSCI=y
 CONFIG_HIGHMEM=y
-CONFIG_ARCH_FORCE_MAX_ORDER=14
+CONFIG_ARCH_FORCE_MAX_ORDER=13
 CONFIG_CMDLINE="noinitrd console=ttymxc0,115200"
 CONFIG_KEXEC=y
 CONFIG_CPU_FREQ=y
diff --git a/arch/arm/configs/milbeaut_m10v_defconfig b/arch/arm/configs/milbeaut_m10v_defconfig
index bd29e5012cb0..385ad0f391a8 100644
--- a/arch/arm/configs/milbeaut_m10v_defconfig
+++ b/arch/arm/configs/milbeaut_m10v_defconfig
@@ -26,7 +26,7 @@  CONFIG_THUMB2_KERNEL=y
 # CONFIG_THUMB2_AVOID_R_ARM_THM_JUMP11 is not set
 # CONFIG_ARM_PATCH_IDIV is not set
 CONFIG_HIGHMEM=y
-CONFIG_ARCH_FORCE_MAX_ORDER=12
+CONFIG_ARCH_FORCE_MAX_ORDER=11
 CONFIG_SECCOMP=y
 CONFIG_KEXEC=y
 CONFIG_EFI=y
diff --git a/arch/arm/configs/oxnas_v6_defconfig b/arch/arm/configs/oxnas_v6_defconfig
index 70a67b3fc91b..90779812c6dd 100644
--- a/arch/arm/configs/oxnas_v6_defconfig
+++ b/arch/arm/configs/oxnas_v6_defconfig
@@ -12,7 +12,7 @@  CONFIG_ARCH_OXNAS=y
 CONFIG_MACH_OX820=y
 CONFIG_SMP=y
 CONFIG_NR_CPUS=16
-CONFIG_ARCH_FORCE_MAX_ORDER=12
+CONFIG_ARCH_FORCE_MAX_ORDER=11
 CONFIG_SECCOMP=y
 CONFIG_ARM_APPENDED_DTB=y
 CONFIG_ARM_ATAG_DTB_COMPAT=y
diff --git a/arch/arm/configs/pxa_defconfig b/arch/arm/configs/pxa_defconfig
index e656d3af2266..b46e39369dbb 100644
--- a/arch/arm/configs/pxa_defconfig
+++ b/arch/arm/configs/pxa_defconfig
@@ -20,7 +20,7 @@  CONFIG_PXA_SHARPSL=y
 CONFIG_MACH_AKITA=y
 CONFIG_MACH_BORZOI=y
 CONFIG_AEABI=y
-CONFIG_ARCH_FORCE_MAX_ORDER=9
+CONFIG_ARCH_FORCE_MAX_ORDER=8
 CONFIG_CMDLINE="root=/dev/ram0 ro"
 CONFIG_KEXEC=y
 CONFIG_CPU_FREQ=y
diff --git a/arch/arm/configs/sama7_defconfig b/arch/arm/configs/sama7_defconfig
index 0d964c613d71..954112041403 100644
--- a/arch/arm/configs/sama7_defconfig
+++ b/arch/arm/configs/sama7_defconfig
@@ -19,7 +19,7 @@  CONFIG_ATMEL_CLOCKSOURCE_TCB=y
 # CONFIG_CACHE_L2X0 is not set
 # CONFIG_ARM_PATCH_IDIV is not set
 # CONFIG_CPU_SW_DOMAIN_PAN is not set
-CONFIG_ARCH_FORCE_MAX_ORDER=15
+CONFIG_ARCH_FORCE_MAX_ORDER=14
 CONFIG_UACCESS_WITH_MEMCPY=y
 # CONFIG_ATAGS is not set
 CONFIG_CMDLINE="console=ttyS0,115200 earlyprintk ignore_loglevel"
diff --git a/arch/arm/configs/sp7021_defconfig b/arch/arm/configs/sp7021_defconfig
index 5bca2eb59b86..c6448ac860b6 100644
--- a/arch/arm/configs/sp7021_defconfig
+++ b/arch/arm/configs/sp7021_defconfig
@@ -17,7 +17,7 @@  CONFIG_ARCH_SUNPLUS=y
 # CONFIG_VDSO is not set
 CONFIG_SMP=y
 CONFIG_THUMB2_KERNEL=y
-CONFIG_ARCH_FORCE_MAX_ORDER=12
+CONFIG_ARCH_FORCE_MAX_ORDER=11
 CONFIG_VFP=y
 CONFIG_NEON=y
 CONFIG_MODULES=y
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 1023e896d46b..cb5c6aa3254e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1476,22 +1476,22 @@  config XEN
 
 # include/linux/mmzone.h requires the following to be true:
 #
-#   MAX_ORDER - 1 + PAGE_SHIFT <= SECTION_SIZE_BITS
+#   MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
 #
-# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS + 1 - PAGE_SHIFT:
+# so the maximum value of MAX_ORDER is SECTION_SIZE_BITS - PAGE_SHIFT:
 #
 #     | SECTION_SIZE_BITS |  PAGE_SHIFT  |  max MAX_ORDER  |  default MAX_ORDER |
 # ----+-------------------+--------------+-----------------+--------------------+
-# 4K  |       27          |      12      |       16        |         11         |
-# 16K |       27          |      14      |       14        |         12         |
-# 64K |       29          |      16      |       14        |         14         |
+# 4K  |       27          |      12      |       15        |         10         |
+# 16K |       27          |      14      |       13        |         11         |
+# 64K |       29          |      16      |       13        |         13         |
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES
-	default "14" if ARM64_64K_PAGES
-	range 12 14 if ARM64_16K_PAGES
-	default "12" if ARM64_16K_PAGES
-	range 11 16 if ARM64_4K_PAGES
-	default "11"
+	default "13" if ARM64_64K_PAGES
+	range 11 13 if ARM64_16K_PAGES
+	default "11" if ARM64_16K_PAGES
+	range 10 15 if ARM64_4K_PAGES
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -1500,14 +1500,11 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 	  We make sure that we can allocate up to a HugePage size for each configuration.
 	  Hence we have :
-		MAX_ORDER = (PMD_SHIFT - PAGE_SHIFT) + 1 => PAGE_SHIFT - 2
+		MAX_ORDER = PMD_SHIFT - PAGE_SHIFT  => PAGE_SHIFT - 3
 
-	  However for 4K, we choose a higher default value, 11 as opposed to 10, giving us
+	  However for 4K, we choose a higher default value, 10 as opposed to 9, giving us
 	  4M allocations matching the default size used by generic code.
 
 config UNMAP_KERNEL_AT_EL0
diff --git a/arch/arm64/include/asm/sparsemem.h b/arch/arm64/include/asm/sparsemem.h
index 4b73463423c3..5f5437621029 100644
--- a/arch/arm64/include/asm/sparsemem.h
+++ b/arch/arm64/include/asm/sparsemem.h
@@ -10,7 +10,7 @@ 
 /*
  * Section size must be at least 512MB for 64K base
  * page size config. Otherwise it will be less than
- * (MAX_ORDER - 1) and the build process will fail.
+ * MAX_ORDER and the build process will fail.
  */
 #ifdef CONFIG_ARM64_64K_PAGES
 #define SECTION_SIZE_BITS 29
diff --git a/arch/arm64/kvm/hyp/include/nvhe/gfp.h b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
index 0a048dc06a7d..fe5472a184a3 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/gfp.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/gfp.h
@@ -16,7 +16,7 @@  struct hyp_pool {
 	 * API at EL2.
 	 */
 	hyp_spinlock_t lock;
-	struct list_head free_area[MAX_ORDER];
+	struct list_head free_area[MAX_ORDER + 1];
 	phys_addr_t range_start;
 	phys_addr_t range_end;
 	unsigned short max_order;
diff --git a/arch/arm64/kvm/hyp/nvhe/page_alloc.c b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
index 803ba3222e75..b1e392186a0f 100644
--- a/arch/arm64/kvm/hyp/nvhe/page_alloc.c
+++ b/arch/arm64/kvm/hyp/nvhe/page_alloc.c
@@ -110,7 +110,7 @@  static void __hyp_attach_page(struct hyp_pool *pool,
 	 * after coalescing, so make sure to mark it HYP_NO_ORDER proactively.
 	 */
 	p->order = HYP_NO_ORDER;
-	for (; (order + 1) < pool->max_order; order++) {
+	for (; (order + 1) <= pool->max_order; order++) {
 		buddy = __find_buddy_avail(pool, p, order);
 		if (!buddy)
 			break;
@@ -203,9 +203,9 @@  void *hyp_alloc_pages(struct hyp_pool *pool, unsigned short order)
 	hyp_spin_lock(&pool->lock);
 
 	/* Look for a high-enough-order page */
-	while (i < pool->max_order && list_empty(&pool->free_area[i]))
+	while (i <= pool->max_order && list_empty(&pool->free_area[i]))
 		i++;
-	if (i >= pool->max_order) {
+	if (i > pool->max_order) {
 		hyp_spin_unlock(&pool->lock);
 		return NULL;
 	}
@@ -228,8 +228,8 @@  int hyp_pool_init(struct hyp_pool *pool, u64 pfn, unsigned int nr_pages,
 	int i;
 
 	hyp_spin_lock_init(&pool->lock);
-	pool->max_order = min(MAX_ORDER, get_order((nr_pages + 1) << PAGE_SHIFT));
-	for (i = 0; i < pool->max_order; i++)
+	pool->max_order = min(MAX_ORDER, get_order(nr_pages << PAGE_SHIFT));
+	for (i = 0; i <= pool->max_order; i++)
 		INIT_LIST_HEAD(&pool->free_area[i]);
 	pool->range_start = phys;
 	pool->range_end = phys + (nr_pages << PAGE_SHIFT);
diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index dba02da6fa34..c694fac43bed 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -334,7 +334,7 @@  config HIGHMEM
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	default "11"
+	default "10"
 
 config DRAM_BASE
 	hex "DRAM start addr (the same with memory-section in dts)"
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index d7e4a24e8644..0d2f41fa56ee 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -202,10 +202,10 @@  config IA64_CYCLONE
 	  If you're unsure, answer N.
 
 config ARCH_FORCE_MAX_ORDER
-	int "MAX_ORDER (11 - 17)"  if !HUGETLB_PAGE
-	range 11 17  if !HUGETLB_PAGE
-	default "17" if HUGETLB_PAGE
-	default "11"
+	int "MAX_ORDER (10 - 16)"  if !HUGETLB_PAGE
+	range 10 16  if !HUGETLB_PAGE
+	default "16" if HUGETLB_PAGE
+	default "10"
 
 config SMP
 	bool "Symmetric multi-processing support"
diff --git a/arch/ia64/include/asm/sparsemem.h b/arch/ia64/include/asm/sparsemem.h
index 84e8ce387b69..a58f8b466d96 100644
--- a/arch/ia64/include/asm/sparsemem.h
+++ b/arch/ia64/include/asm/sparsemem.h
@@ -12,9 +12,9 @@ 
 #define SECTION_SIZE_BITS	(30)
 #define MAX_PHYSMEM_BITS	(50)
 #ifdef CONFIG_ARCH_FORCE_MAX_ORDER
-#if ((CONFIG_ARCH_FORCE_MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS)
+#if (CONFIG_ARCH_FORCE_MAX_ORDER + PAGE_SHIFT > SECTION_SIZE_BITS)
 #undef SECTION_SIZE_BITS
-#define SECTION_SIZE_BITS (CONFIG_ARCH_FORCE_MAX_ORDER - 1 + PAGE_SHIFT)
+#define SECTION_SIZE_BITS (CONFIG_ARCH_FORCE_MAX_ORDER + PAGE_SHIFT)
 #endif
 #endif
 
diff --git a/arch/ia64/mm/hugetlbpage.c b/arch/ia64/mm/hugetlbpage.c
index 380d2f3966c9..e8dd4323fb86 100644
--- a/arch/ia64/mm/hugetlbpage.c
+++ b/arch/ia64/mm/hugetlbpage.c
@@ -170,7 +170,7 @@  static int __init hugetlb_setup_sz(char *str)
 	size = memparse(str, &str);
 	if (*str || !is_power_of_2(size) || !(tr_pages & size) ||
 		size <= PAGE_SIZE ||
-		size >= (1UL << PAGE_SHIFT << MAX_ORDER)) {
+		size > (1UL << PAGE_SHIFT << MAX_ORDER)) {
 		printk(KERN_WARNING "Invalid huge page size specified\n");
 		return 1;
 	}
diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig
index 7fd51257e0ed..272a3a12c98d 100644
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -420,12 +420,12 @@  config NODES_SHIFT
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	range 14 64 if PAGE_SIZE_64KB
-	default "14" if PAGE_SIZE_64KB
-	range 12 64 if PAGE_SIZE_16KB
-	default "12" if PAGE_SIZE_16KB
-	range 11 64
-	default "11"
+	range 13 63 if PAGE_SIZE_64KB
+	default "13" if PAGE_SIZE_64KB
+	range 11 63 if PAGE_SIZE_16KB
+	default "11" if PAGE_SIZE_16KB
+	range 10 63
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -434,9 +434,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 	  The page size is not necessarily 4KB.  Keep this in mind
 	  when choosing a value for this option.
 
diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
index 9380f6e3bb66..c9df6572133f 100644
--- a/arch/m68k/Kconfig.cpu
+++ b/arch/m68k/Kconfig.cpu
@@ -400,7 +400,7 @@  config SINGLE_MEMORY_CHUNK
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order" if ADVANCED
 	depends on !SINGLE_MEMORY_CHUNK
-	default "11"
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -413,9 +413,6 @@  config ARCH_FORCE_MAX_ORDER
 	  value also defines the minimal size of the hole that allows
 	  freeing unused memory map.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 config 060_WRITETHROUGH
 	bool "Use write-through caching for 68060 supervisor accesses"
 	depends on ADVANCED && M68060
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index e2f3ca73f40d..3e8b765b8c7b 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2137,14 +2137,14 @@  endchoice
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	range 14 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
-	default "14" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
-	range 13 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
-	default "13" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
-	range 12 64 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
-	default "12" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
-	range 0 64
-	default "11"
+	range 13 63 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
+	default "13" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_64KB
+	range 12 63 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
+	default "12" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_32KB
+	range 11 63 if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
+	default "11" if MIPS_HUGE_TLB_SUPPORT && PAGE_SIZE_16KB
+	range 0 63
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -2153,9 +2153,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 	  The page size is not necessarily 4KB.  Keep this in mind
 	  when choosing a value for this option.
 
diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index a582f72104f3..89708b95978c 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -46,8 +46,8 @@  source "kernel/Kconfig.hz"
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	range 9 20
-	default "11"
+	range 8 19
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -56,9 +56,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 endmenu
 
 source "arch/nios2/platform/Kconfig.platform"
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index a6c4407d3ec8..90bc0c7f2728 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -896,18 +896,18 @@  config DATA_SHIFT
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	range 8 9 if PPC64 && PPC_64K_PAGES
-	default "9" if PPC64 && PPC_64K_PAGES
-	range 13 13 if PPC64 && !PPC_64K_PAGES
-	default "13" if PPC64 && !PPC_64K_PAGES
-	range 9 64 if PPC32 && PPC_16K_PAGES
-	default "9" if PPC32 && PPC_16K_PAGES
-	range 7 64 if PPC32 && PPC_64K_PAGES
-	default "7" if PPC32 && PPC_64K_PAGES
-	range 5 64 if PPC32 && PPC_256K_PAGES
-	default "5" if PPC32 && PPC_256K_PAGES
-	range 11 64
-	default "11"
+	range 7 8 if PPC64 && PPC_64K_PAGES
+	default "8" if PPC64 && PPC_64K_PAGES
+	range 12 12 if PPC64 && !PPC_64K_PAGES
+	default "12" if PPC64 && !PPC_64K_PAGES
+	range 8 63 if PPC32 && PPC_16K_PAGES
+	default "8" if PPC32 && PPC_16K_PAGES
+	range 6 63 if PPC32 && PPC_64K_PAGES
+	default "6" if PPC32 && PPC_64K_PAGES
+	range 4 63 if PPC32 && PPC_256K_PAGES
+	default "4" if PPC32 && PPC_256K_PAGES
+	range 10 63
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -916,9 +916,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 	  The page size is not necessarily 4KB.  For example, on 64-bit
 	  systems, 64KB pages can be enabled via CONFIG_PPC_64K_PAGES.  Keep
 	  this in mind when choosing a value for this option.
diff --git a/arch/powerpc/configs/85xx/ge_imp3a_defconfig b/arch/powerpc/configs/85xx/ge_imp3a_defconfig
index ea719898b581..6cb7e90d52c1 100644
--- a/arch/powerpc/configs/85xx/ge_imp3a_defconfig
+++ b/arch/powerpc/configs/85xx/ge_imp3a_defconfig
@@ -30,7 +30,7 @@  CONFIG_PREEMPT=y
 # CONFIG_CORE_DUMP_DEFAULT_ELF_HEADERS is not set
 CONFIG_BINFMT_MISC=m
 CONFIG_MATH_EMULATION=y
-CONFIG_ARCH_FORCE_MAX_ORDER=17
+CONFIG_ARCH_FORCE_MAX_ORDER=16
 CONFIG_PCI=y
 CONFIG_PCIEPORTBUS=y
 CONFIG_PCI_MSI=y
diff --git a/arch/powerpc/configs/fsl-emb-nonhw.config b/arch/powerpc/configs/fsl-emb-nonhw.config
index ab8a8c4530d9..3009b0efaf34 100644
--- a/arch/powerpc/configs/fsl-emb-nonhw.config
+++ b/arch/powerpc/configs/fsl-emb-nonhw.config
@@ -41,7 +41,7 @@  CONFIG_FIXED_PHY=y
 CONFIG_FONT_8x16=y
 CONFIG_FONT_8x8=y
 CONFIG_FONTS=y
-CONFIG_ARCH_FORCE_MAX_ORDER=13
+CONFIG_ARCH_FORCE_MAX_ORDER=12
 CONFIG_FRAMEBUFFER_CONSOLE=y
 CONFIG_FRAME_WARN=1024
 CONFIG_FTL=y
diff --git a/arch/powerpc/mm/book3s64/iommu_api.c b/arch/powerpc/mm/book3s64/iommu_api.c
index 7fcfba162e0d..81d7185e2ae8 100644
--- a/arch/powerpc/mm/book3s64/iommu_api.c
+++ b/arch/powerpc/mm/book3s64/iommu_api.c
@@ -97,7 +97,7 @@  static long mm_iommu_do_alloc(struct mm_struct *mm, unsigned long ua,
 	}
 
 	mmap_read_lock(mm);
-	chunk = (1UL << (PAGE_SHIFT + MAX_ORDER - 1)) /
+	chunk = (1UL << (PAGE_SHIFT + MAX_ORDER)) /
 			sizeof(struct vm_area_struct *);
 	chunk = min(chunk, entries);
 	for (entry = 0; entry < entries; entry += chunk) {
diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
index f1ba8d1e8c1a..b900933507da 100644
--- a/arch/powerpc/mm/hugetlbpage.c
+++ b/arch/powerpc/mm/hugetlbpage.c
@@ -615,7 +615,7 @@  void __init gigantic_hugetlb_cma_reserve(void)
 		order = mmu_psize_to_shift(MMU_PAGE_16G) - PAGE_SHIFT;
 
 	if (order) {
-		VM_WARN_ON(order < MAX_ORDER);
+		VM_WARN_ON(order <= MAX_ORDER);
 		hugetlb_cma_reserve(order);
 	}
 }
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 4f6e20a35aa1..5a81f106068e 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -1740,7 +1740,7 @@  static long pnv_pci_ioda2_setup_default_config(struct pnv_ioda_pe *pe)
 	 * DMA window can be larger than available memory, which will
 	 * cause errors later.
 	 */
-	const u64 maxblock = 1UL << (PAGE_SHIFT + MAX_ORDER - 1);
+	const u64 maxblock = 1UL << (PAGE_SHIFT + MAX_ORDER);
 
 	/*
 	 * We create the default window as big as we can. The constraint is
diff --git a/arch/sh/configs/ecovec24_defconfig b/arch/sh/configs/ecovec24_defconfig
index b52e14ccb450..4d655e8d4d74 100644
--- a/arch/sh/configs/ecovec24_defconfig
+++ b/arch/sh/configs/ecovec24_defconfig
@@ -8,7 +8,7 @@  CONFIG_MODULES=y
 CONFIG_MODULE_UNLOAD=y
 # CONFIG_BLK_DEV_BSG is not set
 CONFIG_CPU_SUBTYPE_SH7724=y
-CONFIG_ARCH_FORCE_MAX_ORDER=12
+CONFIG_ARCH_FORCE_MAX_ORDER=11
 CONFIG_MEMORY_SIZE=0x10000000
 CONFIG_FLATMEM_MANUAL=y
 CONFIG_SH_ECOVEC=y
diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index 411fdc0901f7..40271090bd7d 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -20,13 +20,13 @@  config PAGE_OFFSET
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	range 9 64 if PAGE_SIZE_16KB
-	default "9" if PAGE_SIZE_16KB
-	range 7 64 if PAGE_SIZE_64KB
-	default "7" if PAGE_SIZE_64KB
-	range 11 64
-	default "14" if !MMU
-	default "11"
+	range 8 63 if PAGE_SIZE_16KB
+	default "8" if PAGE_SIZE_16KB
+	range 6 63 if PAGE_SIZE_64KB
+	default "6" if PAGE_SIZE_64KB
+	range 10 63
+	default "13" if !MMU
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -35,9 +35,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 	  The page size is not necessarily 4KB. Keep this in mind when
 	  choosing a value for this option.
 
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 84437a4c6545..e3242bf5a8df 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -271,7 +271,7 @@  config ARCH_SPARSEMEM_DEFAULT
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	default "13"
+	default "12"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -280,9 +280,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 13 means that the largest free memory block is 2^12 pages.
-
 if SPARC64 || COMPILE_TEST
 source "kernel/power/Kconfig"
 endif
diff --git a/arch/sparc/kernel/pci_sun4v.c b/arch/sparc/kernel/pci_sun4v.c
index 384480971805..7d91ca6aa675 100644
--- a/arch/sparc/kernel/pci_sun4v.c
+++ b/arch/sparc/kernel/pci_sun4v.c
@@ -193,7 +193,7 @@  static void *dma_4v_alloc_coherent(struct device *dev, size_t size,
 
 	size = IO_PAGE_ALIGN(size);
 	order = get_order(size);
-	if (unlikely(order >= MAX_ORDER))
+	if (unlikely(order > MAX_ORDER))
 		return NULL;
 
 	npages = size >> IO_PAGE_SHIFT;
diff --git a/arch/sparc/kernel/traps_64.c b/arch/sparc/kernel/traps_64.c
index 5b4de4a89dec..08ffd17d5ec3 100644
--- a/arch/sparc/kernel/traps_64.c
+++ b/arch/sparc/kernel/traps_64.c
@@ -897,7 +897,7 @@  void __init cheetah_ecache_flush_init(void)
 
 	/* Now allocate error trap reporting scoreboard. */
 	sz = NR_CPUS * (2 * sizeof(struct cheetah_err_info));
-	for (order = 0; order < MAX_ORDER; order++) {
+	for (order = 0; order <= MAX_ORDER; order++) {
 		if ((PAGE_SIZE << order) >= sz)
 			break;
 	}
diff --git a/arch/sparc/mm/tsb.c b/arch/sparc/mm/tsb.c
index dba8dffe2113..5e2931a18409 100644
--- a/arch/sparc/mm/tsb.c
+++ b/arch/sparc/mm/tsb.c
@@ -402,8 +402,8 @@  void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
 	unsigned long new_rss_limit;
 	gfp_t gfp_flags;
 
-	if (max_tsb_size > (PAGE_SIZE << (MAX_ORDER - 1)))
-		max_tsb_size = (PAGE_SIZE << (MAX_ORDER - 1));
+	if (max_tsb_size > PAGE_SIZE << MAX_ORDER)
+		max_tsb_size = PAGE_SIZE << MAX_ORDER;
 
 	new_cache_index = 0;
 	for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
diff --git a/arch/um/kernel/um_arch.c b/arch/um/kernel/um_arch.c
index 5e5a9c8e0e5d..8dcda617b8bf 100644
--- a/arch/um/kernel/um_arch.c
+++ b/arch/um/kernel/um_arch.c
@@ -368,10 +368,10 @@  int __init linux_main(int argc, char **argv)
 	max_physmem = TASK_SIZE - uml_physmem - iomem_size - MIN_VMALLOC;
 
 	/*
-	 * Zones have to begin on a 1 << MAX_ORDER-1 page boundary,
+	 * Zones have to begin on a 1 << MAX_ORDER page boundary,
 	 * so this makes sure that's true for highmem
 	 */
-	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER - 1)) - 1);
+	max_physmem &= ~((1 << (PAGE_SHIFT + MAX_ORDER)) - 1);
 	if (physmem_size + iomem_size > max_physmem) {
 		highmem = physmem_size + iomem_size - max_physmem;
 		physmem_size -= highmem;
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index bcb0c5d2abc2..3eee334ba873 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -773,7 +773,7 @@  config HIGHMEM
 
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order"
-	default "11"
+	default "10"
 	help
 	  The kernel memory allocator divides physically contiguous memory
 	  blocks into "zones", where each zone is a power of two number of
@@ -782,9 +782,6 @@  config ARCH_FORCE_MAX_ORDER
 	  blocks of physically contiguous memory, then you may need to
 	  increase this value.
 
-	  This config option is actually maximum order plus one. For example,
-	  a value of 11 means that the largest free memory block is 2^10 pages.
-
 endmenu
 
 menu "Power management options"
diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 817eda2075aa..c491fabe3617 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -226,8 +226,8 @@  static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 	if (*ppos < 0 || !count)
 		return -EINVAL;
 
-	if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
-		count = PAGE_SIZE << (MAX_ORDER - 1);
+	if (count > (PAGE_SIZE << MAX_ORDER))
+		count = PAGE_SIZE << MAX_ORDER;
 
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
@@ -373,8 +373,8 @@  static ssize_t regmap_reg_ranges_read_file(struct file *file,
 	if (*ppos < 0 || !count)
 		return -EINVAL;
 
-	if (count > (PAGE_SIZE << (MAX_ORDER - 1)))
-		count = PAGE_SIZE << (MAX_ORDER - 1);
+	if (count > (PAGE_SIZE << MAX_ORDER))
+		count = PAGE_SIZE << MAX_ORDER;
 
 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
index 90d2dfb6448e..cec2c20f5e59 100644
--- a/drivers/block/floppy.c
+++ b/drivers/block/floppy.c
@@ -3079,7 +3079,7 @@  static void raw_cmd_free(struct floppy_raw_cmd **ptr)
 	}
 }
 
-#define MAX_LEN (1UL << (MAX_ORDER - 1) << PAGE_SHIFT)
+#define MAX_LEN (1UL << MAX_ORDER << PAGE_SHIFT)
 
 static int raw_cmd_copyin(int cmd, void __user *param,
 				 struct floppy_raw_cmd **rcmd)
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index e2f25926eb51..bf095baca244 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -886,7 +886,7 @@  static int sev_ioctl_do_get_id2(struct sev_issue_cmd *argp)
 		/*
 		 * The length of the ID shouldn't be assumed by software since
 		 * it may change in the future.  The allocation size is limited
-		 * to 1 << (PAGE_SHIFT + MAX_ORDER - 1) by the page allocator.
+		 * to 1 << (PAGE_SHIFT + MAX_ORDER) by the page allocator.
 		 * If the allocation fails, simply return ENOMEM rather than
 		 * warning in the kernel log.
 		 */
diff --git a/drivers/crypto/hisilicon/sgl.c b/drivers/crypto/hisilicon/sgl.c
index 09586a837b1e..3df7a256e919 100644
--- a/drivers/crypto/hisilicon/sgl.c
+++ b/drivers/crypto/hisilicon/sgl.c
@@ -70,11 +70,11 @@  struct hisi_acc_sgl_pool *hisi_acc_create_sgl_pool(struct device *dev,
 			 HISI_ACC_SGL_ALIGN_SIZE);
 
 	/*
-	 * the pool may allocate a block of memory of size PAGE_SIZE * 2^(MAX_ORDER - 1),
+	 * the pool may allocate a block of memory of size PAGE_SIZE * 2^MAX_ORDER,
 	 * block size may exceed 2^31 on ia64, so the max of block size is 2^31
 	 */
-	block_size = 1 << (PAGE_SHIFT + MAX_ORDER <= 32 ?
-			   PAGE_SHIFT + MAX_ORDER - 1 : 31);
+	block_size = 1 << (PAGE_SHIFT + MAX_ORDER < 32 ?
+			   PAGE_SHIFT + MAX_ORDER : 31);
 	sgl_num_per_block = block_size / sgl_size;
 	block_num = count / sgl_num_per_block;
 	remain_sgl = count % sgl_num_per_block;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_internal.c b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
index eae9e9f6d3bf..6bc26b4b06b8 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_internal.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_internal.c
@@ -36,7 +36,7 @@  static int i915_gem_object_get_pages_internal(struct drm_i915_gem_object *obj)
 	struct sg_table *st;
 	struct scatterlist *sg;
 	unsigned int npages; /* restricted by sg_alloc_table */
-	int max_order = MAX_ORDER - 1;
+	int max_order = MAX_ORDER;
 	unsigned int max_segment;
 	gfp_t gfp;
 
diff --git a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
index defece0bcb81..99f39a5feca1 100644
--- a/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
+++ b/drivers/gpu/drm/i915/gem/selftests/huge_pages.c
@@ -115,7 +115,7 @@  static int get_huge_pages(struct drm_i915_gem_object *obj)
 		do {
 			struct page *page;
 
-			GEM_BUG_ON(order >= MAX_ORDER);
+			GEM_BUG_ON(order > MAX_ORDER);
 			page = alloc_pages(GFP | __GFP_ZERO, order);
 			if (!page)
 				goto err;
diff --git a/drivers/gpu/drm/ttm/ttm_pool.c b/drivers/gpu/drm/ttm/ttm_pool.c
index aa116a7bbae3..6c8585abe08d 100644
--- a/drivers/gpu/drm/ttm/ttm_pool.c
+++ b/drivers/gpu/drm/ttm/ttm_pool.c
@@ -65,11 +65,11 @@  module_param(page_pool_size, ulong, 0644);
 
 static atomic_long_t allocated_pages;
 
-static struct ttm_pool_type global_write_combined[MAX_ORDER];
-static struct ttm_pool_type global_uncached[MAX_ORDER];
+static struct ttm_pool_type global_write_combined[MAX_ORDER + 1];
+static struct ttm_pool_type global_uncached[MAX_ORDER + 1];
 
-static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER];
-static struct ttm_pool_type global_dma32_uncached[MAX_ORDER];
+static struct ttm_pool_type global_dma32_write_combined[MAX_ORDER + 1];
+static struct ttm_pool_type global_dma32_uncached[MAX_ORDER + 1];
 
 static spinlock_t shrinker_lock;
 static struct list_head shrinker_list;
@@ -405,7 +405,7 @@  int ttm_pool_alloc(struct ttm_pool *pool, struct ttm_tt *tt,
 	else
 		gfp_flags |= GFP_HIGHUSER;
 
-	for (order = min_t(unsigned int, MAX_ORDER - 1, __fls(num_pages));
+	for (order = min_t(unsigned int, MAX_ORDER, __fls(num_pages));
 	     num_pages;
 	     order = min_t(unsigned int, order, __fls(num_pages))) {
 		struct ttm_pool_type *pt;
@@ -542,7 +542,7 @@  void ttm_pool_init(struct ttm_pool *pool, struct device *dev,
 
 	if (use_dma_alloc) {
 		for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
-			for (j = 0; j < MAX_ORDER; ++j)
+			for (j = 0; j <= MAX_ORDER; ++j)
 				ttm_pool_type_init(&pool->caching[i].orders[j],
 						   pool, i, j);
 	}
@@ -562,7 +562,7 @@  void ttm_pool_fini(struct ttm_pool *pool)
 
 	if (pool->use_dma_alloc) {
 		for (i = 0; i < TTM_NUM_CACHING_TYPES; ++i)
-			for (j = 0; j < MAX_ORDER; ++j)
+			for (j = 0; j <= MAX_ORDER; ++j)
 				ttm_pool_type_fini(&pool->caching[i].orders[j]);
 	}
 
@@ -616,7 +616,7 @@  static void ttm_pool_debugfs_header(struct seq_file *m)
 	unsigned int i;
 
 	seq_puts(m, "\t ");
-	for (i = 0; i < MAX_ORDER; ++i)
+	for (i = 0; i <= MAX_ORDER; ++i)
 		seq_printf(m, " ---%2u---", i);
 	seq_puts(m, "\n");
 }
@@ -627,7 +627,7 @@  static void ttm_pool_debugfs_orders(struct ttm_pool_type *pt,
 {
 	unsigned int i;
 
-	for (i = 0; i < MAX_ORDER; ++i)
+	for (i = 0; i <= MAX_ORDER; ++i)
 		seq_printf(m, " %8u", ttm_pool_type_count(&pt[i]));
 	seq_puts(m, "\n");
 }
@@ -736,7 +736,7 @@  int ttm_pool_mgr_init(unsigned long num_pages)
 	spin_lock_init(&shrinker_lock);
 	INIT_LIST_HEAD(&shrinker_list);
 
-	for (i = 0; i < MAX_ORDER; ++i) {
+	for (i = 0; i <= MAX_ORDER; ++i) {
 		ttm_pool_type_init(&global_write_combined[i], NULL,
 				   ttm_write_combined, i);
 		ttm_pool_type_init(&global_uncached[i], NULL, ttm_uncached, i);
@@ -769,7 +769,7 @@  void ttm_pool_mgr_fini(void)
 {
 	unsigned int i;
 
-	for (i = 0; i < MAX_ORDER; ++i) {
+	for (i = 0; i <= MAX_ORDER; ++i) {
 		ttm_pool_type_fini(&global_write_combined[i]);
 		ttm_pool_type_fini(&global_uncached[i]);
 
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 8d772ea8a583..b574c58a3487 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -182,7 +182,7 @@ 
 #ifdef CONFIG_CMA_ALIGNMENT
 #define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + CONFIG_CMA_ALIGNMENT)
 #else
-#define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + MAX_ORDER - 1)
+#define Q_MAX_SZ_SHIFT			(PAGE_SHIFT + MAX_ORDER)
 #endif
 
 /*
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index ac996fd6bd9c..7a9f0b0bddbd 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -736,7 +736,7 @@  static struct page **__iommu_dma_alloc_pages(struct device *dev,
 	struct page **pages;
 	unsigned int i = 0, nid = dev_to_node(dev);
 
-	order_mask &= GENMASK(MAX_ORDER - 1, 0);
+	order_mask &= GENMASK(MAX_ORDER, 0);
 	if (!order_mask)
 		return NULL;
 
diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index 586271b8aa39..85790b870877 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -2440,8 +2440,8 @@  static bool its_parse_indirect_baser(struct its_node *its,
 	 * feature is not supported by hardware.
 	 */
 	new_order = max_t(u32, get_order(esz << ids), new_order);
-	if (new_order >= MAX_ORDER) {
-		new_order = MAX_ORDER - 1;
+	if (new_order > MAX_ORDER) {
+		new_order = MAX_ORDER;
 		ids = ilog2(PAGE_ORDER_TO_SIZE(new_order) / (int)esz);
 		pr_warn("ITS@%pa: %s Table too large, reduce ids %llu->%u\n",
 			&its->phys_base, its_base_type_string[type],
diff --git a/drivers/md/dm-bufio.c b/drivers/md/dm-bufio.c
index cf077f9b30c3..733053c2eaa0 100644
--- a/drivers/md/dm-bufio.c
+++ b/drivers/md/dm-bufio.c
@@ -408,7 +408,7 @@  static void __cache_size_refresh(void)
  * If the allocation may fail we use __get_free_pages. Memory fragmentation
  * won't have a fatal effect here, but it just causes flushes of some other
  * buffers and more I/O will be performed. Don't use __get_free_pages if it
- * always fails (i.e. order >= MAX_ORDER).
+ * always fails (i.e. order > MAX_ORDER).
  *
  * If the allocation shouldn't fail we use __vmalloc. This is only for the
  * initial reserve allocation, so there's no risk of wasting all vmalloc
diff --git a/drivers/misc/genwqe/card_dev.c b/drivers/misc/genwqe/card_dev.c
index d0e27438a73c..55fc5b80e649 100644
--- a/drivers/misc/genwqe/card_dev.c
+++ b/drivers/misc/genwqe/card_dev.c
@@ -443,7 +443,7 @@  static int genwqe_mmap(struct file *filp, struct vm_area_struct *vma)
 	if (vsize == 0)
 		return -EINVAL;
 
-	if (get_order(vsize) >= MAX_ORDER)
+	if (get_order(vsize) > MAX_ORDER)
 		return -ENOMEM;
 
 	dma_map = kzalloc(sizeof(struct dma_mapping), GFP_KERNEL);
diff --git a/drivers/misc/genwqe/card_utils.c b/drivers/misc/genwqe/card_utils.c
index ac29698d085a..1c798d6b2dfb 100644
--- a/drivers/misc/genwqe/card_utils.c
+++ b/drivers/misc/genwqe/card_utils.c
@@ -210,7 +210,7 @@  u32 genwqe_crc32(u8 *buff, size_t len, u32 init)
 void *__genwqe_alloc_consistent(struct genwqe_dev *cd, size_t size,
 			       dma_addr_t *dma_handle)
 {
-	if (get_order(size) >= MAX_ORDER)
+	if (get_order(size) > MAX_ORDER)
 		return NULL;
 
 	return dma_alloc_coherent(&cd->pci_dev->dev, size, dma_handle,
@@ -308,7 +308,7 @@  int genwqe_alloc_sync_sgl(struct genwqe_dev *cd, struct genwqe_sgl *sgl,
 	sgl->write = write;
 	sgl->sgl_size = genwqe_sgl_size(sgl->nr_pages);
 
-	if (get_order(sgl->sgl_size) >= MAX_ORDER) {
+	if (get_order(sgl->sgl_size) > MAX_ORDER) {
 		dev_err(&pci_dev->dev,
 			"[%s] err: too much memory requested!\n", __func__);
 		return ret;
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 25be7f8ac7cd..3973ca6adf4c 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -1041,7 +1041,7 @@  static void hns3_init_tx_spare_buffer(struct hns3_enet_ring *ring)
 		return;
 
 	order = get_order(alloc_size);
-	if (order >= MAX_ORDER) {
+	if (order > MAX_ORDER) {
 		if (net_ratelimit())
 			dev_warn(ring_to_dev(ring), "failed to allocate tx spare buffer, exceed to max order\n");
 		return;
diff --git a/drivers/net/ethernet/ibm/ibmvnic.h b/drivers/net/ethernet/ibm/ibmvnic.h
index b35c9b6f913b..4e18b4cefa97 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.h
+++ b/drivers/net/ethernet/ibm/ibmvnic.h
@@ -75,7 +75,7 @@ 
  * pool for the 4MB. Thus the 16 Rx and Tx queues require 32 * 5 = 160
  * plus 16 for the TSO pools for a total of 176 LTB mappings per VNIC.
  */
-#define IBMVNIC_ONE_LTB_MAX	((u32)((1 << (MAX_ORDER - 1)) * PAGE_SIZE))
+#define IBMVNIC_ONE_LTB_MAX	((u32)((1 << MAX_ORDER) * PAGE_SIZE))
 #define IBMVNIC_ONE_LTB_SIZE	min((u32)(8 << 20), IBMVNIC_ONE_LTB_MAX)
 #define IBMVNIC_LTB_SET_SIZE	(38 << 20)
 
diff --git a/drivers/video/fbdev/hyperv_fb.c b/drivers/video/fbdev/hyperv_fb.c
index ec3f6cf05f8c..34781dec3856 100644
--- a/drivers/video/fbdev/hyperv_fb.c
+++ b/drivers/video/fbdev/hyperv_fb.c
@@ -946,7 +946,7 @@  static phys_addr_t hvfb_get_phymem(struct hv_device *hdev,
 	if (request_size == 0)
 		return -1;
 
-	if (order < MAX_ORDER) {
+	if (order <= MAX_ORDER) {
 		/* Call alloc_pages if the size is less than 2^MAX_ORDER */
 		page = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
 		if (!page)
@@ -977,7 +977,7 @@  static void hvfb_release_phymem(struct hv_device *hdev,
 {
 	unsigned int order = get_order(size);
 
-	if (order < MAX_ORDER)
+	if (order <= MAX_ORDER)
 		__free_pages(pfn_to_page(paddr >> PAGE_SHIFT), order);
 	else
 		dma_free_coherent(&hdev->device,
diff --git a/drivers/video/fbdev/vermilion/vermilion.c b/drivers/video/fbdev/vermilion/vermilion.c
index 0374ee6b6d03..32e74e02a02f 100644
--- a/drivers/video/fbdev/vermilion/vermilion.c
+++ b/drivers/video/fbdev/vermilion/vermilion.c
@@ -197,7 +197,7 @@  static int vmlfb_alloc_vram(struct vml_info *vinfo,
 		va = &vinfo->vram[i];
 		order = 0;
 
-		while (requested > (PAGE_SIZE << order) && order < MAX_ORDER)
+		while (requested > (PAGE_SIZE << order) && order <= MAX_ORDER)
 			order++;
 
 		err = vmlfb_alloc_vram_area(va, order, 0);
diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index 3f78a3a1eb75..5b15936a5214 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -33,7 +33,7 @@ 
 #define VIRTIO_BALLOON_FREE_PAGE_ALLOC_FLAG (__GFP_NORETRY | __GFP_NOWARN | \
 					     __GFP_NOMEMALLOC)
 /* The order of free page blocks to report to host */
-#define VIRTIO_BALLOON_HINT_BLOCK_ORDER (MAX_ORDER - 1)
+#define VIRTIO_BALLOON_HINT_BLOCK_ORDER MAX_ORDER
 /* The size of a free page block in bytes */
 #define VIRTIO_BALLOON_HINT_BLOCK_BYTES \
 	(1 << (VIRTIO_BALLOON_HINT_BLOCK_ORDER + PAGE_SHIFT))
diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
index 0c2892ec6817..835f6cc2fb66 100644
--- a/drivers/virtio/virtio_mem.c
+++ b/drivers/virtio/virtio_mem.c
@@ -1120,13 +1120,13 @@  static void virtio_mem_clear_fake_offline(unsigned long pfn,
  */
 static void virtio_mem_fake_online(unsigned long pfn, unsigned long nr_pages)
 {
-	unsigned long order = MAX_ORDER - 1;
+	unsigned long order = MAX_ORDER;
 	unsigned long i;
 
 	/*
 	 * We might get called for ranges that don't cover properly aligned
-	 * MAX_ORDER - 1 pages; however, we can only online properly aligned
-	 * pages with an order of MAX_ORDER - 1 at maximum.
+	 * MAX_ORDER pages; however, we can only online properly aligned
+	 * pages with an order of MAX_ORDER at maximum.
 	 */
 	while (!IS_ALIGNED(pfn | nr_pages, 1 << order))
 		order--;
@@ -1237,9 +1237,9 @@  static void virtio_mem_online_page(struct virtio_mem *vm,
 	bool do_online;
 
 	/*
-	 * We can get called with any order up to MAX_ORDER - 1. If our
-	 * subblock size is smaller than that and we have a mixture of plugged
-	 * and unplugged subblocks within such a page, we have to process in
+	 * We can get called with any order up to MAX_ORDER. If our subblock
+	 * size is smaller than that and we have a mixture of plugged and
+	 * unplugged subblocks within such a page, we have to process in
 	 * smaller granularity. In that case we'll adjust the order exactly once
 	 * within the loop.
 	 */
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index 2f67516bb9bf..9fbb9b5256f7 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -70,7 +70,7 @@  int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
 
 	/* make various checks */
 	order = get_order(newsize);
-	if (unlikely(order >= MAX_ORDER))
+	if (unlikely(order > MAX_ORDER))
 		return -EFBIG;
 
 	ret = inode_newsize_ok(inode, newsize);
diff --git a/include/drm/ttm/ttm_pool.h b/include/drm/ttm/ttm_pool.h
index ef09b23d29e3..8ce14f9d202a 100644
--- a/include/drm/ttm/ttm_pool.h
+++ b/include/drm/ttm/ttm_pool.h
@@ -72,7 +72,7 @@  struct ttm_pool {
 	bool use_dma32;
 
 	struct {
-		struct ttm_pool_type orders[MAX_ORDER];
+		struct ttm_pool_type orders[MAX_ORDER + 1];
 	} caching[TTM_NUM_CACHING_TYPES];
 };
 
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 7c977d234aba..8fb7d91cd0b1 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -818,7 +818,7 @@  static inline unsigned huge_page_shift(struct hstate *h)
 
 static inline bool hstate_is_gigantic(struct hstate *h)
 {
-	return huge_page_order(h) >= MAX_ORDER;
+	return huge_page_order(h) > MAX_ORDER;
 }
 
 static inline unsigned int pages_per_huge_page(const struct hstate *h)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 9fb1b03b83b2..54a07b8862b9 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -26,11 +26,11 @@ 
 
 /* Free memory management - zoned buddy allocator.  */
 #ifndef CONFIG_ARCH_FORCE_MAX_ORDER
-#define MAX_ORDER 11
+#define MAX_ORDER 10
 #else
 #define MAX_ORDER CONFIG_ARCH_FORCE_MAX_ORDER
 #endif
-#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
+#define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
 
 /*
  * PAGE_ALLOC_COSTLY_ORDER is the order at which allocations are deemed
@@ -93,7 +93,7 @@  static inline bool migratetype_is_mergeable(int mt)
 }
 
 #define for_each_migratetype_order(order, type) \
-	for (order = 0; order < MAX_ORDER; order++) \
+	for (order = 0; order <= MAX_ORDER; order++) \
 		for (type = 0; type < MIGRATE_TYPES; type++)
 
 extern int page_group_by_mobility_disabled;
@@ -922,7 +922,7 @@  struct zone {
 	CACHELINE_PADDING(_pad1_);
 
 	/* free areas of different sizes */
-	struct free_area	free_area[MAX_ORDER];
+	struct free_area	free_area[MAX_ORDER + 1];
 
 	/* zone flags, see below */
 	unsigned long		flags;
@@ -1745,7 +1745,7 @@  static inline bool movable_only_nodes(nodemask_t *nodes)
 #define SECTION_BLOCKFLAGS_BITS \
 	((1UL << (PFN_SECTION_SHIFT - pageblock_order)) * NR_PAGEBLOCK_BITS)
 
-#if (MAX_ORDER - 1 + PAGE_SHIFT) > SECTION_SIZE_BITS
+#if (MAX_ORDER + PAGE_SHIFT) > SECTION_SIZE_BITS
 #error Allocator MAX_ORDER exceeds SECTION_SIZE
 #endif
 
diff --git a/include/linux/pageblock-flags.h b/include/linux/pageblock-flags.h
index 5f1ae07d724b..e83c4c095041 100644
--- a/include/linux/pageblock-flags.h
+++ b/include/linux/pageblock-flags.h
@@ -41,14 +41,14 @@  extern unsigned int pageblock_order;
  * Huge pages are a constant size, but don't exceed the maximum allocation
  * granularity.
  */
-#define pageblock_order		min_t(unsigned int, HUGETLB_PAGE_ORDER, MAX_ORDER - 1)
+#define pageblock_order		min_t(unsigned int, HUGETLB_PAGE_ORDER, MAX_ORDER)
 
 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
 
 #else /* CONFIG_HUGETLB_PAGE */
 
 /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
-#define pageblock_order		(MAX_ORDER-1)
+#define pageblock_order		MAX_ORDER
 
 #endif /* CONFIG_HUGETLB_PAGE */
 
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 45af70315a94..aa4575ef2965 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -284,7 +284,7 @@  static inline unsigned int arch_slab_minalign(void)
  * (PAGE_SIZE*2).  Larger requests are passed to the page allocator.
  */
 #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
-#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
+#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
 #ifndef KMALLOC_SHIFT_LOW
 #define KMALLOC_SHIFT_LOW	5
 #endif
@@ -292,7 +292,7 @@  static inline unsigned int arch_slab_minalign(void)
 
 #ifdef CONFIG_SLUB
 #define KMALLOC_SHIFT_HIGH	(PAGE_SHIFT + 1)
-#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
+#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
 #ifndef KMALLOC_SHIFT_LOW
 #define KMALLOC_SHIFT_LOW	3
 #endif
@@ -305,7 +305,7 @@  static inline unsigned int arch_slab_minalign(void)
  * be allocated from the same page.
  */
 #define KMALLOC_SHIFT_HIGH	PAGE_SHIFT
-#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT - 1)
+#define KMALLOC_SHIFT_MAX	(MAX_ORDER + PAGE_SHIFT)
 #ifndef KMALLOC_SHIFT_LOW
 #define KMALLOC_SHIFT_LOW	3
 #endif
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 755f5f08ab38..90ce1dfd591c 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -474,7 +474,7 @@  static int __init crash_save_vmcoreinfo_init(void)
 	VMCOREINFO_OFFSET(list_head, prev);
 	VMCOREINFO_OFFSET(vmap_area, va_start);
 	VMCOREINFO_OFFSET(vmap_area, list);
-	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER);
+	VMCOREINFO_LENGTH(zone.free_area, MAX_ORDER + 1);
 	log_buf_vmcoreinfo_setup();
 	VMCOREINFO_LENGTH(free_area.free_list, MIGRATE_TYPES);
 	VMCOREINFO_NUMBER(NR_FREE_PAGES);
diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 4d40dcce7604..1acec2e22827 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -84,8 +84,8 @@  static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
 	void *addr;
 	int ret = -ENOMEM;
 
-	/* Cannot allocate larger than MAX_ORDER-1 */
-	order = min(get_order(pool_size), MAX_ORDER-1);
+	/* Cannot allocate larger than MAX_ORDER */
+	order = min(get_order(pool_size), MAX_ORDER);
 
 	do {
 		pool_size = 1 << (PAGE_SHIFT + order);
@@ -190,7 +190,7 @@  static int __init dma_atomic_pool_init(void)
 
 	/*
 	 * If coherent_pool was not used on the command line, default the pool
-	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
+	 * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER.
 	 */
 	if (!atomic_pool_size) {
 		unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index d6bbdb7830b2..273a0fe7910a 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -609,8 +609,8 @@  static struct page *rb_alloc_aux_page(int node, int order)
 {
 	struct page *page;
 
-	if (order >= MAX_ORDER)
-		order = MAX_ORDER - 1;
+	if (order > MAX_ORDER)
+		order = MAX_ORDER;
 
 	do {
 		page = alloc_pages_node(node, PERF_AUX_GFP, order);
diff --git a/mm/Kconfig b/mm/Kconfig
index 4751031f3f05..fc059969d7ba 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -346,9 +346,9 @@  config SHUFFLE_PAGE_ALLOCATOR
 	  the presence of a memory-side-cache. There are also incidental
 	  security benefits as it reduces the predictability of page
 	  allocations to compliment SLAB_FREELIST_RANDOM, but the
-	  default granularity of shuffling on the "MAX_ORDER - 1" i.e,
-	  10th order of pages is selected based on cache utilization
-	  benefits on x86.
+	  default granularity of shuffling on the MAX_ORDER i.e, 10th
+	  order of pages is selected based on cache utilization benefits
+	  on x86.
 
 	  While the randomization improves cache utilization it may
 	  negatively impact workloads on platforms without a cache. For
diff --git a/mm/compaction.c b/mm/compaction.c
index 5a9501e0ae01..709136556b9e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -583,7 +583,7 @@  static unsigned long isolate_freepages_block(struct compact_control *cc,
 		if (PageCompound(page)) {
 			const unsigned int order = compound_order(page);
 
-			if (likely(order < MAX_ORDER)) {
+			if (likely(order <= MAX_ORDER)) {
 				blockpfn += (1UL << order) - 1;
 				cursor += (1UL << order) - 1;
 			}
@@ -938,7 +938,7 @@  isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 			 * a valid page order. Consider only values in the
 			 * valid order range to prevent low_pfn overflow.
 			 */
-			if (freepage_order > 0 && freepage_order < MAX_ORDER)
+			if (freepage_order > 0 && freepage_order <= MAX_ORDER)
 				low_pfn += (1UL << freepage_order) - 1;
 			continue;
 		}
@@ -954,7 +954,7 @@  isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn,
 		if (PageCompound(page) && !cc->alloc_contig) {
 			const unsigned int order = compound_order(page);
 
-			if (likely(order < MAX_ORDER))
+			if (likely(order <= MAX_ORDER))
 				low_pfn += (1UL << order) - 1;
 			goto isolate_fail;
 		}
@@ -2124,7 +2124,7 @@  static enum compact_result __compact_finished(struct compact_control *cc)
 
 	/* Direct compactor: Is a suitable page free? */
 	ret = COMPACT_NO_SUITABLE_PAGE;
-	for (order = cc->order; order < MAX_ORDER; order++) {
+	for (order = cc->order; order <= MAX_ORDER; order++) {
 		struct free_area *area = &cc->zone->free_area[order];
 		bool can_steal;
 
diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c
index af59cc7bd307..c9eb007fedcc 100644
--- a/mm/debug_vm_pgtable.c
+++ b/mm/debug_vm_pgtable.c
@@ -1086,7 +1086,7 @@  debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)
 	struct page *page = NULL;
 
 #ifdef CONFIG_CONTIG_ALLOC
-	if (order >= MAX_ORDER) {
+	if (order > MAX_ORDER) {
 		page = alloc_contig_pages((1 << order), GFP_KERNEL,
 					  first_online_node, NULL);
 		if (page) {
@@ -1096,7 +1096,7 @@  debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)
 	}
 #endif
 
-	if (order < MAX_ORDER)
+	if (order <= MAX_ORDER)
 		page = alloc_pages(GFP_KERNEL, order);
 
 	return page;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 4fc43859e59a..1c03cab29d22 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -471,7 +471,7 @@  static int __init hugepage_init(void)
 	/*
 	 * hugepages can't be allocated by the buddy allocator
 	 */
-	MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER >= MAX_ORDER);
+	MAYBE_BUILD_BUG_ON(HPAGE_PMD_ORDER > MAX_ORDER);
 	/*
 	 * we use page->mapping and page->index in second tail page
 	 * as list_head: assuming THP order >= 2
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 07abcb6eb203..9525bced1e82 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2090,7 +2090,7 @@  pgoff_t hugetlb_basepage_index(struct page *page)
 	pgoff_t index = page_index(page_head);
 	unsigned long compound_idx;
 
-	if (compound_order(page_head) >= MAX_ORDER)
+	if (compound_order(page_head) > MAX_ORDER)
 		compound_idx = page_to_pfn(page) - page_to_pfn(page_head);
 	else
 		compound_idx = page - page_head;
@@ -4497,7 +4497,7 @@  static int __init default_hugepagesz_setup(char *s)
 	 * The number of default huge pages (for this size) could have been
 	 * specified as the first hugetlb parameter: hugepages=X.  If so,
 	 * then default_hstate_max_huge_pages is set.  If the default huge
-	 * page size is gigantic (>= MAX_ORDER), then the pages must be
+	 * page size is gigantic (> MAX_ORDER), then the pages must be
 	 * allocated here from bootmem allocator.
 	 */
 	if (default_hstate_max_huge_pages) {
diff --git a/mm/kmsan/init.c b/mm/kmsan/init.c
index 7fb794242fad..ffedf4dbc49d 100644
--- a/mm/kmsan/init.c
+++ b/mm/kmsan/init.c
@@ -96,7 +96,7 @@  void __init kmsan_init_shadow(void)
 struct metadata_page_pair {
 	struct page *shadow, *origin;
 };
-static struct metadata_page_pair held_back[MAX_ORDER] __initdata;
+static struct metadata_page_pair held_back[MAX_ORDER + 1] __initdata;
 
 /*
  * Eager metadata allocation. When the memblock allocator is freeing pages to
@@ -211,8 +211,8 @@  static void kmsan_memblock_discard(void)
 	 *    order=N-1,
 	 *  - repeat.
 	 */
-	collect.order = MAX_ORDER - 1;
-	for (int i = MAX_ORDER - 1; i >= 0; i--) {
+	collect.order = MAX_ORDER;
+	for (int i = MAX_ORDER; i >= 0; i--) {
 		if (held_back[i].shadow)
 			smallstack_push(&collect, held_back[i].shadow);
 		if (held_back[i].origin)
diff --git a/mm/memblock.c b/mm/memblock.c
index 25fd0626a9e7..338b8cb0793e 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -2043,7 +2043,7 @@  static void __init __free_pages_memory(unsigned long start, unsigned long end)
 	int order;
 
 	while (start < end) {
-		order = min(MAX_ORDER - 1UL, __ffs(start));
+		order = min(MAX_ORDER, __ffs(start));
 
 		while (start + (1UL << order) > end)
 			order--;
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index db3b270254f1..86291c79a764 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -596,7 +596,7 @@  static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
 	unsigned long pfn;
 
 	/*
-	 * Online the pages in MAX_ORDER - 1 aligned chunks. The callback might
+	 * Online the pages in MAX_ORDER aligned chunks. The callback might
 	 * decide to not expose all pages to the buddy (e.g., expose them
 	 * later). We account all pages as being online and belonging to this
 	 * zone ("present").
@@ -605,7 +605,7 @@  static void online_pages_range(unsigned long start_pfn, unsigned long nr_pages)
 	 * this and the first chunk to online will be pageblock_nr_pages.
 	 */
 	for (pfn = start_pfn; pfn < end_pfn;) {
-		int order = min(MAX_ORDER - 1UL, __ffs(pfn));
+		int order = min(MAX_ORDER, __ffs(pfn));
 
 		(*online_page_callback)(pfn_to_page(pfn), order);
 		pfn += (1UL << order);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ac1fc986af44..66700f27b4c6 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1059,7 +1059,7 @@  buddy_merge_likely(unsigned long pfn, unsigned long buddy_pfn,
 	unsigned long higher_page_pfn;
 	struct page *higher_page;
 
-	if (order >= MAX_ORDER - 2)
+	if (order >= MAX_ORDER - 1)
 		return false;
 
 	higher_page_pfn = buddy_pfn & pfn;
@@ -1114,7 +1114,7 @@  static inline void __free_one_page(struct page *page,
 	VM_BUG_ON_PAGE(pfn & ((1 << order) - 1), page);
 	VM_BUG_ON_PAGE(bad_range(zone, page), page);
 
-	while (order < MAX_ORDER - 1) {
+	while (order < MAX_ORDER) {
 		if (compaction_capture(capc, page, order, migratetype)) {
 			__mod_zone_freepage_state(zone, -(1 << order),
 								migratetype);
@@ -2579,7 +2579,7 @@  struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
 	struct page *page;
 
 	/* Find a page of the appropriate size in the preferred list */
-	for (current_order = order; current_order < MAX_ORDER; ++current_order) {
+	for (current_order = order; current_order <= MAX_ORDER; ++current_order) {
 		area = &(zone->free_area[current_order]);
 		page = get_page_from_free_area(area, migratetype);
 		if (!page)
@@ -2951,7 +2951,7 @@  static bool unreserve_highatomic_pageblock(const struct alloc_context *ac,
 			continue;
 
 		spin_lock_irqsave(&zone->lock, flags);
-		for (order = 0; order < MAX_ORDER; order++) {
+		for (order = 0; order <= MAX_ORDER; order++) {
 			struct free_area *area = &(zone->free_area[order]);
 
 			page = get_page_from_free_area(area, MIGRATE_HIGHATOMIC);
@@ -3035,7 +3035,7 @@  __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
 	 * approximates finding the pageblock with the most free pages, which
 	 * would be too costly to do exactly.
 	 */
-	for (current_order = MAX_ORDER - 1; current_order >= min_order;
+	for (current_order = MAX_ORDER; current_order >= min_order;
 				--current_order) {
 		area = &(zone->free_area[current_order]);
 		fallback_mt = find_suitable_fallback(area, current_order,
@@ -3061,7 +3061,7 @@  __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
 	return false;
 
 find_smallest:
-	for (current_order = order; current_order < MAX_ORDER;
+	for (current_order = order; current_order <= MAX_ORDER;
 							current_order++) {
 		area = &(zone->free_area[current_order]);
 		fallback_mt = find_suitable_fallback(area, current_order,
@@ -3074,7 +3074,7 @@  __rmqueue_fallback(struct zone *zone, int order, int start_migratetype,
 	 * This should not happen - we already found a suitable fallback
 	 * when looking for the largest page.
 	 */
-	VM_BUG_ON(current_order == MAX_ORDER);
+	VM_BUG_ON(current_order > MAX_ORDER);
 
 do_steal:
 	page = get_page_from_free_area(area, fallback_mt);
@@ -4044,7 +4044,7 @@  bool __zone_watermark_ok(struct zone *z, unsigned int order, unsigned long mark,
 		return true;
 
 	/* For a high-order request, check at least one suitable page is free */
-	for (o = order; o < MAX_ORDER; o++) {
+	for (o = order; o <= MAX_ORDER; o++) {
 		struct free_area *area = &z->free_area[o];
 		int mt;
 
@@ -5564,7 +5564,7 @@  struct page *__alloc_pages(gfp_t gfp, unsigned int order, int preferred_nid,
 	 * There are several places where we assume that the order value is sane
 	 * so bail out early if the request is out of bound.
 	 */
-	if (WARN_ON_ONCE_GFP(order >= MAX_ORDER, gfp))
+	if (WARN_ON_ONCE_GFP(order > MAX_ORDER, gfp))
 		return NULL;
 
 	gfp &= gfp_allowed_mask;
@@ -6294,8 +6294,8 @@  void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_i
 
 	for_each_populated_zone(zone) {
 		unsigned int order;
-		unsigned long nr[MAX_ORDER], flags, total = 0;
-		unsigned char types[MAX_ORDER];
+		unsigned long nr[MAX_ORDER + 1], flags, total = 0;
+		unsigned char types[MAX_ORDER + 1];
 
 		if (zone_idx(zone) > max_zone_idx)
 			continue;
@@ -6305,7 +6305,7 @@  void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_i
 		printk(KERN_CONT "%s: ", zone->name);
 
 		spin_lock_irqsave(&zone->lock, flags);
-		for (order = 0; order < MAX_ORDER; order++) {
+		for (order = 0; order <= MAX_ORDER; order++) {
 			struct free_area *area = &zone->free_area[order];
 			int type;
 
@@ -6319,7 +6319,7 @@  void __show_free_areas(unsigned int filter, nodemask_t *nodemask, int max_zone_i
 			}
 		}
 		spin_unlock_irqrestore(&zone->lock, flags);
-		for (order = 0; order < MAX_ORDER; order++) {
+		for (order = 0; order <= MAX_ORDER; order++) {
 			printk(KERN_CONT "%lu*%lukB ",
 			       nr[order], K(1UL) << order);
 			if (nr[order])
@@ -7670,7 +7670,7 @@  static inline void setup_usemap(struct zone *zone) {}
 /* Initialise the number of pages represented by NR_PAGEBLOCK_BITS */
 void __init set_pageblock_order(void)
 {
-	unsigned int order = MAX_ORDER - 1;
+	unsigned int order = MAX_ORDER;
 
 	/* Check that pageblock_nr_pages has not already been setup */
 	if (pageblock_order)
@@ -9165,7 +9165,7 @@  void *__init alloc_large_system_hash(const char *tablename,
 			else
 				table = memblock_alloc_raw(size,
 							   SMP_CACHE_BYTES);
-		} else if (get_order(size) >= MAX_ORDER || hashdist) {
+		} else if (get_order(size) > MAX_ORDER || hashdist) {
 			table = vmalloc_huge(size, gfp_flags);
 			virt = true;
 			if (table)
@@ -9379,7 +9379,7 @@  int alloc_contig_range(unsigned long start, unsigned long end,
 	order = 0;
 	outer_start = start;
 	while (!PageBuddy(pfn_to_page(outer_start))) {
-		if (++order >= MAX_ORDER) {
+		if (++order > MAX_ORDER) {
 			outer_start = start;
 			break;
 		}
@@ -9629,7 +9629,7 @@  bool is_free_buddy_page(struct page *page)
 	unsigned long pfn = page_to_pfn(page);
 	unsigned int order;
 
-	for (order = 0; order < MAX_ORDER; order++) {
+	for (order = 0; order <= MAX_ORDER; order++) {
 		struct page *page_head = page - (pfn & ((1 << order) - 1));
 
 		if (PageBuddy(page_head) &&
@@ -9637,7 +9637,7 @@  bool is_free_buddy_page(struct page *page)
 			break;
 	}
 
-	return order < MAX_ORDER;
+	return order <= MAX_ORDER;
 }
 EXPORT_SYMBOL(is_free_buddy_page);
 
@@ -9688,7 +9688,7 @@  bool take_page_off_buddy(struct page *page)
 	bool ret = false;
 
 	spin_lock_irqsave(&zone->lock, flags);
-	for (order = 0; order < MAX_ORDER; order++) {
+	for (order = 0; order <= MAX_ORDER; order++) {
 		struct page *page_head = page - (pfn & ((1 << order) - 1));
 		int page_order = buddy_order(page_head);
 
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 47fbc1696466..c6f3605e37ab 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -226,7 +226,7 @@  static void unset_migratetype_isolate(struct page *page, int migratetype)
 	 */
 	if (PageBuddy(page)) {
 		order = buddy_order(page);
-		if (order >= pageblock_order && order < MAX_ORDER - 1) {
+		if (order >= pageblock_order && order < MAX_ORDER) {
 			buddy = find_buddy_page_pfn(page, page_to_pfn(page),
 						    order, NULL);
 			if (buddy && !is_migrate_isolate_page(buddy)) {
@@ -290,11 +290,11 @@  __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  *			isolate_single_pageblock()
  * @migratetype:	migrate type to set in error recovery.
  *
- * Free and in-use pages can be as big as MAX_ORDER-1 and contain more than one
+ * Free and in-use pages can be as big as MAX_ORDER and contain more than one
  * pageblock. When not all pageblocks within a page are isolated at the same
  * time, free page accounting can go wrong. For example, in the case of
- * MAX_ORDER-1 = pageblock_order + 1, a MAX_ORDER-1 page has two pagelbocks.
- * [         MAX_ORDER-1         ]
+ * MAX_ORDER = pageblock_order + 1, a MAX_ORDER page has two pagelbocks.
+ * [         MAX_ORDER           ]
  * [  pageblock0  |  pageblock1  ]
  * When either pageblock is isolated, if it is a free page, the page is not
  * split into separate migratetype lists, which is supposed to; if it is an
@@ -451,7 +451,7 @@  static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
 				 * the free page to the right migratetype list.
 				 *
 				 * head_pfn is not used here as a hugetlb page order
-				 * can be bigger than MAX_ORDER-1, but after it is
+				 * can be bigger than MAX_ORDER, but after it is
 				 * freed, the free page order is not. Use pfn within
 				 * the range to find the head of the free page.
 				 */
@@ -459,7 +459,7 @@  static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
 				outer_pfn = pfn;
 				while (!PageBuddy(pfn_to_page(outer_pfn))) {
 					/* stop if we cannot find the free page */
-					if (++order >= MAX_ORDER)
+					if (++order > MAX_ORDER)
 						goto failed;
 					outer_pfn &= ~0UL << order;
 				}
diff --git a/mm/page_owner.c b/mm/page_owner.c
index 220cdeddc295..31169b3e7f06 100644
--- a/mm/page_owner.c
+++ b/mm/page_owner.c
@@ -315,7 +315,7 @@  void pagetypeinfo_showmixedcount_print(struct seq_file *m,
 				unsigned long freepage_order;
 
 				freepage_order = buddy_order_unsafe(page);
-				if (freepage_order < MAX_ORDER)
+				if (freepage_order <= MAX_ORDER)
 					pfn += (1UL << freepage_order) - 1;
 				continue;
 			}
@@ -549,7 +549,7 @@  read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos)
 		if (PageBuddy(page)) {
 			unsigned long freepage_order = buddy_order_unsafe(page);
 
-			if (freepage_order < MAX_ORDER)
+			if (freepage_order <= MAX_ORDER)
 				pfn += (1UL << freepage_order) - 1;
 			continue;
 		}
@@ -657,7 +657,7 @@  static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone)
 			if (PageBuddy(page)) {
 				unsigned long order = buddy_order_unsafe(page);
 
-				if (order > 0 && order < MAX_ORDER)
+				if (order > 0 && order <= MAX_ORDER)
 					pfn += (1UL << order) - 1;
 				continue;
 			}
diff --git a/mm/page_reporting.c b/mm/page_reporting.c
index 275b466de37b..b021f482a4cb 100644
--- a/mm/page_reporting.c
+++ b/mm/page_reporting.c
@@ -20,7 +20,7 @@  static int page_order_update_notify(const char *val, const struct kernel_param *
 	 * If param is set beyond this limit, order is set to default
 	 * pageblock_order value
 	 */
-	return  param_set_uint_minmax(val, kp, 0, MAX_ORDER-1);
+	return  param_set_uint_minmax(val, kp, 0, MAX_ORDER);
 }
 
 static const struct kernel_param_ops page_reporting_param_ops = {
@@ -276,7 +276,7 @@  page_reporting_process_zone(struct page_reporting_dev_info *prdev,
 		return err;
 
 	/* Process each free list starting from lowest order/mt */
-	for (order = page_reporting_order; order < MAX_ORDER; order++) {
+	for (order = page_reporting_order; order <= MAX_ORDER; order++) {
 		for (mt = 0; mt < MIGRATE_TYPES; mt++) {
 			/* We do not pull pages from the isolate free list */
 			if (is_migrate_isolate(mt))
@@ -370,7 +370,7 @@  int page_reporting_register(struct page_reporting_dev_info *prdev)
 	 */
 
 	if (page_reporting_order == -1) {
-		if (prdev->order > 0 && prdev->order < MAX_ORDER)
+		if (prdev->order > 0 && prdev->order <= MAX_ORDER)
 			page_reporting_order = prdev->order;
 		else
 			page_reporting_order = pageblock_order;
diff --git a/mm/shuffle.h b/mm/shuffle.h
index cec62984f7d3..a6bdf54f96f1 100644
--- a/mm/shuffle.h
+++ b/mm/shuffle.h
@@ -4,7 +4,7 @@ 
 #define _MM_SHUFFLE_H
 #include <linux/jump_label.h>
 
-#define SHUFFLE_ORDER (MAX_ORDER-1)
+#define SHUFFLE_ORDER MAX_ORDER
 
 #ifdef CONFIG_SHUFFLE_PAGE_ALLOCATOR
 DECLARE_STATIC_KEY_FALSE(page_alloc_shuffle_key);
diff --git a/mm/slab.c b/mm/slab.c
index dabc2a671fc6..dea1d580a053 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -465,7 +465,7 @@  static int __init slab_max_order_setup(char *str)
 {
 	get_option(&str, &slab_max_order);
 	slab_max_order = slab_max_order < 0 ? 0 :
-				min(slab_max_order, MAX_ORDER - 1);
+				min(slab_max_order, MAX_ORDER);
 	slab_max_order_set = true;
 
 	return 1;
diff --git a/mm/slub.c b/mm/slub.c
index 32eb6b50fe18..0e19c0d647e6 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4171,8 +4171,8 @@  static inline int calculate_order(unsigned int size)
 	/*
 	 * Doh this slab cannot be placed using slub_max_order.
 	 */
-	order = calc_slab_order(size, 1, MAX_ORDER - 1, 1);
-	if (order < MAX_ORDER)
+	order = calc_slab_order(size, 1, MAX_ORDER, 1);
+	if (order <= MAX_ORDER)
 		return order;
 	return -ENOSYS;
 }
@@ -4697,7 +4697,7 @@  __setup("slub_min_order=", setup_slub_min_order);
 static int __init setup_slub_max_order(char *str)
 {
 	get_option(&str, (int *)&slub_max_order);
-	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
+	slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER);
 
 	return 1;
 }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 9c1c5e8b24b8..0b611d4c16f1 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -6990,7 +6990,7 @@  unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
 	 * scan_control uses s8 fields for order, priority, and reclaim_idx.
 	 * Confirm they are large enough for max values.
 	 */
-	BUILD_BUG_ON(MAX_ORDER > S8_MAX);
+	BUILD_BUG_ON(MAX_ORDER >= S8_MAX);
 	BUILD_BUG_ON(DEF_PRIORITY > S8_MAX);
 	BUILD_BUG_ON(MAX_NR_ZONES > S8_MAX);
 
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1ea6a5ce1c41..b7307627772d 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1055,7 +1055,7 @@  static void fill_contig_page_info(struct zone *zone,
 	info->free_blocks_total = 0;
 	info->free_blocks_suitable = 0;
 
-	for (order = 0; order < MAX_ORDER; order++) {
+	for (order = 0; order <= MAX_ORDER; order++) {
 		unsigned long blocks;
 
 		/*
@@ -1088,7 +1088,7 @@  static int __fragmentation_index(unsigned int order, struct contig_page_info *in
 {
 	unsigned long requested = 1UL << order;
 
-	if (WARN_ON_ONCE(order >= MAX_ORDER))
+	if (WARN_ON_ONCE(order > MAX_ORDER))
 		return 0;
 
 	if (!info->free_blocks_total)
@@ -1462,7 +1462,7 @@  static void frag_show_print(struct seq_file *m, pg_data_t *pgdat,
 	int order;
 
 	seq_printf(m, "Node %d, zone %8s ", pgdat->node_id, zone->name);
-	for (order = 0; order < MAX_ORDER; ++order)
+	for (order = 0; order <= MAX_ORDER; ++order)
 		/*
 		 * Access to nr_free is lockless as nr_free is used only for
 		 * printing purposes. Use data_race to avoid KCSAN warning.
@@ -1491,7 +1491,7 @@  static void pagetypeinfo_showfree_print(struct seq_file *m,
 					pgdat->node_id,
 					zone->name,
 					migratetype_names[mtype]);
-		for (order = 0; order < MAX_ORDER; ++order) {
+		for (order = 0; order <= MAX_ORDER; ++order) {
 			unsigned long freecount = 0;
 			struct free_area *area;
 			struct list_head *curr;
@@ -1531,7 +1531,7 @@  static void pagetypeinfo_showfree(struct seq_file *m, void *arg)
 
 	/* Print header */
 	seq_printf(m, "%-43s ", "Free pages count per migrate type at order");
-	for (order = 0; order < MAX_ORDER; ++order)
+	for (order = 0; order <= MAX_ORDER; ++order)
 		seq_printf(m, "%6d ", order);
 	seq_putc(m, '\n');
 
@@ -2153,7 +2153,7 @@  static void unusable_show_print(struct seq_file *m,
 	seq_printf(m, "Node %d, zone %8s ",
 				pgdat->node_id,
 				zone->name);
-	for (order = 0; order < MAX_ORDER; ++order) {
+	for (order = 0; order <= MAX_ORDER; ++order) {
 		fill_contig_page_info(zone, order, &info);
 		index = unusable_free_index(order, &info);
 		seq_printf(m, "%d.%03d ", index / 1000, index % 1000);
@@ -2205,7 +2205,7 @@  static void extfrag_show_print(struct seq_file *m,
 	seq_printf(m, "Node %d, zone %8s ",
 				pgdat->node_id,
 				zone->name);
-	for (order = 0; order < MAX_ORDER; ++order) {
+	for (order = 0; order <= MAX_ORDER; ++order) {
 		fill_contig_page_info(zone, order, &info);
 		index = __fragmentation_index(order, &info);
 		seq_printf(m, "%2d.%03d ", index / 1000, index % 1000);
diff --git a/net/smc/smc_ib.c b/net/smc/smc_ib.c
index 854772dd52fd..9b66d6aeeb1a 100644
--- a/net/smc/smc_ib.c
+++ b/net/smc/smc_ib.c
@@ -843,7 +843,7 @@  long smc_ib_setup_per_ibdev(struct smc_ib_device *smcibdev)
 		goto out;
 	/* the calculated number of cq entries fits to mlx5 cq allocation */
 	cqe_size_order = cache_line_size() == 128 ? 7 : 6;
-	smc_order = MAX_ORDER - cqe_size_order - 1;
+	smc_order = MAX_ORDER - cqe_size_order;
 	if (SMC_MAX_CQE + 2 > (0x00000001 << smc_order) * PAGE_SIZE)
 		cqattr.cqe = (0x00000001 << smc_order) * PAGE_SIZE - 2;
 	smcibdev->roce_cq_send = ib_create_cq(smcibdev->ibdev,
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c
index 64499056648a..51ad29940f05 100644
--- a/security/integrity/ima/ima_crypto.c
+++ b/security/integrity/ima/ima_crypto.c
@@ -38,7 +38,7 @@  static int param_set_bufsize(const char *val, const struct kernel_param *kp)
 
 	size = memparse(val, NULL);
 	order = get_order(size);
-	if (order >= MAX_ORDER)
+	if (order > MAX_ORDER)
 		return -EINVAL;
 	ima_maxorder = order;
 	ima_bufsize = PAGE_SIZE << order;
diff --git a/tools/testing/memblock/linux/mmzone.h b/tools/testing/memblock/linux/mmzone.h
index e65f89b12f1c..134f8eab0768 100644
--- a/tools/testing/memblock/linux/mmzone.h
+++ b/tools/testing/memblock/linux/mmzone.h
@@ -17,10 +17,10 @@  enum zone_type {
 };
 
 #define MAX_NR_ZONES __MAX_NR_ZONES
-#define MAX_ORDER 11
-#define MAX_ORDER_NR_PAGES (1 << (MAX_ORDER - 1))
+#define MAX_ORDER 10
+#define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
 
-#define pageblock_order		(MAX_ORDER - 1)
+#define pageblock_order		MAX_ORDER
 #define pageblock_nr_pages	BIT(pageblock_order)
 #define pageblock_align(pfn)	ALIGN((pfn), pageblock_nr_pages)
 #define pageblock_start_pfn(pfn)	ALIGN_DOWN((pfn), pageblock_nr_pages)