[PATCH 00/14] arch,mm: cleanup Kconfig entries for ARCH_FORCE_MAX_ORDER

[PATCH 00/14] arch,mm: cleanup Kconfig entries for ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

Hi,

Several architectures have ARCH_FORCE_MAX_ORDER in their Kconfig and
they all have wrong and misleading prompt and help text for this option.

Besides, some define insane limits for possible values of
ARCH_FORCE_MAX_ORDER, some carefully define ranges only for a subset of
possible configurations, some make this option configurable by users for no
good reason.

This set updates the prompt and help text everywhere and does its best to
update actual definitions of ranges where applicable.

Mike Rapoport (IBM) (14):
  arm: reword ARCH_FORCE_MAX_ORDER prompt and help text
  arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER
  arm64: reword ARCH_FORCE_MAX_ORDER prompt and help text
  csky: drop ARCH_FORCE_MAX_ORDER
  ia64: don't allow users to override ARCH_FORCE_MAX_ORDER
  m68k: reword ARCH_FORCE_MAX_ORDER prompt and help text
  nios2: reword ARCH_FORCE_MAX_ORDER prompt and help text
  nios2: drop ranges for definition of ARCH_FORCE_MAX_ORDER
  powerpc: reword ARCH_FORCE_MAX_ORDER prompt and help text
  powerpc: drop ranges for definition of ARCH_FORCE_MAX_ORDER
  sh: reword ARCH_FORCE_MAX_ORDER prompt and help text
  sh: drop ranges for definition of ARCH_FORCE_MAX_ORDER
  sparc: reword ARCH_FORCE_MAX_ORDER prompt and help text
  xtensa: reword ARCH_FORCE_MAX_ORDER prompt and help text

 arch/arm/Kconfig      | 16 +++++++++-------
 arch/arm64/Kconfig    | 27 ++++++++++++---------------
 arch/csky/Kconfig     |  4 ----
 arch/ia64/Kconfig     |  3 +--
 arch/m68k/Kconfig.cpu | 16 +++++++++-------
 arch/nios2/Kconfig    | 17 +++++++++--------
 arch/powerpc/Kconfig  | 22 +++++++++-------------
 arch/sh/mm/Kconfig    | 19 +++++++++----------
 arch/sparc/Kconfig    | 16 +++++++++-------
 arch/xtensa/Kconfig   | 16 +++++++++-------
 10 files changed, 76 insertions(+), 80 deletions(-)


base-commit: 51551d71edbc998fd8c8afa7312db3d270f5998e
-- 
2.35.1

[PATCH 01/14] arm: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/arm/Kconfig | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 929e646e84b9..0b15384c62e6 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1354,17 +1354,19 @@ config ARM_MODULE_PLTS
 	  configurations. If unsure, say y.
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
+	int "Order of maximal physically contiguous allocations"
 	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
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
+
+	  Don't change if unsure.
 
 config ALIGNMENT_TRAP
 	def_bool CPU_CP15_MMU
-- 
2.35.1

[PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

It is not a good idea to change fundamental parameters of core memory
management. Having predefined ranges suggests that the values within
those ranges are sensible, but one has to *really* understand
implications of changing MAX_ORDER before actually amending it and
ranges don't help here.

Drop ranges in definition of ARCH_FORCE_MAX_ORDER

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/arm64/Kconfig | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index e60baf7859d1..bab6483e4317 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1489,9 +1489,7 @@ config XEN
 config ARCH_FORCE_MAX_ORDER
 	int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES
 	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
-- 
2.35.1

Re: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER

[Catalin Marinas]

On Thu, Mar 23, 2023 at 11:21:44AM +0200, Mike Rapoport wrote:
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> 
> It is not a good idea to change fundamental parameters of core memory
> management. Having predefined ranges suggests that the values within
> those ranges are sensible, but one has to *really* understand
> implications of changing MAX_ORDER before actually amending it and
> ranges don't help here.
> 
> Drop ranges in definition of ARCH_FORCE_MAX_ORDER
> 
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
> ---
>  arch/arm64/Kconfig | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index e60baf7859d1..bab6483e4317 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1489,9 +1489,7 @@ config XEN
>  config ARCH_FORCE_MAX_ORDER
>  	int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES
>  	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"

I don't mind rewriting the help text as in the subsequent patch but I'd
keep the ranges as a safety measure. It's less wasted time explaining to
people why some random max order doesn't work. Alternatively, we can
drop the ranges but make this option configurable only if EXPERT.

-- 
Catalin

Re: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

On Thu, Mar 23, 2023 at 10:15:33AM +0000, Catalin Marinas wrote:
> On Thu, Mar 23, 2023 at 11:21:44AM +0200, Mike Rapoport wrote:
> > From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> > 
> > It is not a good idea to change fundamental parameters of core memory
> > management. Having predefined ranges suggests that the values within
> > those ranges are sensible, but one has to *really* understand
> > implications of changing MAX_ORDER before actually amending it and
> > ranges don't help here.
> > 
> > Drop ranges in definition of ARCH_FORCE_MAX_ORDER
> > 
> > Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
> > ---
> >  arch/arm64/Kconfig | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index e60baf7859d1..bab6483e4317 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -1489,9 +1489,7 @@ config XEN
> >  config ARCH_FORCE_MAX_ORDER
> >  	int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES
> >  	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"
> 
> I don't mind rewriting the help text as in the subsequent patch but I'd
> keep the ranges as a safety measure. It's less wasted time explaining to
> people why some random max order doesn't work. Alternatively, we can
> drop the ranges but make this option configurable only if EXPERT.

I like the EXPERT alternative more. I'll add it in v2.
 
> -- 
> Catalin

-- 
Sincerely yours,
Mike.

Re: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER

[Zi Yan]

[-- Attachment #1: Type: text/plain, Size: 1965 bytes --]

On 23 Mar 2023, at 6:37, Mike Rapoport wrote:

> On Thu, Mar 23, 2023 at 10:15:33AM +0000, Catalin Marinas wrote:
>> On Thu, Mar 23, 2023 at 11:21:44AM +0200, Mike Rapoport wrote:
>>> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
>>>
>>> It is not a good idea to change fundamental parameters of core memory
>>> management. Having predefined ranges suggests that the values within
>>> those ranges are sensible, but one has to *really* understand
>>> implications of changing MAX_ORDER before actually amending it and
>>> ranges don't help here.
>>>
>>> Drop ranges in definition of ARCH_FORCE_MAX_ORDER
>>>
>>> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
>>> ---
>>>  arch/arm64/Kconfig | 2 --
>>>  1 file changed, 2 deletions(-)
>>>
>>> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
>>> index e60baf7859d1..bab6483e4317 100644
>>> --- a/arch/arm64/Kconfig
>>> +++ b/arch/arm64/Kconfig
>>> @@ -1489,9 +1489,7 @@ config XEN
>>>  config ARCH_FORCE_MAX_ORDER
>>>  	int "Maximum zone order" if ARM64_4K_PAGES || ARM64_16K_PAGES
>>>  	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"
>>
>> I don't mind rewriting the help text as in the subsequent patch but I'd
>> keep the ranges as a safety measure. It's less wasted time explaining to
>> people why some random max order doesn't work. Alternatively, we can
>> drop the ranges but make this option configurable only if EXPERT.
>
> I like the EXPERT alternative more. I'll add it in v2.

I got an error report from kernel test robot, which set -1 to ARCH_FORCE_MAX_ORDER
via random config generator[1].

Does the EXPERT option prevent kernel test robot from generating such config?
Or we should fix random config generator?

[1] https://lore.kernel.org/linux-mm/91E887E4-0867-421F-9C75-FB9CFF15C33A@nvidia.com/


--
Best Regards,
Yan, Zi

[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 854 bytes --]

Re: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER

[kernel test robot]

Hi Mike,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on 51551d71edbc998fd8c8afa7312db3d270f5998e]

url:    https://github.com/intel-lab-lkp/linux/commits/Mike-Rapoport/arm-reword-ARCH_FORCE_MAX_ORDER-prompt-and-help-text/20230323-172512
base:   51551d71edbc998fd8c8afa7312db3d270f5998e
patch link:    https://lore.kernel.org/r/20230323092156.2545741-3-rppt%40kernel.org
patch subject: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER
config: arm64-randconfig-r022-20230322 (https://download.01.org/0day-ci/archive/20230323/202303232149.Chh6KhiI-lkp@intel.com/config)
compiler: aarch64-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/0522f943c071abf1610651ea40405b7489c50987
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Mike-Rapoport/arm-reword-ARCH_FORCE_MAX_ORDER-prompt-and-help-text/20230323-172512
        git checkout 0522f943c071abf1610651ea40405b7489c50987
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/base/regmap/ drivers/iommu/ fs/proc/ mm/

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/202303232149.Chh6KhiI-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   In file included from include/linux/kernel.h:25,
                    from mm/mm_init.c:9:
   mm/mm_init.c: In function 'find_zone_movable_pfns_for_nodes':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/math.h:61:25: note: in definition of macro 'roundup'
      61 |         typeof(y) __y = y;                              \
         |                         ^
   mm/mm_init.c:429:55: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     429 |                         roundup(required_movablecore, MAX_ORDER_NR_PAGES);
         |                                                       ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/math.h:61:25: note: in definition of macro 'roundup'
      61 |         typeof(y) __y = y;                              \
         |                         ^
   mm/mm_init.c:540:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     540 |                         roundup(zone_movable_pfn[nid], MAX_ORDER_NR_PAGES);
         |                                                        ^~~~~~~~~~~~~~~~~~
--
   In file included from include/linux/gfp.h:7,
                    from include/linux/mm.h:7,
                    from mm/debug.c:10:
   mm/debug.c: In function '__dump_page':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   mm/debug.c:70:44: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
      70 |         if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
         |                                            ^~~~~~~~~~~~~~~~~~
--
   In file included from include/linux/build_bug.h:5,
                    from include/linux/container_of.h:5,
                    from include/linux/list.h:5,
                    from include/linux/smp.h:12,
                    from include/linux/kernel_stat.h:5,
                    from mm/memory.c:42:
   mm/memory.c: In function 'clear_huge_page':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/compiler.h:78:45: note: in definition of macro 'unlikely'
      78 | # define unlikely(x)    __builtin_expect(!!(x), 0)
         |                                             ^
   mm/memory.c:5791:44: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
    5791 |         if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
         |                                            ^~~~~~~~~~~~~~~~~~
   mm/memory.c: In function 'copy_user_huge_page':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/compiler.h:78:45: note: in definition of macro 'unlikely'
      78 | # define unlikely(x)    __builtin_expect(!!(x), 0)
         |                                             ^
   mm/memory.c:5843:44: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
    5843 |         if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
         |                                            ^~~~~~~~~~~~~~~~~~
--
   mm/shuffle.c: In function '__shuffle_zone':
>> mm/shuffle.c:86:35: warning: left shift count is negative [-Wshift-count-negative]
      86 |         const int order_pages = 1 << order;
         |                                 ~~^~~~~~~~
--
   In file included from include/vdso/const.h:5,
                    from include/linux/const.h:4,
                    from include/linux/list.h:9,
                    from include/linux/wait.h:7,
                    from include/linux/wait_bit.h:8,
                    from include/linux/fs.h:6,
                    from include/linux/debugfs.h:15,
                    from mm/page_owner.c:2:
   mm/page_owner.c: In function 'pagetypeinfo_showmixedcount_print':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/uapi/linux/const.h:32:50: note: in definition of macro '__ALIGN_KERNEL_MASK'
      32 | #define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
         |                                                  ^~~~
   include/linux/align.h:8:33: note: in expansion of macro '__ALIGN_KERNEL'
       8 | #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_owner.c:298:31: note: in expansion of macro 'ALIGN'
     298 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                               ^~~~~
   mm/page_owner.c:298:46: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     298 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                                              ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/uapi/linux/const.h:32:61: note: in definition of macro '__ALIGN_KERNEL_MASK'
      32 | #define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
         |                                                             ^~~~
   include/linux/align.h:8:33: note: in expansion of macro '__ALIGN_KERNEL'
       8 | #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_owner.c:298:31: note: in expansion of macro 'ALIGN'
     298 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                               ^~~~~
   mm/page_owner.c:298:46: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     298 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                                              ^~~~~~~~~~~~~~~~~~
   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:
   mm/page_owner.c: In function 'read_page_owner':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   mm/page_owner.c:526:43: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     526 |         while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0)
         |                                           ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   mm/page_owner.c:543:29: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     543 |                 if ((pfn & (MAX_ORDER_NR_PAGES - 1)) == 0 && !pfn_valid(pfn)) {
         |                             ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   mm/page_owner.c:544:32: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     544 |                         pfn += MAX_ORDER_NR_PAGES - 1;
         |                                ^~~~~~~~~~~~~~~~~~
   mm/page_owner.c: In function 'init_pages_in_zone':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/uapi/linux/const.h:32:50: note: in definition of macro '__ALIGN_KERNEL_MASK'
      32 | #define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
         |                                                  ^~~~
   include/linux/align.h:8:33: note: in expansion of macro '__ALIGN_KERNEL'
       8 | #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_owner.c:636:31: note: in expansion of macro 'ALIGN'
     636 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                               ^~~~~
   mm/page_owner.c:636:46: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     636 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                                              ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/uapi/linux/const.h:32:61: note: in definition of macro '__ALIGN_KERNEL_MASK'
      32 | #define __ALIGN_KERNEL_MASK(x, mask)    (((x) + (mask)) & ~(mask))
         |                                                             ^~~~
   include/linux/align.h:8:33: note: in expansion of macro '__ALIGN_KERNEL'
       8 | #define ALIGN(x, a)             __ALIGN_KERNEL((x), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_owner.c:636:31: note: in expansion of macro 'ALIGN'
     636 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                               ^~~~~
   mm/page_owner.c:636:46: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     636 |                         pfn = ALIGN(pfn + 1, MAX_ORDER_NR_PAGES);
         |                                              ^~~~~~~~~~~~~~~~~~
--
   In file included from include/linux/kernel.h:26,
                    from arch/arm64/include/asm/cpufeature.h:22,
                    from arch/arm64/include/asm/ptrace.h:11,
                    from arch/arm64/include/asm/irqflags.h:10,
                    from include/linux/irqflags.h:16,
                    from include/linux/spinlock.h:59,
                    from include/linux/mmzone.h:8,
                    from include/linux/gfp.h:7,
                    from include/linux/mm.h:7,
                    from mm/page_isolation.c:6:
   mm/page_isolation.c: In function 'isolate_single_pageblock':
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:28:27: note: in definition of macro '__cmp'
      28 | #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
         |                           ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:28:27: note: in definition of macro '__cmp'
      28 | #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
         |                           ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:28:27: note: in definition of macro '__cmp'
      28 | #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
         |                           ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:28:40: note: in definition of macro '__cmp'
      28 | #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
         |                                        ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:28:40: note: in definition of macro '__cmp'
      28 | #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
         |                                        ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:28:40: note: in definition of macro '__cmp'
      28 | #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
         |                                        ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:31:39: note: in definition of macro '__cmp_once'
      31 |                 typeof(x) unique_x = (x);               \
         |                                       ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:31:39: note: in definition of macro '__cmp_once'
      31 |                 typeof(x) unique_x = (x);               \
         |                                       ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
>> include/linux/mmzone.h:33:31: warning: left shift count is negative [-Wshift-count-negative]
      33 | #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
         |                               ^~
   include/linux/minmax.h:31:39: note: in definition of macro '__cmp_once'
      31 |                 typeof(x) unique_x = (x);               \
         |                                       ^
   include/linux/minmax.h:74:25: note: in expansion of macro '__careful_cmp'
      74 | #define max(x, y)       __careful_cmp(x, y, >)
         |                         ^~~~~~~~~~~~~
   mm/page_isolation.c:329:22: note: in expansion of macro 'max'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                      ^~~
   include/uapi/linux/const.h:31:41: note: in expansion of macro '__ALIGN_KERNEL_MASK'
      31 | #define __ALIGN_KERNEL(x, a)            __ALIGN_KERNEL_MASK(x, (typeof(x))(a) - 1)
         |                                         ^~~~~~~~~~~~~~~~~~~
   include/linux/align.h:9:33: note: in expansion of macro '__ALIGN_KERNEL'
       9 | #define ALIGN_DOWN(x, a)        __ALIGN_KERNEL((x) - ((a) - 1), (a))
         |                                 ^~~~~~~~~~~~~~
   mm/page_isolation.c:329:26: note: in expansion of macro 'ALIGN_DOWN'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                          ^~~~~~~~~~
   mm/page_isolation.c:329:56: note: in expansion of macro 'MAX_ORDER_NR_PAGES'
     329 |         start_pfn  = max(ALIGN_DOWN(isolate_pageblock, MAX_ORDER_NR_PAGES),
         |                                                        ^~~~~~~~~~~~~~~~~~
..


vim +16 include/linux/build_bug.h

bc6245e5efd70c Ian Abbott       2017-07-10   6  
bc6245e5efd70c Ian Abbott       2017-07-10   7  #ifdef __CHECKER__
bc6245e5efd70c Ian Abbott       2017-07-10   8  #define BUILD_BUG_ON_ZERO(e) (0)
bc6245e5efd70c Ian Abbott       2017-07-10   9  #else /* __CHECKER__ */
bc6245e5efd70c Ian Abbott       2017-07-10  10  /*
bc6245e5efd70c Ian Abbott       2017-07-10  11   * Force a compilation error if condition is true, but also produce a
8788994376d84d Rikard Falkeborn 2019-12-04  12   * result (of value 0 and type int), so the expression can be used
bc6245e5efd70c Ian Abbott       2017-07-10  13   * e.g. in a structure initializer (or where-ever else comma expressions
bc6245e5efd70c Ian Abbott       2017-07-10  14   * aren't permitted).
bc6245e5efd70c Ian Abbott       2017-07-10  15   */
8788994376d84d Rikard Falkeborn 2019-12-04 @16  #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
527edbc18a70e7 Masahiro Yamada  2019-01-03  17  #endif /* __CHECKER__ */
527edbc18a70e7 Masahiro Yamada  2019-01-03  18  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Re: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER

[kernel test robot]

Hi Mike,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on 51551d71edbc998fd8c8afa7312db3d270f5998e]

url:    https://github.com/intel-lab-lkp/linux/commits/Mike-Rapoport/arm-reword-ARCH_FORCE_MAX_ORDER-prompt-and-help-text/20230323-172512
base:   51551d71edbc998fd8c8afa7312db3d270f5998e
patch link:    https://lore.kernel.org/r/20230323092156.2545741-3-rppt%40kernel.org
patch subject: [PATCH 02/14] arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER
config: arm64-randconfig-r031-20230322 (https://download.01.org/0day-ci/archive/20230324/202303240155.01y6T6Fj-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 arm64 cross compiling tool for clang build
        # apt-get install binutils-aarch64-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/0522f943c071abf1610651ea40405b7489c50987
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Mike-Rapoport/arm-reword-ARCH_FORCE_MAX_ORDER-prompt-and-help-text/20230323-172512
        git checkout 0522f943c071abf1610651ea40405b7489c50987
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash drivers/iommu/ kernel/dma/ mm/

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/202303240155.01y6T6Fj-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

>> mm/memory.c:5791:37: warning: shift count is negative [-Wshift-count-negative]
           if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
                                              ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/compiler.h:48:41: note: expanded from macro 'unlikely'
   #  define unlikely(x)   (__branch_check__(x, 0, __builtin_constant_p(x)))
                                             ^
   include/linux/compiler.h:33:34: note: expanded from macro '__branch_check__'
                           ______r = __builtin_expect(!!(x), expect);      \
                                                         ^
>> mm/memory.c:5791:37: warning: shift count is negative [-Wshift-count-negative]
           if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
                                              ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/compiler.h:48:68: note: expanded from macro 'unlikely'
   #  define unlikely(x)   (__branch_check__(x, 0, __builtin_constant_p(x)))
                                                                        ^
   include/linux/compiler.h:35:19: note: expanded from macro '__branch_check__'
                                                expect, is_constant);      \
                                                        ^~~~~~~~~~~
   mm/memory.c:5843:37: warning: shift count is negative [-Wshift-count-negative]
           if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
                                              ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/compiler.h:48:41: note: expanded from macro 'unlikely'
   #  define unlikely(x)   (__branch_check__(x, 0, __builtin_constant_p(x)))
                                             ^
   include/linux/compiler.h:33:34: note: expanded from macro '__branch_check__'
                           ______r = __builtin_expect(!!(x), expect);      \
                                                         ^
   mm/memory.c:5843:37: warning: shift count is negative [-Wshift-count-negative]
           if (unlikely(pages_per_huge_page > MAX_ORDER_NR_PAGES)) {
                                              ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/compiler.h:48:68: note: expanded from macro 'unlikely'
   #  define unlikely(x)   (__branch_check__(x, 0, __builtin_constant_p(x)))
                                                                        ^
   include/linux/compiler.h:35:19: note: expanded from macro '__branch_check__'
                                                expect, is_constant);      \
                                                        ^~~~~~~~~~~
   4 warnings generated.
--
>> drivers/iommu/dma-iommu.c:739:16: error: anonymous bit-field has negative width (-1)
           order_mask &= GENMASK(MAX_ORDER, 0);
                         ^
   include/linux/bits.h:37:3: note: expanded from macro 'GENMASK'
           (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
            ^
   include/linux/bits.h:23:3: note: expanded from macro 'GENMASK_INPUT_CHECK'
           (BUILD_BUG_ON_ZERO(__builtin_choose_expr( \
            ^
   include/linux/build_bug.h:16:53: note: expanded from macro 'BUILD_BUG_ON_ZERO'
   #define BUILD_BUG_ON_ZERO(e) ((int)(sizeof(struct { int:(-!!(e)); })))
                                                       ^
>> drivers/iommu/dma-iommu.c:739:16: warning: shift count >= width of type [-Wshift-count-overflow]
           order_mask &= GENMASK(MAX_ORDER, 0);
                         ^~~~~~~~~~~~~~~~~~~~~
   include/linux/bits.h:37:31: note: expanded from macro 'GENMASK'
           (GENMASK_INPUT_CHECK(h, l) + __GENMASK(h, l))
                                        ^~~~~~~~~~~~~~~
   include/linux/bits.h:35:11: note: expanded from macro '__GENMASK'
            (~UL(0) >> (BITS_PER_LONG - 1 - (h))))
                    ^  ~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning and 1 error generated.
--
>> kernel/dma/pool.c:197:39: warning: shift count is negative [-Wshift-count-negative]
                   pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
                                                       ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/minmax.h:126:59: note: expanded from macro 'min_t'
   #define min_t(type, x, y)       __careful_cmp((type)(x), (type)(y), <)
                                                                   ^
   include/linux/minmax.h:37:12: note: expanded from macro '__careful_cmp'
                   __cmp(x, y, op), \
                            ^
   include/linux/minmax.h:28:34: note: expanded from macro '__cmp'
   #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
                                    ^
>> kernel/dma/pool.c:197:39: warning: shift count is negative [-Wshift-count-negative]
                   pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
                                                       ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/minmax.h:126:59: note: expanded from macro 'min_t'
   #define min_t(type, x, y)       __careful_cmp((type)(x), (type)(y), <)
                                                                   ^
   include/linux/minmax.h:37:12: note: expanded from macro '__careful_cmp'
                   __cmp(x, y, op), \
                            ^
   include/linux/minmax.h:28:46: note: expanded from macro '__cmp'
   #define __cmp(x, y, op) ((x) op (y) ? (x) : (y))
                                                ^
>> kernel/dma/pool.c:197:39: warning: shift count is negative [-Wshift-count-negative]
                   pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
                                                       ^~~~~~~~~~~~~~~~~~
   include/linux/mmzone.h:33:31: note: expanded from macro 'MAX_ORDER_NR_PAGES'
   #define MAX_ORDER_NR_PAGES (1 << MAX_ORDER)
                                 ^  ~~~~~~~~~
   include/linux/minmax.h:126:59: note: expanded from macro 'min_t'
   #define min_t(type, x, y)       __careful_cmp((type)(x), (type)(y), <)
                                                                   ^
   include/linux/minmax.h:38:17: note: expanded from macro '__careful_cmp'
                   __cmp_once(x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y), op))
                                 ^
   include/linux/minmax.h:32:25: note: expanded from macro '__cmp_once'
                   typeof(y) unique_y = (y);               \
                                         ^
   3 warnings generated.


vim +739 drivers/iommu/dma-iommu.c

0db2e5d18f76a6 Robin Murphy        2015-10-01  732  
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  733  static struct page **__iommu_dma_alloc_pages(struct device *dev,
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  734  		unsigned int count, unsigned long order_mask, gfp_t gfp)
0db2e5d18f76a6 Robin Murphy        2015-10-01  735  {
0db2e5d18f76a6 Robin Murphy        2015-10-01  736  	struct page **pages;
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  737  	unsigned int i = 0, nid = dev_to_node(dev);
3b6b7e19e31a81 Robin Murphy        2016-04-13  738  
98d56389a5e38b Kirill A. Shutemov  2023-03-15 @739  	order_mask &= GENMASK(MAX_ORDER, 0);
3b6b7e19e31a81 Robin Murphy        2016-04-13  740  	if (!order_mask)
3b6b7e19e31a81 Robin Murphy        2016-04-13  741  		return NULL;
0db2e5d18f76a6 Robin Murphy        2015-10-01  742  
ab6f4b001c8c72 Gustavo A. R. Silva 2021-09-28  743  	pages = kvcalloc(count, sizeof(*pages), GFP_KERNEL);
0db2e5d18f76a6 Robin Murphy        2015-10-01  744  	if (!pages)
0db2e5d18f76a6 Robin Murphy        2015-10-01  745  		return NULL;
0db2e5d18f76a6 Robin Murphy        2015-10-01  746  
0db2e5d18f76a6 Robin Murphy        2015-10-01  747  	/* IOMMU can map any pages, so himem can also be used here */
0db2e5d18f76a6 Robin Murphy        2015-10-01  748  	gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
0db2e5d18f76a6 Robin Murphy        2015-10-01  749  
0db2e5d18f76a6 Robin Murphy        2015-10-01  750  	while (count) {
0db2e5d18f76a6 Robin Murphy        2015-10-01  751  		struct page *page = NULL;
3b6b7e19e31a81 Robin Murphy        2016-04-13  752  		unsigned int order_size;
0db2e5d18f76a6 Robin Murphy        2015-10-01  753  
0db2e5d18f76a6 Robin Murphy        2015-10-01  754  		/*
0db2e5d18f76a6 Robin Murphy        2015-10-01  755  		 * Higher-order allocations are a convenience rather
0db2e5d18f76a6 Robin Murphy        2015-10-01  756  		 * than a necessity, hence using __GFP_NORETRY until
3b6b7e19e31a81 Robin Murphy        2016-04-13  757  		 * falling back to minimum-order allocations.
0db2e5d18f76a6 Robin Murphy        2015-10-01  758  		 */
a706e6e10225fb Kirill A. Shutemov  2023-03-15  759  		for (order_mask &= GENMASK(__fls(count), 0);
3b6b7e19e31a81 Robin Murphy        2016-04-13  760  		     order_mask; order_mask &= ~order_size) {
3b6b7e19e31a81 Robin Murphy        2016-04-13  761  			unsigned int order = __fls(order_mask);
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  762  			gfp_t alloc_flags = gfp;
3b6b7e19e31a81 Robin Murphy        2016-04-13  763  
3b6b7e19e31a81 Robin Murphy        2016-04-13  764  			order_size = 1U << order;
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  765  			if (order_mask > order_size)
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  766  				alloc_flags |= __GFP_NORETRY;
c4b17afb0a4e8d Ganapatrao Kulkarni 2018-11-30  767  			page = alloc_pages_node(nid, alloc_flags, order);
0db2e5d18f76a6 Robin Murphy        2015-10-01  768  			if (!page)
0db2e5d18f76a6 Robin Murphy        2015-10-01  769  				continue;
4604393ca0c6e4 Robin Murphy        2020-09-03  770  			if (order)
0db2e5d18f76a6 Robin Murphy        2015-10-01  771  				split_page(page, order);
0db2e5d18f76a6 Robin Murphy        2015-10-01  772  			break;
0db2e5d18f76a6 Robin Murphy        2015-10-01  773  		}
0db2e5d18f76a6 Robin Murphy        2015-10-01  774  		if (!page) {
0db2e5d18f76a6 Robin Murphy        2015-10-01  775  			__iommu_dma_free_pages(pages, i);
0db2e5d18f76a6 Robin Murphy        2015-10-01  776  			return NULL;
0db2e5d18f76a6 Robin Murphy        2015-10-01  777  		}
3b6b7e19e31a81 Robin Murphy        2016-04-13  778  		count -= order_size;
3b6b7e19e31a81 Robin Murphy        2016-04-13  779  		while (order_size--)
0db2e5d18f76a6 Robin Murphy        2015-10-01  780  			pages[i++] = page++;
0db2e5d18f76a6 Robin Murphy        2015-10-01  781  	}
0db2e5d18f76a6 Robin Murphy        2015-10-01  782  	return pages;
0db2e5d18f76a6 Robin Murphy        2015-10-01  783  }
0db2e5d18f76a6 Robin Murphy        2015-10-01  784  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

[PATCH 03/14] arm64: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/arm64/Kconfig | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index bab6483e4317..75af4c329224 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -1487,24 +1487,24 @@ config XEN
 # 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
+	int "Order of maximal physically contiguous allocations" if ARM64_4K_PAGES || ARM64_16K_PAGES
 	default "13" if ARM64_64K_PAGES
 	default "11" if ARM64_16K_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
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
 
-	  We make sure that we can allocate up to a HugePage size for each configuration.
-	  Hence we have :
-		MAX_ORDER = PMD_SHIFT - PAGE_SHIFT  => PAGE_SHIFT - 3
+	  The maximal size of allocation cannot exceed the size of the
+	  section, so the value of MAX_ORDER should satisfy
 
-	  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.
+	    MAX_ORDER + PAGE_SHIFT <= SECTION_SIZE_BITS
+
+	  Don't change if unsure.
 
 config UNMAP_KERNEL_AT_EL0
 	bool "Unmap kernel when running in userspace (aka \"KAISER\")" if EXPERT
@@ -2298,4 +2298,3 @@ endmenu # "CPU Power Management"
 source "drivers/acpi/Kconfig"
 
 source "arch/arm64/kvm/Kconfig"
-
-- 
2.35.1

Re: [PATCH 03/14] arm64: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Catalin Marinas]

On Thu, Mar 23, 2023 at 11:21:45AM +0200, Mike Rapoport wrote:
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> 
> The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
> describe this configuration option.
> 
> Update both to actually describe what this option does.
> 
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

[PATCH 04/14] csky: drop ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The default value of ARCH_FORCE_MAX_ORDER matches the generic default
defined in the MM code, the architecture does not support huge pages, so
there is no need to keep ARCH_FORCE_MAX_ORDER option available.

Drop it.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/csky/Kconfig | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
index c694fac43bed..00379a843c37 100644
--- a/arch/csky/Kconfig
+++ b/arch/csky/Kconfig
@@ -332,10 +332,6 @@ config HIGHMEM
 	select KMAP_LOCAL
 	default y
 
-config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
-	default "10"
-
 config DRAM_BASE
 	hex "DRAM start addr (the same with memory-section in dts)"
 	default 0x0
-- 
2.35.1

[PATCH 05/14] ia64: don't allow users to override ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

It is enough to keep default values for base and huge pages without
letting users to override ARCH_FORCE_MAX_ORDER.

Drop the prompt to make the option unvisible in *config.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/ia64/Kconfig | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index 0d2f41fa56ee..b61437cae162 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -202,8 +202,7 @@ config IA64_CYCLONE
 	  If you're unsure, answer N.
 
 config ARCH_FORCE_MAX_ORDER
-	int "MAX_ORDER (10 - 16)"  if !HUGETLB_PAGE
-	range 10 16  if !HUGETLB_PAGE
+	int
 	default "16" if HUGETLB_PAGE
 	default "10"
 
-- 
2.35.1

[PATCH 06/14] m68k: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/m68k/Kconfig.cpu | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
index c9df6572133f..e530bc8f240f 100644
--- a/arch/m68k/Kconfig.cpu
+++ b/arch/m68k/Kconfig.cpu
@@ -398,21 +398,23 @@ config SINGLE_MEMORY_CHUNK
 	  Say N if not sure.
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order" if ADVANCED
+	int "Order of maximal physically contiguous allocations" if ADVANCED
 	depends on !SINGLE_MEMORY_CHUNK
 	default "10"
 	help
-	  The kernel memory allocator divides physically contiguous memory
-	  blocks into "zones", where each zone is a power of two number of
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
 
 	  For systems that have holes in their physical address space this
 	  value also defines the minimal size of the hole that allows
 	  freeing unused memory map.
 
+	  Don't change if unsure.
+
 config 060_WRITETHROUGH
 	bool "Use write-through caching for 68060 supervisor accesses"
 	depends on ADVANCED && M68060
-- 
2.35.1

Re: [PATCH 06/14] m68k: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Geert Uytterhoeven]

On Thu, Mar 23, 2023 at 10:23 AM Mike Rapoport <rppt@kernel.org> wrote:
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
>
> The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
> describe this configuration option.
>
> Update both to actually describe what this option does.
>
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

[PATCH 07/14] nios2: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/nios2/Kconfig | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index 89708b95978c..fcaa6bbda3fc 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -45,16 +45,18 @@ menu "Kernel features"
 source "kernel/Kconfig.hz"
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
+	int "Order of maximal physically contiguous allocations"
 	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
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
+
+	  Don't change if unsure.
 
 endmenu
 
-- 
2.35.1

[PATCH 08/14] nios2: drop ranges for definition of ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

nios2 defines range for ARCH_FORCE_MAX_ORDER allowing MAX_ORDER
up to 19, which implies maximal contiguous allocation size of 2^19
pages or 2GiB.

Drop bogus definition of ranges for ARCH_FORCE_MAX_ORDER and leave it a
simple integer with sensible default.

Users that *really* need to change the value of ARCH_FORCE_MAX_ORDER
will be able to do so but they won't be mislead by the bogus ranges.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/nios2/Kconfig | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
index fcaa6bbda3fc..e5936417d3cd 100644
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -46,7 +46,6 @@ source "kernel/Kconfig.hz"
 
 config ARCH_FORCE_MAX_ORDER
 	int "Order of maximal physically contiguous allocations"
-	range 8 19
 	default "10"
 	help
 	  The kernel page allocator limits the size of maximal physically
-- 
2.35.1

[PATCH 09/14] powerpc: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/powerpc/Kconfig | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 24d56536b269..c0095bf795ca 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -896,7 +896,7 @@ config DATA_SHIFT
 	  8M pages will be pinned.
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
+	int "Order of maximal physically contiguous allocations"
 	range 7 8 if PPC64 && PPC_64K_PAGES
 	default "8" if PPC64 && PPC_64K_PAGES
 	range 12 12 if PPC64 && !PPC_64K_PAGES
@@ -910,17 +910,19 @@ config ARCH_FORCE_MAX_ORDER
 	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
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
 
 	  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.
 
+	  Don't change if unsure.
+
 config PPC_SUBPAGE_PROT
 	bool "Support setting protections for 4k subpages (subpage_prot syscall)"
 	default n
-- 
2.35.1

[PATCH 10/14] powerpc: drop ranges for definition of ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

PowerPC defines ranges for ARCH_FORCE_MAX_ORDER some of which are
insanely allowing MAX_ORDER up to 63, which implies maximal contiguous
allocation size of 2^63 pages.

Drop bogus definitions of ranges for ARCH_FORCE_MAX_ORDER and leave it a
simple integer with sensible defaults.

Users that *really* need to change the value of ARCH_FORCE_MAX_ORDER
will be able to do so but they won't be mislead by the bogus ranges.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/powerpc/Kconfig | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c0095bf795ca..419be4a71004 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -897,17 +897,11 @@ config DATA_SHIFT
 
 config ARCH_FORCE_MAX_ORDER
 	int "Order of maximal physically contiguous allocations"
-	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 page allocator limits the size of maximal physically
-- 
2.35.1

[PATCH 11/14] sh: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/sh/mm/Kconfig | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index 40271090bd7d..fb15ba1052ba 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -19,8 +19,7 @@ config PAGE_OFFSET
 	default "0x00000000"
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
-	range 8 63 if PAGE_SIZE_16KB
+	int "Order of maximal physically contiguous allocations"
 	default "8" if PAGE_SIZE_16KB
 	range 6 63 if PAGE_SIZE_64KB
 	default "6" if PAGE_SIZE_64KB
@@ -28,16 +27,18 @@ config ARCH_FORCE_MAX_ORDER
 	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
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
 
 	  The page size is not necessarily 4KB. Keep this in mind when
 	  choosing a value for this option.
 
+	  Don't change if unsure.
+
 config MEMORY_START
 	hex "Physical memory start address"
 	default "0x08000000"
-- 
2.35.1

[PATCH 12/14] sh: drop ranges for definition of ARCH_FORCE_MAX_ORDER

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

sh defines insane ranges for ARCH_FORCE_MAX_ORDER allowing MAX_ORDER
up to 63, which implies maximal contiguous allocation size of 2^63
pages.

Drop bogus definitions of ranges for ARCH_FORCE_MAX_ORDER and leave it a
simple integer with sensible defaults.

Users that *really* need to change the value of ARCH_FORCE_MAX_ORDER
will be able to do so but they won't be mislead by the bogus ranges.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/sh/mm/Kconfig | 2 --
 1 file changed, 2 deletions(-)

diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index fb15ba1052ba..511c17aede4a 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -21,9 +21,7 @@ config PAGE_OFFSET
 config ARCH_FORCE_MAX_ORDER
 	int "Order of maximal physically contiguous allocations"
 	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
-- 
2.35.1

[PATCH 13/14] sparc: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/sparc/Kconfig | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index e3242bf5a8df..959e43a1aaca 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -270,15 +270,17 @@ config ARCH_SPARSEMEM_DEFAULT
 	def_bool y if SPARC64
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
+	int "Order of maximal physically contiguous allocations"
 	default "12"
 	help
-	  The kernel memory allocator divides physically contiguous memory
-	  blocks into "zones", where each zone is a power of two number of
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
+
+	  Don't change if unsure.
 
 if SPARC64 || COMPILE_TEST
 source "kernel/power/Kconfig"
-- 
2.35.1

[PATCH 14/14] xtensa: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Mike Rapoport]

From: "Mike Rapoport (IBM)" <rppt@kernel.org>

The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
describe this configuration option.

Update both to actually describe what this option does.

Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
---
 arch/xtensa/Kconfig | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 3eee334ba873..3c6e5471f025 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -772,15 +772,17 @@ config HIGHMEM
 	  If unsure, say Y.
 
 config ARCH_FORCE_MAX_ORDER
-	int "Maximum zone order"
+	int "Order of maximal physically contiguous allocations"
 	default "10"
 	help
-	  The kernel memory allocator divides physically contiguous memory
-	  blocks into "zones", where each zone is a power of two number of
-	  pages.  This option selects the largest power of two that the kernel
-	  keeps in the memory allocator.  If you need to allocate very large
-	  blocks of physically contiguous memory, then you may need to
-	  increase this value.
+	  The kernel page allocator limits the size of maximal physically
+	  contiguous allocations. The limit is called MAX_ORDER and it
+	  defines the maximal power of two of number of pages that can be
+	  allocated as a single contiguous block. This option allows
+	  overriding the default setting when ability to allocate very
+	  large blocks of physically contiguous memory is required.
+
+	  Don't change if unsure.
 
 endmenu
 
-- 
2.35.1

Re: [PATCH 14/14] xtensa: reword ARCH_FORCE_MAX_ORDER prompt and help text

[Max Filippov]

On Thu, Mar 23, 2023 at 2:24 AM Mike Rapoport <rppt@kernel.org> wrote:
>
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
>
> The prompt and help text of ARCH_FORCE_MAX_ORDER are not even close to
> describe this configuration option.
>
> Update both to actually describe what this option does.
>
> Signed-off-by: Mike Rapoport (IBM) <rppt@kernel.org>
> ---
>  arch/xtensa/Kconfig | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)

Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>

-- 
Thanks.
-- Max

Re: [PATCH 00/14] arch,mm: cleanup Kconfig entries for ARCH_FORCE_MAX_ORDER

[Kirill A. Shutemov]

On Thu, Mar 23, 2023 at 11:21:42AM +0200, Mike Rapoport wrote:
> From: "Mike Rapoport (IBM)" <rppt@kernel.org>
> 
> Hi,
> 
> Several architectures have ARCH_FORCE_MAX_ORDER in their Kconfig and
> they all have wrong and misleading prompt and help text for this option.
> 
> Besides, some define insane limits for possible values of
> ARCH_FORCE_MAX_ORDER, some carefully define ranges only for a subset of
> possible configurations, some make this option configurable by users for no
> good reason.
> 
> This set updates the prompt and help text everywhere and does its best to
> update actual definitions of ranges where applicable.
> 
> Mike Rapoport (IBM) (14):
>   arm: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   arm64: drop ranges in definition of ARCH_FORCE_MAX_ORDER
>   arm64: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   csky: drop ARCH_FORCE_MAX_ORDER
>   ia64: don't allow users to override ARCH_FORCE_MAX_ORDER
>   m68k: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   nios2: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   nios2: drop ranges for definition of ARCH_FORCE_MAX_ORDER
>   powerpc: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   powerpc: drop ranges for definition of ARCH_FORCE_MAX_ORDER
>   sh: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   sh: drop ranges for definition of ARCH_FORCE_MAX_ORDER
>   sparc: reword ARCH_FORCE_MAX_ORDER prompt and help text
>   xtensa: reword ARCH_FORCE_MAX_ORDER prompt and help text
> 
>  arch/arm/Kconfig      | 16 +++++++++-------
>  arch/arm64/Kconfig    | 27 ++++++++++++---------------
>  arch/csky/Kconfig     |  4 ----
>  arch/ia64/Kconfig     |  3 +--
>  arch/m68k/Kconfig.cpu | 16 +++++++++-------
>  arch/nios2/Kconfig    | 17 +++++++++--------
>  arch/powerpc/Kconfig  | 22 +++++++++-------------
>  arch/sh/mm/Kconfig    | 19 +++++++++----------
>  arch/sparc/Kconfig    | 16 +++++++++-------
>  arch/xtensa/Kconfig   | 16 +++++++++-------
>  10 files changed, 76 insertions(+), 80 deletions(-)

Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

-- 
  Kiryl Shutsemau / Kirill A. Shutemov