Re: [PATCH 1/4] hugetlb: skip to end of PT page mapping when pte not present

On 06/17/22 19:26, kernel test robot wrote:

Hi Mike,

I love your patch! Yet something to improve:

[auto build test ERROR on soc/for-next]
[also build test ERROR on linus/master v5.19-rc2 next-20220617]
[cannot apply to arm64/for-next/core arm/for-next kvmarm/next xilinx-xlnx/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]

url:    https://github.com/intel-lab-lkp/linux/commits/Mike-Kravetz/hugetlb-speed-up-linear-address-scanning/20220617-050726
base:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git for-next
config: i386-randconfig-a002 (https://download.01.org/0day-ci/archive/20220617/202206171929.ZIUrNg6p-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project f0e608de27b3d568000046eebf3712ab542979d6)
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/4c647687607f10fece04967b8180c0dadaf765e6
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Mike-Kravetz/hugetlb-speed-up-linear-address-scanning/20220617-050726
        git checkout 4c647687607f10fece04967b8180c0dadaf765e6
        # 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=i386 SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <redacted>

All errors (new ones prefixed by >>):

A couple of things here,

quoted

quoted

mm/hugetlb.c:6901:7: error: duplicate case value '4194304'

           case PUD_SIZE:
                ^
   include/asm-generic/pgtable-nopud.h:20:20: note: expanded from macro 'PUD_SIZE'
   #define PUD_SIZE        (1UL << PUD_SHIFT)
                           ^
   mm/hugetlb.c:6899:7: note: previous case defined here
           case P4D_SIZE:
                ^
   include/asm-generic/pgtable-nop4d.h:13:19: note: expanded from macro 'P4D_SIZE'
   #define P4D_SIZE                (1UL << P4D_SHIFT)

In the CONFIG_ARCH_WANT_GENERAL_HUGETLB case covered by this version of
hugetlb_mask_last_page, huge pages can only be PMD_SIZE or PUD_SIZE.
So, the 'case P4D_SIZE:' should not exist and can be removed.

                                   ^
   mm/hugetlb.c:6903:7: error: duplicate case value '4194304'
           case PMD_SIZE:
                ^
   include/asm-generic/pgtable-nopmd.h:22:20: note: expanded from macro 'PMD_SIZE'
   #define PMD_SIZE        (1UL << PMD_SHIFT)
                           ^

On i386 with CONFIG_PGTABLE_LEVELS=2, PUD_SIZE == PMD_SIZE.
Originally, I coded this as a if .. else if ... statement instead of a
switch.  If coded this way, the compiler does not complain about the
duplicate values.  The only other alternative I can think of is
something like '#if CONFIG_PGTABLE_LEVELS > 2' around the PUD_SIZE case.

I would prefer the if else if, unless someone can suggest something else?
-- 
Mike Kravetz

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