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From: Lance Yang <ioworker0@gmail.com>
To: baolin.wang@linux.alibaba.com
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Subject: Re: [PATCH 0/8] add mTHP support for anonymous shmem
Date: Mon,  6 May 2024 18:54:47 +0800
Message-Id: <20240506105447.1171-1-ioworker0@gmail.com>
In-Reply-To: <cover.1714978902.git.baolin.wang@linux.alibaba.com>
References: <cover.1714978902.git.baolin.wang@linux.alibaba.com>
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Hey Baolin,

I found a compilation issue that failed one[1] of my configurations
after applying this series. The error message is as follows:

mm/shmem.c: In function ‘shmem_get_unmapped_area’:
/./include/linux/compiler_types.h:460:45: error: call to ‘__compiletime_assert_481’ declared with attribute error: BUILD_BUG failed
        _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
                                            ^
/./include/linux/compiler_types.h:441:25: note: in definition of macro ‘__compiletime_assert’
                         prefix ## suffix();                             \
                         ^~~~~~
/./include/linux/compiler_types.h:460:9: note: in expansion of macro ‘_compiletime_assert’
        _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
        ^~~~~~~~~~~~~~~~~~~
/include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
 #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
                                     ^~~~~~~~~~~~~~~~~~
/include/linux/build_bug.h:59:21: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
 #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
                     ^~~~~~~~~~~~~~~~
/include/linux/huge_mm.h:97:28: note: in expansion of macro ‘BUILD_BUG’
 #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
                            ^~~~~~~~~
/include/linux/huge_mm.h:104:35: note: in expansion of macro ‘HPAGE_PMD_SHIFT’
 #define HPAGE_PMD_SIZE  ((1UL) << HPAGE_PMD_SHIFT)
                                   ^~~~~~~~~~~~~~~
mm/shmem.c:2419:36: note: in expansion of macro ‘HPAGE_PMD_SIZE’
        unsigned long hpage_size = HPAGE_PMD_SIZE;
                                   ^~~~~~~~~~~~~~~

It seems like we need to handle the case where CONFIG_PGTABLE_HAS_HUGE_LEAVES
is undefined.

[1] export ARCH=arm64 && make allnoconfig && make olddefconfig && make -j$(nproc)

Thanks,
Lance