On Mon, 28 Feb 2022 14:35:34 +0800 Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
> The devmap pages can not use page_vma_mapped_walk() to check if a huge
> devmap page is mapped into a vma. Add support for walking huge devmap
> pages so that DAX can use it in the next patch.
>
x86_64 allnoconfig:
In file included from <command-line>:
In function 'check_pmd',
inlined from 'page_vma_mapped_walk' at mm/page_vma_mapped.c:219:10:
././include/linux/compiler_types.h:347:45: error: call to '__compiletime_assert_232' declared with attribute error: BUILD_BUG failed
347 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^
././include/linux/compiler_types.h:328:25: note: in definition of macro '__compiletime_assert'
328 | prefix ## suffix(); \
| ^~~~~~
././include/linux/compiler_types.h:347:9: note: in expansion of macro '_compiletime_assert'
347 | _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
| ^~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:39:37: note: in expansion of macro 'compiletime_assert'
39 | #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'
59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
| ^~~~~~~~~~~~~~~~
./include/linux/huge_mm.h:307:28: note: in expansion of macro 'BUILD_BUG'
307 | #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
| ^~~~~~~~~
./include/linux/huge_mm.h:104:26: note: in expansion of macro 'HPAGE_PMD_SHIFT'
104 | #define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
| ^~~~~~~~~~~~~~~
./include/linux/huge_mm.h:105:26: note: in expansion of macro 'HPAGE_PMD_ORDER'
105 | #define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
| ^~~~~~~~~~~~~~~
mm/page_vma_mapped.c:113:20: note: in expansion of macro 'HPAGE_PMD_NR'
113 | if ((pfn + HPAGE_PMD_NR - 1) < pvmw->pfn)
| ^~~~~~~~~~~~
make[1]: *** [scripts/Makefile.build:288: mm/page_vma_mapped.o] Error 1
make: *** [Makefile:1971: mm] Error 2
because check_pmd() uses HPAGE_PMD_NR and
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
I don't immediately see why this patch triggers it...
