Re: [PATCH v2 07/12] mm: thp: check pmd migration entry in common path

[Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>]

On Tue, Nov 08, 2016 at 08:23:50AM +0800, kbuild test robot wrote:
> Hi Naoya,
> 
> [auto build test ERROR on mmotm/master]
> [also build test ERROR on v4.9-rc4 next-20161028]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Naoya-Horiguchi/mm-x86-move-_PAGE_SWP_SOFT_DIRTY-from-bit-7-to-bit-6/20161108-080615
> base:   git://git.cmpxchg.org/linux-mmotm.git master
> config: i386-randconfig-x007-201645 (attached as .config)
> compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=i386 
> 
> All error/warnings (new ones prefixed by >>):
> 
>    mm/memory.c: In function 'copy_pmd_range':
> >> mm/memory.c:1002:7: error: implicit declaration of function 'pmd_related' [-Werror=implicit-function-declaration]
>       if (pmd_related(*src_pmd)) {
>           ^~~~~~~~~~~
>    cc1: some warnings being treated as errors
> --

I forgot to declare a noop routine for CONFIG_TRANSPARENT_HUGEPAGE=n.

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -222,6 +229,10 @@ static inline void vma_adjust_trans_huge(struct vm_area_struct *vma,
 					 long adjust_next)
 {
 }
+static inline int pmd_related(pmd_t pmd)
+{
+	return 0;
+}
 static inline spinlock_t *pmd_trans_huge_lock(pmd_t *pmd,
 		struct vm_area_struct *vma)
 {


>    mm/mremap.c: In function 'move_page_tables':
> >> mm/mremap.c:197:7: error: implicit declaration of function 'pmd_related' [-Werror=implicit-function-declaration]
>       if (pmd_related(*old_pmd)) {
>           ^~~~~~~~~~~
>    In file included from include/asm-generic/bug.h:4:0,
>                     from arch/x86/include/asm/bug.h:35,
>                     from include/linux/bug.h:4,
>                     from include/linux/mmdebug.h:4,
>                     from include/linux/mm.h:8,
>                     from mm/mremap.c:10:
> >> include/linux/compiler.h:518:38: error: call to '__compiletime_assert_198' declared with attribute error: BUILD_BUG failed
>      _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
>                                          ^
>    include/linux/compiler.h:501:4: note: in definition of macro '__compiletime_assert'
>        prefix ## suffix();    \
>        ^~~~~~
>    include/linux/compiler.h:518:2: note: in expansion of macro '_compiletime_assert'
>      _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__)
>      ^~~~~~~~~~~~~~~~~~~
>    include/linux/bug.h:54:37: note: in expansion of macro 'compiletime_assert'
>     #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
>                                         ^~~~~~~~~~~~~~~~~~
>    include/linux/bug.h:88:21: 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:183:27: note: in expansion of macro 'BUILD_BUG'
>     #define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
>                               ^~~~~~~~~
> >> mm/mremap.c:198:18: note: in expansion of macro 'HPAGE_PMD_SIZE'
>        if (extent == HPAGE_PMD_SIZE) {
>                      ^~~~~~~~~~~~~~
>    cc1: some warnings being treated as errors

HPAGE_PMD_SIZE is available only in CONFIG_TRANSPARENT_HUGEPAGE=y, and
this code looks to violate the rule, but it is in if (pmd_related()) block
which is compiled out in CONFIG_TRANSPARENT_HUGEPAGE=n, so this is OK
only with the above change.

Thanks,
Naoya Horiguchi

> --
>    mm/madvise.c: In function 'madvise_free_pte_range':
> >> mm/madvise.c:277:6: error: implicit declaration of function 'pmd_related' [-Werror=implicit-function-declaration]
>      if (pmd_related(*pmd))
>          ^~~~~~~~~~~
>    cc1: some warnings being treated as errors
> 
> vim +/pmd_related +1002 mm/memory.c
> 
>    996		dst_pmd = pmd_alloc(dst_mm, dst_pud, addr);
>    997		if (!dst_pmd)
>    998			return -ENOMEM;
>    999		src_pmd = pmd_offset(src_pud, addr);
>   1000		do {
>   1001			next = pmd_addr_end(addr, end);
> > 1002			if (pmd_related(*src_pmd)) {
>   1003				int err;
>   1004				VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
>   1005				err = copy_huge_pmd(dst_mm, src_mm,
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation