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 <20240506105447.1171-1-ioworker0@gmail.com> <eaddd00d-8160-4800-b60f-25280dfe339b@linux.alibaba.com>
In-Reply-To: <eaddd00d-8160-4800-b60f-25280dfe339b@linux.alibaba.com>
From: Lance Yang <ioworker0@gmail.com>
Date: Tue, 7 May 2024 14:50:33 +0800
Message-ID: <CAK1f24nB8D+zgphX3XXLWRq0_xwT+7EfV8dfxNmkHh_CCQrA-A@mail.gmail.com>
Subject: Re: [PATCH 0/8] add mTHP support for anonymous shmem
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: 21cnbao@gmail.com, akpm@linux-foundation.org, david@redhat.com, 
	hughd@google.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, 
	ryan.roberts@arm.com, shy828301@gmail.com, wangkefeng.wang@huawei.com, 
	willy@infradead.org, ying.huang@intel.com, ziy@nvidia.com
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On Tue, May 7, 2024 at 9:47=E2=80=AFAM Baolin Wang
<baolin.wang@linux.alibaba.com> wrote:
>
> Hi Lance,
>
> On 2024/5/6 18:54, Lance Yang wrote:
> > 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 =E2=80=98shmem_get_unmapped_area=E2=80=99:
> > ././include/linux/compiler_types.h:460:45: error: call to =E2=80=98__co=
mpiletime_assert_481=E2=80=99 declared with attribute error: BUILD_BUG fail=
ed
> >          _compiletime_assert(condition, msg, __compiletime_assert_, __C=
OUNTER__)
> >                                              ^
> > ././include/linux/compiler_types.h:441:25: note: in definition of macro=
 =E2=80=98__compiletime_assert=E2=80=99
> >                           prefix ## suffix();                          =
   \
> >                           ^~~~~~
> > ././include/linux/compiler_types.h:460:9: note: in expansion of macro =
=E2=80=98_compiletime_assert=E2=80=99
> >          _compiletime_assert(condition, msg, __compiletime_assert_, __C=
OUNTER__)
> >          ^~~~~~~~~~~~~~~~~~~
> > ./include/linux/build_bug.h:39:37: note: in expansion of macro =E2=80=
=98compiletime_assert=E2=80=99
> >   #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
> >                                       ^~~~~~~~~~~~~~~~~~
> > ./include/linux/build_bug.h:59:21: note: in expansion of macro =E2=80=
=98BUILD_BUG_ON_MSG=E2=80=99
> >   #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
> >                       ^~~~~~~~~~~~~~~~
> > ./include/linux/huge_mm.h:97:28: note: in expansion of macro =E2=80=98B=
UILD_BUG=E2=80=99
> >   #define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
> >                              ^~~~~~~~~
> > ./include/linux/huge_mm.h:104:35: note: in expansion of macro =E2=80=98=
HPAGE_PMD_SHIFT=E2=80=99
> >   #define HPAGE_PMD_SIZE  ((1UL) << HPAGE_PMD_SHIFT)
> >                                     ^~~~~~~~~~~~~~~
> > mm/shmem.c:2419:36: note: in expansion of macro =E2=80=98HPAGE_PMD_SIZE=
=E2=80=99
> >          unsigned long hpage_size =3D HPAGE_PMD_SIZE;
> >                                     ^~~~~~~~~~~~~~~
> >
> > It seems like we need to handle the case where CONFIG_PGTABLE_HAS_HUGE_=
LEAVES
> > is undefined.
> >
> > [1] export ARCH=3Darm64 && make allnoconfig && make olddefconfig && mak=
e -j$(nproc)
>
> Thanks for reporting. I can move the use of HPAGE_PMD_SIZE to after the
> check for CONFIG_TRANSPARENT_HUGEPAGE, which can avoid the building error=
:

I confirmed that the issue I reported before has disappeared after applying
this change. For the fix,

Tested-by: Lance Yang <ioworker0@gmail.com>

Thanks,
Lance

>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 1af2f0aa384d..d603e36e0f4f 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -2416,7 +2416,7 @@ unsigned long shmem_get_unmapped_area(struct file
> *file,
>          unsigned long inflated_len;
>          unsigned long inflated_addr;
>          unsigned long inflated_offset;
> -       unsigned long hpage_size =3D HPAGE_PMD_SIZE;
> +       unsigned long hpage_size;
>
>          if (len > TASK_SIZE)
>                  return -ENOMEM;
> @@ -2446,6 +2446,7 @@ unsigned long shmem_get_unmapped_area(struct file
> *file,
>          if (uaddr =3D=3D addr)
>                  return addr;
>
> +       hpage_size =3D HPAGE_PMD_SIZE;
>          if (shmem_huge !=3D SHMEM_HUGE_FORCE) {
>                  struct super_block *sb;
>                  unsigned long __maybe_unused hpage_orders;