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From: Barry Song <21cnbao@gmail.com>
Date: Tue, 23 Apr 2024 09:13:25 +0800
Message-ID: <CAGsJ_4zyVt13F=zwQNDuWZMKVtgh9U7pPAqgrRpM3nTn17or4g@mail.gmail.com>
Subject: Re: [RFC PATCH 3/5] mm: shmem: add THP validation for PMD-mapped THP
 related statistics
To: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: akpm@linux-foundation.org, hughd@google.com, willy@infradead.org, 
	david@redhat.com, wangkefeng.wang@huawei.com, ryan.roberts@arm.com, 
	ying.huang@intel.com, shy828301@gmail.com, ziy@nvidia.com, linux-mm@kvack.org, 
	linux-kernel@vger.kernel.org
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On Mon, Apr 22, 2024 at 3:03=E2=80=AFPM Baolin Wang
<baolin.wang@linux.alibaba.com> wrote:
>
> In order to extend support for mTHP, add THP validation for PMD-mapped TH=
P
> related statistics to avoid statistical confusion.
>
> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> ---

Reviewed-by: Barry  Song <v-songbaohua@oppo.com>

>  mm/shmem.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/mm/shmem.c b/mm/shmem.c
> index 893c88efc45f..b4afda71a3f0 100644
> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -1662,7 +1662,7 @@ static struct folio *shmem_alloc_and_add_folio(gfp_=
t gfp,
>                         return ERR_PTR(-E2BIG);
>
>                 folio =3D shmem_alloc_hugefolio(gfp, info, index, order);
> -               if (!folio)
> +               if (!folio && pages =3D=3D HPAGE_PMD_NR)
>                         count_vm_event(THP_FILE_FALLBACK);
>         } else {
>                 pages =3D 1;
> @@ -1680,7 +1680,7 @@ static struct folio *shmem_alloc_and_add_folio(gfp_=
t gfp,
>                 if (xa_find(&mapping->i_pages, &index,
>                                 index + pages - 1, XA_PRESENT)) {
>                         error =3D -EEXIST;
> -               } else if (huge) {
> +               } else if (pages =3D=3D HPAGE_PMD_NR) {
>                         count_vm_event(THP_FILE_FALLBACK);
>                         count_vm_event(THP_FILE_FALLBACK_CHARGE);
>                 }
> @@ -2046,7 +2046,8 @@ static int shmem_get_folio_gfp(struct inode *inode,=
 pgoff_t index,
>                 folio =3D shmem_alloc_and_add_folio(huge_gfp,
>                                 inode, index, fault_mm, true);
>                 if (!IS_ERR(folio)) {
> -                       count_vm_event(THP_FILE_ALLOC);
> +                       if (folio_test_pmd_mappable(folio))
> +                               count_vm_event(THP_FILE_ALLOC);
>                         goto alloced;
>                 }
>                 if (PTR_ERR(folio) =3D=3D -EEXIST)
> --
> 2.39.3
>