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References: <20240417211836.2742593-1-peterx@redhat.com> <20240417211836.2742593-4-peterx@redhat.com>
In-Reply-To: <20240417211836.2742593-4-peterx@redhat.com>
From: Mina Almasry <almasrymina@google.com>
Date: Fri, 19 Apr 2024 08:03:08 -0700
Message-ID: <CAHS8izPMjBMNUStsUjobbo4rUXirFtkOZVvJTFFqD4SUafQZaQ@mail.gmail.com>
Subject: Re: [PATCH 3/3] mm/hugetlb: Assert hugetlb_lock in __hugetlb_cgroup_commit_charge
To: Peter Xu <peterx@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, 
	David Hildenbrand <david@redhat.com>, Andrew Morton <akpm@linux-foundation.org>, 
	Muchun Song <muchun.song@linux.dev>, David Rientjes <rientjes@google.com>
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On Wed, Apr 17, 2024 at 2:18=E2=80=AFPM Peter Xu <peterx@redhat.com> wrote:
>
> This is similar to __hugetlb_cgroup_uncharge_folio() where it relies on
> holding hugetlb_lock.  Add the similar assertion like the other one, sinc=
e
> it looks like such things may help some day.
>
> Signed-off-by: Peter Xu <peterx@redhat.com>

Reviewed-by: Mina Almasry <almasrymina@google.com>

> ---
>  mm/hugetlb_cgroup.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/mm/hugetlb_cgroup.c b/mm/hugetlb_cgroup.c
> index aa4486bd3904..e20339a346b9 100644
> --- a/mm/hugetlb_cgroup.c
> +++ b/mm/hugetlb_cgroup.c
> @@ -308,7 +308,7 @@ static void __hugetlb_cgroup_commit_charge(int idx, u=
nsigned long nr_pages,
>  {
>         if (hugetlb_cgroup_disabled() || !h_cg)
>                 return;
> -
> +       lockdep_assert_held(&hugetlb_lock);

Maybe also remove the comment on the top of the function:

/* Should be called with hugetlb_lock held */

Now that the function asserts, the comment seems redundant, but up to you.

>         __set_hugetlb_cgroup(folio, h_cg, rsvd);
>         if (!rsvd) {
>                 unsigned long usage =3D
> --
> 2.44.0
>


--=20
Thanks,
Mina