Re: [mm-unstable v7 01/18] mm/khugepaged: remove redundant transhuge_vma_suitable() check

From: Yang Shi <shy828301@gmail.com>
To: "Zach O'Keefe" <zokeefe@google.com>
Cc: Alex Shi <alex.shi@linux.alibaba.com>,
	David Hildenbrand <david@redhat.com>,
	 David Rientjes <rientjes@google.com>,
	Matthew Wilcox <willy@infradead.org>,
	 Michal Hocko <mhocko@suse.com>,
	Pasha Tatashin <pasha.tatashin@soleen.com>,
	 Peter Xu <peterx@redhat.com>,
	Rongwei Wang <rongwei.wang@linux.alibaba.com>,
	 SeongJae Park <sj@kernel.org>, Song Liu <songliubraving@fb.com>,
	Vlastimil Babka <vbabka@suse.cz>,  Zi Yan <ziy@nvidia.com>,
	Linux MM <linux-mm@kvack.org>,
	 Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	 Arnd Bergmann <arnd@arndb.de>,
	Axel Rasmussen <axelrasmussen@google.com>,
	 Chris Kennelly <ckennelly@google.com>,
	Chris Zankel <chris@zankel.net>, Helge Deller <deller@gmx.de>,
	 Hugh Dickins <hughd@google.com>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	 "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
	Jens Axboe <axboe@kernel.dk>,
	 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Matt Turner <mattst88@gmail.com>,
	 Max Filippov <jcmvbkbc@gmail.com>,
	Miaohe Lin <linmiaohe@huawei.com>,
	 Minchan Kim <minchan@kernel.org>,
	Patrick Xia <patrickx@google.com>,
	 Pavel Begunkov <asml.silence@gmail.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Subject: Re: [mm-unstable v7 01/18] mm/khugepaged: remove redundant transhuge_vma_suitable() check
Date: Mon, 11 Jul 2022 13:38:25 -0700	[thread overview]
Message-ID: <CAHbLzko7H9cgTL7VF+oNBnBSSfdLUyyk7+ABrpaGJpA0TjKmsQ@mail.gmail.com> (raw)
In-Reply-To: <20220706235936.2197195-2-zokeefe@google.com>

On Wed, Jul 6, 2022 at 5:06 PM Zach O'Keefe <zokeefe@google.com> wrote:
>
> transhuge_vma_suitable() is called twice in hugepage_vma_revalidate()
> path.  Remove the first check, and rely on the second check inside
> hugepage_vma_check().
>
> Signed-off-by: Zach O'Keefe <zokeefe@google.com>
> ---
>  mm/khugepaged.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/mm/khugepaged.c b/mm/khugepaged.c
> index cfe231c5958f..5269d15e20f6 100644
> --- a/mm/khugepaged.c
> +++ b/mm/khugepaged.c
> @@ -918,8 +918,6 @@ static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
>         if (!vma)
>                 return SCAN_VMA_NULL;
>
> -       if (!transhuge_vma_suitable(vma, address))
> -               return SCAN_ADDRESS_RANGE;

It seems this is the only user of SCAN_ADDRESS_RANGE, so
SCAN_ADDRESS_RANGE could be deleted as well.

>         if (!hugepage_vma_check(vma, vma->vm_flags, false, false))
>                 return SCAN_VMA_CHECK;
>         /*
> --
> 2.37.0.rc0.161.g10f37bed90-goog
>