From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Nadav Amit <nadav.amit@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Peter Xu <peterx@redhat.com>, Nadav Amit <namit@vmware.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Minchan Kim <minchan@kernel.org>, Colin Cross <ccross@google.com>,
Suren Baghdasarya <surenb@google.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>
Subject: Re: [RFC PATCH 3/8] mm/madvise: remove unnecessary checks on madvise_free_single_vma()
Date: Mon, 27 Sep 2021 12:17:09 +0300 [thread overview]
Message-ID: <20210927091709.ksv2fjudjpqhnu3n@box.shutemov.name> (raw)
In-Reply-To: <20210926161259.238054-4-namit@vmware.com>
On Sun, Sep 26, 2021 at 09:12:54AM -0700, Nadav Amit wrote:
> From: Nadav Amit <namit@vmware.com>
>
> madvise_free_single_vma() currently rechecks that the range fits within
> the VMA, adapts it accordingly, and returns -EINVAL if the range is
> entirely outside of the VMA.
>
> The error-code of -EINVAL is incorrect according to the man pages (as it
> should have been -ENOMEM), but anyhow the range that is provided to
> madvise_free_single_vma() should always be valid. It is set correctly in
> do_madvise() and then rechecked in madvise_dontneed_free() is the
> mmap-lock is dropped.
>
> Remove this check.
>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Colin Cross <ccross@google.com>
> Cc: Suren Baghdasarya <surenb@google.com>
> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Signed-off-by: Nadav Amit <namit@vmware.com>
> ---
> mm/madvise.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/mm/madvise.c b/mm/madvise.c
> index fe843513a4e8..17e39c70704b 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -716,14 +716,8 @@ static int madvise_free_single_vma(struct vm_area_struct *vma,
> if (!vma_is_anonymous(vma))
> return -EINVAL;
>
> - range.start = max(vma->vm_start, start_addr);
> - if (range.start >= vma->vm_end)
> - return -EINVAL;
> - range.end = min(vma->vm_end, end_addr);
> - if (range.end <= vma->vm_start)
> - return -EINVAL;
How did you test this change?
As far as I can see, you leave 'range' uninitialized, but used for
walk_page_range() and mmu_notifiers.
NAK.
> mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm,
> - range.start, range.end);
> + start_addr, end_addr);
>
> lru_add_drain();
> tlb_gather_mmu(&tlb, mm);
> --
> 2.25.1
>
>
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-09-27 9:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-26 16:12 [RFC PATCH 0/8] mm/madvise: support process_madvise(MADV_DONTNEED) Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 1/8] mm/madvise: propagate vma->vm_end changes Nadav Amit
2021-09-27 9:08 ` Kirill A. Shutemov
2021-09-27 10:11 ` Nadav Amit
2021-09-27 11:55 ` Kirill A. Shutemov
2021-09-27 12:33 ` Nadav Amit
2021-09-27 12:45 ` Kirill A. Shutemov
2021-09-27 12:59 ` Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 2/8] mm/madvise: remove unnecessary check on madvise_dontneed_free() Nadav Amit
2021-09-27 9:11 ` Kirill A. Shutemov
2021-09-27 11:05 ` Nadav Amit
2021-09-27 12:19 ` Kirill A. Shutemov
2021-09-27 12:52 ` Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 3/8] mm/madvise: remove unnecessary checks on madvise_free_single_vma() Nadav Amit
2021-09-27 9:17 ` Kirill A. Shutemov [this message]
2021-09-27 9:24 ` Kirill A. Shutemov
2021-09-26 16:12 ` [RFC PATCH 4/8] mm/madvise: define madvise behavior in a struct Nadav Amit
2021-09-27 9:31 ` Kirill A. Shutemov
2021-09-27 10:31 ` Nadav Amit
2021-09-27 12:14 ` Kirill A. Shutemov
2021-09-27 20:36 ` Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 5/8] mm/madvise: perform certain operations once on process_madvise() Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 6/8] mm/madvise: more aggressive TLB batching Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 7/8] mm/madvise: deduplicate code in madvise_dontneed_free() Nadav Amit
2021-09-26 16:12 ` [RFC PATCH 8/8] mm/madvise: process_madvise(MADV_DONTNEED) Nadav Amit
2021-09-27 9:24 ` [RFC PATCH 0/8] mm/madvise: support process_madvise(MADV_DONTNEED) David Hildenbrand
2021-09-27 10:41 ` Nadav Amit
2021-09-27 10:58 ` David Hildenbrand
2021-09-27 12:00 ` Nadav Amit
2021-09-27 12:16 ` Michal Hocko
2021-09-27 19:12 ` Nadav Amit
2021-09-29 7:52 ` Michal Hocko
2021-09-29 18:31 ` Nadav Amit
2021-10-12 23:14 ` Peter Xu
2021-10-13 15:47 ` Nadav Amit
2021-10-13 23:09 ` Peter Xu
2021-09-27 17:05 ` David Hildenbrand
2021-09-27 19:59 ` Nadav Amit
2021-09-28 8:53 ` David Hildenbrand
2021-09-28 22:56 ` Nadav Amit
2021-10-04 17:58 ` David Hildenbrand
2021-10-07 16:19 ` Nadav Amit
2021-10-07 16:46 ` David Hildenbrand
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