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Message-ID: <cfb2e9de-3bf8-6380-f336-dc3d7a5ecc29@redhat.com>
Date:   Mon, 14 Nov 2022 10:06:18 +0100
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Subject: Re: [PATCH v9 2/3] hugetlb: remove duplicate mmu notifications
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To:     Mike Kravetz <mike.kravetz@oracle.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Cc:     Naoya Horiguchi <naoya.horiguchi@linux.dev>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Mina Almasry <almasrymina@google.com>,
        Peter Xu <peterx@redhat.com>,
        Nadav Amit <nadav.amit@gmail.com>,
        Rik van Riel <riel@surriel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Matthew Wilcox <willy@infradead.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Wei Chen <harperchen1110@gmail.com>, stable@vger.kernel.org
References: <20221111232628.290160-1-mike.kravetz@oracle.com>
 <20221111232628.290160-3-mike.kravetz@oracle.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20221111232628.290160-3-mike.kravetz@oracle.com>
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On 12.11.22 00:26, Mike Kravetz wrote:
> The common hugetlb unmap routine __unmap_hugepage_range performs mmu
> notification calls.  However, in the case where __unmap_hugepage_range
> is called via __unmap_hugepage_range_final, mmu notification calls are
> performed earlier in other calling routines.
> 
> Remove mmu notification calls from __unmap_hugepage_range.  Add
> notification calls to the only other caller: unmap_hugepage_range.
> unmap_hugepage_range is called for truncation and hole punch, so
> change notification type from UNMAP to CLEAR as this is more appropriate.
> 
> Fixes: 90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings")
> Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
> Reported-by: Wei Chen <harperchen1110@gmail.com>
> Cc: <stable@vger.kernel.org>

Why exactly do we care about stable backports here? What's the 
user-visible impact?

-- 
Thanks,

David / dhildenb