Message-ID: <7f35b4a3-8a31-d74c-fcc0-ecc87071d9a5@redhat.com>
Date:   Fri, 17 Dec 2021 19:11:15 +0100
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Subject: Re: [PATCH v1 03/11] mm: simplify hugetlb and file-THP handling in
 __page_mapcount()
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To:     Mike Kravetz <mike.kravetz@oracle.com>,
        linux-kernel@vger.kernel.org
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Hugh Dickins <hughd@google.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        David Rientjes <rientjes@google.com>,
        Shakeel Butt <shakeelb@google.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Yang Shi <shy828301@gmail.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Vlastimil Babka <vbabka@suse.cz>, Jann Horn <jannh@google.com>,
        Michal Hocko <mhocko@kernel.org>,
        Nadav Amit <namit@vmware.com>, Rik van Riel <riel@surriel.com>,
        Roman Gushchin <guro@fb.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        Donald Dutile <ddutile@redhat.com>,
        Christoph Hellwig <hch@lst.de>,
        Oleg Nesterov <oleg@redhat.com>, Jan Kara <jack@suse.cz>,
        linux-mm@kvack.org, linux-kselftest@vger.kernel.org,
        linux-doc@vger.kernel.org
References: <20211217113049.23850-1-david@redhat.com>
 <20211217113049.23850-4-david@redhat.com>
 <0b0007b3-bf6f-ccd7-96cf-3dd861abf224@oracle.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <0b0007b3-bf6f-ccd7-96cf-3dd861abf224@oracle.com>
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On 17.12.21 19:06, Mike Kravetz wrote:
> On 12/17/21 03:30, David Hildenbrand wrote:
>> Let's return early for hugetlb, which really only relies on the compound
>> mapcount so far and does not support PageDoubleMap() yet. Use the chance
> 
> It is too early to say if hugetlb double mapping will use PageDoubleMap().
> I do not think (hope) it will be necessary.  So, I think you can drop mention
> of it here.

Desires have most certainly been expressed from a couple of parties --
to PTE map huge pages :) Hopefully we'll find a way to avoid
PageDoubleMap, I agree.

Dropping the comment!

> 
>> to cleanup the file-THP case to make it easier to grasp. While at it, use
>> head_compound_mapcount().
>>
>> This is a preparation for further changes.
>>
>> Reviewed-by: Peter Xu <peterx@redhat.com>
>> Signed-off-by: David Hildenbrand <david@redhat.com>
> 
> Acked-by: Mike Kravetz <mike.kravetz@oracle.com>
> 

Thanks!

-- 
Thanks,

David / dhildenb