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Message-ID: <d77ecdac-3712-8d4b-57d5-f8c9e4569e6f@redhat.com>
Date:   Mon, 9 Jan 2023 09:04:44 +0100
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Subject: Re: [PATCH 2/3] mm/mprotect: Use long for page accountings and retval
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To:     Peter Xu <peterx@redhat.com>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Mike Kravetz <mike.kravetz@oracle.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Nadav Amit <nadav.amit@gmail.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        James Houghton <jthoughton@google.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Andrew Morton <akpm@linux-foundation.org>
References: <20230104225207.1066932-1-peterx@redhat.com>
 <20230104225207.1066932-3-peterx@redhat.com>
 <aabd4bb8-560b-10b0-9837-b656e1a0a9e1@redhat.com> <Y7cjir3+MpT8XqJT@x1n>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <Y7cjir3+MpT8XqJT@x1n>
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On 05.01.23 20:22, Peter Xu wrote:
> On Thu, Jan 05, 2023 at 09:44:16AM +0100, David Hildenbrand wrote:
>> I'm wondering if we should just return the number of changed pages via a
>> separate pointer and later using an int for returning errors -- when
>> touching this interface already.
>>
>> Only who's actually interested in the number of pages would pass a pointer
>> to an unsigned long (NUMA).
>>
>> And code that expects that there never ever are failures (mprotect, NUMA)
>> could simply check for WARN_ON_ONCE(ret).
>>
>> I assume you evaluated that option as well, what was your conclusion?
> 
> Since a single long can cover both things as retval, it's better to keep it
> simple?  Thanks,
> 

Fine with me.

-- 
Thanks,

David / dhildenb