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Date:   Thu, 5 Jan 2023 14:22:50 -0500
From:   Peter Xu <peterx@redhat.com>
To:     David Hildenbrand <david@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>
Subject: Re: [PATCH 2/3] mm/mprotect: Use long for page accountings and retval
Message-ID: <Y7cjir3+MpT8XqJT@x1n>
References: <20230104225207.1066932-1-peterx@redhat.com>
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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,

-- 
Peter Xu