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Date:   Fri, 26 Jul 2019 09:12:19 +0200
From:   Michal Hocko <mhocko@kernel.org>
To:     Pengfei Li <lpf.vector@gmail.com>
Cc:     Qian Cai <cai@lca.pw>, Andrew Morton <akpm@linux-foundation.org>,
        mgorman@techsingularity.net, vbabka@suse.cz,
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        mingo@redhat.com, pavel.tatashin@microsoft.com, rppt@linux.ibm.com,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 00/10] make "order" unsigned int
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On Fri 26-07-19 07:48:36, Pengfei Li wrote:
[...]
> For the benefit, "order" may be negative, which is confusing and weird.

order = -1 has a special meaning.

> There is no good reason not to do this since it can be avoided.

"This is good because we can do it" doesn't really sound like a
convincing argument to me. I would understand if this reduced a
generated code, made an overall code readability much better or
something along those lines. Also we only use MAX_ORDER range of values
so I could argue that a smaller data type (e.g. short) should be
sufficient for this data type.

Please note that _any_ change, alebit seemingly small, can introduce a
subtle bug. Also each patch requires a man power to review so you have
to understand that "just because we can" is not a strong motivation for
people to spend their time on such a patch.
-- 
Michal Hocko
SUSE Labs