linux-kernel - Re: [PATCH 00/10] make "order" unsigned int

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Date:   Fri, 26 Jul 2019 09:12:19 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     Pengfei Li <lpf.vector@...il.com>
Cc:     Qian Cai <cai@....pw>, Andrew Morton <akpm@...ux-foundation.org>,
        mgorman@...hsingularity.net, vbabka@...e.cz,
        aryabinin@...tuozzo.com, osalvador@...e.de, rostedt@...dmis.org,
        mingo@...hat.com, pavel.tatashin@...rosoft.com, rppt@...ux.ibm.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org
Subject: Re: [PATCH 00/10] make "order" unsigned int

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