Re: [PATCH] proc: move the adding option Ngid to the end of proc/PID/status

From: Tejun Heo <tj@kernel.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: xiaoming.wang@intel.com,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@suse.de>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] proc: move the adding option Ngid to the end of proc/PID/status
Date: Fri, 17 Apr 2015 11:12:59 -0400	[thread overview]
Message-ID: <20150417151259.GA16743@htj.duckdns.org> (raw)
In-Reply-To: <CACVxJT_bpNFUFTL9oZJiK2LEXL8wrjY3Q__tXd3jyZB=1-k9ig@mail.gmail.com>

On Fri, Apr 17, 2015 at 06:05:55PM +0300, Alexey Dobriyan wrote:
> Moving Ngid to the end of file minimizes risk of breakage.

Hmmm... how so?  The only reason for changing the position is because
there's this specific breakage.  The goal should be working around
that specific case while keeping the impact minimum on everyone else.
It doesn't matter whether the initial change was good or bad, the
kernel w/ the new layout is already out in the wild and it has been
out there for a while.  How is risking changing offsets on most of the
fields on those kernels a good idea?  Mimize the changes to work
around the specific case.

> Correctly written code doesn't care.
> Code which hardcodes layout won't notice.

Huh?  Code which hardcodes layout since 1.5 years ago will definitely
notice.

> It would be OK argument if gentlemen from Intel send "let's futureproof and
> move Ngid because someone might depend on exact position" patch.
> 
> Primum non nocere.

ajlkjaeligjlakd lakjeilgjal flekjfa.

-- 
tejun