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Date:   Fri, 15 May 2020 09:03:54 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Xiaoming Ni <nixiaoming@huawei.com>
Cc:     mcgrof@kernel.org, yzaikin@google.com, adobriyan@gmail.com,
        mingo@kernel.org, peterz@infradead.org, akpm@linux-foundation.org,
        yamada.masahiro@socionext.com, bauerman@linux.ibm.com,
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        dvyukov@google.com, svens@stackframe.org, joel@joelfernandes.org,
        tglx@linutronix.de, Jisheng.Zhang@synaptics.com, pmladek@suse.com,
        bigeasy@linutronix.de, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, wangle6@huawei.com
Subject: Re: [PATCH 1/4] hung_task: Move hung_task sysctl interface to
 hung_task_sysctl.c
Message-ID: <202005150902.9293E99B8@keescook>
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On Fri, May 15, 2020 at 04:56:34PM +0800, Xiaoming Ni wrote:
> On 2020/5/15 16:04, Kees Cook wrote:
> > On Fri, May 15, 2020 at 12:33:41PM +0800, Xiaoming Ni wrote:
> > > Move hung_task sysctl interface to hung_task_sysctl.c.
> > > Use register_sysctl() to register the sysctl interface to avoid
> > > merge conflicts when different features modify sysctl.c at the same time.
> > > 
> > > Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
> > > ---
> > >   include/linux/sched/sysctl.h |  8 +----
> > >   kernel/Makefile              |  4 ++-
> > >   kernel/hung_task.c           |  6 ++--
> > >   kernel/hung_task.h           | 21 ++++++++++++
> > >   kernel/hung_task_sysctl.c    | 80 ++++++++++++++++++++++++++++++++++++++++++++
> > 
> > Why a separate file? That ends up needing changes to Makefile, the
> > creation of a new header file, etc. Why not just put it all into
> > hung_task.c directly?
> > 
> > -Kees
> > 
> But Luis Chamberlain's suggestion is to put the hung_task sysctl code in a
> separate file. Details are in https://lkml.org/lkml/2020/5/13/762.
> I am a little confused, not sure which way is better.

Ah, yes, I see now. Luis, I disagree with your recommendation here -- I
think complicating the Makefile is much less intuitive than just
wrapping this code in an #ifdef block in the existing .c file.

-- 
Kees Cook