From mboxrd@z Thu Jan  1 00:00:00 1970
From: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
Subject: Re: [PATCH] hugetlb_cgroup: explicitly init the early_init field
Date: Tue, 22 Apr 2014 15:14:33 +0800
Message-ID: <535616D9.8060702@huawei.com>
References: <1398144620-9630-1-git-send-email-nasa4836@gmail.com>
	<CAJd=RBA6ZUZ2UBetmcwGciqY8snme-aY60ZhW9F=8CO6kDzMBA@mail.gmail.com>
	<CAHz2CGXsvdtVdwZfyFAwtRHJ_vkeJZXtLv4fTGTYEeEwN7H6Qw@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
In-Reply-To: <CAHz2CGXsvdtVdwZfyFAwtRHJ_vkeJZXtLv4fTGTYEeEwN7H6Qw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
List-Id: <cgroups.vger.kernel.org>
List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/containers>, 
	<mailto:containers-request-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org?subject=unsubscribe>
List-Archive: <http://lists.linuxfoundation.org/pipermail/containers/>
List-Post: <mailto:containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org>
List-Help: <mailto:containers-request-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org?subject=help>
List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/containers>,
	<mailto:containers-request-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org?subject=subscribe>
Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
To: Jianyu Zhan <nasa4836-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Linux-MM <linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org>, Hillf Danton <dhillf-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Cgroups <cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>

On 2014/4/22 15:01, Jianyu Zhan wrote:
> Hi, hillf,
> 
> On Tue, Apr 22, 2014 at 2:47 PM, Hillf Danton <dhillf-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> But other fields still missed, if any. Fair?
> 
> yep, it is not fair.
> 
> Sure for this global variable struct, if not initailized, its all
> fields will be initialized
> to 0 or null(depending on its type).  The point here is no to deprive
> the rights of
> compiler/linker of doing this initialization, it is mainly for
> documentation reason.
> Actually this field's value would affect how ->css_alloc should implemented.
> 
> Concretely, if early_init is nonzero, then ->css_alloc *must not* call kzalloc,
> because in cgroup implementation, ->css_alloc will be called earlier before
> mm_init().
> 
> I don't think that the value of one field(early_init) has a so subtle
> restrition on the
> another field(css_alloc) is a good thing, but since it is there,
> docment it should
> be needed.
> 

I don't see how things can be improved by initializing it to 0 explicitly,
if anything needs to be improved.