From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S1752019AbcIMNIt (ORCPT <rfc822;w@1wt.eu>);
        Tue, 13 Sep 2016 09:08:49 -0400
Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:46639 "EHLO
        mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL)
        by vger.kernel.org with ESMTP id S1750747AbcIMNIr (ORCPT
        <rfc822;linux-kernel@vger.kernel.org>);
        Tue, 13 Sep 2016 09:08:47 -0400
X-IBM-Helo: d03dlp03.boulder.ibm.com
X-IBM-MailFrom: rui.teng@linux.vnet.ibm.com
Subject: Re: [RFC] mm: Change the data type of huge page size from unsigned
 long to u64
To: "Kirill A. Shutemov" <kirill@shutemov.name>
References: <1473758765-13673-1-git-send-email-rui.teng@linux.vnet.ibm.com>
 <20160913093257.GA31186@node>
 <09ab7941-07fa-0003-46d8-9fa5c07eba2d@linux.vnet.ibm.com>
 <20160913114001.GB31186@node>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Hocko <mhocko@suse.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        Chen Gang <chengang@emindsoft.com.cn>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>,
        hejianet@linux.vnet.ibm.com
From: Rui Teng <rui.teng@linux.vnet.ibm.com>
Date: Tue, 13 Sep 2016 21:08:33 +0800
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0)
 Gecko/20100101 Thunderbird/45.3.0
MIME-Version: 1.0
In-Reply-To: <20160913114001.GB31186@node>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
X-TM-AS-GCONF: 00
X-Content-Scanned: Fidelis XPS MAILER
x-cbid: 16091313-0020-0000-0000-000009C4C5EE
X-IBM-SpamModules-Scores: 
X-IBM-SpamModules-Versions: BY=3.00005754; HX=3.00000240; KW=3.00000007;
 PH=3.00000004; SC=3.00000185; SDB=6.00757239; UDB=6.00359044; IPR=6.00530605;
 BA=6.00004715; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000;
 ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00012661; XFM=3.00000011;
 UTC=2016-09-13 13:08:44
X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused
x-cbparentid: 16091313-0021-0000-0000-0000556F4172
Message-Id: <cc71f567-918d-ea01-e262-0a4458b5cfee@linux.vnet.ibm.com>
X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-09-13_08:,,
 signatures=0
X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0
 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam
 adjust=0 reason=mlx scancount=1 engine=8.0.1-1609020000
 definitions=main-1609130193
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 9/13/16 7:40 PM, Kirill A. Shutemov wrote:
> On Tue, Sep 13, 2016 at 07:21:07PM +0800, Rui Teng wrote:
>> On 9/13/16 5:32 PM, Kirill A. Shutemov wrote:
>>> On Tue, Sep 13, 2016 at 05:26:05PM +0800, Rui Teng wrote:
>>>> The huge page size could be 16G(0x400000000) on ppc64 architecture, and it will
>>>> cause an overflow on unsigned long data type(0xFFFFFFFF).
>>>
>>> Huh? ppc64 is 64-bit system and sizeof(void *) is equal to
>>> sizeof(unsigned long) on Linux (LP64 model).
>>>
>>> So where your 0xFFFFFFFF comes from?
>>>
>> The size of unsigned long data type is 4 bytes
>
> No, it's not.
>
Sorry, my fault!
I print the unsigned long with "%ul" instead of "%lu" and got the wrong
result. Sorry!