From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id B818D5957 for ; Mon, 23 Nov 2015 06:05:24 +0100 (CET) Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga101.fm.intel.com with ESMTP; 22 Nov 2015 21:05:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.20,335,1444719600"; d="scan'208";a="605517423" Received: from fmsmsx105.amr.corp.intel.com ([10.18.124.203]) by FMSMGA003.fm.intel.com with ESMTP; 22 Nov 2015 21:05:23 -0800 Received: from shsmsx102.ccr.corp.intel.com (10.239.4.154) by FMSMSX105.amr.corp.intel.com (10.18.124.203) with Microsoft SMTP Server (TLS) id 14.3.248.2; Sun, 22 Nov 2015 21:05:23 -0800 Received: from shsmsx101.ccr.corp.intel.com ([169.254.1.83]) by shsmsx102.ccr.corp.intel.com ([169.254.2.42]) with mapi id 14.03.0248.002; Mon, 23 Nov 2015 13:05:21 +0800 From: "Xie, Huawei" To: Stephen Hemminger Thread-Topic: [dpdk-dev] [RFC PATCH 2/2] lib/librte_eal: Remove unnecessary hugepage zero-filling Thread-Index: AQHRJaGKxL2Z5sKfnk+JPinAT7c0ug== Date: Mon, 23 Nov 2015 05:05:21 +0000 Message-ID: References: <1447817231-10510-1-git-send-email-zhihong.wang@intel.com> <1447817231-10510-3-git-send-email-zhihong.wang@intel.com> <8F6C2BD409508844A0EFC19955BE094183467C@SHSMSX152.ccr.corp.intel.com> <564D930C.7060108@intel.com> <20151122200743.34511547@xeon-e3> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [RFC PATCH 2/2] lib/librte_eal: Remove unnecessary hugepage zero-filling X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Nov 2015 05:05:25 -0000 On 11/23/2015 12:07 PM, Stephen Hemminger wrote:=0A= > On Mon, 23 Nov 2015 03:46:31 +0000=0A= > "Xie, Huawei" wrote:=0A= >=0A= >>> Why cannot we rely on the kernel zeroing the memory ?=0A= >>> If that behavior were to change, then we can zero out the memory=0A= >>> ourselves. =0A= >> It is undocumented kernel behavior. My opinion is if not a big burden,= =0A= >> zero out the needed memory ourselves, otherwise resort to this kernel=0A= >> behavior.=0A= > Really, I think it is more an oversight of missing documentation,=0A= > the kernel has always (and will continue) to zero out memory that is give= n=0A= > to a process. If it didn't it would be a massive security hole.=0A= Agree. I believe this behavior will not change in future. For the=0A= security issue, kernel could also set all bits like to 1. Just wonder if=0A= this is best practice and whether there are other user space programs=0A= rely on this behavior.=0A= =0A=