From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <stephen@networkplumber.org> Received: from mail-pa0-f45.google.com (mail-pa0-f45.google.com [209.85.220.45]) by dpdk.org (Postfix) with ESMTP id 66F145A92 for <dev@dpdk.org>; Wed, 18 Nov 2015 17:00:18 +0100 (CET) Received: by padhx2 with SMTP id hx2so48737020pad.1 for <dev@dpdk.org>; Wed, 18 Nov 2015 08:00:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; bh=edPQ+R757kyLsBqTsVuOj65iVTOIAOQAGHfa82jsOCE=; b=N4DURqBxr0uB4Fis5kpVUOPwCEX/G+lLiRmqh4kTvUDiMdzXfEQmQiXw2TaoucCAFF 73dHRJa/HcEvlOweIc9XrjcuCnjK2Ll2CMWNWJLZIwLJFi/YIUZnKsyX2QhDRUNrRq// zmuC/dfi3XV+HZ+xyy8CFWNAIXi6G0hw0wGzBqKB53sDtwpjkxDf7CP4mmOSHBITND2t D3QdbRD1381RpEsnDHV9vAnC/bpmx/8ZfHrdx6tqJl6TJsySpdKeV4f76ynuebaebpVe 1fLQJj0Yh3u1prUlRHnuEgwqW3FjGzRj7nPEbs4U75wfx0GMvf9KtWgXOFOiGRQ97USh dCnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-type:content-transfer-encoding; bh=edPQ+R757kyLsBqTsVuOj65iVTOIAOQAGHfa82jsOCE=; b=f7lHOrWd3tL4RSXVZBaekehUIExv92yX5hfIkvZqhV/7xXJp+agCRYNioREk9EPbCn Ugos1Lrlxtt1q6vSuz2c6qeDr+WfU6nykAohmypbP3axiqyNoBTL1ixFEt/Gs9jdpOPr 7kFI9LFSpA35/B59AEdvTvyNS3SzZopVcTbz+7tahvNDqSZQdnV7m2Qd1HsyBBF5El4z cUfWJ7Ad9bHkmTpnt/bwOQX0yAL82wK4QZxmBaT6tCGpex4csuzDwVfkdWLyfKlNKucm PtBpKoWk3sbF8Uca457KBK45YP9xTynNgOcwMKqRo73Sj7S8YFZUP56++SmoZ7Z0ILzx JrgA== X-Gm-Message-State: ALoCoQkgNAEyda7vNpJmEuuCkwe2x5jJtIMRxuffj51AvDfO5P0PMdIVy+alH+Quy9arXq3LU0x7 X-Received: by 10.68.131.201 with SMTP id oo9mr3141496pbb.74.1447862416823; Wed, 18 Nov 2015 08:00:16 -0800 (PST) Received: from samsung9 ([144.49.132.22]) by smtp.gmail.com with ESMTPSA id ij3sm5068236pbb.62.2015.11.18.08.00.16 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Nov 2015 08:00:16 -0800 (PST) Date: Wed, 18 Nov 2015 08:00:13 -0800 From: Stephen Hemminger <stephen@networkplumber.org> To: "Xie, Huawei" <huawei.xie@intel.com> Message-ID: <20151118080013.3cad8f5b@samsung9> In-Reply-To: <C37D651A908B024F974696C65296B57B4B198CF8@SHSMSX101.ccr.corp.intel.com> References: <1447817231-10510-1-git-send-email-zhihong.wang@intel.com> <1447817231-10510-3-git-send-email-zhihong.wang@intel.com> <B27915DBBA3421428155699D51E4CFE2023BE52A@IRSMSX103.ger.corp.intel.com> <8F6C2BD409508844A0EFC19955BE094183467C@SHSMSX152.ccr.corp.intel.com> <C37D651A908B024F974696C65296B57B4B198CF8@SHSMSX101.ccr.corp.intel.com> X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.25; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "dev@dpdk.org" <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 <dev.dpdk.org> List-Unsubscribe: <http://dpdk.org/ml/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://dpdk.org/ml/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <http://dpdk.org/ml/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> X-List-Received-Date: Wed, 18 Nov 2015 16:00:18 -0000 On Wed, 18 Nov 2015 12:07:54 +0000 "Xie, Huawei" <huawei.xie@intel.com> wrote: > >>> The kernel fills new allocated (huge) pages with zeros. > >>> DPDK just has to touch the pages to trigger the allocation. > I think we shouldn't reply on the assumption that kernel has zeroed the > memory. Kernel zeroes the memory mostly to avoid information leakage.It > could also achieve this by setting each bit to 1. > What we indeed need to check is later DPDK initialization code doesn't > assume the memory has been zeroed. Otherwise zero only that part of the > memory. Does this makes sense? If all new pages are zero, why does DPDK have to pre-touch the pages at all? I thought there as some optimization to initialize hugepages since Oracle has same problem with their Shared Global Area which was why hugpages were invented anyway