From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f45.google.com (mail-pa0-f45.google.com [209.85.220.45]) by dpdk.org (Postfix) with ESMTP id B94965AA0 for ; Wed, 18 Nov 2015 20:09:11 +0100 (CET) Received: by pacdm15 with SMTP id dm15so53438815pac.3 for ; Wed, 18 Nov 2015 11:09:11 -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=N8XGTSbuU8/PF24zzjov2GeD8TF1BM38nsyJGSaXnTU=; b=KOMRCE/aAFeNIcqZWNP+jhxCYfgGbPS8VhKZnFAYm5hxgj8EhqsK05x1iWUeU4fbPc gM6dJdDe4U29HR/MdBphW1AuDGKcYmj9CpSBxYzj7fpiWQNDoCLxNTuK2ulWnTAEZAsx 0PoNHfF/I3x9KTEIZNQYRkXaBu3HlrAz9pjYRO9v4iLQlym6Mxq/FzppZk4BF8PehilS vTD3876P5eZ9x0Vp4JvsvnNUfusJjfD/PP61atd1DIV+maZjD+a0xTvqpKQLi9/PzDSL 6RMKF8i9NNtM3QGY6VKFYx16pGvSQDghuxGPig3smYMoVge4VbnXCOTmAwAsE30GNA1d IVdw== 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=N8XGTSbuU8/PF24zzjov2GeD8TF1BM38nsyJGSaXnTU=; b=jjWGKc2Cu97/b3iJpGKxYa6FLIw/K1gQfkFnyVQQ9edkU7QmNhQeQGpfviSb+MgFRj W/wzkVUYNpgeg1NnZXQMJQmPfunI7OLita12KZuj8Hr4Azsd6yF5Spa69xo3KlWp4bHf pZDM5Rkowb7iM6ZcNP45X5slGW64wmfmL2Hs+BdL5h+rdEx7bqX2eZhkPTwq+sUeCUA/ tXWfX07jh0wRH5KNMEddNCfDqbrKbWvve28kTU6N+GHZ4XseJuSDxAcD13sZSQz0mtPU kgr+uP9bGWzyzEQBymo8ah0mzdgnofPAyn2DNVw9m/XSv+X4QGNJRf7XDppUco1TpTEh RW/Q== X-Gm-Message-State: ALoCoQn8vb6laKm6rY5IL9XY+HE9zGgZHksepuAv1+DcI7eYQuSZye7raNrG+ZdQOjfEc50jq48C X-Received: by 10.66.219.194 with SMTP id pq2mr4395240pac.107.1447873750978; Wed, 18 Nov 2015 11:09:10 -0800 (PST) Received: from samsung9 (50-206-118-3-static.hfc.comcastbusiness.net. [50.206.118.3]) by smtp.gmail.com with ESMTPSA id ud10sm5721184pab.27.2015.11.18.11.09.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 18 Nov 2015 11:09:10 -0800 (PST) Date: Wed, 18 Nov 2015 11:09:06 -0800 From: Stephen Hemminger To: "Richardson, Bruce" Message-ID: <20151118110906.3e0b3dcd@samsung9> In-Reply-To: <59AF69C657FD0841A61C55336867B5B035985B24@IRSMSX103.ger.corp.intel.com> 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> <20151118080013.3cad8f5b@samsung9> <59AF69C657FD0841A61C55336867B5B035985B24@IRSMSX103.ger.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" 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: Wed, 18 Nov 2015 19:09:12 -0000 On Wed, 18 Nov 2015 16:13:32 +0000 "Richardson, Bruce" wrote: > > > > -----Original Message----- > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Stephen Hemminger > > Sent: Wednesday, November 18, 2015 4:00 PM > > To: Xie, Huawei > > Cc: dev@dpdk.org > > Subject: Re: [dpdk-dev] [RFC PATCH 2/2] lib/librte_eal: Remove unnecessary > > hugepage zero-filling > > > > On Wed, 18 Nov 2015 12:07:54 +0000 > > "Xie, Huawei" 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? > > The pages won't actually be mapped into the processes address space until accessed. > > /Bruce Isn't that what mmap MAP_POPULATE flag (not currently used) will do.