From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id A5D3DF72; Mon, 8 May 2017 11:11:48 +0200 (CEST) Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 May 2017 02:11:47 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.38,308,1491289200"; d="scan'208";a="84838120" Received: from debian.sh.intel.com (HELO debian) ([10.239.67.137]) by orsmga004.jf.intel.com with ESMTP; 08 May 2017 02:11:46 -0700 Date: Mon, 8 May 2017 17:13:34 +0800 From: Tiwei Bie To: Bruce Richardson Cc: dev@dpdk.org, stable@dpdk.org Message-ID: <20170508091334.GB11935@debian> References: <20170508080916.4317-1-tiwei.bie@intel.com> <20170508085357.GA47408@bricha3-MOBL3.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20170508085357.GA47408@bricha3-MOBL3.ger.corp.intel.com> User-Agent: Mutt/1.7.2 (2016-11-26) Subject: Re: [dpdk-dev] [PATCH] eal/bsd: don't zero the pages during mmap in contigmem X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 08 May 2017 09:11:49 -0000 On Mon, May 08, 2017 at 09:53:57AM +0100, Bruce Richardson wrote: > On Mon, May 08, 2017 at 08:09:16AM +0000, Tiwei Bie wrote: > > Don't zero the pages during mmap in contigmem. Instead, zero the > > pages after mmap in primary process. Otherwise, the multi-process > > support will be broken, as the pages will be zeroed when secondary > > processes map the memory. > > > > Fixes: 82f931805506 ("contigmem: zero all pages during mmap") > > Cc: stable@dpdk.org > > > > Signed-off-by: Tiwei Bie > > --- > I agree there is a problem here, but I'm not sure about the solution to > it. I still think that the kernel should zero the pages before they get > given to userspace. Is there any way to keep that working e.g > > * have them zeroed on mmap only when they are not already mmaped into > another process? > * have them zeroed on init, and again on unmap by the last process to > have them mapped? > I think it's the simplest way to fix it in userspace, so I just did it. I'd like to fix it in kernel if you also prefer this. Best regards, Tiwei Bie