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 CA4E6F72; Mon, 8 May 2017 10:54:02 +0200 (CEST) Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 May 2017 01:54:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.38,308,1491289200"; d="scan'208";a="965721014" Received: from bricha3-mobl3.ger.corp.intel.com ([10.237.221.42]) by orsmga003.jf.intel.com with SMTP; 08 May 2017 01:53:59 -0700 Received: by (sSMTP sendmail emulation); Mon, 08 May 2017 09:53:58 +0100 Date: Mon, 8 May 2017 09:53:57 +0100 From: Bruce Richardson To: Tiwei Bie Cc: dev@dpdk.org, stable@dpdk.org Message-ID: <20170508085357.GA47408@bricha3-MOBL3.ger.corp.intel.com> References: <20170508080916.4317-1-tiwei.bie@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170508080916.4317-1-tiwei.bie@intel.com> Organization: Intel Research and =?iso-8859-1?Q?De=ACvel?= =?iso-8859-1?Q?opment?= Ireland Ltd. User-Agent: Mutt/1.8.0 (2017-02-23) 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 08:54:03 -0000 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? /Bruce