From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 1AFBC7F79 for ; Thu, 13 Nov 2014 14:34:07 +0100 (CET) Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP; 13 Nov 2014 05:44:04 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.07,377,1413270000"; d="scan'208";a="607239858" Received: from irsmsx104.ger.corp.intel.com ([163.33.3.159]) by orsmga001.jf.intel.com with ESMTP; 13 Nov 2014 05:44:04 -0800 Received: from irsmsx108.ger.corp.intel.com (163.33.3.3) by IRSMSX104.ger.corp.intel.com (163.33.3.159) with Microsoft SMTP Server (TLS) id 14.3.195.1; Thu, 13 Nov 2014 13:44:03 +0000 Received: from irsmsx109.ger.corp.intel.com ([169.254.13.101]) by IRSMSX108.ger.corp.intel.com ([169.254.11.82]) with mapi id 14.03.0195.001; Thu, 13 Nov 2014 13:44:03 +0000 From: "Burakov, Anatoly" To: "Richardson, Bruce" Thread-Topic: [dpdk-dev] [PATCH v8] eal: map PCI memory resources after hugepages Thread-Index: AQHP/Ze/g7jr2A7Af06zlboPmaVZspxeb8uAgAAYHoCAAAqdEA== Date: Thu, 13 Nov 2014 13:44:02 +0000 Message-ID: References: <1415619272-8281-1-git-send-email-anatoly.burakov@intel.com> <1415700565-19157-1-git-send-email-anatoly.burakov@intel.com> <20141113125840.GA9932@bricha3-MOBL3> In-Reply-To: <20141113125840.GA9932@bricha3-MOBL3> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [163.33.239.180] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH v8] eal: map PCI memory resources after hugepages 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: Thu, 13 Nov 2014 13:34:09 -0000 > Why has this check been removed from here. I assume it is replaced by a > new check in secondary processes that I see added below, but perhaps you > could explain the reason for the change? Sure. The reason behind that change is that we can't expect that we will ge= t a mapping at exact same address (for whatever reasons, i.e. something els= e is mapped there, alignment, etc.), and in primary process, it's not an er= ror. In other words, removing this check makes it a "best-effort" type mech= anism, rather than mandates PCI resources to be mapped exactly after hugepa= ges, exactly one after another. "Wrong" mapping will still result in failur= e in secondary processes, and we still are risking mapping something somewh= ere the secondary process can't map, but that probability is decreased beca= use we're now asking EAL to map PCI resources closer to where we most likel= y have some free virtual space (as evidenced by tests being done by the ori= ginal submitter of the patch). Hope that makes sense. Thanks, Anatoly