Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932232AbcLLP3B (ORCPT ); Mon, 12 Dec 2016 10:29:01 -0500 Received: from mail-io0-f180.google.com ([209.85.223.180]:35220 "EHLO mail-io0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932094AbcLLP27 (ORCPT ); Mon, 12 Dec 2016 10:28:59 -0500 Date: Mon, 12 Dec 2016 10:28:20 -0500 (EST) From: Nicolas Pitre To: Vaneet Narang cc: Russell King - ARM Linux , Maninder Singh , "ssantosh@kernel.org" , "panand@redhat.com" , "arnd@arndb.de" , "chris.brandt@renesas.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , PANKAJ MISHRA , Ajeet Kumar Yadav Subject: RE: Re: [PATCH 1/1] arm/module: maximum utilization of module area. In-Reply-To: <20161212112230epcms5p6af05aef34f72eab15061a166d18cff00@epcms5p6> Message-ID: References: <1481012975-44478-1-git-send-email-maninder1.s@samsung.com> <20161212112230epcms5p6af05aef34f72eab15061a166d18cff00@epcms5p6> User-Agent: Alpine 2.20 (LFD 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1140 Lines: 28 On Mon, 12 Dec 2016, Vaneet Narang wrote: > Hi, > > >A PC24 relocation has a range of +/-32MB. This means that where-ever > >the module is placed, it must be capable of reaching any function > >within the kernel text, which may itself be quite large (eg, 8MB, or > >possibly larger). The module area exists to allow modules to be > >located in an area where PC24 relocations are able to reach all of the > >kernel text on sensibly configured kernels, thereby allowing for > >optimal performance. > > > >If you wish to load large modules, then enable ARM_MODULE_PLTS, which > >will use the less efficient PLT method (which is basically an indirect > >function call) for relocations that PC24 can't handle, and will allow > >the module to be loaded into the vmalloc area. > > > >Growing the module area so that smaller modules also get penalised by > >the PLT indirection is not sane. > > This is exactly what i am saying. These changes are useful to accomdate > 22MB modules without enabling ARM_MODULE_PLTS. I think you need to figure out why you need such a huge module in the first place. That is very uncommon indeed. Nicolas