From mboxrd@z Thu Jan 1 00:00:00 1970 From: Boaz Harrosh Subject: Re: [Linux-nvdimm] [PATCH v2] pmem: Initial version of persistent memory driver Date: Wed, 10 Sep 2014 20:47:54 +0300 Message-ID: <54108ECA.6090200@plexistor.com> References: <1409173922-7484-1-git-send-email-ross.zwisler@linux.intel.com> <1409173922-7484-2-git-send-email-ross.zwisler@linux.intel.com> <540F2977.7010006@plexistor.com> <541050E5.60502@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Ross Zwisler , Jens Axboe , Matthew Wilcox , Nick Piggin , linux-fsdevel , "linux-kernel@vger.kernel.org" , linux-nvdimm@lists.01.org To: Dan Williams , Boaz Harrosh Return-path: Received: from mail-pa0-f42.google.com ([209.85.220.42]:62914 "EHLO mail-pa0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750734AbaIJRsA (ORCPT ); Wed, 10 Sep 2014 13:48:00 -0400 Received: by mail-pa0-f42.google.com with SMTP id lj1so6935284pab.1 for ; Wed, 10 Sep 2014 10:47:59 -0700 (PDT) In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 09/10/2014 08:03 PM, Dan Williams wrote: > Hi Boaz, > <> >> We please need to start somewhere, no? > > Sure, but you used the operative term "start", as in you already > expect to enhance this capability down the road, right? > Yes > It's fine to dismiss this request_firmware() based approach, but don't > mis-characterize it in the process. With regards to describing device > boundaries, a bus-descriptor-blob handed to the kernel is a superset > of the capability provided by the kernel command line. It can be > injected statically at compile time, or dynamically loaded from the > initrd or the rootfs. It has the added benefit of being flexible to > change whereas the kernel command line is a more permanent contract > that we will need to maintain compatibility with in perpetuity. > initrd or rootfs means for me "make install". But I want my fedora to never make or install. Pre-compiled binary blobs including rootfs and it needs to work. > If you already see this bus description as a "starting" point, then I > think we need an interface that is more amenable to ongoing change, > that's not the kernel-command-line. > module-command-line. a module can be loaded via udev and/or module param can be changed dynamically on the fly. And also be specified via kernel-command-line. So it is much less permanent contract API than "rootfs" And yes, I intend to add more interfaces. And No! I do not intend to ever extend this module-param interface, that I can see. This one is that, which it is right now. Later a sysfs/ objects will enable dynamic management of devices. So both: initial device list on load - more devices or removal on the fly, unload all on unload. This is my plan. So right now I do not see this map= need ever change in the future. Only more interfaces added in (the very near) future. Thanks Boaz