From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp.tuxdriver.com (charlotte.tuxdriver.com [70.61.120.58]) by dpdk.org (Postfix) with ESMTP id B55897F1C for ; Fri, 8 Jul 2016 16:13:56 +0200 (CEST) Received: from cpe-2606-a000-111b-40ed-7aac-c0ff-fec2-933b.dyn6.twc.com ([2606:a000:111b:40ed:7aac:c0ff:fec2:933b] helo=localhost) by smtp.tuxdriver.com with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.63) (envelope-from ) id 1bLWWs-0005e2-EJ; Fri, 08 Jul 2016 10:13:28 -0400 Date: Fri, 8 Jul 2016 10:13:12 -0400 From: Neil Horman To: Thomas Monjalon Cc: David Marchand , dev@dpdk.org, Jan Viktorin Message-ID: <20160708141312.GD14917@hmsreliant.think-freely.org> References: <1467905790-10597-1-git-send-email-thomas.monjalon@6wind.com> <20160708135643.GC14917@hmsreliant.think-freely.org> <1960485.iIdzW2D0ke@xps13> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1960485.iIdzW2D0ke@xps13> User-Agent: Mutt/1.6.1 (2016-04-27) X-Spam-Score: -1.0 (-) X-Spam-Status: No Subject: Re: [dpdk-dev] [PATCH 09/11] eal: move PCI table macro 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: Fri, 08 Jul 2016 14:13:57 -0000 On Fri, Jul 08, 2016 at 04:03:40PM +0200, Thomas Monjalon wrote: > 2016-07-08 09:56, Neil Horman: > > On Fri, Jul 08, 2016 at 10:49:25AM +0200, David Marchand wrote: > > > Hello Thomas, Neil, > > > > > > (will be back in a couple of days, thanks Thomas for pointing this thread) > > > > > > > > > On Thu, Jul 7, 2016 at 6:25 PM, Thomas Monjalon > > > wrote: > > > > 2016-07-07 12:11, Neil Horman: > > > >> On Thu, Jul 07, 2016 at 05:36:28PM +0200, Thomas Monjalon wrote: > > > >> > Remove include of rte_pci.h in the generic header rte_dev.h > > > >> > and move the macro DRIVER_REGISTER_PCI_TABLE in rte_pci.h. > > > > [...] > > > >> > > > >> This seems strange to me, in that its odd for the driver information export > > > >> macros to be spread out in multiple locations. Specifically it enjoins the use > > > >> of the DRV_EXP_TAG macro, which helps centralize tag naming. Perhaps the happy > > > >> medium is to place all the export macros (includnig PMD_REGISTER_DRIVER) into > > > >> its own pmd_register.h header? > > > > > > > > I don't know. > > > > David, your opinion? > > > > > > - The suggestion I did offline to Thomas was to move pci stuff in pci headers. > > > We are trying to move from the "all pci" code in eal to accomodate for > > > other "buses" / architectures. > > I get that, but I'm not sure that applies here. The macro in question is > > specific to pci busses, and if there is additional bus information to export, it > > will have its own macro (e.g. DRIVER_REGISTER_USB_TABLE or some such). While > > I could see that being an argument for putting each macro in with its own bus > > type, I think thats the wrong organization here, in that people writing drivers > > will want to know what export macros are available and will expect to look in a > > single place for it. > > > > > Having a pci macro in a generic header like rte_dev.h is wrong to me. > > > Moving this to a new header like pmd_register.h sounds like a new > > > generic header with pci specific stuff in it. > > Well, yes, but I see that as no different than rte_ethdev.c or rte_pdump.c. > > both of those files will need to know about all the different types of busses > > you support and have to include those corresponding header files (i.e. they will > > have to include rte_pci.h, rte_usb.h, rte_i2c.h, etc). This is really no > > different in my mind. > > > > > So, I am not sure I follow you Neil. > > > > > > Can you elaborate ? > > > > > I suppose the best way to describe it is that while I understand and support the > > desire to separate and abstract bus information away from device function, I > > think theres a pragmatic descision here to prioritize functional domain over > > header inclusion. That is to say, I think when people are writing a driver, it > > will be helpful to have all the export macros in a single location so they know > > what information they can export, and that includes registration of various bus > > type identifiers. So a file like pmd_registration.h that includes rte_pci.h, > > rte_usb.h, rte_i2c.h, etc is more useful to a developer, than spreading these > > macros out to those various header files, for the sake of avoiding a potentially > > unneeded include. > > > > > > > > - Why do you want to centralise the tag naming ? > > > To avoid collisions ? > > Yes, and to centralize that information. Since the pmdinfogen tool needs to > > know what those tag names are as well, its useful to keep them in the same area > > to maintain co-ordination. Its also useful because it means we can use one > > macro to define tag naming convention, instead of having to re-implement or > > dead-reckon it in multiple files. > > > > > Well, adding those tags should not happen that often and I think we > > > can maintain this with careful reviews. > > I don't agree with that. This discussion is based on the fact that you expect > > that we will be adding additional bus types in the future correct? Well, given > > that we have a pci bus specific export macro, I would expect that to proliferate > > to every other bus type as well, and so we can expect to at least have a new > > tag added for every bus that is added, in addition to any other bus agnostic > > information people wish to export (just off hand, looking at the linux modinfo > > section, we might expect module author, module version, alias names, licensing > > infomration, and others to be potential export candidates). So, depending on > > how much this is adopted, I think we can potentially expect a great deal of > > additional tagging to be needed. > > Anyway, this macro do not need rte_pci.h. > So the minimal patch can be to just remove this include. > Oh my gosh! I've been an idiot! you're absolutely right. The macro is just defining a string to point to the pci_table symbol name, its not typed to the pci_tbl symbol at all, and so we can just remove the header file. Somehow I had it in my head that the macro created a pci specific typed symbol, but it totally doesn't. Apologies. Yes, just removing the include is exactly the right move here. Neil