Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756148AbbDOLtq (ORCPT ); Wed, 15 Apr 2015 07:49:46 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:35193 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881AbbDOLtk (ORCPT ); Wed, 15 Apr 2015 07:49:40 -0400 Date: Wed, 15 Apr 2015 13:49:36 +0200 From: Greg Kroah-Hartman To: One Thousand Gnomes Cc: Jiri Kosina , Al Viro , Borislav Petkov , Andy Lutomirski , Linus Torvalds , Andrew Morton , Arnd Bergmann , "Eric W. Biederman" , Tom Gundersen , "linux-kernel@vger.kernel.org" , Daniel Mack , David Herrmann , Djalal Harouni Subject: Re: [GIT PULL] kdbus for 4.1-rc1 Message-ID: <20150415114936.GD19274@kroah.com> References: <20150414175019.GA2874@kroah.com> <20150414192357.GA6107@kroah.com> <20150414192429.GC26075@pd.tnic> <20150414193229.GB6107@kroah.com> <20150414194004.GG889@ZenIV.linux.org.uk> <20150414194804.GB7540@kroah.com> <20150415113727.0cfd5224@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150415113727.0cfd5224@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3891 Lines: 82 On Wed, Apr 15, 2015 at 11:37:27AM +0100, One Thousand Gnomes wrote: > On Wed, 15 Apr 2015 00:39:22 +0200 (CEST) > Jiri Kosina wrote: > > > On Tue, 14 Apr 2015, Greg Kroah-Hartman wrote: > > > > > I don't understand. You can not like the D-Bus model (and accordingly > > > the X11 model), > > > > I thought that the general hatred level of the X11 "model" and the > > protocol lead to al the efforts to reimplement this properly ... in > > userspace (for example Wayland, right?). > > > > I don't think anyone was ever seriously suggesting "X11 model is broken, > > so let's push it to kernel" ... ? > > The X11 model is *nothing* to do with the dbus/kdbus model. X11 does > properties by attaching them to windows. Those properties can be > monitored for changes and they can be queried. Setting them is > asynchronous, querying them is sync or with the newer event based > libraries can be async. X11 properties are network safe, handled through > the same X11 authority as everything else. Two apps can happily run on > different systems sharing a display over the network and sharing and > responding to changes in X11 properties - and it just works. > > The Gnome people tried to re-invent X11 properties and embedding badly > with CORBA, then with dbus, despite the fact the Andrew system could > already do it really fast and cleanly even before Gnome was thought of. > > There is no comparison between the elegance of X11 property setting and a > chunk of proposed kernel code that is half the size of a tiny X server! Hey, take that up with Havoc, he made the comparison :) > The dbus model is also flawed in a load of other ways in user space > because message handling in the hands of people with no concept of > systemic performance analysis just leads to disaster. One of the big > reasons dbus is so "slow" isn't that dbus is "slow", it's that the > crapware on top of it makes *thousands* of dbus queries. There's the issue of thousands of dbus queries, and then there's the issue that making those queries takes a measurable amount of time. We can fix the later one, the first one, well, not so much, but we can provide the resources for them to make a faster system if they want to. > If you must do it in kernel why not use the Android binder - it's awful, > broken, and dubiously secure, but at least we'd still only have one awful, > broken dubiously secure rpc/property layer in kernel. Binder does not match up to the dbus model at all, I've written about this in the past, and can dig it up again if you want. And, there is active research in moving the binder userspace library onto the kdbus code base, allowing the binder kernel driver to be removed one day. That would be a good thing to have happen, but I'm not holding my breath for it. Using it the other way around isn't going to work. > "It's the issue that a stateful bus is required for > applications that is the main point I'm trying to get across." > > That would be the "if dbus crashes I have to reboot" design flaw of > Gnome and friends. The only state you need is beyond the endpoints. It's a > message passing system. If you think message passing needs state then I'd > take a look at the internet. State belongs in the end points. The internet model with state in the endpoints doesn't always transfer properly to local applications, see Havoc's email for the details about that. > It's telling that I can lose and recover my internet connection without > rebooting but not my desktops internal messaging. Yes, as those are totally different things, let's not mix the issue up here please. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/