From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Weinberger Subject: Re: [RFC PATCH 00/11] an introduction of library operating system for Linux (LibOS) Date: Tue, 24 Mar 2015 15:32:05 +0100 Message-ID: <55117565.6080002@nod.at> References: <1427202642-1716-1-git-send-email-tazaki@sfc.wide.ad.jp> <551164ED.5000907@nod.at> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from a.ns.miles-group.at ([95.130.255.143]:65278 "EHLO radon.swed.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752420AbbCXOcL (ORCPT ); Tue, 24 Mar 2015 10:32:11 -0400 In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Hajime Tazaki Cc: linux-arch@vger.kernel.org, arnd@arndb.de, corbet@lwn.net, cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, jdike@addtoit.com, rusty@rustcorp.com.au, mathieu.lacage@gmail.com Am 24.03.2015 um 15:25 schrieb Hajime Tazaki: > At Tue, 24 Mar 2015 14:21:49 +0100, > Richard Weinberger wrote: >> >> Am 24.03.2015 um 14:10 schrieb Hajime Tazaki: >> > == More information == >>> >>> The crucial difference between UML (user-mode linux) and this approach >>> is that we allow multiple network stack instances to co-exist within a >>> single process with dlmopen(3) like linking for easy debugging. >> >> Is this the only difference? >> We already have arch/um, why do you need arch/lib/ then? >> My point is, can't you merge your arch/lib into the existing arch/um stuff? >> From a very rough look your arch/lib seems like a micro UML. > > I understand your point. > but ptrace(2) based system call interception used by UML > makes it depend on the host OS (i.e., linux kernel), while > LibOS uses symbol hijacking with weak alias and LD_PRELOAD. > > we're really thinking to run this library on other > POSIX-like hosts (e.g., osx) though it's not coming yet. Yeah, but this does not mean that arch/um and arch/lib can't coexist in arch/um. Maybe you can add a "library operation mode" to UML. I'll happily help you in that area. >> BTW: There was already an idea for having UML as regular library. >> See: http://user-mode-linux.sourceforge.net/old/projects.html >> "UML as a normal userspace library" > > thanks, it's new information for me. > were there any trial on this idea ? IIRC Jeff (the original author of UML) wanted to create a special linker script such that you can build UML as shared object. Thanks, //richard