At Tue, 24 Mar 2015 15:32:05 +0100, Richard Weinberger wrote: > > 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. I was thinking that such 'architectural' differences in core idea (like system call handling, execution model, process context design, etc) is better to have a different architecture even if some part of the code is similar. Isn't it also the same to the other 'hardware-dependent' architectures' case like between arm and arm64 ? of course I'm also happy to share the code between us, especially _pure_ userspace part like (virtual) NIC with tap or pcap because we also need that part, but we kept such code at an external codebase (i.e., linux-libos-tools). > >> 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. okay. thanks. -- Hajime -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
