Prerequisite mechanism that Genode expects from a new kernel

[Norman Feske]

Hi Althaf,

> Yes, and lxc make use of these mechanisms to implement the resource
> container concept. As i read from linux Documentaton, it is called
> 'cgroups'.
> 
> Will this make genode a redundant implementation over linux? I See many
> things common at concept level in cgroups and genode.

it depends on your actual goal. If you are seeking a UNIX-like system
with OS-level virtualization and a way to restrict resource usage on a
per-process (or per process-group basis), the plain use of cgroups looks
to me like a very good idea. Similarly, if you are seeking a UNIX-like
system with support for expressive security policies, seLinux fits very
well.

However, if you consider to take a step back from UNIX in the first
place, alternative and far less complex approaches come into reach.

For example, even with cgroups, Linux needs a central authority (mostly
in the form of an administrator) with a global view on the system to
manage cgroups. The same for seLinux, where you need a central authority
to administer the global seLinux policy. In fact, on Linux there is a
bunch of those "global authorities" in the form of kernel services and
daemons. In contrast, Genode largely alleviates the need for an
authority with global knowledge. The system is composed of arbitrarily
nested subsystems, each taking care of its local concerns only. It turns
out that the resulting system is orders of magnitude less complex in
terms of TCB complexity and at the same time more flexible as the
complete OS can be virtualized at each node in the process hierarchy.

Genode was not created to improve Linux in the first place. Instead it
poses an architectural *alternative* to UNIX. The Linux version exists
solely for the pragmatic reason that it vastly accelerates development
and testing.

That said, I think that the Linux version of Genode using cgroups (and
capsicum?) as underlying mechanism could bring value to both Genode and
Linux. For Genode, this base platform would become a feasible host for
all those real-world applications where a low-complexity kernel is not
the prime concern. For Linux, Genode could be an alternative to the GNU
userland for applications that rely on the feature-rich Linux kernel but
do not need (nor want) the complexity of GNU. E.g., Android and Chrome
OS hardly anticipate the GNU userland. Both somehow try to cut back the
complexity of their respective userland but come nowhere as close to the
low complexity of Genode.

Finally, this would be cool project because it completely blurs the line
between monolithic kernels and microkernels, putting the long-winded and
heated discussions between both camps in an interesting perspective. ;-)

Best regards
Norman

-- 
Dr.-Ing. Norman Feske
Genode Labs

http://www.genode-labs.com · http://genode.org

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