Quota Preservation

[Norman Feske]

Hi Ben,

On 11.03.2018 04:06, Nobody III wrote:
> Thanks. How about CAP quotas? What happens when a component runs out of
> CAPs? And init doesn't seem to indicate the number or CAPs each child is
> using. Shouldn't CAPs be added to the report?

you can add this information to init's state report via the
'child_caps="yes"' attribute. Currently, unlike RAM, init does not
support the dynamic adjustment of cap quota. This is not an inherent
limitation but just not implemented.

> Also, how can a process determine how much RAM quota is required to
> start a process? Is there a good heuristic at least, perhaps in noux?

This information should be covered by the 'runtime' file of a pkg
archive. For an example, have a look at the pkg/noux-system as used by
Sculpt:


https://github.com/genodelabs/genode/blob/master/repos/ports/recipes/pkg/noux-system/runtime

When thinking of building blocks, we should start thinking about depot
pkgs, not ELF executables. E.g., one ELF executable may be referred to
by several pkgs (with different configurations). The RAM and caps
demands may very well vary depending on the configuration. By
introducing a pkg for each flavor, we can nicely capture this. E.g., the
pkg/nic_router-nat runtime employs the NIC router in one particular flavour.


https://github.com/genodelabs/genode/blob/master/repos/os/recipes/pkg/nic_router-nat/runtime

The same NIC router could be used as an ingredient of many other
building blocks.

Cheers
Norman

-- 
Dr.-Ing. Norman Feske
Genode Labs

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

Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth