here - Stefan-Marr.de

9. Conclusion and Future Work
A solution to the problem could either be to change the primitives to be
aware of the changed situation, or to ensure that the reflective invocation
of primitives is performed with the correct context.
Conceptual limitations, as discussed in Sec. 6.5.2, are:
Deadlock freedom is a guarantee that cannot be given if a language or VM
enables arbitrary and unconstrained use of blocking operations. However,
restricting the use of blocking operations seems impractical in
multi-language VMs where some languages might require blocking semantics.
However, the OMOP provides the ability to customize all primitives,
and thus, enables a domain to manage calls to blocking operations and
adapt them as necessary, which could be used to facilitate the guarantee
of deadlock freedom.
Domain interaction requires explicit handling. A language or library implementer
has to anticipate and adapt domain implementations to account
for the semantics of other domains and ensure that interactions have
reasonable semantics.
Currently, there is no mechanism that enables the specification of desired
interactions in a general way, since the OMOP only takes the
owner of an object into account for determining which intercession handler
implements the desired semantics.
Object-based ownership notion has tradeoffs. The granularity of ownership
per object might preclude relevant designs, especially when it comes to
large arrays or objects that need to be shared. Together with the notion
of having a single owner per object, the OMOP restricts the design space
within which concurrent programming concepts can be expressed.
Limited support for guaranteeing scheduling policies. During the execution
of primitives, complete control is yielded to the underlying platform by
the VM, and thus, its ability to enforce scheduling policies is restricted.
While intercession handlers for primitives enable customization, they
do not provide a full solution.
To gain full control, the language implementer would need to be able to
express policies which are communicated to the underlying platform as
well. This is currently not concidered in the design of the OMOP.
240