...even while this situation is unlikely, it needs to be considered:
A worker thread might terminate unexpectedly, due to an error;
all thread-local objects will be destroyed automatically — while the
`EngineBufferManager` might be processing further allocations requested
by that very thread, and dispatch them towards an already destroyed `LocalMemPool`
This turns out to be a nasty problem, since the whole setup was created
to allow the workers to operate independently from each other; any handshake
or registration/deregistration mechanism would require a lock of sorts,
thereby defeating the whole purpose of the setup.
The best solution I could find is to rely on a instance marker hash,
that can be checked with an atomic read prior to each dispatch of a
memory allocation. The destructor of the local pool would then be able
to ''disengage'', by invalidating that hash.
To evaluate this solution, I developed this mechanism
as a free-standing library component, called `LiveMark`
Most relevant parts of the `LocalBufferStore` are already available
and just need to be connected. One point poses a challenge however:
when and how to trigger the heuristic clean-up of the local pool,
so that ''on average neither too much memory is wasted, nor
to much unnecessary allocations'' are performed...
Signed-off-by: Ichthyostega <prg@ichthyostega.de>
As staring point, it is clear that the `BufferStore` side of the
implementation will rely on a similar structure with a thread-local
base service — which in this case will have to maintain a small pool
of recently used buffer allocations...
