On base-hw/x86_64 the quota of the signal session is not sufficient due to
the large size of the Signal_session_component. Increasing the quota to
16K avoids signal-context resource exhaustion messages as emmitted by the
run/launcher scenario:
...
Quota exceeded! amount=4096, size=4096, consumed=4096
failed to allocate signal-context resources
upgrading quota donation for signal session
C++ runtime: Genode::Parent::Quota_exceeded
void* abort(): abort called
...
Note: This change increases the quota for all kernels even though it is
strictly only required for base-hw/x86_64.
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
