This patch reduces the number of exception types by facilitating
globally defined exceptions for common usage patterns shared by most
services. In particular, RPC functions that demand a session-resource
upgrade not longer reflect this condition via a session-specific
exception but via the 'Out_of_ram' or 'Out_of_caps' types.
Furthermore, the 'Parent::Service_denied', 'Parent::Unavailable',
'Root::Invalid_args', 'Root::Unavailable', 'Service::Invalid_args',
'Service::Unavailable', and 'Local_service::Factory::Denied' types have
been replaced by the single 'Service_denied' exception type defined in
'session/session.h'.
This consolidation eases the error handling (there are fewer exceptions
to handle), alleviates the need to convert exceptions along the
session-creation call chain, and avoids possible aliasing problems
(catching the wrong type with the same name but living in a different
scope).
This patch mirrors the accounting and trading scheme that Genode employs
for physical memory to the accounting of capability allocations.
Capability quotas must now be explicitly assigned to subsystems by
specifying a 'caps=<amount>' attribute to init's start nodes.
Analogously to RAM quotas, cap quotas can be traded between clients and
servers as part of the session protocol. The capability budget of each
component is maintained by the component's corresponding PD session at
core.
At the current stage, the accounting is applied to RPC capabilities,
signal-context capabilities, and dataspace capabilities. Capabilities
that are dynamically allocated via core's CPU and TRACE service are not
yet covered. Also, the capabilities allocated by resource multiplexers
outside of core (like nitpicker) must be accounted by the respective
servers, which is not covered yet.
If a component runs out of capabilities, core's PD service prints a
warning to the log. To observe the consumption of capabilities per
component in detail, the PD service is equipped with a diagnostic
mode, which can be enabled via the 'diag' attribute in the target
node of init's routing rules. E.g., the following route enables the
diagnostic mode for the PD session of the "timer" component:
<default-route>
<service name="PD" unscoped_label="timer">
<parent diag="yes"/>
</service>
...
</default-route>
For subsystems based on a sub-init instance, init can be configured
to report the capability-quota information of its subsystems by
adding the attribute 'child_caps="yes"' to init's '<report>'
config node. Init's own capability quota can be reported by adding
the attribute 'init_caps="yes"'.
Fixes#2398
This patch reworks the implementation of core's RAM service to make use
of the 'Session_object' and to remove the distinction between the
"metadata" quota and the managed RAM quota. With the new implementation,
the session implicitly allocates its metadata from its own account. So
there is not need to handle 'Out_of_metadata' and 'Quota_exceeded' via
different exceptions. Instead, the new version solely uses the
'Out_of_ram' exception.
Furthermore, the 'Allocator::Out_of_memory' exception has become an alias
for 'Out_of_ram', which simplifies the error handling.
Issue #2398
The 'Session_object' unifies several aspects of server-component
implementations:
* It keeps track of session quotas and is equipped with standardized
interfaces (Quota_guard) to upgrade (and in the future potentially
downgrade) session quotas in a uniform way.
* It follows the pattern of modern RPC objects / signal handlers that
manage/dissolve themselves at the entrypoint given as constructor
argument. Thereby, the relationship with its entrypoint is always
coupled with the lifetime of the session-component object.
* It stores the session label, which was previously done manually by
most but not all server-component implementations.
* It stores the session 'diag' flag.
* It is equipped with output methods 'diag', 'error', and 'warning'.
All messages printed from the context of a session component is
automatically prefixed with the session type and client label.
Messages passed via 'diag' are only printed if the 'diag' flag of
the session is set.
Issue #2398
The 'diag' flag can be defined by a target node of a route in init's
configuration. It is propagated as session argument to the server, which
may evaluate the flag to enable diagnostic output for the corresponding
session.
Issue #2398
This patch makes use of the new 'Quota_transfer::Account' by the service
types in base/service.h and uses 'Quota_transfer' objects in
base/child.cc and init/server.cc.
Furthermore, it decouples the notion of an 'Async_service' from
'Child_service'. Init's 'Routed_service' is no longer a 'Child_service'
but is based on the new 'Async_service' instead.
With this patch in place, quota transfers do no longer implicitly use
'Ram_session_client' objects. So transfers can in principle originate
from component-local 'Ram_session_component' objects, e.g., as used by
noux. Therefore, this patch removes a strumbling block for turning noux
into a single threaded component in the future.
Issue #2398
The 'Quota_transfer' helper facilitated the implementation of quota
transfers between components in a transactional manner. It is designated
for framework-internal use (replacing the 'Transfer' class in child.h).
However, since it is also useful for init, we make it publicly
available.
The 'Quota_transfer::Account' class serves as an interface representing
the donor or receiver of quotas (parent, service, client).
Issue #2398
This patch replaces the 'Parent::Quota_exceeded',
'Service::Quota_exceeded', and 'Root::Quota_exceeded' exceptions
by the single 'Insufficient_ram_quota' exception type.
Furthermore, the 'Parent' interface distinguished now between
'Out_of_ram' (the child's RAM is exhausted) from
'Insufficient_ram_quota' (the child's RAM donation does not suffice to
establish the session).
This eliminates ambiguities and removes the need to convert exception
types along the path of the session creation.
Issue #2398
This patch adds sanity checks to the RPC entrypoint that detect attempts
to manage or dissolve the same RPC object twice. This is not always a
bug. I.e., if RPC objects are implemented in the modern way where the
object manages/dissolves itself. As the generic framework code (in
particular root/component.h) cannot rely on this pattern, it has to
call manage/dissolve for session objects anyway. For modern session
objects, this double attempt would result in a serious error (double
insertion into the object pool's AVL tree).
Issue #2398
This patch replaces the former use of size_t with the use of the
'Ram_quota' type to improve type safety (in particular to avoid
accidentally mixing up RAM quotas with cap quotas).
Issue #2398
The 'Ram_allocator' interface contains the subset of the RAM session
interface that is needed to satisfy the needs of the 'Heap' and
'Sliced_heap'. Its small size makes it ideal for intercepting memory
allocations as done by the new 'Constrained_ram_allocator' wrapper
class, which is meant to replace the existing 'base/allocator_guard.h'
and 'os/ram_session_guard.h'.
Issue #2398
This patch augments the existing session/session.h with useful types for
the session creation:
* The new 'Insufficient_ram_quota' and 'Insufficient_cap_quota'
exceptions are meant to supersede the old 'Quota_exceeded' exception
of the 'Parent' and 'Root' interfaces.
* The 'Session::Resources' struct subsumes the information about the
session quota provided by the client.
* The boolean 'Session::Diag' type will allow sessions to operate in a
diagnostic mode.
* The existing 'Session_label' is not also available under the alias
'Session::Label'.
* A few helper functions ease the extraction of typed session arguments
from the session-argument string.
Issue #2398
This patch upgrades the cap-space slab only if the kernel runs out of
entries, instead of consuming as much PD-session quota as possible.
Until now, the behavior worked well because the cap-space slab was the
only consumer of PD-session quota. However, once we start accounting all
PD session meta data - and eventually merging the PD and RAM services -
the aggressive scheme stands in the way.
Issue #2398
This accessor is useful to eagerly expand the slab with new slab blocks,
side stepping the slab's built-in policy for the allocation of new slab
blocks.
This is particularly important when using the slab for allocating the
cap space meta-data for the base-hw kernel. To guarantee that the slab
gets never exhausted in the kernel, it is expanded before entering the
kernel.
With the introduction of the 'Out_of_caps' exception type, the slab
needs to consider exceptions during the call of '_new_slab_block' by
reverting the 'nested' state.
The old download location is very shaky resp. currently unavailable and
also other projects (e.g., Gentoo and Linux From Scratch) use this
location. Note, the archive hash does _not_ change.
By building the posix library as shared object with an ABI, we
effectively decouple posix-using programs from the library
implementation (which happens to depend on several os-level APIs such as
the VFS).
This commit moves the headers residing in `repos/base/include/spec/*/drivers`
to `repos/base/include/drivers/defs` or repos/base/include/drivers/uart`
respectively. The first one contains definitions about board-specific MMIO
iand RAM addresses, or IRQ lines. While the latter contains device driver
code for UART devices. Those definitions are used by driver implementations
in `repos/base-hw`, `repos/os`, and `repos/dde-linux`, which now need to
include them more explicitely.
This work is a step in the direction of reducing 'SPEC' identifiers overall.
Ref #2403
causes the rem timer callback pending check to run more often (every 1 ms
instead 10 ms). This is essential to met the timeout requirements of the
audio backend, which must be checked&run every 5ms.
