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genode/base-foc/src/base/env/cap_sel_alloc.cc

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Imported Genode release 11.11
2011-12-22 16:19:25 +01:00
/*
Fiasco.OC: Re-use existing capability selectors This is an interim fix for issue #112. This patch extends the 'Capability_allocator' class with the ability to register the global ID of a Genode capability so that the ID gets associated with a process-local kernel capability. Whenever a Genode capability gets unmarshalled from an IPC message, the capability-allocator is asked, with the global ID as key, whether the kernel-cap already exists. This significantly reduces the waste of kernel-capability slots. To circumvent problems of having one and the same ID for different kernel objects, the following problems had to be solved: * Replace pseudo IDs with unique ones from core's badge allocator * When freeing a session object, free the global ID _after_ unmapping the kernel object, otherwise the global ID might get re-used in some process and the registry will find a valid but wrong capability for the ID Because core aggregates all capabilities of all different processes, its capability registry needs much more memory compared to a regular process. By parametrizing capability allocators differently for core and non-core processes, the global memory overhead for capability registries is kept at a reasonable level.
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* \brief Capability-selector allocator for non-core tasks.
Imported Genode release 11.11
2011-12-22 16:19:25 +01:00
* \author Stefan Kalkowski
* \date 2010-12-06
*
* This is a Fiasco.OC-specific addition to the process enviroment.
*/
/*
Bump year in copyright headers to 2012
2012-01-03 15:35:05 +01:00
* Copyright (C) 2010-2012 Genode Labs GmbH
Imported Genode release 11.11
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*
* This file is part of the Genode OS framework, which is distributed
* under the terms of the GNU General Public License version 2.
*/
/* Genode includes */
#include <base/cap_sel_alloc.h>
Fiasco.OC: Re-use existing capability selectors This is an interim fix for issue #112. This patch extends the 'Capability_allocator' class with the ability to register the global ID of a Genode capability so that the ID gets associated with a process-local kernel capability. Whenever a Genode capability gets unmarshalled from an IPC message, the capability-allocator is asked, with the global ID as key, whether the kernel-cap already exists. This significantly reduces the waste of kernel-capability slots. To circumvent problems of having one and the same ID for different kernel objects, the following problems had to be solved: * Replace pseudo IDs with unique ones from core's badge allocator * When freeing a session object, free the global ID _after_ unmapping the kernel object, otherwise the global ID might get re-used in some process and the registry will find a valid but wrong capability for the ID Because core aggregates all capabilities of all different processes, its capability registry needs much more memory compared to a regular process. By parametrizing capability allocators differently for core and non-core processes, the global memory overhead for capability registries is kept at a reasonable level.
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Genode::Capability_allocator* Genode::cap_alloc()
Imported Genode release 11.11
2011-12-22 16:19:25 +01:00
{
Fiasco.OC: Reduce capability-allocator size The old variant provided 8K capability slots to all processes on core, which increased binaries by 180 KB for the static allocator. I reduced it to 4K capabilities stay under 100 KB overhead for the allocator. Anyway, pci_drv and pl11x_drv need more RAM quota now: 2M for pl11x_drv and 1M for pci_drv.
2012-02-28 10:48:37 +01:00
static Genode::Capability_allocator_tpl<4096> _alloc;
Fiasco.OC: Re-use existing capability selectors This is an interim fix for issue #112. This patch extends the 'Capability_allocator' class with the ability to register the global ID of a Genode capability so that the ID gets associated with a process-local kernel capability. Whenever a Genode capability gets unmarshalled from an IPC message, the capability-allocator is asked, with the global ID as key, whether the kernel-cap already exists. This significantly reduces the waste of kernel-capability slots. To circumvent problems of having one and the same ID for different kernel objects, the following problems had to be solved: * Replace pseudo IDs with unique ones from core's badge allocator * When freeing a session object, free the global ID _after_ unmapping the kernel object, otherwise the global ID might get re-used in some process and the registry will find a valid but wrong capability for the ID Because core aggregates all capabilities of all different processes, its capability registry needs much more memory compared to a regular process. By parametrizing capability allocators differently for core and non-core processes, the global memory overhead for capability registries is kept at a reasonable level.
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return &_alloc;
Imported Genode release 11.11
2011-12-22 16:19:25 +01:00
}