C Specification
Each allocation has an allocation scope defining its lifetime and which
object it is associated with.
Possible values passed to the allocationScope parameter of the
callback functions specified by VkAllocationCallbacks, indicating the
allocation scope, are:
typedef enum VkSystemAllocationScope {
VK_SYSTEM_ALLOCATION_SCOPE_COMMAND = 0,
VK_SYSTEM_ALLOCATION_SCOPE_OBJECT = 1,
VK_SYSTEM_ALLOCATION_SCOPE_CACHE = 2,
VK_SYSTEM_ALLOCATION_SCOPE_DEVICE = 3,
VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE = 4,
VK_SYSTEM_ALLOCATION_SCOPE_MAX_ENUM = 0x7FFFFFFF
} VkSystemAllocationScope;
Description
-
VK_SYSTEM_ALLOCATION_SCOPE_COMMANDspecifies that the allocation is scoped to the duration of the Vulkan command. -
VK_SYSTEM_ALLOCATION_SCOPE_OBJECTspecifies that the allocation is scoped to the lifetime of the Vulkan object that is being created or used. -
VK_SYSTEM_ALLOCATION_SCOPE_CACHEspecifies that the allocation is scoped to the lifetime of aVkPipelineCacheorVkValidationCacheEXTobject. -
VK_SYSTEM_ALLOCATION_SCOPE_DEVICEspecifies that the allocation is scoped to the lifetime of the Vulkan device. -
VK_SYSTEM_ALLOCATION_SCOPE_INSTANCEspecifies that the allocation is scoped to the lifetime of the Vulkan instance.
Most Vulkan commands operate on a single object, or there is a sole object
that is being created or manipulated.
When an allocation uses an allocation scope of
VK_SYSTEM_ALLOCATION_SCOPE_OBJECT or
VK_SYSTEM_ALLOCATION_SCOPE_CACHE, the allocation is scoped to the
object being created or manipulated.
When an implementation requires host memory, it will make callbacks to the application using the most specific allocator and allocation scope available:
-
If an allocation is scoped to the duration of a command, the allocator will use the
VK_SYSTEM_ALLOCATION_SCOPE_COMMANDallocation scope. The most specific allocator available is used: if the object being created or manipulated has an allocator, that object’s allocator will be used, else if the parentVkDevicehas an allocator it will be used, else if the parentVkInstancehas an allocator it will be used. Else, -
If an allocation is associated with a
VkValidationCacheEXTorVkPipelineCacheobject, the allocator will use theVK_SYSTEM_ALLOCATION_SCOPE_CACHEallocation scope. The most specific allocator available is used (cache, else device, else instance). Else, -
If an allocation is scoped to the lifetime of an object, that object is being created or manipulated by the command, and that object’s type is not
VkDeviceorVkInstance, the allocator will use an allocation scope ofVK_SYSTEM_ALLOCATION_SCOPE_OBJECT. The most specific allocator available is used (object, else device, else instance). Else, -
If an allocation is scoped to the lifetime of a device, the allocator will use an allocation scope of
VK_SYSTEM_ALLOCATION_SCOPE_DEVICE. The most specific allocator available is used (device, else instance). Else, -
If the allocation is scoped to the lifetime of an instance and the instance has an allocator, its allocator will be used with an allocation scope of
VK_SYSTEM_ALLOCATION_SCOPE_INSTANCE. -
Otherwise an implementation will allocate memory through an alternative mechanism that is unspecified.
See Also
Document Notes
For more information, see the Vulkan Specification
This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.
Copyright
Copyright (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.