VkSystemAllocationScope - Allocation scope

Description

• SYSTEM_ALLOCATION_SCOPE_COMMAND specifies that the allocation is scoped to the duration of the Vulkan command.

• SYSTEM_ALLOCATION_SCOPE_OBJECT specifies that the allocation is scoped to the lifetime of the Vulkan object that is being created or used.
• SYSTEM_ALLOCATION_SCOPE_CACHE specifies that the allocation is scoped to the lifetime of a PipelineCache or ValidationCacheEXT object.
• SYSTEM_ALLOCATION_SCOPE_DEVICE specifies that the allocation is scoped to the lifetime of the Vulkan device.
• SYSTEM_ALLOCATION_SCOPE_INSTANCE specifies 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 SYSTEM_ALLOCATION_SCOPE_OBJECT or 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 SYSTEM_ALLOCATION_SCOPE_COMMAND allocation 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 parent Device has an allocator it will be used, else if the parent Instance has an allocator it will be used. Else,
• If an allocation is associated with a ValidationCacheEXT or PipelineCache object, the allocator will use the SYSTEM_ALLOCATION_SCOPE_CACHE allocation 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 Device or Instance, the allocator will use an allocation scope of 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 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 SYSTEM_ALLOCATION_SCOPE_INSTANCE.
• Otherwise an implementation will allocate memory through an alternative mechanism that is unspecified.

See Also

AllocationCallbacks