Vulkan Memory Allocator
Classes | Typedefs | Enumerations | Functions
Virtual allocator

API elements related to the mechanism of Virtual allocator - using the core allocation algorithm for user-defined purpose without allocating any real GPU memory. More...

Classes

struct  VmaVirtualBlockCreateInfo
 Parameters of created VmaVirtualBlock object to be passed to vmaCreateVirtualBlock(). More...
 
struct  VmaVirtualAllocationCreateInfo
 Parameters of created virtual allocation to be passed to vmaVirtualAllocate(). More...
 
struct  VmaVirtualAllocationInfo
 Parameters of an existing virtual allocation, returned by vmaGetVirtualAllocationInfo(). More...
 
struct  VmaVirtualAllocation
 Represents single memory allocation done inside VmaVirtualBlock. More...
 
struct  VmaVirtualBlock
 Handle to a virtual block object that allows to use core allocation algorithm without allocating any real GPU memory. More...
 

Typedefs

typedef enum VmaVirtualBlockCreateFlagBits VmaVirtualBlockCreateFlagBits
 Flags to be passed as VmaVirtualBlockCreateInfo::flags. More...
 
typedef VkFlags VmaVirtualBlockCreateFlags
 Flags to be passed as VmaVirtualBlockCreateInfo::flags. See VmaVirtualBlockCreateFlagBits. More...
 
typedef enum VmaVirtualAllocationCreateFlagBits VmaVirtualAllocationCreateFlagBits
 Flags to be passed as VmaVirtualAllocationCreateInfo::flags. More...
 
typedef VkFlags VmaVirtualAllocationCreateFlags
 Flags to be passed as VmaVirtualAllocationCreateInfo::flags. See VmaVirtualAllocationCreateFlagBits. More...
 
typedef struct VmaVirtualBlockCreateInfo VmaVirtualBlockCreateInfo
 Parameters of created VmaVirtualBlock object to be passed to vmaCreateVirtualBlock(). More...
 
typedef struct VmaVirtualAllocationCreateInfo VmaVirtualAllocationCreateInfo
 Parameters of created virtual allocation to be passed to vmaVirtualAllocate(). More...
 
typedef struct VmaVirtualAllocationInfo VmaVirtualAllocationInfo
 Parameters of an existing virtual allocation, returned by vmaGetVirtualAllocationInfo(). More...
 

Enumerations

enum  VmaVirtualBlockCreateFlagBits {
  VMA_VIRTUAL_BLOCK_CREATE_LINEAR_ALGORITHM_BIT = 0x00000001 , VMA_VIRTUAL_BLOCK_CREATE_BUDDY_ALGORITHM_BIT = 0x00000002 , VMA_VIRTUAL_BLOCK_CREATE_TLSF_ALGORITHM_BIT = 0x00000004 , VMA_VIRTUAL_BLOCK_CREATE_ALGORITHM_MASK ,
  VMA_VIRTUAL_BLOCK_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
}
 Flags to be passed as VmaVirtualBlockCreateInfo::flags. More...
 
enum  VmaVirtualAllocationCreateFlagBits {
  VMA_VIRTUAL_ALLOCATION_CREATE_UPPER_ADDRESS_BIT = VMA_ALLOCATION_CREATE_UPPER_ADDRESS_BIT , VMA_VIRTUAL_ALLOCATION_CREATE_STRATEGY_MIN_MEMORY_BIT = VMA_ALLOCATION_CREATE_STRATEGY_MIN_MEMORY_BIT , VMA_VIRTUAL_ALLOCATION_CREATE_STRATEGY_MIN_TIME_BIT = VMA_ALLOCATION_CREATE_STRATEGY_MIN_TIME_BIT , VMA_VIRTUAL_ALLOCATION_CREATE_STRATEGY_MASK = VMA_ALLOCATION_CREATE_STRATEGY_MASK ,
  VMA_VIRTUAL_ALLOCATION_CREATE_FLAG_BITS_MAX_ENUM = 0x7FFFFFFF
}
 Flags to be passed as VmaVirtualAllocationCreateInfo::flags. More...
 

Functions

 VK_DEFINE_NON_DISPATCHABLE_HANDLE (VmaVirtualAllocation)
 
VkResult vmaCreateVirtualBlock (const VmaVirtualBlockCreateInfo *pCreateInfo, VmaVirtualBlock *pVirtualBlock)
 Creates new VmaVirtualBlock object. More...
 
void vmaDestroyVirtualBlock (VmaVirtualBlock virtualBlock)
 Destroys VmaVirtualBlock object. More...
 
VkBool32 vmaIsVirtualBlockEmpty (VmaVirtualBlock virtualBlock)
 Returns true of the VmaVirtualBlock is empty - contains 0 virtual allocations and has all its space available for new allocations. More...
 
void vmaGetVirtualAllocationInfo (VmaVirtualBlock virtualBlock, VmaVirtualAllocation allocation, VmaVirtualAllocationInfo *pVirtualAllocInfo)
 Returns information about a specific virtual allocation within a virtual block, like its size and pUserData pointer. More...
 
VkResult vmaVirtualAllocate (VmaVirtualBlock virtualBlock, const VmaVirtualAllocationCreateInfo *pCreateInfo, VmaVirtualAllocation *pAllocation, VkDeviceSize *pOffset)
 Allocates new virtual allocation inside given VmaVirtualBlock. More...
 
void vmaVirtualFree (VmaVirtualBlock virtualBlock, VmaVirtualAllocation allocation)
 Frees virtual allocation inside given VmaVirtualBlock. More...
 
void vmaClearVirtualBlock (VmaVirtualBlock virtualBlock)
 Frees all virtual allocations inside given VmaVirtualBlock. More...
 
void vmaSetVirtualAllocationUserData (VmaVirtualBlock virtualBlock, VmaVirtualAllocation allocation, void *pUserData)
 Changes custom pointer associated with given virtual allocation. More...
 
void vmaCalculateVirtualBlockStats (VmaVirtualBlock virtualBlock, VmaStatInfo *pStatInfo)
 Calculates and returns statistics about virtual allocations and memory usage in given VmaVirtualBlock. More...
 

Detailed Description

API elements related to the mechanism of Virtual allocator - using the core allocation algorithm for user-defined purpose without allocating any real GPU memory.

Typedef Documentation

◆ VmaVirtualAllocationCreateFlagBits

Flags to be passed as VmaVirtualAllocationCreateInfo::flags.

◆ VmaVirtualAllocationCreateFlags

◆ VmaVirtualAllocationCreateInfo

Parameters of created virtual allocation to be passed to vmaVirtualAllocate().

◆ VmaVirtualAllocationInfo

Parameters of an existing virtual allocation, returned by vmaGetVirtualAllocationInfo().

◆ VmaVirtualBlockCreateFlagBits

Flags to be passed as VmaVirtualBlockCreateInfo::flags.

◆ VmaVirtualBlockCreateFlags

typedef VkFlags VmaVirtualBlockCreateFlags

◆ VmaVirtualBlockCreateInfo

Parameters of created VmaVirtualBlock object to be passed to vmaCreateVirtualBlock().

Enumeration Type Documentation

◆ VmaVirtualAllocationCreateFlagBits

Flags to be passed as VmaVirtualAllocationCreateInfo::flags.

Enumerator
VMA_VIRTUAL_ALLOCATION_CREATE_UPPER_ADDRESS_BIT 

Allocation will be created from upper stack in a double stack pool.

This flag is only allowed for virtual blocks created with VMA_VIRTUAL_BLOCK_CREATE_LINEAR_ALGORITHM_BIT flag.

VMA_VIRTUAL_ALLOCATION_CREATE_STRATEGY_MIN_MEMORY_BIT 

Allocation strategy that tries to minimize memory usage.

VMA_VIRTUAL_ALLOCATION_CREATE_STRATEGY_MIN_TIME_BIT 

Allocation strategy that tries to minimize allocation time.

VMA_VIRTUAL_ALLOCATION_CREATE_STRATEGY_MASK 

A bit mask to extract only STRATEGY bits from entire set of flags.

These strategy flags are binary compatible with equivalent flags in VmaAllocationCreateFlagBits.

VMA_VIRTUAL_ALLOCATION_CREATE_FLAG_BITS_MAX_ENUM 

◆ VmaVirtualBlockCreateFlagBits

Flags to be passed as VmaVirtualBlockCreateInfo::flags.

Enumerator
VMA_VIRTUAL_BLOCK_CREATE_LINEAR_ALGORITHM_BIT 

Enables alternative, linear allocation algorithm in this virtual block.

Specify this flag to enable linear allocation algorithm, which always creates new allocations after last one and doesn't reuse space from allocations freed in between. It trades memory consumption for simplified algorithm and data structure, which has better performance and uses less memory for metadata.

By using this flag, you can achieve behavior of free-at-once, stack, ring buffer, and double stack. For details, see documentation chapter Linear allocation algorithm.

VMA_VIRTUAL_BLOCK_CREATE_BUDDY_ALGORITHM_BIT 

Enables alternative, buddy allocation algorithm in this virtual block.

It operates on a tree of blocks, each having size that is a power of two and a half of its parent's size. Comparing to default algorithm, this one provides faster allocation and deallocation and decreased external fragmentation, at the expense of more memory wasted (internal fragmentation). For details, see documentation chapter Buddy allocation algorithm.

VMA_VIRTUAL_BLOCK_CREATE_TLSF_ALGORITHM_BIT 

Enables alternative, TLSF allocation algorithm in virtual block.

This algorithm is based on 2-level lists dividing address space into smaller chunks. The first level is aligned to power of two which serves as buckets for requested memory to fall into, and the second level is lineary subdivided into lists of free memory. This algorithm aims to achieve bounded response time even in the worst case scenario. Allocation time can be sometimes slightly longer than compared to other algorithms but in return the application can avoid stalls in case of fragmentation, giving predictable results, suitable for real-time use cases.

VMA_VIRTUAL_BLOCK_CREATE_ALGORITHM_MASK 

Bit mask to extract only ALGORITHM bits from entire set of flags.

VMA_VIRTUAL_BLOCK_CREATE_FLAG_BITS_MAX_ENUM 

Function Documentation

◆ VK_DEFINE_NON_DISPATCHABLE_HANDLE()

VK_DEFINE_NON_DISPATCHABLE_HANDLE ( VmaVirtualAllocation  )

◆ vmaCalculateVirtualBlockStats()

void vmaCalculateVirtualBlockStats ( VmaVirtualBlock  virtualBlock,
VmaStatInfo pStatInfo 
)

Calculates and returns statistics about virtual allocations and memory usage in given VmaVirtualBlock.

◆ vmaClearVirtualBlock()

void vmaClearVirtualBlock ( VmaVirtualBlock  virtualBlock)

Frees all virtual allocations inside given VmaVirtualBlock.

You must either call this function or free each virtual allocation individually with vmaVirtualFree() before destroying a virtual block. Otherwise, an assert is called.

If you keep pointer to some additional metadata associated with your virtual allocation in its pUserData, don't forget to free it as well.

◆ vmaCreateVirtualBlock()

VkResult vmaCreateVirtualBlock ( const VmaVirtualBlockCreateInfo pCreateInfo,
VmaVirtualBlock pVirtualBlock 
)

Creates new VmaVirtualBlock object.

Parameters
pCreateInfoParameters for creation.
[out]pVirtualBlockReturned virtual block object or VMA_NULL if creation failed.

◆ vmaDestroyVirtualBlock()

void vmaDestroyVirtualBlock ( VmaVirtualBlock  virtualBlock)

Destroys VmaVirtualBlock object.

Please note that you should consciously handle virtual allocations that could remain unfreed in the block. You should either free them individually using vmaVirtualFree() or call vmaClearVirtualBlock() if you are sure this is what you want. If you do neither, an assert is called.

If you keep pointers to some additional metadata associated with your virtual allocations in their pUserData, don't forget to free them.

◆ vmaGetVirtualAllocationInfo()

void vmaGetVirtualAllocationInfo ( VmaVirtualBlock  virtualBlock,
VmaVirtualAllocation  allocation,
VmaVirtualAllocationInfo pVirtualAllocInfo 
)

Returns information about a specific virtual allocation within a virtual block, like its size and pUserData pointer.

◆ vmaIsVirtualBlockEmpty()

VkBool32 vmaIsVirtualBlockEmpty ( VmaVirtualBlock  virtualBlock)

Returns true of the VmaVirtualBlock is empty - contains 0 virtual allocations and has all its space available for new allocations.

◆ vmaSetVirtualAllocationUserData()

void vmaSetVirtualAllocationUserData ( VmaVirtualBlock  virtualBlock,
VmaVirtualAllocation  allocation,
void *  pUserData 
)

Changes custom pointer associated with given virtual allocation.

◆ vmaVirtualAllocate()

VkResult vmaVirtualAllocate ( VmaVirtualBlock  virtualBlock,
const VmaVirtualAllocationCreateInfo pCreateInfo,
VmaVirtualAllocation pAllocation,
VkDeviceSize *  pOffset 
)

Allocates new virtual allocation inside given VmaVirtualBlock.

There is no handle type for a virtual allocation. Virtual allocations within a specific virtual block are uniquely identified by their offsets.

If the allocation fails due to not enough free space available, VK_ERROR_OUT_OF_DEVICE_MEMORY is returned (despite the function doesn't ever allocate actual GPU memory).

Parameters
virtualBlockVirtual block
pCreateInfoParameters for the allocation
[out]pAllocationReturned handle of the new allocation
[out]pOffsetReturned offset of the new allocation. Optional, can be null.

◆ vmaVirtualFree()

void vmaVirtualFree ( VmaVirtualBlock  virtualBlock,
VmaVirtualAllocation  allocation 
)

Frees virtual allocation inside given VmaVirtualBlock.