Vulkan Memory Allocator
Custom memory pools

A memory pool contains a number of VkDeviceMemory blocks. The library automatically creates and manages default pool for each memory type available on the device. Default memory pool automatically grows in size. Size of allocated blocks is also variable and managed automatically.

You can create custom pool and allocate memory out of it. It can be useful if you want to:

To use custom memory pools:

  1. Fill VmaPoolCreateInfo structure.
  2. Call vmaCreatePool() to obtain VmaPool handle.
  3. When making an allocation, set VmaAllocationCreateInfo::pool to this handle. You don't need to specify any other parameters of this structure, like usage.

Example:

// Create a pool that can have at most 2 blocks, 128 MiB each.
VmaPoolCreateInfo poolCreateInfo = {};
poolCreateInfo.memoryTypeIndex = ...
poolCreateInfo.blockSize = 128ull * 1024 * 1024;
poolCreateInfo.maxBlockCount = 2;
VmaPool pool;
vmaCreatePool(allocator, &poolCreateInfo, &pool);
// Allocate a buffer out of it.
VkBufferCreateInfo bufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
bufCreateInfo.size = 1024;
bufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT;
VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.pool = pool;
VkBuffer buf;
VmaAllocation alloc;
vmaCreateBuffer(allocator, &bufCreateInfo, &allocCreateInfo, &buf, &alloc, &allocInfo);

You have to free all allocations made from this pool before destroying it.

vmaDestroyBuffer(allocator, buf, alloc);
vmaDestroyPool(allocator, pool);

Choosing memory type index

When creating a pool, you must explicitly specify memory type index. To find the one suitable for your buffers or images, you can use helper functions vmaFindMemoryTypeIndexForBufferInfo(), vmaFindMemoryTypeIndexForImageInfo(). You need to provide structures with example parameters of buffers or images that you are going to create in that pool.

VkBufferCreateInfo exampleBufCreateInfo = { VK_STRUCTURE_TYPE_BUFFER_CREATE_INFO };
exampleBufCreateInfo.size = 1024; // Whatever.
exampleBufCreateInfo.usage = VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT; // Change if needed.
VmaAllocationCreateInfo allocCreateInfo = {};
allocCreateInfo.usage = VMA_MEMORY_USAGE_GPU_ONLY; // Change if needed.
uint32_t memTypeIndex;
vmaFindMemoryTypeIndexForBufferInfo(allocator, &exampleBufCreateInfo, &allocCreateInfo, &memTypeIndex);
VmaPoolCreateInfo poolCreateInfo = {};
poolCreateInfo.memoryTypeIndex = memTypeIndex;
// ...

When creating buffers/images allocated in that pool, provide following parameters: