fixed-size transfer pool

src/Refresh_Driver_Vulkan.c

@@ -75,6 +75,7 @@ static uint32_t deviceExtensionCount = SDL_arraysize(deviceExtensionNames);
 #define MAX_ALLOCATION_SIZE 256000000 		    /* 256MB */
 #define ALLOCATION_INCREMENT 16000000           /* 16MB */
 #define TRANSFER_BUFFER_STARTING_SIZE 8000000 	/* 8MB */
+#define POOLED_TRANSFER_BUFFER_SIZE 16000000    /* 16MB */
 #define UBO_BUFFER_SIZE 16000 			        /* 16KB */
 #define DESCRIPTOR_POOL_STARTING_SIZE 128
 #define WINDOW_DATA "Refresh_VulkanWindowData"
@@ -1516,8 +1517,18 @@ typedef struct VulkanTransferBuffer
 {
 	VulkanBuffer* buffer;
 	VkDeviceSize offset;
+	uint8_t fromPool;
 } VulkanTransferBuffer;
 
+typedef struct VulkanTransferBufferPool
+{
+	SDL_mutex *lock;
+
+	VulkanTransferBuffer **availableBuffers;
+	uint32_t availableBufferCount;
+	uint32_t availableBufferCapacity;
+} VulkanTransferBufferPool;
+
 typedef struct VulkanCommandPool VulkanCommandPool;
 
 typedef struct VulkanCommandBuffer
@@ -1723,6 +1734,8 @@ typedef struct VulkanRenderer
 	uint32_t submittedCommandBufferCount;
 	uint32_t submittedCommandBufferCapacity;
 
+	VulkanTransferBufferPool transferBufferPool;
+
 	CommandPoolHashTable commandPoolHashTable;
 	DescriptorSetLayoutHashTable descriptorSetLayoutHashTable;
 	GraphicsPipelineLayoutHashTable graphicsPipelineLayoutHashTable;
@@ -5151,6 +5164,15 @@ static void VULKAN_DestroyDevice(
 	SDL_free(renderer->dummyFragmentUniformBuffer);
 	SDL_free(renderer->dummyComputeUniformBuffer);
 
+	for (i = 0; i < renderer->transferBufferPool.availableBufferCount; i += 1)
+	{
+		VULKAN_INTERNAL_DestroyBuffer(renderer, renderer->transferBufferPool.availableBuffers[i]->buffer);
+		SDL_free(renderer->transferBufferPool.availableBuffers[i]);
+	}
+
+	SDL_free(renderer->transferBufferPool.availableBuffers);
+	SDL_DestroyMutex(renderer->transferBufferPool.lock);
+
 	for (i = 0; i < NUM_COMMAND_POOL_BUCKETS; i += 1)
 	{
 		commandPoolHashArray = renderer->commandPoolHashTable.buckets[i];
@@ -7099,6 +7121,40 @@ static VulkanTransferBuffer* VULKAN_INTERNAL_AcquireTransferBuffer(
 		}
 	}
 
+	/* Nothing fits, can we get a transfer buffer from the pool? */
+
+	SDL_LockMutex(renderer->transferBufferPool.lock);
+
+	for (i = 0; i < renderer->transferBufferPool.availableBufferCount; i += 1)
+	{
+		transferBuffer = renderer->transferBufferPool.availableBuffers[i];
+		offset = transferBuffer->offset + alignment - (transferBuffer->offset % alignment);
+
+		if (offset + requiredSize <= transferBuffer->buffer->size)
+		{
+			if (commandBuffer->transferBufferCount == commandBuffer->transferBufferCapacity)
+			{
+				commandBuffer->transferBufferCapacity *= 2;
+				commandBuffer->transferBuffers = SDL_realloc(
+					commandBuffer->transferBuffers,
+					commandBuffer->transferBufferCapacity * sizeof(VulkanTransferBuffer*)
+				);
+			}
+
+			commandBuffer->transferBuffers[commandBuffer->transferBufferCount] = transferBuffer;
+			commandBuffer->transferBufferCount += 1;
+
+			renderer->transferBufferPool.availableBuffers[i] = renderer->transferBufferPool.availableBuffers[renderer->transferBufferPool.availableBufferCount - 1];
+			renderer->transferBufferPool.availableBufferCount -= 1;
+			SDL_UnlockMutex(renderer->transferBufferPool.lock);
+
+			transferBuffer->offset = offset;
+			return transferBuffer;
+		}
+	}
+
+	SDL_UnlockMutex(renderer->transferBufferPool.lock);
+
 	/* Nothing fits, so let's create a new transfer buffer */
 
 	size = TRANSFER_BUFFER_STARTING_SIZE;
@@ -7118,10 +7174,12 @@ static VulkanTransferBuffer* VULKAN_INTERNAL_AcquireTransferBuffer(
 		1,
 		1
 	);
+	transferBuffer->fromPool = 0;
 
 	if (transferBuffer->buffer == NULL)
 	{
 		Refresh_LogError("Failed to allocate transfer buffer!");
+		SDL_free(transferBuffer);
 		return NULL;
 	}
 
@@ -10039,11 +10097,24 @@ static void VULKAN_INTERNAL_CleanCommandBuffer(
 	commandBuffer->boundUniformBufferCount = 0;
 
 	for (i = 0; i < commandBuffer->transferBufferCount; i += 1)
+	{
+		if (commandBuffer->transferBuffers[i]->fromPool)
+		{
+			SDL_LockMutex(renderer->transferBufferPool.lock);
+
+			commandBuffer->transferBuffers[i]->offset = 0;
+			renderer->transferBufferPool.availableBuffers[renderer->transferBufferPool.availableBufferCount] = commandBuffer->transferBuffers[i];
+			renderer->transferBufferPool.availableBufferCount += 1;
+
+			SDL_UnlockMutex(renderer->transferBufferPool.lock);
+		}
+		else
 		{
 			VULKAN_INTERNAL_QueueDestroyBuffer(renderer, commandBuffer->transferBuffers[i]->buffer);
 			SDL_free(commandBuffer->transferBuffers[i]);
 			commandBuffer->transferBuffers[i] = NULL;
 		}
+	}
 
 	commandBuffer->transferBufferCount = 0;
 
@@ -11392,6 +11463,9 @@ static Refresh_Device* VULKAN_CreateDevice(
 	/* Variables: Image Format Detection */
 	VkImageFormatProperties imageFormatProperties;
 
+	/* Variables: Transfer buffer init */
+	VulkanTransferBuffer *transferBuffer;
+
 	SDL_memset(renderer, '\0', sizeof(VulkanRenderer));
 	renderer->debugMode = debugMode;
 
@@ -11774,6 +11848,40 @@ static Refresh_Device* VULKAN_CreateDevice(
 	renderer->renderTargetHashArray.count = 0;
 	renderer->renderTargetHashArray.capacity = 0;
 
+	/* Initialize transfer buffer pool */
+
+	renderer->transferBufferPool.lock = SDL_CreateMutex();
+
+	renderer->transferBufferPool.availableBufferCapacity = 4;
+	renderer->transferBufferPool.availableBufferCount = 0;
+	renderer->transferBufferPool.availableBuffers = SDL_malloc(
+		renderer->transferBufferPool.availableBufferCapacity * sizeof(VulkanTransferBuffer*)
+	);
+
+	for (i = 0; i < renderer->transferBufferPool.availableBufferCapacity; i += 1)
+	{
+		transferBuffer = SDL_malloc(sizeof(VulkanTransferBuffer));
+		transferBuffer->offset = 0;
+		transferBuffer->fromPool = 1;
+		transferBuffer->buffer = VULKAN_INTERNAL_CreateBuffer(
+			renderer,
+			POOLED_TRANSFER_BUFFER_SIZE,
+			RESOURCE_ACCESS_TRANSFER_READ_WRITE,
+			VK_BUFFER_USAGE_TRANSFER_SRC_BIT | VK_BUFFER_USAGE_TRANSFER_DST_BIT,
+			1,
+			1
+		);
+
+		if (transferBuffer->buffer == NULL)
+		{
+			Refresh_LogError("Failed to allocate transfer buffer!");
+			SDL_free(transferBuffer);
+		}
+
+		renderer->transferBufferPool.availableBuffers[i] = transferBuffer;
+		renderer->transferBufferPool.availableBufferCount += 1;
+	}
+
 	/* Some drivers don't support D16, so we have to fall back to D32. */
 
 	vulkanResult = renderer->vkGetPhysicalDeviceImageFormatProperties(