Vulkan: Enable persistently mapped buffer objects

include/platform/FeaturesVk.h

@@ -251,6 +251,13 @@ struct FeaturesVk : FeatureSetBase
         "Fill new allocations with non-zero values to flush out errors.", &members,
         "http://anglebug.com/4384"};
 
+    // Persistently map buffer memory until destroy, saves on map/unmap IOCTL overhead
+    // for buffers that are updated frequently.
+    Feature persistentlyMappedBuffers = {
+        "persistently_mapped_buffers", FeatureCategory::VulkanFeatures,
+        "Persistently map buffer memory to reduce map/unmap IOCTL overhead.", &members,
+        "http://anglebug.com/2162"};
+
     // Android needs to pre-rotate surfaces that are not oriented per the native device's
     // orientation (e.g. a landscape application on a Pixel phone).  This feature works for
     // full-screen applications. http://anglebug.com/3502

src/libANGLE/renderer/vulkan/RendererVk.cpp

@@ -1679,6 +1679,8 @@ void RendererVk::initFeatures(DisplayVk *displayVk, const ExtensionNameList &dev
     // that can cause OOM and timeouts.
     ANGLE_FEATURE_CONDITION(&mFeatures, allocateNonZeroMemory, false);
 
+    ANGLE_FEATURE_CONDITION(&mFeatures, persistentlyMappedBuffers, true);
+
     ANGLE_FEATURE_CONDITION(
         &mFeatures, supportsExternalMemoryHost,
         ExtensionFound(VK_EXT_EXTERNAL_MEMORY_HOST_EXTENSION_NAME, deviceExtensionNames));

src/libANGLE/renderer/vulkan/vk_helpers.cpp

@@ -1699,8 +1699,9 @@ angle::Result BufferHelper::init(ContextVk *contextVk,
     VkMemoryPropertyFlags preferredFlags =
         (memoryPropertyFlags & (~VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT));
 
-    mAllocation.createBufferAndMemory(renderer->getAllocator(), createInfo, requiredFlags,
-                                      preferredFlags, &mBuffer, &mMemoryPropertyFlags);
+    mAllocation.createBufferAndMemory(
+        renderer->getAllocator(), createInfo, requiredFlags, preferredFlags,
+        renderer->getFeatures().persistentlyMappedBuffers.enabled, &mBuffer, &mMemoryPropertyFlags);
 
     mCurrentQueueFamilyIndex = contextVk->getRenderer()->getQueueFamilyIndex();
 

src/libANGLE/renderer/vulkan/vk_mem_alloc_wrapper.cpp

@@ -62,6 +62,7 @@ VkResult CreateBuffer(VmaAllocator allocator,
                       const VkBufferCreateInfo *pBufferCreateInfo,
                       VkMemoryPropertyFlags requiredFlags,
                       VkMemoryPropertyFlags preferredFlags,
+                      bool persistentlyMappedBuffers,
                       uint32_t *pMemoryTypeIndexOut,
                       VkBuffer *pBuffer,
                       VmaAllocation *pAllocation)
@@ -70,7 +71,8 @@ VkResult CreateBuffer(VmaAllocator allocator,
     VmaAllocationCreateInfo allocationCreateInfo = {};
     allocationCreateInfo.requiredFlags           = requiredFlags;
     allocationCreateInfo.preferredFlags          = preferredFlags;
-    VmaAllocationInfo allocationInfo             = {};
+    allocationCreateInfo.flags = (persistentlyMappedBuffers) ? VMA_ALLOCATION_CREATE_MAPPED_BIT : 0;
+    VmaAllocationInfo allocationInfo = {};
 
     result = vmaCreateBuffer(allocator, pBufferCreateInfo, &allocationCreateInfo, pBuffer,
                              pAllocation, &allocationInfo);

src/libANGLE/renderer/vulkan/vk_mem_alloc_wrapper.h

@@ -30,6 +30,7 @@ VkResult CreateBuffer(VmaAllocator allocator,
                       const VkBufferCreateInfo *pBufferCreateInfo,
                       VkMemoryPropertyFlags requiredFlags,
                       VkMemoryPropertyFlags preferredFlags,
+                      bool persistentlyMappedBuffers,
                       uint32_t *pMemoryTypeIndexOut,
                       VkBuffer *pBuffer,
                       VmaAllocation *pAllocation);

src/libANGLE/renderer/vulkan/vk_utils.cpp

@@ -408,9 +408,10 @@ angle::Result StagingBuffer::init(Context *context, VkDeviceSize size, StagingUs
     VkMemoryPropertyFlags requiredFlags =
         VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | VK_MEMORY_PROPERTY_HOST_COHERENT_BIT;
 
-    mAllocation.createBufferAndMemory(context->getRenderer()->getAllocator(), &createInfo,
-                                      requiredFlags, preferredFlags, &mBuffer,
-                                      &memoryPropertyOutFlags);
+    mAllocation.createBufferAndMemory(
+        context->getRenderer()->getAllocator(), &createInfo, requiredFlags, preferredFlags,
+        context->getRenderer()->getFeatures().persistentlyMappedBuffers.enabled, &mBuffer,
+        &memoryPropertyOutFlags);
 
     mSize = static_cast<size_t>(size);
     return angle::Result::Continue;

src/libANGLE/renderer/vulkan/vk_wrapper.h

@@ -466,6 +466,7 @@ class Allocation final : public WrappedObject<Allocation, VmaAllocation>
                                    const VkBufferCreateInfo *pBufferCreateInfo,
                                    VkMemoryPropertyFlags requiredFlags,
                                    VkMemoryPropertyFlags preferredFlags,
+                                   bool persistentlyMappedBuffers,
                                    Buffer *buffer,
                                    VkMemoryPropertyFlags *pMemPropertyOut);
     VkResult map(VmaAllocator allocator, uint8_t **mapPointer) const;
@@ -1329,6 +1330,7 @@ ANGLE_INLINE VkResult Allocation::createBufferAndMemory(VmaAllocator allocator,
                                                         const VkBufferCreateInfo *pBufferCreateInfo,
                                                         VkMemoryPropertyFlags requiredFlags,
                                                         VkMemoryPropertyFlags preferredFlags,
+                                                        bool persistentlyMappedBuffers,
                                                         Buffer *buffer,
                                                         VkMemoryPropertyFlags *pMemPropertyOut)
 {
@@ -1336,8 +1338,9 @@ ANGLE_INLINE VkResult Allocation::createBufferAndMemory(VmaAllocator allocator,
     VkResult result;
     uint32_t memoryTypeIndex;
     VkBuffer bufferHandle;
-    result = vma::CreateBuffer(allocator, pBufferCreateInfo, requiredFlags, preferredFlags,
-                               &memoryTypeIndex, &bufferHandle, &mHandle);
+    result =
+        vma::CreateBuffer(allocator, pBufferCreateInfo, requiredFlags, preferredFlags,
+                          persistentlyMappedBuffers, &memoryTypeIndex, &bufferHandle, &mHandle);
     vma::GetMemoryTypeProperties(allocator, memoryTypeIndex, pMemPropertyOut);
     buffer->setHandle(bufferHandle);