[dxvk] Add option to limit memory chunk size

dxvk.conf

@@ -294,6 +294,17 @@
 # dxvk.useRawSsbo = Auto
 
 
+# Changes memory chunk size.
+#
+# Can be used to override the maximum memory chunk size.
+#
+# Supported values:
+# - 0 to use the defaults
+# - any positive integer to limit the chunk size, in MiB
+
+# dxvk.maxChunkSize = 0
+
+
 # Controls graphics pipeline library behaviour
 #
 # Can be used to change VK_EXT_graphics_pipeline_library usage for

src/dxvk/dxvk_memory.cpp

@@ -183,7 +183,8 @@ namespace dxvk {
 
   DxvkMemoryAllocator::DxvkMemoryAllocator(DxvkDevice* device)
   : m_device          (device),
-    m_memProps        (device->adapter()->memoryProperties()) {
+    m_memProps        (device->adapter()->memoryProperties()),
+    m_maxChunkSize    (determineMaxChunkSize(device)) {
     for (uint32_t i = 0; i < m_memProps.memoryHeapCount; i++) {
       m_memHeaps[i].properties = m_memProps.memoryHeaps[i];
       m_memHeaps[i].stats      = DxvkMemoryStats { 0, 0 };
@@ -493,15 +494,15 @@ namespace dxvk {
     VkMemoryHeap heap = m_memProps.memoryHeaps[type.heapIndex];
 
     // Default to a chunk size of 256 MiB
-    VkDeviceSize chunkSize = 256 << 20;
+    VkDeviceSize chunkSize = m_maxChunkSize;
 
     if (hints.test(DxvkMemoryFlag::Small))
-      chunkSize = 16 << 20;
+      chunkSize = std::min<VkDeviceSize>(chunkSize, 16 << 20);
 
     // Try to waste a bit less system memory especially in
     // 32-bit applications due to address space constraints
     if (type.propertyFlags & VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT)
-      chunkSize = (env::is32BitHostPlatform() ? 16 : 64) << 20;
+      chunkSize = std::min<VkDeviceSize>((env::is32BitHostPlatform() ? 16 : 64) << 20, chunkSize);
 
     // Reduce the chunk size on small heaps so
     // we can at least fit in 15 allocations
@@ -638,6 +639,17 @@ namespace dxvk {
   }
 
 
+  VkDeviceSize DxvkMemoryAllocator::determineMaxChunkSize(
+          DxvkDevice*           device) const {
+    int32_t option = device->config().maxChunkSize;
+
+    if (option <= 0)
+      option = 256;
+
+    return VkDeviceSize(option) << 20;
+  }
+
+
   void DxvkMemoryAllocator::logMemoryError(const VkMemoryRequirements& req) const {
     std::stringstream sstr;
     sstr << "DxvkMemoryAllocator: Memory allocation failed" << std::endl

src/dxvk/dxvk_memory.h

@@ -352,6 +352,8 @@ namespace dxvk {
     std::array<DxvkMemoryHeap, VK_MAX_MEMORY_HEAPS> m_memHeaps;
     std::array<DxvkMemoryType, VK_MAX_MEMORY_TYPES> m_memTypes;
 
+    VkDeviceSize                                    m_maxChunkSize;
+
     uint32_t m_sparseMemoryTypes = 0u;
 
     DxvkMemory tryAlloc(
@@ -403,6 +405,9 @@ namespace dxvk {
     uint32_t determineSparseMemoryTypes(
             DxvkDevice*           device) const;
 
+    VkDeviceSize determineMaxChunkSize(
+            DxvkDevice*           device) const;
+
     void logMemoryError(
       const VkMemoryRequirements& req) const;
 

src/dxvk/dxvk_options.cpp

@@ -9,6 +9,7 @@ namespace dxvk {
     enableGraphicsPipelineLibrary = config.getOption<Tristate>("dxvk.enableGraphicsPipelineLibrary", Tristate::Auto);
     trackPipelineLifetime = config.getOption<Tristate>("dxvk.trackPipelineLifetime",  Tristate::Auto);
     useRawSsbo            = config.getOption<Tristate>("dxvk.useRawSsbo",             Tristate::Auto);
+    maxChunkSize          = config.getOption<int32_t> ("dxvk.maxChunkSize",           0);
     hud                   = config.getOption<std::string>("dxvk.hud", "");
   }
 

src/dxvk/dxvk_options.h

@@ -27,6 +27,9 @@ namespace dxvk {
     /// Shader-related options
     Tristate useRawSsbo;
 
+    /// Maximum memory chunk size in MiB
+    int32_t maxChunkSize;
+
     /// HUD elements
     std::string hud;
   };