[D3D12] SHM - mark pages as modified in the beginning of a frame

src/xenia/gpu/d3d12/shared_memory.h

@@ -10,6 +10,9 @@
 #ifndef XENIA_GPU_D3D12_SHARED_MEMORY_H_
 #define XENIA_GPU_D3D12_SHARED_MEMORY_H_
 
+#include <mutex>
+
+#include "xenia/memory.h"
 #include "xenia/ui/d3d12/d3d12_api.h"
 #include "xenia/ui/d3d12/d3d12_context.h"
 
@@ -19,22 +22,28 @@ namespace d3d12 {
 
 // Manages memory for unconverted textures, resolve targets, vertex and index
 // buffers that can be accessed from shaders with Xenon physical addresses, with
-// 4 KB granularity.
+// system page size granularity.
 class SharedMemory {
  public:
-  SharedMemory(ui::d3d12::D3D12Context* context);
+  SharedMemory(Memory* memory, ui::d3d12::D3D12Context* context);
   ~SharedMemory();
 
   bool Initialize();
   void Shutdown();
 
-  // Ensures the backing memory for the address range is present in the tiled
-  // buffer, allocating if needed. If couldn't allocate, false is returned -
-  // it's unsafe to use this portion (on tiled resources tier 1 at least).
-  bool EnsureRangeAllocated(uint32_t start, uint32_t length);
+  void BeginFrame();
+
+  // Marks the range as used in this frame, queues it for upload if it was
+  // modified. Ensures the backing memory for the address range is present in
+  // the tiled buffer, allocating if needed. If couldn't allocate, false is
+  // returned - it's unsafe to use this portion (on tiled resources tier 1 at
+  // least).
+  bool UseRange(uint32_t start, uint32_t length);
 
  private:
-  ui::d3d12::D3D12Context* context_ = nullptr;
+  Memory* memory_;
+
+  ui::d3d12::D3D12Context* context_;
 
   // The 512 MB tiled buffer.
   static constexpr uint32_t kBufferSizeLog2 = 29;
@@ -51,11 +60,29 @@ class SharedMemory {
   static constexpr uint32_t kHeapSize = 1 << kHeapSizeLog2;
   // Resident portions of the tiled buffer.
   ID3D12Heap* heaps_[kBufferSize >> kHeapSizeLog2] = {};
+  // Whether creation of a heap has failed in the current frame.
+  bool heap_creation_failed_ = false;
 
   // Log2 of system page size.
   uint32_t page_size_log2_;
+  // Total physical page count.
+  uint32_t page_count_;
+
   // Bit vector containing whether physical memory system pages are up to date.
   std::vector<uint64_t> pages_in_sync_;
+
+  // Watched page management - must be synchronized.
+  std::mutex watch_mutex_;
+  // Whether each physical page is watched by the GPU (after uploading).
+  // Once a watch is triggered, it's not watched anymore.
+  std::vector<uint64_t> watched_pages_;
+  // Whether each page was modified while the current frame is being processed.
+  // This is checked and cleared in the beginning of a GPU frame.
+  // Because this is done with a locked CPU-GPU mutex, it's stored in 2 levels,
+  // so unmodified pages can be skipped quickly, and clearing is also fast.
+  // On L1, each bit corresponds to a single page, on L2, to 64 pages.
+  std::vector<uint64_t> watches_triggered_l1_;
+  std::vector<uint64_t> watches_triggered_l2_;
 };
 
 }  // namespace d3d12