graphics: drop image heap table snapshots superseded at the same base

src/graphics/host_gpu/renderer/pipeline/imageHeap.cpp

@@ -526,26 +526,46 @@ void ImageHeap::UnmapMemory(uint64_t address, uint64_t size) {
 	} else {
 		m_unmapped.push_back({address, size});
 	}
-	auto&           scheduler = m_context.GetCommandScheduler();
 	std::scoped_lock lock {m_mutex};
 	std::erase_if(m_memories, [&](const std::unique_ptr<Memory>& memory) {
 		if (address >= memory->base + memory->size || memory->base >= address + size) {
 			return false;
 		}
-		Unwatch(*memory);
-		for (auto& view: memory->views) {
-			std::erase(m_active, view.get());
-			for (const auto& [value, index]: view->elements) {
-				Unreference(m_elements[index]);
-				view->released.push_back(index);
-			}
-			Retire(*view);
-			if (scheduler.Active()) {
-				scheduler.DeferOperation([buffer = std::move(view->buffer)] {});
-			}
-		}
+		Drop(*memory);
 		return true;
 	});
 }
 
+void ImageHeap::RunGarbageCollector() {
+	// A table whose descriptor grew keeps its old snapshot until a frame passes without it.
+	std::scoped_lock      lock {m_mutex};
+	std::vector<uint64_t> acquired;
+	for (const auto& memory: m_memories) {
+		if (memory->draw > m_frame_draw) acquired.push_back(memory->base);
+	}
+	std::erase_if(m_memories, [&](const std::unique_ptr<Memory>& memory) {
+		const bool superseded = memory->draw <= m_frame_draw &&
+		                        std::ranges::find(acquired, memory->base) != acquired.end();
+		if (superseded) Drop(*memory);
+		return superseded;
+	});
+	m_frame_draw = m_draw;
+}
+
+void ImageHeap::Drop(Memory& memory) {
+	auto& scheduler = m_context.GetCommandScheduler();
+	Unwatch(memory);
+	for (auto& view: memory.views) {
+		std::erase(m_active, view.get());
+		for (const auto& [value, index]: view->elements) {
+			Unreference(m_elements[index]);
+			view->released.push_back(index);
+		}
+		Retire(*view);
+		if (scheduler.Active()) {
+			scheduler.DeferOperation([buffer = std::move(view->buffer)] {});
+		}
+	}
+}
+
 } // namespace Libs::Graphics

src/graphics/host_gpu/renderer/pipeline/imageHeap.h

@@ -46,6 +46,8 @@ public:
 	// CPU write fault, on any thread.
 	void InvalidateMemory(uint64_t address, uint64_t size);
 	void UnmapMemory(uint64_t address, uint64_t size);
+	// Frame boundary: drops table snapshots that another at the same base replaced this frame.
+	void RunGarbageCollector();
 
 private:
 	using DescriptorValue = ShaderRecompiler::IR::DescriptorValue;
@@ -113,6 +115,7 @@ private:
 	Image*   ImageOf(const Element& element) const;
 	uint32_t Allocate();
 	void     Retire(View& view);
+	void     Drop(Memory& memory);
 	void     WriteDescriptors();
 
 	RenderContext&                       m_context;
@@ -120,7 +123,8 @@ private:
 	std::mutex                           m_mutex; // Fault-visible Memory state and m_memories.
 	std::vector<std::unique_ptr<Memory>> m_memories;
 	std::vector<View*>                   m_active; // Acquired since the last commit.
-	uint64_t                             m_draw = 1;
+	uint64_t                             m_draw       = 1;
+	uint64_t                             m_frame_draw = 0; // Last draw before this frame.
 	std::vector<Element>                 m_elements;
 	std::vector<uint32_t>                m_free;
 	std::deque<std::pair<uint64_t, uint32_t>> m_retired; // Tick, element.

src/graphics/host_gpu/renderer/renderContext.cpp

@@ -148,6 +148,7 @@ void RenderContext::RunGarbageCollector() {
 		m_buffer_cache.ProcessFaultBuffer();
 	}
 	m_texture_cache.ProcessDownloadImages();
+	m_image_heap.RunGarbageCollector();
 	m_texture_cache.RunGarbageCollector();
 	m_buffer_cache.RunGarbageCollector();
 }

tests/ShaderRecompilerComputeTests.cpp

@@ -5511,6 +5511,17 @@ public:
                   ImageHeapTestAccess::ImageOf(heap, filtered.slots[240]),
               "a reactivated view kept an element whose image slot holds a new image");
 
+      // A table whose descriptor grew keeps its old snapshot until a frame passes without it.
+      const IR::ImageHeapRequest grown{table, table_size * 2u, 32u, 0u, table_size / 16u, &sampled};
+      for (uint32_t frame = 0; frame < 2u; ++frame) {
+        Require(name, "grown table", heap.Acquire(grown, view), "a grown table was declined");
+        draw();
+        heap.RunGarbageCollector();
+        heap.BeginDraw();
+        Require(name, "superseded table", ImageHeapTestAccess::MemoryCount(heap) == 2u - frame,
+                "a snapshot was dropped in a frame that acquired it or kept after one without it");
+      }
+
       heap.UnmapMemory(table, table_size);
       Require(name, "unmapped table",
               ImageHeapTestAccess::MemoryCount(heap) == 0u &&