From 32cd85dc113c537ee5b8c1ad834717e8389b698d Mon Sep 17 00:00:00 2001
From: Philip Rebohle <philip.rebohle@tu-dortmund.de>
Date: Fri, 22 Jun 2018 00:27:52 +0200
Subject: [PATCH] [dxvk] Discard slices from old physical buffers

Improves effectiveness of an optimization that allows
using dynamic buffer offsets for descriptor sets.
---
 src/dxvk/dxvk_buffer.cpp | 12 ++++++++----
 src/dxvk/dxvk_buffer.h   |  2 ++
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/dxvk/dxvk_buffer.cpp b/src/dxvk/dxvk_buffer.cpp
index 948c6004..32419265 100644
--- a/src/dxvk/dxvk_buffer.cpp
+++ b/src/dxvk/dxvk_buffer.cpp
@@ -42,11 +42,11 @@ namespace dxvk {
     // If there are still no slices available, create a new
     // physical buffer and add all slices to the free list.
     if (m_freeSlices.size() == 0) {
-      const Rc<DxvkPhysicalBuffer> buffer
-        = this->allocPhysicalBuffer(m_physSliceCount);
+      std::unique_lock<std::mutex> swapLock(m_swapMutex);
+      m_physBuffer = this->allocPhysicalBuffer(m_physSliceCount);
       
       for (uint32_t i = 0; i < m_physSliceCount; i++) {
-        m_freeSlices.push_back(buffer->slice(
+        m_freeSlices.push_back(m_physBuffer->slice(
           m_physSliceStride * i,
           m_physSliceLength));
       }
@@ -64,7 +64,11 @@ namespace dxvk {
   void DxvkBuffer::freePhysicalSlice(const DxvkPhysicalBufferSlice& slice) {
     // Add slice to a separate free list to reduce lock contention.
     std::unique_lock<std::mutex> swapLock(m_swapMutex);
-    m_nextSlices.push_back(slice);
+
+    // Discard slices allocated from other physical buffers.
+    // This may make descriptor set binding more efficient.
+    if (m_physBuffer->handle() == slice.handle())
+      m_nextSlices.push_back(slice);
   }
   
   
diff --git a/src/dxvk/dxvk_buffer.h b/src/dxvk/dxvk_buffer.h
index 66b18739..e41a40dc 100644
--- a/src/dxvk/dxvk_buffer.h
+++ b/src/dxvk/dxvk_buffer.h
@@ -149,6 +149,8 @@ namespace dxvk {
     VkDeviceSize m_physSliceLength  = 0;
     VkDeviceSize m_physSliceStride  = 0;
     VkDeviceSize m_physSliceCount   = 2;
+
+    Rc<DxvkPhysicalBuffer>  m_physBuffer;
     
     Rc<DxvkPhysicalBuffer> allocPhysicalBuffer(
             VkDeviceSize    sliceCount) const;