From bcc5b0d21ec68732c3db37147e07800e3851892a Mon Sep 17 00:00:00 2001
From: gdkchan <gab.dark.100@gmail.com>
Date: Sat, 25 Apr 2020 10:25:22 -0300
Subject: [PATCH] Fix kernel memory allocator block coalescing (#1155)

* Fix kernel memory allocator block coalescing

* Fix and move clear bit logic to a separate method
---
 .../HOS/Kernel/Memory/KMemoryRegionBlock.cs   | 64 ++++++++++++++++---
 1 file changed, 54 insertions(+), 10 deletions(-)

diff --git a/Ryujinx.HLE/HOS/Kernel/Memory/KMemoryRegionBlock.cs b/Ryujinx.HLE/HOS/Kernel/Memory/KMemoryRegionBlock.cs
index 3334ff43..9a773495 100644
--- a/Ryujinx.HLE/HOS/Kernel/Memory/KMemoryRegionBlock.cs
+++ b/Ryujinx.HLE/HOS/Kernel/Memory/KMemoryRegionBlock.cs
@@ -12,20 +12,68 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
         public int   Order;
         public int   NextOrder;
 
-        public bool TryCoalesce(int index, int size)
+        public bool TryCoalesce(int index, int count)
         {
-            long mask = ((1L << size) - 1) << (index & 63);
+            long mask = ((1L << count) - 1) << (index & 63);
 
             index /= 64;
 
-            if ((mask & ~Masks[MaxLevel - 1][index]) != 0)
+            if (count >= 64)
             {
-                return false;
+                int remaining = count;
+                int tempIdx = index;
+
+                do
+                {
+                    if (Masks[MaxLevel - 1][tempIdx++] != -1L)
+                    {
+                        return false;
+                    }
+
+                    remaining -= 64;
+                }
+                while (remaining != 0);
+
+                remaining = count;
+                tempIdx = index;
+
+                do
+                {
+                    Masks[MaxLevel - 1][tempIdx] = 0;
+
+                    ClearMaskBit(MaxLevel - 2, tempIdx++);
+
+                    remaining -= 64;
+                }
+                while (remaining != 0);
+            }
+            else
+            {
+                long value = Masks[MaxLevel - 1][index];
+
+                if ((mask & ~value) != 0)
+                {
+                    return false;
+                }
+
+                value &= ~mask;
+
+                Masks[MaxLevel - 1][index] = value;
+
+                if (value == 0)
+                {
+                    ClearMaskBit(MaxLevel - 2, index);
+                }
             }
 
-            Masks[MaxLevel - 1][index] &= ~mask;
+            FreeCount -= (ulong)count;
 
-            for (int level = MaxLevel - 2; level >= 0; level--, index /= 64)
+            return true;
+        }
+
+        public void ClearMaskBit(int startLevel, int index)
+        {
+            for (int level = startLevel; level >= 0; level--, index /= 64)
             {
                 Masks[level][index / 64] &= ~(1L << (index & 63));
 
@@ -34,10 +82,6 @@ namespace Ryujinx.HLE.HOS.Kernel.Memory
                     break;
                 }
             }
-
-            FreeCount -= (ulong)size;
-
-            return true;
         }
     }
 }
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