1 files changed, 209 insertions, 0 deletions
diff --git a/Ryujinx.HLE/Gpu/NvGpuVmmCache.cs b/Ryujinx.HLE/Gpu/NvGpuVmmCache.cs
new file mode 100644
index 00000000..38b25e4f
--- /dev/null
+++ b/Ryujinx.HLE/Gpu/NvGpuVmmCache.cs
@@ -0,0 +1,209 @@
+using ChocolArm64.Memory;
+using System;
+using System.Collections.Generic;
+
+namespace Ryujinx.HLE.Gpu
+{
+    class NvGpuVmmCache
+    {
+        private const int MaxCpCount     = 10000;
+        private const int MaxCpTimeDelta = 60000;
+
+        private class CachedPage
+        {
+            private List<(long Start, long End)> Regions;
+
+            public LinkedListNode<long> Node { get; set; }
+
+            public int Count => Regions.Count;
+
+            public int Timestamp { get; private set; }
+
+            public long PABase { get; private set; }
+
+            public NvGpuBufferType BufferType { get; private set; }
+
+            public CachedPage(long PABase, NvGpuBufferType BufferType)
+            {
+                this.PABase     = PABase;
+                this.BufferType = BufferType;
+
+                Regions = new List<(long, long)>();
+            }
+
+            public bool AddRange(long Start, long End)
+            {
+                for (int Index = 0; Index < Regions.Count; Index++)
+                {
+                    (long RgStart, long RgEnd) = Regions[Index];
+
+                    if (Start >= RgStart && End <= RgEnd)
+                    {
+                        return false;
+                    }
+
+                    if (Start <= RgEnd && RgStart <= End)
+                    {
+                        long MinStart = Math.Min(RgStart, Start);
+                        long MaxEnd   = Math.Max(RgEnd,   End);
+
+                        Regions[Index] = (MinStart, MaxEnd);
+
+                        Timestamp = Environment.TickCount;
+
+                        return true;
+                    }
+                }
+
+                Regions.Add((Start, End));
+
+                Timestamp = Environment.TickCount;
+
+                return true;
+            }
+        }
+
+        private Dictionary<long, CachedPage> Cache;
+
+        private LinkedList<long> SortedCache;
+
+        private int CpCount;
+
+        public NvGpuVmmCache()
+        {
+            Cache = new Dictionary<long, CachedPage>();
+
+            SortedCache = new LinkedList<long>();
+        }
+
+        public bool IsRegionModified(
+            AMemory         Memory,
+            NvGpuBufferType BufferType,
+            long            VA,
+            long            PA,
+            long            Size)
+        {
+            ClearCachedPagesIfNeeded();
+
+            long PageSize = Memory.GetHostPageSize();
+
+            long Mask = PageSize - 1;
+
+            long VAEnd = VA + Size;
+            long PAEnd = PA + Size;
+
+            bool RegMod = false;
+
+            while (VA < VAEnd)
+            {
+                long Key    = VA & ~Mask;
+                long PABase = PA & ~Mask;
+
+                long VAPgEnd = Math.Min((VA + PageSize) & ~Mask, VAEnd);
+                long PAPgEnd = Math.Min((PA + PageSize) & ~Mask, PAEnd);
+
+                bool IsCached = Cache.TryGetValue(Key, out CachedPage Cp);
+
+                bool PgReset = false;
+
+                if (!IsCached)
+                {
+                    Cp = new CachedPage(PABase, BufferType);
+
+                    Cache.Add(Key, Cp);
+                }
+                else
+                {
+                    CpCount -= Cp.Count;
+
+                    SortedCache.Remove(Cp.Node);
+
+                    if (Cp.PABase     != PABase ||
+                        Cp.BufferType != BufferType)
+                    {
+                        PgReset = true;
+                    }
+                }
+
+                PgReset |= Memory.IsRegionModified(PA, PAPgEnd - PA) && IsCached;
+
+                if (PgReset)
+                {
+                    Cp = new CachedPage(PABase, BufferType);
+
+                    Cache[Key] = Cp;
+                }
+
+                Cp.Node = SortedCache.AddLast(Key);
+
+                RegMod |= Cp.AddRange(VA, VAPgEnd);
+
+                CpCount += Cp.Count;
+
+                VA = VAPgEnd;
+                PA = PAPgEnd;
+            }
+
+            return RegMod;
+        }
+
+        private void ClearCachedPagesIfNeeded()
+        {
+            if (CpCount <= MaxCpCount)
+            {
+                return;
+            }
+
+            int Timestamp = Environment.TickCount;
+
+            int TimeDelta;
+
+            do
+            {
+                if (!TryPopOldestCachedPageKey(Timestamp, out long Key))
+                {
+                    break;
+                }
+
+                CachedPage Cp = Cache[Key];
+
+                Cache.Remove(Key);
+
+                CpCount -= Cp.Count;
+
+                TimeDelta = RingDelta(Cp.Timestamp, Timestamp);
+            }
+            while (CpCount > (MaxCpCount >> 1) || (uint)TimeDelta > (uint)MaxCpTimeDelta);
+        }
+
+        private bool TryPopOldestCachedPageKey(int Timestamp, out long Key)
+        {
+            LinkedListNode<long> Node = SortedCache.First;
+
+            if (Node == null)
+            {
+                Key = 0;
+
+                return false;
+            }
+
+            SortedCache.Remove(Node);
+
+            Key = Node.Value;
+
+            return true;
+        }
+
+        private int RingDelta(int Old, int New)
+        {
+            if ((uint)New < (uint)Old)
+            {
+                return New + (~Old + 1);
+            }
+            else
+            {
+                return New - Old;
+            }
+        }
+    }
+}
+\ No newline at end of file