11 files changed, 450 insertions, 86 deletions
diff --git a/Ryujinx.Graphics.GAL/IRenderer.cs b/Ryujinx.Graphics.GAL/IRenderer.cs
index cf67f648..c72320a2 100644
--- a/Ryujinx.Graphics.GAL/IRenderer.cs
+++ b/Ryujinx.Graphics.GAL/IRenderer.cs
@@ -29,6 +29,7 @@ namespace Ryujinx.Graphics.GAL
         ReadOnlySpan<byte> GetBufferData(BufferHandle buffer, int offset, int size);
 
         Capabilities GetCapabilities();
+        ulong GetCurrentSync();
         HardwareInfo GetHardwareInfo();
 
         IProgram LoadProgramBinary(byte[] programBinary, bool hasFragmentShader, ShaderInfo info);
diff --git a/Ryujinx.Graphics.GAL/Multithreading/ThreadedRenderer.cs b/Ryujinx.Graphics.GAL/Multithreading/ThreadedRenderer.cs
index 7a625af3..a9e3b75c 100644
--- a/Ryujinx.Graphics.GAL/Multithreading/ThreadedRenderer.cs
+++ b/Ryujinx.Graphics.GAL/Multithreading/ThreadedRenderer.cs
@@ -338,6 +338,11 @@ namespace Ryujinx.Graphics.GAL.Multithreading
             return box.Result;
         }
 
+        public ulong GetCurrentSync()
+        {
+            return _baseRenderer.GetCurrentSync();
+        }
+
         public HardwareInfo GetHardwareInfo()
         {
             return _baseRenderer.GetHardwareInfo();
diff --git a/Ryujinx.Graphics.Gpu/GpuContext.cs b/Ryujinx.Graphics.Gpu/GpuContext.cs
index 5913ac94..52733165 100644
--- a/Ryujinx.Graphics.Gpu/GpuContext.cs
+++ b/Ryujinx.Graphics.Gpu/GpuContext.cs
@@ -70,6 +70,12 @@ namespace Ryujinx.Graphics.Gpu
         internal List<Action> SyncpointActions { get; }
 
         /// <summary>
+        /// Buffer migrations that are currently in-flight. These are checked whenever sync is created to determine if buffer migration
+        /// copies have completed on the GPU, and their data can be freed.
+        /// </summary>
+        internal List<BufferMigration> BufferMigrations { get; }
+
+        /// <summary>
         /// Queue with deferred actions that must run on the render thread.
         /// </summary>
         internal Queue<Action> DeferredActions { get; }
@@ -90,6 +96,7 @@ namespace Ryujinx.Graphics.Gpu
         public event Action<ShaderCacheState, int, int> ShaderCacheStateChanged;
 
         private Thread _gpuThread;
+        private bool _pendingSync;
 
         /// <summary>
         /// Creates a new instance of the GPU emulation context.
@@ -109,6 +116,7 @@ namespace Ryujinx.Graphics.Gpu
 
             SyncActions = new List<Action>();
             SyncpointActions = new List<Action>();
+            BufferMigrations = new List<BufferMigration>();
 
             DeferredActions = new Queue<Action>();
 
@@ -274,6 +282,17 @@ namespace Ryujinx.Graphics.Gpu
         }
 
         /// <summary>
+        /// Registers a buffer migration. These are checked to see if they can be disposed when the sync number increases,
+        /// and the migration copy has completed.
+        /// </summary>
+        /// <param name="migration">The buffer migration</param>
+        internal void RegisterBufferMigration(BufferMigration migration)
+        {
+            BufferMigrations.Add(migration);
+            _pendingSync = true;
+        }
+
+        /// <summary>
         /// Registers an action to be performed the next time a syncpoint is incremented.
         /// This will also ensure a host sync object is created, and <see cref="SyncNumber"/> is incremented.
         /// </summary>
@@ -288,6 +307,7 @@ namespace Ryujinx.Graphics.Gpu
             else
             {
                 SyncActions.Add(action);
+                _pendingSync = true;
             }
         }
 
@@ -298,7 +318,24 @@ namespace Ryujinx.Graphics.Gpu
         /// <param name="syncpoint">True if host sync is being created by a syncpoint</param>
         public void CreateHostSyncIfNeeded(bool syncpoint)
         {
-            if (SyncActions.Count > 0 || (syncpoint && SyncpointActions.Count > 0))
+            if (BufferMigrations.Count > 0)
+            {
+                ulong currentSyncNumber = Renderer.GetCurrentSync();
+
+                for (int i = 0; i < BufferMigrations.Count; i++)
+                {
+                    BufferMigration migration = BufferMigrations[i];
+                    long diff = (long)(currentSyncNumber - migration.SyncNumber);
+
+                    if (diff >= 0)
+                    {
+                        migration.Dispose();
+                        BufferMigrations.RemoveAt(i--);
+                    }
+                }
+            }
+
+            if (_pendingSync || (syncpoint && SyncpointActions.Count > 0))
             {
                 Renderer.CreateSync(SyncNumber);
 
@@ -317,6 +354,8 @@ namespace Ryujinx.Graphics.Gpu
                 SyncActions.Clear();
                 SyncpointActions.Clear();
             }
+
+            _pendingSync = false;
         }
 
         /// <summary>
diff --git a/Ryujinx.Graphics.Gpu/Memory/Buffer.cs b/Ryujinx.Graphics.Gpu/Memory/Buffer.cs
index 1e49f6bf..842249f3 100644
--- a/Ryujinx.Graphics.Gpu/Memory/Buffer.cs
+++ b/Ryujinx.Graphics.Gpu/Memory/Buffer.cs
@@ -65,6 +65,8 @@ namespace Ryujinx.Graphics.Gpu.Memory
         private bool _useGranular;
         private bool _syncActionRegistered;
 
+        private int _referenceCount = 1;
+
         /// <summary>
         /// Creates a new instance of the buffer.
         /// </summary>
@@ -229,7 +231,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
         {
             if (_modifiedRanges == null)
             {
-                _modifiedRanges = new BufferModifiedRangeList(_context);
+                _modifiedRanges = new BufferModifiedRangeList(_context, this, Flush);
             }
         }
 
@@ -290,7 +292,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
         /// <param name="from">The buffer to inherit from</param>
         public void InheritModifiedRanges(Buffer from)
         {
-            if (from._modifiedRanges != null)
+            if (from._modifiedRanges != null && from._modifiedRanges.HasRanges)
             {
                 if (from._syncActionRegistered && !_syncActionRegistered)
                 {
@@ -310,17 +312,9 @@ namespace Ryujinx.Graphics.Gpu.Memory
                     }
                 };
 
-                if (_modifiedRanges == null)
-                {
-                    _modifiedRanges = from._modifiedRanges;
-                    _modifiedRanges.ReregisterRanges(registerRangeAction);
+                EnsureRangeList();
 
-                    from._modifiedRanges = null;
-                }
-                else
-                {
-                    _modifiedRanges.InheritRanges(from._modifiedRanges, registerRangeAction);
-                }
+                _modifiedRanges.InheritRanges(from._modifiedRanges, registerRangeAction);
             }
         }
 
@@ -456,7 +450,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
                 if (ranges != null)
                 {
                     (address, size) = PageAlign(address, size);
-                    ranges.WaitForAndGetRanges(address, size, Flush);
+                    ranges.WaitForAndFlushRanges(address, size);
                 }
             }, true);
         }
@@ -509,6 +503,25 @@ namespace Ryujinx.Graphics.Gpu.Memory
         }
 
         /// <summary>
+        /// Increments the buffer reference count.
+        /// </summary>
+        public void IncrementReferenceCount()
+        {
+            _referenceCount++;
+        }
+
+        /// <summary>
+        /// Decrements the buffer reference count.
+        /// </summary>
+        public void DecrementReferenceCount()
+        {
+            if (--_referenceCount == 0)
+            {
+                DisposeData();
+            }
+        }
+
+        /// <summary>
         /// Disposes the host buffer's data, not its tracking handles.
         /// </summary>
         public void DisposeData()
@@ -528,7 +541,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
             _memoryTrackingGranular?.Dispose();
             _memoryTracking?.Dispose();
 
-            DisposeData();
+            DecrementReferenceCount();
         }
     }
 }
 \ No newline at end of file
diff --git a/Ryujinx.Graphics.Gpu/Memory/BufferCache.cs b/Ryujinx.Graphics.Gpu/Memory/BufferCache.cs
index a523c76f..00f59083 100644
--- a/Ryujinx.Graphics.Gpu/Memory/BufferCache.cs
+++ b/Ryujinx.Graphics.Gpu/Memory/BufferCache.cs
@@ -273,7 +273,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
                         buffer.CopyTo(newBuffer, dstOffset);
                         newBuffer.InheritModifiedRanges(buffer);
 
-                        buffer.DisposeData();
+                        buffer.DecrementReferenceCount();
                     }
 
                     newBuffer.SynchronizeMemory(address, newSize);
diff --git a/Ryujinx.Graphics.Gpu/Memory/BufferMigration.cs b/Ryujinx.Graphics.Gpu/Memory/BufferMigration.cs
new file mode 100644
index 00000000..e020c0c3
--- /dev/null
+++ b/Ryujinx.Graphics.Gpu/Memory/BufferMigration.cs
@@ -0,0 +1,125 @@
+using System;
+
+namespace Ryujinx.Graphics.Gpu.Memory
+{
+    /// <summary>
+    /// A record of when buffer data was copied from one buffer to another, along with the SyncNumber when the migration will be complete.
+    /// Keeps the source buffer alive for data flushes until the migration is complete.
+    /// </summary>
+    internal class BufferMigration : IDisposable
+    {
+        /// <summary>
+        /// The offset for the migrated region.
+        /// </summary>
+        private readonly ulong _offset;
+
+        /// <summary>
+        /// The size for the migrated region.
+        /// </summary>
+        private readonly ulong _size;
+
+        /// <summary>
+        /// The buffer that was migrated from.
+        /// </summary>
+        private readonly Buffer _buffer;
+
+        /// <summary>
+        /// The source range action, to be called on overlap with an unreached sync number.
+        /// </summary>
+        private readonly Action<ulong, ulong> _sourceRangeAction;
+
+        /// <summary>
+        /// The source range list.
+        /// </summary>
+        private readonly BufferModifiedRangeList _source;
+
+        /// <summary>
+        /// The destination range list. This range list must be updated when flushing the source.
+        /// </summary>
+        public readonly BufferModifiedRangeList Destination;
+
+        /// <summary>
+        /// The sync number that needs to be reached for this migration to be removed. This is set to the pending sync number on creation.
+        /// </summary>
+        public readonly ulong SyncNumber;
+
+        /// <summary>
+        /// Creates a record for a buffer migration.
+        /// </summary>
+        /// <param name="buffer">The source buffer for this migration</param>
+        /// <param name="sourceRangeAction">The flush action for the source buffer</param>
+        /// <param name="source">The modified range list for the source buffer</param>
+        /// <param name="dest">The modified range list for the destination buffer</param>
+        /// <param name="syncNumber">The sync number for when the migration is complete</param>
+        public BufferMigration(
+            Buffer buffer,
+            Action<ulong, ulong> sourceRangeAction,
+            BufferModifiedRangeList source,
+            BufferModifiedRangeList dest,
+            ulong syncNumber)
+        {
+            _offset = buffer.Address;
+            _size = buffer.Size;
+            _buffer = buffer;
+            _sourceRangeAction = sourceRangeAction;
+            _source = source;
+            Destination = dest;
+            SyncNumber = syncNumber;
+        }
+
+        /// <summary>
+        /// Determine if the given range overlaps this migration, and has not been completed yet.
+        /// </summary>
+        /// <param name="offset">Start offset</param>
+        /// <param name="size">Range size</param>
+        /// <param name="syncNumber">The sync number that was waited on</param>
+        /// <returns>True if overlapping and in progress, false otherwise</returns>
+        public bool Overlaps(ulong offset, ulong size, ulong syncNumber)
+        {
+            ulong end = offset + size;
+            ulong destEnd = _offset + _size;
+            long syncDiff = (long)(syncNumber - SyncNumber); // syncNumber is less if the copy has not completed.
+
+            return !(end <= _offset || offset >= destEnd) && syncDiff < 0;
+        }
+
+        /// <summary>
+        /// Determine if the given range matches this migration.
+        /// </summary>
+        /// <param name="offset">Start offset</param>
+        /// <param name="size">Range size</param>
+        /// <returns>True if the range exactly matches, false otherwise</returns>
+        public bool FullyMatches(ulong offset, ulong size)
+        {
+            return _offset == offset && _size == size;
+        }
+
+        /// <summary>
+        /// Perform the migration source's range action on the range provided, clamped to the bounds of the source buffer.
+        /// </summary>
+        /// <param name="offset">Start offset</param>
+        /// <param name="size">Range size</param>
+        /// <param name="syncNumber">Current sync number</param>
+        /// <param name="parent">The modified range list that originally owned this range</param>
+        public void RangeActionWithMigration(ulong offset, ulong size, ulong syncNumber, BufferModifiedRangeList parent)
+        {
+            ulong end = offset + size;
+            end = Math.Min(_offset + _size, end);
+            offset = Math.Max(_offset, offset);
+
+            size = end - offset;
+
+            _source.RangeActionWithMigration(offset, size, syncNumber, parent, _sourceRangeAction);
+        }
+
+        /// <summary>
+        /// Removes this reference to the range list, potentially allowing for the source buffer to be disposed.
+        /// </summary>
+        public void Dispose()
+        {
+            Destination.RemoveMigration(this);
+
+            _buffer.DecrementReferenceCount();
+        }
+    }
+}
diff --git a/Ryujinx.Graphics.Gpu/Memory/BufferModifiedRangeList.cs b/Ryujinx.Graphics.Gpu/Memory/BufferModifiedRangeList.cs
index 07dbd209..d0230b62 100644
--- a/Ryujinx.Graphics.Gpu/Memory/BufferModifiedRangeList.cs
+++ b/Ryujinx.Graphics.Gpu/Memory/BufferModifiedRangeList.cs
@@ -1,6 +1,8 @@
-using Ryujinx.Common.Pools;
+using Ryujinx.Common.Logging;
+using Ryujinx.Common.Pools;
 using Ryujinx.Memory.Range;
 using System;
+using System.Collections.Generic;
 using System.Linq;
 
 namespace Ryujinx.Graphics.Gpu.Memory
@@ -31,16 +33,23 @@ namespace Ryujinx.Graphics.Gpu.Memory
         public ulong SyncNumber { get; internal set; }
 
         /// <summary>
+        /// The range list that originally owned this range.
+        /// </summary>
+        public BufferModifiedRangeList Parent { get; internal set; }
+
+        /// <summary>
         /// Creates a new instance of a modified range.
         /// </summary>
         /// <param name="address">Start address of the range</param>
         /// <param name="size">Size of the range in bytes</param>
         /// <param name="syncNumber">The GPU sync number at the time of creation</param>
-        public BufferModifiedRange(ulong address, ulong size, ulong syncNumber)
+        /// <param name="parent">The range list that owns this range</param>
+        public BufferModifiedRange(ulong address, ulong size, ulong syncNumber, BufferModifiedRangeList parent)
         {
             Address = address;
             Size = size;
             SyncNumber = syncNumber;
+            Parent = parent;
         }
 
         /// <summary>
@@ -63,16 +72,39 @@ namespace Ryujinx.Graphics.Gpu.Memory
         private const int BackingInitialSize = 8;
 
         private GpuContext _context;
+        private Buffer _parent;
+        private Action<ulong, ulong> _flushAction;
+
+        private List<BufferMigration> _sources;
+        private BufferMigration _migrationTarget;
 
         private object _lock = new object();
 
         /// <summary>
+        /// Whether the modified range list has any entries or not.
+        /// </summary>
+        public bool HasRanges
+        {
+            get
+            {
+                lock (_lock)
+                {
+                    return Count > 0;
+                }
+            }
+        }
+
+        /// <summary>
         /// Creates a new instance of a modified range list.
         /// </summary>
         /// <param name="context">GPU context that the buffer range list belongs to</param>
-        public BufferModifiedRangeList(GpuContext context) : base(BackingInitialSize)
+        /// <param name="parent">The parent buffer that owns this range list</param>
+        /// <param name="flushAction">The flush action for the parent buffer</param>
+        public BufferModifiedRangeList(GpuContext context, Buffer parent, Action<ulong, ulong> flushAction) : base(BackingInitialSize)
         {
             _context = context;
+            _parent = parent;
+            _flushAction = flushAction;
         }
 
         /// <summary>
@@ -142,6 +174,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
                     {
                         // Region already exists. Just update the existing sync number.
                         overlap.SyncNumber = syncNumber;
+                        overlap.Parent = this;
 
                         return;
                     }
@@ -152,18 +185,18 @@ namespace Ryujinx.Graphics.Gpu.Memory
                     {
                         // A split item must be created behind this overlap.
 
-                        Add(new BufferModifiedRange(overlap.Address, address - overlap.Address, overlap.SyncNumber));
+                        Add(new BufferModifiedRange(overlap.Address, address - overlap.Address, overlap.SyncNumber, overlap.Parent));
                     }
 
                     if (overlap.Address < endAddress && overlap.EndAddress > endAddress)
                     {
                         // A split item must be created after this overlap.
 
-                        Add(new BufferModifiedRange(endAddress, overlap.EndAddress - endAddress, overlap.SyncNumber));
+                        Add(new BufferModifiedRange(endAddress, overlap.EndAddress - endAddress, overlap.SyncNumber, overlap.Parent));
                     }
                 }
 
-                Add(new BufferModifiedRange(address, size, syncNumber));
+                Add(new BufferModifiedRange(address, size, syncNumber, this));
             }
         }
 
@@ -208,8 +241,101 @@ namespace Ryujinx.Graphics.Gpu.Memory
         }
 
         /// <summary>
+        /// Performs the given range action, or one from a migration that overlaps and has not synced yet.
+        /// </summary>
+        /// <param name="offset">The offset to pass to the action</param>
+        /// <param name="size">The size to pass to the action</param>
+        /// <param name="syncNumber">The sync number that has been reached</param>
+        /// <param name="parent">The modified range list that originally owned this range</param>
+        /// <param name="rangeAction">The action to perform</param>
+        public void RangeActionWithMigration(ulong offset, ulong size, ulong syncNumber, BufferModifiedRangeList parent, Action<ulong, ulong> rangeAction)
+        {
+            bool firstSource = true;
+
+            if (parent != this)
+            {
+                lock (_lock)
+                {
+                    if (_sources != null)
+                    {
+                        foreach (BufferMigration source in _sources)
+                        {
+                            if (source.Overlaps(offset, size, syncNumber))
+                            {
+                                if (firstSource && !source.FullyMatches(offset, size))
+                                {
+                                    // Perform this buffer's action first. The migrations will run after.
+                                    rangeAction(offset, size);
+                                }
+
+                                source.RangeActionWithMigration(offset, size, syncNumber, parent);
+
+                                firstSource = false;
+                            }
+                        }
+                    }
+                }
+            }
+
+            if (firstSource)
+            {
+                // No overlapping migrations, or they are not meant for this range, flush the data using the given action.
+                rangeAction(offset, size);
+            }
+        }
+
+        /// <summary>
+        /// Removes modified ranges ready by the sync number from the list, and flushes their buffer data within a given address range.
+        /// </summary>
+        /// <param name="overlaps">Overlapping ranges to check</param>
+        /// <param name="rangeCount">Number of overlapping ranges</param>
+        /// <param name="highestDiff">The highest difference between an overlapping range's sync number and the current one</param>
+        /// <param name="currentSync">The current sync number</param>
+        /// <param name="address">The start address of the flush range</param>
+        /// <param name="endAddress">The end address of the flush range</param>
+        private void RemoveRangesAndFlush(
+            BufferModifiedRange[] overlaps,
+            int rangeCount,
+            long highestDiff,
+            ulong currentSync,
+            ulong address,
+            ulong endAddress)
+        {
+            lock (_lock)
+            {
+                if (_migrationTarget == null)
+                {
+                    ulong waitSync = currentSync + (ulong)highestDiff;
+
+                    for (int i = 0; i < rangeCount; i++)
+                    {
+                        BufferModifiedRange overlap = overlaps[i];
+
+                        long diff = (long)(overlap.SyncNumber - currentSync);
+
+                        if (diff <= highestDiff)
+                        {
+                            ulong clampAddress = Math.Max(address, overlap.Address);
+                            ulong clampEnd = Math.Min(endAddress, overlap.EndAddress);
+
+                            ClearPart(overlap, clampAddress, clampEnd);
+
+                            RangeActionWithMigration(clampAddress, clampEnd - clampAddress, waitSync, overlap.Parent, _flushAction);
+                        }
+                    }
+
+                    return;
+                }
+            }
+
+            // There is a migration target to call instead. This can't be changed after set so accessing it outside the lock is fine.
+
+            _migrationTarget.Destination.RemoveRangesAndFlush(overlaps, rangeCount, highestDiff, currentSync, address, endAddress);
+        }
+
+        /// <summary>
         /// Gets modified ranges within the specified region, waits on ones from a previous sync number,
-        /// and then fires the given action for each range individually.
+        /// and then fires the flush action for each range individually.
         /// </summary>
         /// <remarks>
         /// This function assumes it is called from the background thread.
@@ -218,8 +344,7 @@ namespace Ryujinx.Graphics.Gpu.Memory
         /// </remarks>
         /// <param name="address">Start address to query</param>
         /// <param name="size">Size to query</param>
-        /// <param name="rangeAction">The action to call for each modified range</param>
-        public void WaitForAndGetRanges(ulong address, ulong size, Action<ulong, ulong> rangeAction)
+        public void WaitForAndFlushRanges(ulong address, ulong size)
         {
             ulong endAddress = address + size;
             ulong currentSync = _context.SyncNumber;
@@ -231,10 +356,23 @@ namespace Ryujinx.Graphics.Gpu.Memory
             // Range list must be consistent for this operation
             lock (_lock)
             {
-                rangeCount = FindOverlapsNonOverlapping(address, size, ref overlaps);
+                if (_migrationTarget != null)
+                {
+                    rangeCount = -1;
+                }
+                else
+                {
+                    rangeCount = FindOverlapsNonOverlapping(address, size, ref overlaps);
+                }
             }
 
-            if (rangeCount == 0)
+            if (rangeCount == -1)
+            {
+                _migrationTarget.Destination.WaitForAndFlushRanges(address, size);
+
+                return;
+            }
+            else if (rangeCount == 0)
             {
                 return;
             }
@@ -264,47 +402,37 @@ namespace Ryujinx.Graphics.Gpu.Memory
             // Wait for the syncpoint.
             _context.Renderer.WaitSync(currentSync + (ulong)highestDiff);
 
-            // Flush and remove all regions with the older syncpoint.
-            lock (_lock)
-            {
-                for (int i = 0; i < rangeCount; i++)
-                {
-                    BufferModifiedRange overlap = overlaps[i];
-
-                    long diff = (long)(overlap.SyncNumber - currentSync);
-
-                    if (diff <= highestDiff)
-                    {
-                        ulong clampAddress = Math.Max(address, overlap.Address);
-                        ulong clampEnd = Math.Min(endAddress, overlap.EndAddress);
-
-                        ClearPart(overlap, clampAddress, clampEnd);
-
-                        rangeAction(clampAddress, clampEnd - clampAddress);
-                    }
-                }
-            }
+            RemoveRangesAndFlush(overlaps, rangeCount, highestDiff, currentSync, address, endAddress);
         }
 
         /// <summary>
         /// Inherit ranges from another modified range list.
         /// </summary>
         /// <param name="ranges">The range list to inherit from</param>
-        /// <param name="rangeAction">The action to call for each modified range</param>
-        public void InheritRanges(BufferModifiedRangeList ranges, Action<ulong, ulong> rangeAction)
+        /// <param name="registerRangeAction">The action to call for each modified range</param>
+        public void InheritRanges(BufferModifiedRangeList ranges, Action<ulong, ulong> registerRangeAction)
         {
             BufferModifiedRange[] inheritRanges;
 
             lock (ranges._lock)
             {
+                BufferMigration migration = new(ranges._parent, ranges._flushAction, ranges, this, _context.SyncNumber);
+
+                ranges._parent.IncrementReferenceCount();
+                ranges._migrationTarget = migration;
+
+                _context.RegisterBufferMigration(migration);
+
                 inheritRanges = ranges.ToArray();
-            }
 
-            lock (_lock)
-            {
-                foreach (BufferModifiedRange range in inheritRanges)
+                lock (_lock)
                 {
-                    Add(range);
+                    (_sources ??= new List<BufferMigration>()).Add(migration);
+
+                    foreach (BufferModifiedRange range in inheritRanges)
+                    {
+                        Add(range);
+                    }
                 }
             }
 
@@ -313,44 +441,20 @@ namespace Ryujinx.Graphics.Gpu.Memory
             {
                 if (range.SyncNumber != currentSync)
                 {
-                    rangeAction(range.Address, range.Size);
+                    registerRangeAction(range.Address, range.Size);
                 }
             }
         }
 
         /// <summary>
-        /// Calls the given action for modified ranges that aren't from the current sync number.
+        /// Removes a source buffer migration, indicating its copy has completed.
         /// </summary>
-        /// <param name="rangeAction">The action to call for each modified range</param>
-        public void ReregisterRanges(Action<ulong, ulong> rangeAction)
+        /// <param name="migration">The migration to remove</param>
+        public void RemoveMigration(BufferMigration migration)
         {
-            ref var ranges = ref ThreadStaticArray<BufferModifiedRange>.Get();
-            int count;
-
-            // Range list must be consistent for this operation.
             lock (_lock)
             {
-                count = Count;
-                if (ranges.Length < count)
-                {
-                    Array.Resize(ref ranges, count);
-                }
-
-                int i = 0;
-                foreach (BufferModifiedRange range in this)
-                {
-                    ranges[i++] = range;
-                }
-            }
-
-            ulong currentSync = _context.SyncNumber;
-            for (int i = 0; i < count; i++)
-            {
-                BufferModifiedRange range = ranges[i];
-                if (range.SyncNumber != currentSync)
-                {
-                    rangeAction(range.Address, range.Size);
-                }
+                _sources.Remove(migration);
             }
         }
 
@@ -362,12 +466,12 @@ namespace Ryujinx.Graphics.Gpu.Memory
 
             if (overlap.Address < address)
             {
-                Add(new BufferModifiedRange(overlap.Address, address - overlap.Address, overlap.SyncNumber));
+                Add(new BufferModifiedRange(overlap.Address, address - overlap.Address, overlap.SyncNumber, overlap.Parent));
             }
 
             if (overlap.EndAddress > endAddress)
             {
-                Add(new BufferModifiedRange(endAddress, overlap.EndAddress - endAddress, overlap.SyncNumber));
+                Add(new BufferModifiedRange(endAddress, overlap.EndAddress - endAddress, overlap.SyncNumber, overlap.Parent));
             }
         }
 
diff --git a/Ryujinx.Graphics.OpenGL/OpenGLRenderer.cs b/Ryujinx.Graphics.OpenGL/OpenGLRenderer.cs
index e26fe6b6..63c96fa2 100644
--- a/Ryujinx.Graphics.OpenGL/OpenGLRenderer.cs
+++ b/Ryujinx.Graphics.OpenGL/OpenGLRenderer.cs
@@ -238,6 +238,11 @@ namespace Ryujinx.Graphics.OpenGL
             _sync.Wait(id);
         }
 
+        public ulong GetCurrentSync()
+        {
+            return _sync.GetCurrent();
+        }
+
         public void Screenshot()
         {
             _window.ScreenCaptureRequested = true;
diff --git a/Ryujinx.Graphics.OpenGL/Sync.cs b/Ryujinx.Graphics.OpenGL/Sync.cs
index de94fd31..58818e6a 100644
--- a/Ryujinx.Graphics.OpenGL/Sync.cs
+++ b/Ryujinx.Graphics.OpenGL/Sync.cs
@@ -40,6 +40,37 @@ namespace Ryujinx.Graphics.OpenGL
             }
         }
 
+        public ulong GetCurrent()
+        {
+            lock (_handles)
+            {
+                ulong lastHandle = _firstHandle;
+
+                foreach (SyncHandle handle in _handles)
+                {
+                    lock (handle)
+                    {
+                        if (handle.Handle == IntPtr.Zero)
+                        {
+                            continue;
+                        }
+
+                        if (handle.ID > lastHandle)
+                        {
+                            WaitSyncStatus syncResult = GL.ClientWaitSync(handle.Handle, _syncFlags, 0);
+
+                            if (syncResult == WaitSyncStatus.AlreadySignaled)
+                            {
+                                lastHandle = handle.ID;
+                            }
+                        }
+                    }
+                }
+
+                return lastHandle;
+            }
+        }
+
         public void Wait(ulong id)
         {
             SyncHandle result = null;
diff --git a/Ryujinx.Graphics.Vulkan/SyncManager.cs b/Ryujinx.Graphics.Vulkan/SyncManager.cs
index a39862d0..35e3adf1 100644
--- a/Ryujinx.Graphics.Vulkan/SyncManager.cs
+++ b/Ryujinx.Graphics.Vulkan/SyncManager.cs
@@ -11,6 +11,7 @@ namespace Ryujinx.Graphics.Vulkan
         {
             public ulong ID;
             public MultiFenceHolder Waitable;
+            public bool Signalled;
         }
 
         private ulong _firstHandle = 0;
@@ -45,6 +46,37 @@ namespace Ryujinx.Graphics.Vulkan
             }
         }
 
+        public ulong GetCurrent()
+        {
+            lock (_handles)
+            {
+                ulong lastHandle = _firstHandle;
+
+                foreach (SyncHandle handle in _handles)
+                {
+                    lock (handle)
+                    {
+                        if (handle.Waitable == null)
+                        {
+                            continue;
+                        }
+
+                        if (handle.ID > lastHandle)
+                        {
+                            bool signaled = handle.Signalled || handle.Waitable.WaitForFences(_gd.Api, _device, 0);
+                            if (signaled)
+                            {
+                                lastHandle = handle.ID;
+                                handle.Signalled = true;
+                            }
+                        }
+                    }
+                }
+
+                return lastHandle;
+            }
+        }
+
         public void Wait(ulong id)
         {
             SyncHandle result = null;
@@ -75,11 +107,15 @@ namespace Ryujinx.Graphics.Vulkan
                         return;
                     }
 
-                    bool signaled = result.Waitable.WaitForFences(_gd.Api, _device, 1000000000);
+                    bool signaled = result.Signalled || result.Waitable.WaitForFences(_gd.Api, _device, 1000000000);
                     if (!signaled)
                     {
                         Logger.Error?.PrintMsg(LogClass.Gpu, $"VK Sync Object {result.ID} failed to signal within 1000ms. Continuing...");
                     }
+                    else
+                    {
+                        result.Signalled = true;
+                    }
                 }
             }
         }
diff --git a/Ryujinx.Graphics.Vulkan/VulkanRenderer.cs b/Ryujinx.Graphics.Vulkan/VulkanRenderer.cs
index 22e30329..5acbe841 100644
--- a/Ryujinx.Graphics.Vulkan/VulkanRenderer.cs
+++ b/Ryujinx.Graphics.Vulkan/VulkanRenderer.cs
@@ -565,6 +565,11 @@ namespace Ryujinx.Graphics.Vulkan
             _syncManager.Wait(id);
         }
 
+        public ulong GetCurrentSync()
+        {
+            return _syncManager.GetCurrent();
+        }
+
         public void Screenshot()
         {
             _window.ScreenCaptureRequested = true;