GPU: Don't trigger uploads for redundant buffer updates (#3828)

* Initial implementation

* Actually do The Thing

* Add remark about performance to IVirtualMemoryManager

2 files changed, 19 insertions, 0 deletions

diff --git a/Ryujinx.Memory/AddressSpaceManager.cs b/Ryujinx.Memory/AddressSpaceManager.cs
index 45f3225e..ffe880bf 100644
--- a/Ryujinx.Memory/AddressSpaceManager.cs
+++ b/Ryujinx.Memory/AddressSpaceManager.cs
@@ -137,6 +137,14 @@ namespace Ryujinx.Memory
         }
 
         /// <inheritdoc/>
+        public bool WriteWithRedundancyCheck(ulong va, ReadOnlySpan<byte> data)
+        {
+            Write(va, data);
+
+            return true;
+        }
+
+        /// <inheritdoc/>
         public ReadOnlySpan<byte> GetSpan(ulong va, int size, bool tracked = false)
         {
             if (size == 0)
diff --git a/Ryujinx.Memory/IVirtualMemoryManager.cs b/Ryujinx.Memory/IVirtualMemoryManager.cs
index f97cb0b5..c8a74f66 100644
--- a/Ryujinx.Memory/IVirtualMemoryManager.cs
+++ b/Ryujinx.Memory/IVirtualMemoryManager.cs
@@ -58,6 +58,17 @@ namespace Ryujinx.Memory
         /// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
         void Write(ulong va, ReadOnlySpan<byte> data);
 
+        /// <summary>
+        /// Writes data to the application process, returning false if the data was not changed.
+        /// This triggers read memory tracking, as a redundancy check would be useless if the data is not up to date.
+        /// </summary>
+        /// <remarks>The memory manager can return that memory has changed when it hasn't to avoid expensive data copies.</remarks>
+        /// <param name="va">Virtual address to write the data into</param>
+        /// <param name="data">Data to be written</param>
+        /// <exception cref="InvalidMemoryRegionException">Throw for unhandled invalid or unmapped memory accesses</exception>
+        /// <returns>True if the data was changed, false otherwise</returns>
+        bool WriteWithRedundancyCheck(ulong va, ReadOnlySpan<byte> data);
+
         void Fill(ulong va, ulong size, byte value)
         {
             const int MaxChunkSize = 1 << 24;