Vulkan: Migrate buffers between memory types to improve GPU performance (#4540)

* Initial implementation of migration between memory heaps

- Missing OOM handling
- Missing `_map` data safety when remapping
  - Copy may not have completed yet (needs some kind of fence)
  - Map may be unmapped before it is done being used. (needs scoped access)
- SSBO accesses are all "writes" - maybe pass info in another way.
- Missing keeping map type when resizing buffers (should this be done?)

* Ensure migrated data is in place before flushing.

* Fix issue where old waitable would be signalled.

- There is a real issue where existing Auto<> references need to be replaced.

* Swap bound Auto<> instances when swapping buffer backing

* Fix conversion buffers

* Don't try move buffers if the host has shared memory.

* Make GPU methods return PinnedSpan with scope

* Storage Hint

* Fix stupidity

* Fix rebase

* Tweak rules

Attempt to sidestep BOTW slowdown

* Remove line

* Migrate only when command buffers flush

* Change backing swap log to debug

* Address some feedback

* Disallow backing swap when the flush lock is held by the current thread

* Make PinnedSpan from ReadOnlySpan explicitly unsafe

* Fix some small issues

- Index buffer swap fixed
- Allocate DeviceLocal buffers using a separate block list to images.

* Remove alternative flags

* Address feedback

1 files changed, 53 insertions, 0 deletions

diff --git a/Ryujinx.Graphics.GAL/PinnedSpan.cs b/Ryujinx.Graphics.GAL/PinnedSpan.cs
new file mode 100644
index 00000000..275b3b86
--- /dev/null
+++ b/Ryujinx.Graphics.GAL/PinnedSpan.cs
@@ -0,0 +1,53 @@
+using System;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Graphics.GAL
+{
+    public unsafe struct PinnedSpan<T> : IDisposable where T : unmanaged
+    {
+        private void* _ptr;
+        private int _size;
+        private Action _disposeAction;
+
+        /// <summary>
+        /// Creates a new PinnedSpan from an existing ReadOnlySpan. The span *must* be pinned in memory.
+        /// The data must be guaranteed to live until disposeAction is called.
+        /// </summary>
+        /// <param name="span">Existing span</param>
+        /// <param name="disposeAction">Action to call on dispose</param>
+        /// <remarks>
+        /// If a dispose action is not provided, it is safe to assume the resource will be available until the next call.
+        /// </remarks>
+        public static PinnedSpan<T> UnsafeFromSpan(ReadOnlySpan<T> span, Action disposeAction = null)
+        {
+            return new PinnedSpan<T>(Unsafe.AsPointer(ref MemoryMarshal.GetReference(span)), span.Length, disposeAction);
+        }
+
+        /// <summary>
+        /// Creates a new PinnedSpan from an existing unsafe region. The data must be guaranteed to live until disposeAction is called.
+        /// </summary>
+        /// <param name="ptr">Pointer to the region</param>
+        /// <param name="size">The total items of T the region contains</param>
+        /// <param name="disposeAction">Action to call on dispose</param>
+        /// <remarks>
+        /// If a dispose action is not provided, it is safe to assume the resource will be available until the next call.
+        /// </remarks>
+        public PinnedSpan(void* ptr, int size, Action disposeAction = null)
+        {
+            _ptr = ptr;
+            _size = size;
+            _disposeAction = disposeAction;
+        }
+
+        public ReadOnlySpan<T> Get()
+        {
+            return new ReadOnlySpan<T>(_ptr, _size * Unsafe.SizeOf<T>());
+        }
+
+        public void Dispose()
+        {
+            _disposeAction?.Invoke();
+        }
+    }
+}