Implement support for page sizes > 4KB (#4252)

* Implement support for page sizes > 4KB

* Check and work around more alignment issues

* Was not meant to change this

* Use MemoryBlock.GetPageSize() value for signal handler code

* Do not take the path for private allocations if host supports 4KB pages

* Add Flags attribute on MemoryMapFlags

* Fix dirty region size with 16kb pages

Would accidentally report a size that was too high (generally 16k instead of 4k, uploading 4x as much data)

Co-authored-by: riperiperi <rhy3756547@hotmail.com>

Ryujinx.Graphics.Gpu/Image/TextureGroup.cs

@@ -1420,6 +1420,14 @@ namespace Ryujinx.Graphics.Gpu.Image
         /// <param name="size">The size of the flushing memory access</param>
         public void FlushAction(TextureGroupHandle handle, ulong address, ulong size)
         {
+            // If the page size is larger than 4KB, we will have a lot of false positives for flushing.
+            // Let's avoid flushing textures that are unlikely to be read from CPU to improve performance
+            // on those platforms.
+            if (!_physicalMemory.Supports4KBPages && !Storage.Info.IsLinear && !_context.IsGpuThread())
+            {
+                return;
+            }
+
             // There is a small gap here where the action is removed but _actionRegistered is still 1.
             // In this case it will skip registering the action, but here we are already handling it,
             // so there shouldn't be any issue as it's the same handler for all actions.