GPUThread: Push settings through FIFO

Saves the std::function heap allocation.

src/core/gpu_thread.cpp

@@ -82,7 +82,7 @@ static bool CreateGPUBackendOnThread(GPURenderer renderer, bool upload_vram, Err
 static void DestroyGPUBackendOnThread();
 static void DestroyGPUPresenterOnThread();
 
-static void UpdateSettingsOnThread(const GPUSettings& old_settings);
+static void UpdateSettingsOnThread(GPUThreadUpdateSettingsCommand* cmd);
 
 static void UpdateRunIdle();
 
@@ -507,6 +507,14 @@ void GPUThread::Internal::GPUThreadEntryPoint()
         }
         break;
 
+        case GPUBackendCommandType::UpdateSettings:
+        {
+          GPUThreadUpdateSettingsCommand* ccmd = static_cast<GPUThreadUpdateSettingsCommand*>(cmd);
+          UpdateSettingsOnThread(ccmd);
+          ccmd->~GPUThreadUpdateSettingsCommand();
+        }
+        break;
+
         case GPUBackendCommandType::Shutdown:
         {
           // Should have consumed everything, and be shutdown.
@@ -553,6 +561,7 @@ bool GPUThread::Reconfigure(std::string serial, std::optional<GPURenderer> rende
   cmd->upload_vram = upload_vram;
   cmd->error_ptr = error;
   cmd->out_result = &result;
+  cmd->settings = g_settings;
 
   if (!s_state.use_gpu_thread) [[unlikely]]
     ReconfigureOnThread(cmd);
@@ -819,7 +828,7 @@ void GPUThread::ReconfigureOnThread(GPUThreadReconfigureCommand* cmd)
   s_state.requested_allow_present_throttle = cmd->allow_present_throttle;
   s_state.requested_fullscreen_ui = cmd->start_fullscreen_ui.value_or(s_state.requested_fullscreen_ui);
   s_state.game_serial = std::move(cmd->game_serial);
-  g_gpu_settings = g_settings;
+  g_gpu_settings = std::move(cmd->settings);
 
   // Readback old VRAM for hardware renderers.
   const bool had_renderer = static_cast<bool>(s_state.gpu_backend);
@@ -966,8 +975,13 @@ bool GPUThread::Internal::PresentFrameAndRestoreContext()
   return true;
 }
 
-void GPUThread::UpdateSettingsOnThread(const GPUSettings& old_settings)
+void GPUThread::UpdateSettingsOnThread(GPUThreadUpdateSettingsCommand* cmd)
 {
+  VERBOSE_LOG("Updating GPU settings on thread...");
+
+  GPUSettings old_settings = std::move(g_gpu_settings);
+  g_gpu_settings = std::move(cmd->settings);
+
   if (g_gpu_device)
   {
     if (g_gpu_settings.display_osd_scale != old_settings.display_osd_scale)
@@ -1067,14 +1081,9 @@ void GPUThread::UpdateSettings(bool gpu_settings_changed, bool device_settings_c
   }
   else if (gpu_settings_changed)
   {
-    RunOnThread([settings = g_settings]() {
-      VERBOSE_LOG("Updating GPU settings on thread...");
-
-      GPUSettings old_settings = std::move(g_gpu_settings);
-      g_gpu_settings = std::move(settings);
-
-      UpdateSettingsOnThread(old_settings);
-    });
+    GPUThreadUpdateSettingsCommand* cmd =
+      AllocateCommand<GPUThreadUpdateSettingsCommand>(GPUBackendCommandType::UpdateSettings, g_settings);
+    PushCommandAndWakeThread(cmd);
   }
   else
   {

src/core/gpu_thread_commands.h

@@ -1,9 +1,10 @@
-// SPDX-FileCopyrightText: 2019-2024 Connor McLaughlin <stenzek@gmail.com>
+// SPDX-FileCopyrightText: 2019-2025 Connor McLaughlin <stenzek@gmail.com>
 // SPDX-License-Identifier: CC-BY-NC-ND-4.0
 
 #pragma once
 
 #include "gpu_types.h"
+#include "settings.h"
 
 #include "common/align.h"
 
@@ -29,6 +30,7 @@ enum class GPUBackendCommandType : u8
   AsyncCall,
   AsyncBackendCall,
   Reconfigure,
+  UpdateSettings,
   Shutdown,
   ClearVRAM,
   ClearDisplay,
@@ -78,6 +80,14 @@ struct GPUThreadReconfigureCommand : public GPUThreadCommand
   bool allow_present_throttle;
   bool force_recreate_device;
   bool upload_vram;
+  GPUSettings settings;
+};
+
+struct GPUThreadUpdateSettingsCommand : public GPUThreadCommand
+{
+  GPUThreadUpdateSettingsCommand(const GPUSettings& settings_) : settings(settings_) {}
+
+  GPUSettings settings;
 };
 
 struct GPUThreadAsyncCallCommand : public GPUThreadCommand