From b6eb3b703e74cb09671c3648370124b54cb7b136 Mon Sep 17 00:00:00 2001
From: El <eldargafiyatov@gmail.com>
Date: Thu, 16 Apr 2026 09:31:49 +0000
Subject: [PATCH] VNC-151 Use arena

---
 common/rfb/encoders/ScreenEncoderManager.cxx | 23 ++++++++++++--------
 common/rfb/encoders/ScreenEncoderManager.h   |  6 ++---
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/common/rfb/encoders/ScreenEncoderManager.cxx b/common/rfb/encoders/ScreenEncoderManager.cxx
index 6927986..da7f347 100644
--- a/common/rfb/encoders/ScreenEncoderManager.cxx
+++ b/common/rfb/encoders/ScreenEncoderManager.cxx
@@ -38,6 +38,7 @@ namespace rfb {
         base_video_encoder(encoder),
         available_encoders(encoders) {
         screens_to_refresh.reserve(T);
+        arena.initialize(MAX_SCREENS);
     }
 
     template<uint8_t T>
@@ -219,16 +220,20 @@ namespace rfb {
         if (screens_to_refresh.size() > 1) {
             tbb::task_group_context ctx;
 
-            tbb::parallel_for_each(screens_to_refresh.begin(), screens_to_refresh.end(), [this, pb, &ctx, forceKeyFrame](uint8_t index) {
-                if (ctx.is_group_execution_cancelled())
-                    return;
+            arena.execute([&] {
+                tbb::parallel_for_each(screens_to_refresh.begin(),
+                    screens_to_refresh.end(),
+                    [this, pb, &ctx, forceKeyFrame](uint8_t index) {
+                        if (ctx.is_group_execution_cancelled())
+                            return;
 
-                auto &screen = screens[index];
-                if (auto *encoder = screen.encoder; encoder) {
-                    screen.dirty = encoder->render(pb, forceKeyFrame);
-                    if (!screen.dirty)
-                        ctx.cancel_group_execution();
-                }
+                        auto &screen = screens[index];
+                        if (auto *encoder = screen.encoder; encoder) {
+                            screen.dirty = encoder->render(pb, forceKeyFrame);
+                            if (!screen.dirty)
+                                ctx.cancel_group_execution();
+                        }
+                    });
             });
 
             if (ctx.is_group_execution_cancelled())
diff --git a/common/rfb/encoders/ScreenEncoderManager.h b/common/rfb/encoders/ScreenEncoderManager.h
index bb7c810..fa9537a 100644
--- a/common/rfb/encoders/ScreenEncoderManager.h
+++ b/common/rfb/encoders/ScreenEncoderManager.h
@@ -16,14 +16,14 @@
  * USA.
  */
 #pragma once
-#include <tbb/spin_mutex.h>
+#include <tbb/task_arena.h>
 #include <vector>
 #include "KasmVideoConstants.h"
 #include "VideoEncoder.h"
 #include "rfb/Encoder.h"
 #include "rfb/ffmpeg.h"
 
-inline constexpr uint8_t MAX_SCREENS = 8;
+inline constexpr uint8_t MAX_SCREENS = 4;
 
 namespace rfb {
     template<uint8_t T = MAX_SCREENS>
@@ -41,9 +41,9 @@ namespace rfb {
 
         uint64_t mask{};
         std::vector<uint8_t> screens_to_refresh;
-        tbb::spin_mutex conn_mutex;
 
         std::array<screen_t, T> screens{};
+        tbb::task_arena arena;
         const FFmpeg &ffmpeg;
         VideoEncoderParams current_params;