From 37a9ad6a0d40e46f131813672b477a0e1622adc1 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Wed, 6 Aug 2025 22:34:46 -1000
Subject: [PATCH] [esp32_ble_tracker] Optimize member variable ordering to
 reduce memory padding (#10113)

---
 .../esp32_ble_tracker/esp32_ble_tracker.h     | 26 +++++++++++--------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h
index fba9dbd97e..4b09d521b6 100644
--- a/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h
+++ b/esphome/components/esp32_ble_tracker/esp32_ble_tracker.h
@@ -333,33 +333,37 @@ class ESP32BLETracker : public Component,
     return counts;
   }
 
-  uint8_t app_id_{0};
-
+  // Group 1: Large objects (12+ bytes) - vectors and callback manager
+  std::vector<ESPBTDeviceListener *> listeners_;
+  std::vector<ESPBTClient *> clients_;
+  CallbackManager<void(ScannerState)> scanner_state_callbacks_;
 #ifdef USE_ESP32_BLE_DEVICE
   /// Vector of addresses that have already been printed in print_bt_device_info
   std::vector<uint64_t> already_discovered_;
 #endif
-  std::vector<ESPBTDeviceListener *> listeners_;
-  /// Client parameters.
-  std::vector<ESPBTClient *> clients_;
+
+  // Group 2: Structs (aligned to 4 bytes)
   /// A structure holding the ESP BLE scan parameters.
   esp_ble_scan_params_t scan_params_;
+  ClientStateCounts client_state_counts_;
+
+  // Group 3: 4-byte types
   /// The interval in seconds to perform scans.
   uint32_t scan_duration_;
   uint32_t scan_interval_;
   uint32_t scan_window_;
+  esp_bt_status_t scan_start_failed_{ESP_BT_STATUS_SUCCESS};
+  esp_bt_status_t scan_set_param_failed_{ESP_BT_STATUS_SUCCESS};
+
+  // Group 4: 1-byte types (enums, uint8_t, bool)
+  uint8_t app_id_{0};
   uint8_t scan_start_fail_count_{0};
+  ScannerState scanner_state_{ScannerState::IDLE};
   bool scan_continuous_;
   bool scan_active_;
-  ScannerState scanner_state_{ScannerState::IDLE};
-  CallbackManager<void(ScannerState)> scanner_state_callbacks_;
   bool ble_was_disabled_{true};
   bool raw_advertisements_{false};
   bool parse_advertisements_{false};
-
-  esp_bt_status_t scan_start_failed_{ESP_BT_STATUS_SUCCESS};
-  esp_bt_status_t scan_set_param_failed_{ESP_BT_STATUS_SUCCESS};
-  ClientStateCounts client_state_counts_;
 #ifdef USE_ESP32_BLE_SOFTWARE_COEXISTENCE
   bool coex_prefer_ble_{false};
 #endif