Stabilize concurrent SSH and WebSocket transports

src/session_broker.c

@@ -11,6 +11,7 @@
 #include "serial_service.h"
 
 #define SESSION_BROKER_RX_CHUNK_SIZE 256U
+#define SESSION_BROKER_ACTIVE_BURST_BYTES (8U * SESSION_BROKER_RX_CHUNK_SIZE)
 #define SESSION_BROKER_TASK_STACK_SIZE 4096U
 #define SESSION_BROKER_TASK_PRIORITY 9U
 #define SESSION_BROKER_IDLE_POLL_MS 5U
@@ -160,6 +161,7 @@ static void broker_task(void *context)
 {
     (void)context;
     uint8_t data[SESSION_BROKER_RX_CHUNK_SIZE];
+    size_t active_burst_bytes = 0U;
 
     for (;;) {
         /*
@@ -175,7 +177,20 @@ static void broker_task(void *context)
         xSemaphoreGive(s_mutex);
 
         if (received == 0U) {
+            active_burst_bytes = 0U;
             vTaskDelay(milliseconds_to_ticks(SESSION_BROKER_IDLE_POLL_MS));
+        } else {
+            active_burst_bytes += received;
+            if (active_burst_bytes >= SESSION_BROKER_ACTIVE_BURST_BYTES) {
+                active_burst_bytes = 0U;
+                /*
+                 * A continuously readable UART must not make this priority-9
+                 * task permanently runnable. One tick after each bounded burst
+                 * preserves 1 Mbaud headroom while allowing idle and transports
+                 * to run on a loaded dual-core system.
+                 */
+                vTaskDelay(1U);
+            }
         }
     }
 }