core/thread: introduce THREAD_CREATE_NO_STACKTEST

benpicco · benpicco · commit 0fbc10fb4511 · 2024-07-29T11:45:58.000+02:00
diff --git a/core/include/thread.h b/core/include/thread.h
@@ -43,10 +43,11 @@
  * In addition to the priority, flags can be used when creating a thread to
  * alter the thread's behavior after creation. The following flags are available:
  *
- *  Flags                         | Description
- *  ----------------------------- | --------------------------------------------------
- *  @ref THREAD_CREATE_SLEEPING   | the thread will sleep until woken up manually
- *  @ref THREAD_CREATE_WOUT_YIELD | the thread might not run immediately after creation
+ *  Flags                          | Description
+ *  ------------------------------ | --------------------------------------------------
+ *  @ref THREAD_CREATE_SLEEPING    | the thread will sleep until woken up manually
+ *  @ref THREAD_CREATE_WOUT_YIELD  | the thread might not run immediately after creation
+ *  @ref THREAD_CREATE_NO_STACKTEST| never measure the stack's memory usage
  *
  * Thread creation
  * ===============
@@ -229,6 +230,13 @@ struct _thread {
  */
 #define THREAD_CREATE_WOUT_YIELD        (4)
 
+/**
+ * @brief Never write markers into the thread's stack to measure stack usage
+ *
+ * This flag is ignored when DEVELHELP or SCHED_TEST_STACK is not enabled
+ */
+#define THREAD_CREATE_NO_STACKTEST      (8)
+
 /**
  * @brief Legacy flag kept for compatibility.
  *
diff --git a/core/thread.c b/core/thread.c
@@ -265,14 +265,21 @@ kernel_pid_t thread_create(char *stack, int stacksize, uint8_t priority,
 
 #if defined(DEVELHELP) || defined(SCHED_TEST_STACK) \
     || defined(MODULE_TEST_UTILS_PRINT_STACK_USAGE)
-    /* assign each int of the stack the value of it's address. Alignment
-     * has been handled above, so silence -Wcast-align */
-    uintptr_t *stackmax = (uintptr_t *)(uintptr_t)(stack + stacksize);
-    uintptr_t *stackp = (uintptr_t *)(uintptr_t)stack;
-
-    while (stackp < stackmax) {
-        *stackp = (uintptr_t)stackp;
-        stackp++;
+    if (flags & THREAD_CREATE_NO_STACKTEST) {
+        /* create stack guard. Alignment has been handled above, so silence
+         * -Wcast-align */
+        *(uintptr_t *)(uintptr_t)stack = (uintptr_t)stack;
+    }
+    else {
+        /* assign each int of the stack the value of it's address. Alignment
+         * has been handled above, so silence -Wcast-align */
+        uintptr_t *stackmax = (uintptr_t *)(uintptr_t)(stack + stacksize);
+        uintptr_t *stackp = (uintptr_t *)(uintptr_t)stack;
+
+        while (stackp < stackmax) {
+            *stackp = (uintptr_t)stackp;
+            stackp++;
+        }
     }
 #endif
 
