samples: Basic system heap Demo

A demo to showcase some of the sys_heap functions

Signed-off-by: Jeppe Odgaard <jeppe.odgaard@prevas.dk>

samples/basic/sys_heap/CMakeLists.txt

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+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(sys_heap)
+
+target_sources(app PRIVATE src/main.c)

samples/basic/sys_heap/README.rst

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+.. _system_heap:
+
+System heap
+###########
+
+Overview
+********
+
+A simple sample that can be used with any :ref:`supported board <boards>` and
+prints system heap usage to the console.
+
+Building
+********************
+
+This application can be built on native_posix as follows:
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/basic/sys_heap
+   :host-os: unix
+   :board: native_posix
+   :goals: build
+   :compact:
+
+To build for another board, change "native_posix" above to that board's name.
+
+Running
+*******
+
+Run build/zephyr/zephyr.exe
+
+Sample Output
+*************
+
+.. code-block:: console
+
+    System heap sample
+
+    allocated 0, free 196, max allocated 0, heap size 256
+    allocated 156, free 36, max allocated 156, heap size 256
+    allocated 100, free 92, max allocated 156, heap size 256
+    allocated 0, free 196, max allocated 156, heap size 256

samples/basic/sys_heap/prj.conf

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+CONFIG_SYS_HEAP_RUNTIME_STATS=y

samples/basic/sys_heap/sample.yaml

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+sample:
+  description: System heap sample showing how to use sys_heap functions
+  name: Basic system heap sample
+common:
+  integration_platforms:
+    - native_posix
+  harness: console
+  harness_config:
+    type: multi_line
+    ordered: true
+    regex:
+      - ".*allocated 15.,.*"
+      - ".*allocated 10.,.*"
+      - ".*allocated 0, free ..., max allocated ..., heap size 256.*"
+tests:
+  sample.basic.sys_heap:
+    tags: heap statistics dynamic_memory

samples/basic/sys_heap/src/main.c

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+/*
+ * Copyright (c) 2022 Jeppe Odgaard
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/sys/sys_heap.h>
+
+#define HEAP_SIZE	256
+
+static char heap_mem[HEAP_SIZE];
+static struct sys_heap heap;
+
+void print_sys_memory_stats(void);
+
+void main(void)
+{
+	void *p;
+
+	printk("System heap sample\n\n");
+
+	sys_heap_init(&heap, heap_mem, HEAP_SIZE);
+	print_sys_memory_stats();
+
+	p = sys_heap_alloc(&heap, 150);
+	print_sys_memory_stats();
+
+	p = sys_heap_realloc(&heap, p, 100);
+	print_sys_memory_stats();
+
+	sys_heap_free(&heap, p);
+	print_sys_memory_stats();
+}
+
+void print_sys_memory_stats(void)
+{
+	struct sys_memory_stats stats;
+
+	sys_heap_runtime_stats_get(&heap, &stats);
+
+	printk("allocated %zu, free %zu, max allocated %zu, heap size %u\n",
+		stats.allocated_bytes, stats.free_bytes,
+		stats.max_allocated_bytes, HEAP_SIZE);
+}