linker: do not force keep common kernel objects

include/linker/common-ram.ld

@@ -91,17 +91,17 @@
 	_static_kernel_objects_begin = .;
 #endif /* CONFIG_USERSPACE */
 
-	Z_ITERABLE_SECTION_RAM(k_timer, 4)
-	Z_ITERABLE_SECTION_RAM(k_mem_slab, 4)
-	Z_ITERABLE_SECTION_RAM(k_mem_pool, 4)
-	Z_ITERABLE_SECTION_RAM(k_heap, 4)
-	Z_ITERABLE_SECTION_RAM(k_mutex, 4)
-	Z_ITERABLE_SECTION_RAM(k_stack, 4)
-	Z_ITERABLE_SECTION_RAM(k_msgq, 4)
-	Z_ITERABLE_SECTION_RAM(k_mbox, 4)
-	Z_ITERABLE_SECTION_RAM(k_pipe, 4)
-	Z_ITERABLE_SECTION_RAM(k_sem, 4)
-	Z_ITERABLE_SECTION_RAM(k_queue, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_timer, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_mem_slab, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_mem_pool, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_heap, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_mutex, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_stack, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_msgq, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_mbox, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_pipe, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_sem, 4)
+	Z_ITERABLE_SECTION_RAM_GC_ALLOWED(k_queue, 4)
 
 	SECTION_DATA_PROLOGUE(_net_buf_pool_area,,SUBALIGN(4))
 	{

include/linker/linker-defs.h

@@ -42,30 +42,72 @@
 	KEEP(*(SORT_BY_NAME(._##struct_type.static.*))); \
 	_CONCAT(_##struct_type, _list_end) = .
 
+#define Z_LINK_ITERABLE_GC_ALLOWED(struct_type) \
+	_CONCAT(_##struct_type, _list_start) = .; \
+	*(SORT_BY_NAME(._##struct_type.static.*)); \
+	_CONCAT(_##struct_type, _list_end) = .
+
 /* Define an output section which will set up an iterable area
  * of equally-sized data structures. For use with Z_STRUCT_SECTION_ITERABLE.
  * Input sections will be sorted by name, per ld's SORT_BY_NAME.
  *
  * This macro should be used for read-only data.
+ *
+ * Note that this keeps the symbols in the image even though
+ * they are not being directly referenced. Use this when symbols
+ * are indirectly referenced by iterating through the section.
  */
 #define Z_ITERABLE_SECTION_ROM(struct_type, subalign) \
 	SECTION_PROLOGUE(struct_type##_area,,SUBALIGN(subalign)) \
 	{ \
 		Z_LINK_ITERABLE(struct_type); \
 	} GROUP_LINK_IN(ROMABLE_REGION)
 
+/* Define an output section which will set up an iterable area
+ * of equally-sized data structures. For use with Z_STRUCT_SECTION_ITERABLE.
+ * Input sections will be sorted by name, per ld's SORT_BY_NAME.
+ *
+ * This macro should be used for read-only data.
+ *
+ * Note that the symbols within the section can be garbage collected.
+ */
+#define Z_ITERABLE_SECTION_ROM_GC_ALLOWED(struct_type, subalign) \
+	SECTION_PROLOGUE(struct_type##_area,,SUBALIGN(subalign)) \
+	{ \
+		Z_LINK_ITERABLE_GC_ALLOWED(struct_type); \
+	} GROUP_LINK_IN(ROMABLE_REGION)
+
 /* Define an output section which will set up an iterable area
  * of equally-sized data structures. For use with Z_STRUCT_SECTION_ITERABLE.
  * Input sections will be sorted by name, per ld's SORT_BY_NAME.
  *
  * This macro should be used for read-write data that is modified at runtime.
+ *
+ * Note that this keeps the symbols in the image even though
+ * they are not being directly referenced. Use this when symbols
+ * are indirectly referenced by iterating through the section.
  */
 #define Z_ITERABLE_SECTION_RAM(struct_type, subalign) \
 	SECTION_DATA_PROLOGUE(struct_type##_area,,SUBALIGN(subalign)) \
 	{ \
 		Z_LINK_ITERABLE(struct_type); \
 	} GROUP_DATA_LINK_IN(RAMABLE_REGION, ROMABLE_REGION)
 
+
+/* Define an output section which will set up an iterable area
+ * of equally-sized data structures. For use with Z_STRUCT_SECTION_ITERABLE.
+ * Input sections will be sorted by name, per ld's SORT_BY_NAME.
+ *
+ * This macro should be used for read-write data that is modified at runtime.
+ *
+ * Note that the symbols within the section can be garbage collected.
+ */
+#define Z_ITERABLE_SECTION_RAM_GC_ALLOWED(struct_type, subalign) \
+	SECTION_DATA_PROLOGUE(struct_type##_area,,SUBALIGN(subalign)) \
+	{ \
+		Z_LINK_ITERABLE_GC_ALLOWED(struct_type); \
+	} GROUP_DATA_LINK_IN(RAMABLE_REGION, ROMABLE_REGION)
+
 /*
  * generate a symbol to mark the start of the objects array for
  * the specified object and level, then link all of those objects

kernel/CMakeLists.txt

@@ -11,7 +11,6 @@ add_library(kernel
   kheap.c
   mailbox.c
   mem_slab.c
-  mempool.c
   msg_q.c
   mutex.c
   pipes.c
@@ -42,9 +41,13 @@ target_sources_ifdef(CONFIG_ATOMIC_OPERATIONS_C   kernel PRIVATE atomic_c.c)
 target_sources_ifdef(CONFIG_MMU                   kernel PRIVATE mmu.c)
 target_sources_ifdef(CONFIG_POLL                  kernel PRIVATE poll.c)
 
-if(${CONFIG_MEM_POOL_HEAP_BACKEND})
-else()
-  target_sources(kernel PRIVATE mempool_sys.c)
+if(${CONFIG_KERNEL_MEM_POOL})
+  target_sources(kernel PRIVATE mempool.c)
+
+  if(${CONFIG_MEM_POOL_HEAP_BACKEND})
+  else()
+    target_sources(kernel PRIVATE mempool_sys.c)
+  endif()
 endif()
 
 # The last 2 files inside the target_sources_ifdef should be

kernel/Kconfig

@@ -444,6 +444,16 @@ config NUM_PIPE_ASYNC_MSGS
 	  Setting this option to 0 disables support for asynchronous
 	  pipe messages.
 
+config KERNEL_MEM_POOL
+	bool "Use Kernel Memory Pool"
+	default y
+	help
+	  Enable the use of kernel memory pool.
+
+	  Say y if unsure.
+
+if KERNEL_MEM_POOL
+
 config MEM_POOL_HEAP_BACKEND
 	bool "Use k_heap as the backend for k_mem_pool"
 	default y
@@ -472,6 +482,9 @@ config HEAP_MEM_POOL_MIN_SIZE
 	  This option specifies the size of the smallest block in the pool.
 	  Option must be a power of 2 and lower than or equal to the size
 	  of the entire pool.
+
+endif # KERNEL_MEM_POOL
+
 endmenu
 
 config ARCH_HAS_CUSTOM_SWAP_TO_MAIN

samples/basic/minimal/no-mt.conf

@@ -1,3 +1,4 @@
 # Single-threaded, no timer support in the kernel
 
 CONFIG_MULTITHREADING=n
+CONFIG_KERNEL_MEM_POOL=n