diff --git a/api/gc-api.h b/api/gc-api.h
index 01ad113a8..3de4272e3 100644
--- a/api/gc-api.h
+++ b/api/gc-api.h
@@ -53,12 +53,14 @@ GC_API_ void gc_heap_set_extern_space(struct gc_heap *heap,
 GC_API_ struct gc_mutator* gc_init_for_thread(struct gc_stack_addr base,
                                               struct gc_heap *heap);
 GC_API_ void gc_finish_for_thread(struct gc_mutator *mut);
+GC_API_ void gc_deactivate(struct gc_mutator *mut);
+GC_API_ void gc_reactivate(struct gc_mutator *mut);
 GC_API_ void* gc_deactivate_for_call(struct gc_mutator *mut,
                                      void* (*f)(struct gc_mutator*, void*),
-                                     void *data) GC_NEVER_INLINE;
+                                     void *data);
 GC_API_ void* gc_reactivate_for_call(struct gc_mutator *mut,
                                      void* (*f)(struct gc_mutator*, void*),
-                                     void *data) GC_NEVER_INLINE;
+                                     void *data);
 
 GC_API_ void gc_collect(struct gc_mutator *mut,
                         enum gc_collection_kind requested_kind);
diff --git a/src/bdw.c b/src/bdw.c
index c6e2b4341..da63d7ef5 100644
--- a/src/bdw.c
+++ b/src/bdw.c
@@ -668,6 +668,9 @@ static void* call_with_mutator (void *p) {
   return data->proc(data->mutator, data->data);
 }
 
+void gc_deactivate(struct gc_mutator *mut) {};
+void gc_reactivate(struct gc_mutator *mut) {};
+
 void* gc_deactivate_for_call(struct gc_mutator *mut,
                              void* (*f)(struct gc_mutator *, void*),
                              void *data) {
diff --git a/src/mmc.c b/src/mmc.c
index a1329e239..26e3e0652 100644
--- a/src/mmc.c
+++ b/src/mmc.c
@@ -1297,6 +1297,16 @@ reactivate_mutator(struct gc_heap *heap, struct gc_mutator *mut) {
   heap_unlock(heap);
 }
 
+void gc_deactivate(struct gc_mutator *mut) {
+  GC_ASSERT(mut->active);
+  deactivate_mutator(mutator_heap(mut), mut);
+}
+
+void gc_reactivate(struct gc_mutator *mut) {
+  GC_ASSERT(!mut->active);
+  reactivate_mutator(mutator_heap(mut), mut);
+}
+
 void*
 gc_deactivate_for_call(struct gc_mutator *mut,
                        void* (*f)(struct gc_mutator*, void*),
diff --git a/src/pcc.c b/src/pcc.c
index 609160a15..5e3f459c0 100644
--- a/src/pcc.c
+++ b/src/pcc.c
@@ -1383,6 +1383,16 @@ static void reactivate_mutator(struct gc_heap *heap, struct gc_mutator *mut) {
   heap_unlock(heap);
 }
 
+void gc_deactivate(struct gc_mutator *mut) {
+  GC_ASSERT(mut->active);
+  deactivate_mutator(mutator_heap(mut), mut);
+}
+
+void gc_reactivate(struct gc_mutator *mut) {
+  GC_ASSERT(!mut->active);
+  reactivate_mutator(mutator_heap(mut), mut);
+}
+
 void* gc_deactivate_for_call(struct gc_mutator *mut,
                              void* (*f)(struct gc_mutator*, void*),
                              void *data) {
diff --git a/src/semi.c b/src/semi.c
index 913c983c1..cc8eacb50 100644
--- a/src/semi.c
+++ b/src/semi.c
@@ -763,6 +763,10 @@ struct gc_mutator* gc_init_for_thread(struct gc_stack_addr base,
 void gc_finish_for_thread(struct gc_mutator *space) {
 }
 
+void gc_deactivate(struct gc_mutator *mut) {}
+
+void gc_reactivate(struct gc_mutator *mut) {}
+
 void* gc_deactivate_for_call(struct gc_mutator *mut,
                              void* (*f)(struct gc_mutator *, void*),
                              void *data) {