4 files changed, 25 insertions, 11 deletions
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 4fd82bad10..039f97ef43 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -2658,18 +2658,21 @@ done:
 }
 
 int
-enif_is_on_dirty_scheduler(ErlNifEnv* env)
+enif_thread_type(void)
 {
-    int scheduler;
-    Process *c_p;
+    ErtsSchedulerData *esdp = erts_get_scheduler_data();
 
-    execution_state(env, &c_p, &scheduler);
+    if (!esdp)
+	return ERL_NIF_THR_UNDEFINED;
+
+    if (!ERTS_SCHEDULER_IS_DIRTY(esdp))
+	return ERL_NIF_THR_NORMAL_SCHEDULER;
 
-    if (!c_p || !scheduler)
-	erts_exit(ERTS_ABORT_EXIT, "enif_is_on_dirty_scheduler: "
-		  "Invalid env");
+    if (ERTS_SCHEDULER_IS_DIRTY_CPU(esdp))
+	return ERL_NIF_THR_DIRTY_CPU_SCHEDULER;
 
-    return scheduler < 0;
+    ASSERT(ERTS_SCHEDULER_IS_DIRTY_IO(esdp));
+    return ERL_NIF_THR_DIRTY_IO_SCHEDULER;
 }
 
 /* Maps */
diff --git a/erts/emulator/beam/erl_nif.h b/erts/emulator/beam/erl_nif.h
index da7a754757..494971e118 100644
--- a/erts/emulator/beam/erl_nif.h
+++ b/erts/emulator/beam/erl_nif.h
@@ -209,6 +209,17 @@ typedef enum {
     ERL_NIF_BIN2TERM_SAFE = 0x20000000
 } ErlNifBinaryToTerm;
 
+/*
+ * Return values from enif_thread_type(). Negative values
+ * reserved for specific types of non-scheduler threads.
+ * Positive values reserved for scheduler thread types.
+ */
+
+#define ERL_NIF_THR_UNDEFINED 0
+#define ERL_NIF_THR_NORMAL_SCHEDULER 1
+#define ERL_NIF_THR_DIRTY_CPU_SCHEDULER 2
+#define ERL_NIF_THR_DIRTY_IO_SCHEDULER 3
+
 #if (defined(__WIN32__) || defined(_WIN32) || defined(_WIN32_))
 #  define ERL_NIF_API_FUNC_DECL(RET_TYPE, NAME, ARGS) RET_TYPE (*NAME) ARGS
 typedef struct {
diff --git a/erts/emulator/beam/erl_nif_api_funcs.h b/erts/emulator/beam/erl_nif_api_funcs.h
index b211ab4b16..9a8f216773 100644
--- a/erts/emulator/beam/erl_nif_api_funcs.h
+++ b/erts/emulator/beam/erl_nif_api_funcs.h
@@ -173,7 +173,7 @@ ERL_NIF_API_FUNC_DECL(int, enif_get_local_port, (ErlNifEnv* env, ERL_NIF_TERM, E
 ERL_NIF_API_FUNC_DECL(int, enif_term_to_binary, (ErlNifEnv *env, ERL_NIF_TERM term, ErlNifBinary *bin));
 ERL_NIF_API_FUNC_DECL(size_t, enif_binary_to_term, (ErlNifEnv *env, const unsigned char* data, size_t sz, ERL_NIF_TERM *term, unsigned int opts));
 ERL_NIF_API_FUNC_DECL(int, enif_port_command, (ErlNifEnv *env, const ErlNifPort* to_port, ErlNifEnv *msg_env, ERL_NIF_TERM msg));
-ERL_NIF_API_FUNC_DECL(int,enif_is_on_dirty_scheduler,(ErlNifEnv*));
+ERL_NIF_API_FUNC_DECL(int,enif_thread_type,(void));
 ERL_NIF_API_FUNC_DECL(int,enif_snprintf,(char * buffer, size_t size, const char *format, ...));
 
 /*
@@ -330,7 +330,7 @@ ERL_NIF_API_FUNC_DECL(int,enif_snprintf,(char * buffer, size_t size, const char
 #  define enif_term_to_binary ERL_NIF_API_FUNC_MACRO(enif_term_to_binary)
 #  define enif_binary_to_term ERL_NIF_API_FUNC_MACRO(enif_binary_to_term)
 #  define enif_port_command ERL_NIF_API_FUNC_MACRO(enif_port_command)
-#  define enif_is_on_dirty_scheduler ERL_NIF_API_FUNC_MACRO(enif_is_on_dirty_scheduler)
+#  define enif_thread_type ERL_NIF_API_FUNC_MACRO(enif_thread_type)
 #  define enif_snprintf ERL_NIF_API_FUNC_MACRO(enif_snprintf)
 
 /*
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index c0b1d7246c..5193be85b4 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -10082,7 +10082,7 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 	    }
 	}
 
-	if (ERTS_IS_GC_DESIRED(p)) {
+	if (ERTS_IS_GC_DESIRED(p) && !ERTS_SCHEDULER_IS_DIRTY_IO(esdp)) {
 	    if (!(state & ERTS_PSFLG_EXITING) && !(p->flags & (F_DELAY_GC|F_DISABLE_GC))) {
 		int cost = scheduler_gc_proc(p, reds);
 		calls += cost;