Merge branch 'rickard/ds-purge-module/OTP-13808' into maint

* rickard/ds-purge-module/OTP-13808:
  Perform check_process_code while process is executing dirty

Conflicts:
	erts/doc/src/erl_nif.xml

14 files changed, 419 insertions, 40 deletions

diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 2b627281fe..4ec5ab78d8 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -488,18 +488,6 @@ return term;</code>
               sending process is not alive. Deallocation of certain internal
               resources, such as process heap and process control block, is
               delayed until the dirty NIF has completed.</p>
-            <p>Known issue that are planned to be fixed:</p>
-            <list type="bulleted">
-              <item>
-                <p>As purging of a module might need to garbage
-                  collect a process to determine if it has
-                  references to the module, a process executing a dirty
-                  NIF can delay purging for a very long time. Delaying
-                  a purge operation implies delaying <em>all</em> code
-                  loading operations, which can cause severe problems for
-                  the system as a whole.</p>
-              </item>
-            </list>
           </item>
         </taglist>
       </item>
diff --git a/erts/emulator/Makefile.in b/erts/emulator/Makefile.in
index 5b4e9c779b..e0260205e3 100644
--- a/erts/emulator/Makefile.in
+++ b/erts/emulator/Makefile.in
@@ -605,7 +605,8 @@ PRELOAD_BEAM =		$(ERL_TOP)/erts/preloaded/ebin/otp_ring0.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erlang.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erts_internal.beam \
 			$(ERL_TOP)/erts/preloaded/ebin/erl_tracer.beam \
-			$(ERL_TOP)/erts/preloaded/ebin/erts_literal_area_collector.beam
+			$(ERL_TOP)/erts/preloaded/ebin/erts_literal_area_collector.beam \
+			$(ERL_TOP)/erts/preloaded/ebin/erts_dirty_process_code_checker.beam
 
 ifeq ($(TARGET),win32)
 # On windows the preloaded objects are in a resource object.
diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index ace3dc5230..89c42f4700 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -198,6 +198,7 @@ atom dgroup_leader
 atom dictionary
 atom dirty_cpu
 atom dirty_cpu_schedulers_online
+atom dirty_execution
 atom dirty_io
 atom disable_trace
 atom disabled
diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 92340579ad..ad107b4861 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -58,6 +58,9 @@ static struct {
 Process *erts_code_purger = NULL;
 
 ErtsLiteralArea *erts_copy_literal_area = NULL;
+#ifdef ERTS_DIRTY_SCHEDULERS
+Process *erts_dirty_process_code_checker;
+#endif
 #ifdef ERTS_NEW_PURGE_STRATEGY
 Process *erts_literal_area_collector = NULL;
 
@@ -585,6 +588,43 @@ badarg:
     BIF_ERROR(BIF_P, BADARG);
 }
 
+BIF_RETTYPE erts_internal_check_dirty_process_code_2(BIF_ALIST_2)
+{
+#if !defined(ERTS_DIRTY_SCHEDULERS)
+    BIF_ERROR(BIF_P, EXC_NOTSUP);
+#else
+    Process *rp;
+    int reds = 0;
+    Eterm res;
+
+    if (BIF_P != erts_dirty_process_code_checker)
+	BIF_ERROR(BIF_P, EXC_NOTSUP);
+
+    if (is_not_internal_pid(BIF_ARG_1))
+	BIF_ERROR(BIF_P, BADARG);
+
+    if (is_not_atom(BIF_ARG_2))
+	BIF_ERROR(BIF_P, BADARG);
+
+    rp = erts_pid2proc_not_running(BIF_P, ERTS_PROC_LOCK_MAIN,
+				   BIF_ARG_1, ERTS_PROC_LOCK_MAIN);
+    if (rp == ERTS_PROC_LOCK_BUSY)
+	ERTS_BIF_YIELD2(bif_export[BIF_erts_internal_check_dirty_process_code_2],
+			BIF_P, BIF_ARG_1, BIF_ARG_2);
+    if (!rp)
+	BIF_RET(am_false);
+	
+    res = erts_check_process_code(rp, BIF_ARG_2, 0, &reds, BIF_P->fcalls);
+
+    if (BIF_P != rp)
+	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_MAIN);
+
+    ASSERT(is_value(res));
+
+    BIF_RET2(res, reds);
+#endif
+}
+
 BIF_RETTYPE delete_module_1(BIF_ALIST_1)
 {
     ErtsCodeIndex code_ix;
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 90ac5e9ed8..80db4eb6ff 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -161,6 +161,7 @@ bif erts_internal:port_close/1
 bif erts_internal:port_connect/2
 
 bif erts_internal:request_system_task/3
+bif erts_internal:request_system_task/4
 bif erts_internal:check_process_code/2
 
 bif erts_internal:map_to_tuple_keys/1
@@ -644,6 +645,8 @@ bif erts_debug:map_info/1
 # New in 19.0
 #
 
+bif erts_internal:is_process_executing_dirty/1
+bif erts_internal:check_dirty_process_code/2
 bif erts_internal:purge_module/2
 bif binary:split/2
 bif binary:split/3
diff --git a/erts/emulator/beam/erl_init.c b/erts/emulator/beam/erl_init.c
index 8afda42a71..781bf024dd 100644
--- a/erts/emulator/beam/erl_init.c
+++ b/erts/emulator/beam/erl_init.c
@@ -2274,6 +2274,16 @@ erl_start(int argc, char **argv)
 	erts_proc_inc_refc(erts_literal_area_collector);
 #endif
 
+#ifdef ERTS_DIRTY_SCHEDULERS
+	pid = erl_system_process_otp(otp_ring0_pid, "erts_dirty_process_code_checker");
+	erts_dirty_process_code_checker
+	    = (Process *) erts_ptab_pix2intptr_ddrb(&erts_proc,
+						    internal_pid_index(pid));
+	ASSERT(erts_dirty_process_code_checker
+	       && erts_dirty_process_code_checker->common.id == pid);
+	erts_proc_inc_refc(erts_dirty_process_code_checker);
+#endif
+
     }
 
 #ifdef ERTS_SMP
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index f833aadd91..c1699cb501 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -6674,14 +6674,24 @@ erts_schedule_process(Process *p, erts_aint32_t state, ErtsProcLocks locks)
 }
 
 static int
-schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st)
+schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st,
+			  erts_aint32_t *fail_state_p)
 {
     int res;
     int locked;
     ErtsProcSysTaskQs *stqs, *free_stqs;
-    erts_aint32_t state, a, n, enq_prio;
+    erts_aint32_t fail_state, state, a, n, enq_prio;
     int enqueue; /* < 0 -> use proxy */
     unsigned int prof_runnable_procs;
+    int strict_fail_state;
+
+    fail_state = *fail_state_p;
+    /*
+     * If fail state something other than just exiting process,
+     * ensure that the task wont be scheduled when the 
+     * receiver is in the failure state.
+     */
+    strict_fail_state = fail_state != ERTS_PSFLG_EXITING;
 
     res = 1; /* prepare for success */
     st->next = st->prev = st; /* Prep for empty prio queue */
@@ -6708,7 +6718,8 @@ schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st)
 	erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
 
 	state = erts_smp_atomic32_read_nob(&p->state);
-	if (state & ERTS_PSFLG_EXITING) {
+	if (state & fail_state) {
+	    *fail_state_p = (state & fail_state);
 	    free_stqs = stqs;
 	    res = 0;
 	    goto cleanup;
@@ -6762,7 +6773,7 @@ schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st)
     /* Status lock prevents out of order "runnable proc" trace msgs */
     ERTS_SMP_LC_ASSERT(ERTS_PROC_LOCK_STATUS & erts_proc_lc_my_proc_locks(p));
 
-    if (!prof_runnable_procs) {
+    if (!prof_runnable_procs && !strict_fail_state) {
 	erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
 	locked = 0;
     }
@@ -6773,6 +6784,11 @@ schedule_process_sys_task(Process *p, erts_aint32_t prio, ErtsProcSysTask *st)
 	erts_aint32_t e;
 	n = e = a;
 
+	if (strict_fail_state && (a & fail_state)) {
+	    *fail_state_p = (a & fail_state);
+	    goto cleanup;
+	}
+
 	if (a & ERTS_PSFLG_FREE)
 	    goto cleanup; /* We don't want to schedule free processes... */
 
@@ -9095,6 +9111,27 @@ resume_process_1(BIF_ALIST_1)
     BIF_ERROR(BIF_P, BADARG);
 }
 
+BIF_RETTYPE
+erts_internal_is_process_executing_dirty_1(BIF_ALIST_1)
+{
+    if (is_not_internal_pid(BIF_ARG_1))
+	BIF_ERROR(BIF_P, BADARG);
+#ifdef ERTS_DIRTY_SCHEDULERS
+    else {
+	Process *rp = erts_proc_lookup(BIF_ARG_1);
+	if (rp) {
+	    erts_aint32_t state = erts_smp_atomic32_read_nob(&rp->state);
+	    if (state & (ERTS_PSFLG_DIRTY_RUNNING
+			 |ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
+		BIF_RET(am_true);
+	    }
+	}
+    }
+#endif
+    BIF_RET(am_false);
+}
+
+
 Uint
 erts_run_queues_len(Uint *qlen, int atomic_queues_read, int incl_active_sched)
 {
@@ -9987,6 +10024,11 @@ Process *erts_schedule(ErtsSchedulerData *esdp, Process *p, int calls)
 	    if (state & (ERTS_PSFLG_ACTIVE_SYS
 			 | ERTS_PSFLG_PENDING_EXIT
 			 | ERTS_PSFLG_EXITING)) {
+		/*
+		 * IMPORTANT! We need to take care of
+		 * scheduled check-process-code requests
+		 * before continuing with dirty execution!
+		 */
 		/* Migrate to normal scheduler... */
 		goto sunlock_sched_out_proc;
 	    }
@@ -10496,22 +10538,83 @@ cleanup_sys_tasks(Process *c_p, erts_aint32_t in_state, int in_reds)
     return reds;
 }
 
-BIF_RETTYPE
-erts_internal_request_system_task_3(BIF_ALIST_3)
+#ifdef ERTS_DIRTY_SCHEDULERS
+
+static BIF_RETTYPE
+dispatch_system_task(Process *c_p, erts_aint_t fail_state,
+		     ErtsProcSysTask *st, Eterm target,
+		     Eterm prio, Eterm operation)
 {
-    Process *rp = erts_proc_lookup(BIF_ARG_1);
+    Process *rp;
+    ErtsProcLocks rp_locks = 0;
+    ErlOffHeap *ohp;
+    ErtsMessage *mp;
+    Eterm *hp, msg;
+    Uint hsz, osz;
+    BIF_RETTYPE ret;
+
+    switch (st->type) {
+    case ERTS_PSTT_CPC:
+	rp = erts_dirty_process_code_checker;
+	ASSERT(fail_state & (ERTS_PSFLG_DIRTY_RUNNING
+			     | ERTS_PSFLG_DIRTY_RUNNING_SYS));
+	if (c_p == rp) {
+	    ERTS_BIF_PREP_RET(ret, am_dirty_execution);
+	    return ret;
+	}
+	break;
+    default:
+	rp = NULL;
+	ERTS_INTERNAL_ERROR("Non-dispatchable system task");
+	break;
+    }
+	
+    ERTS_BIF_PREP_RET(ret, am_ok);
+
+    /*
+     * Send message on the form: {Requester, Target, Operation}
+     */
+
+    ASSERT(is_immed(st->requester));
+    ASSERT(is_immed(target));
+    ASSERT(is_immed(prio));
+
+    osz = size_object(operation);
+    hsz = 5 /* 4-tuple */ + osz;
+
+    mp = erts_alloc_message_heap(rp, &rp_locks, hsz, &hp, &ohp);
+
+    msg = copy_struct(operation, osz, &hp, ohp);
+    msg = TUPLE4(hp, st->requester, target, prio, msg);
+
+    erts_queue_message(rp, rp_locks, mp, msg, st->requester);
+
+    if (rp_locks)
+	erts_smp_proc_unlock(rp, rp_locks);
+
+    return ret;
+}
+
+#endif
+
+static BIF_RETTYPE
+request_system_task(Process *c_p, Eterm requester, Eterm target,
+		    Eterm priority, Eterm operation)
+{
+    BIF_RETTYPE ret;
+    Process *rp = erts_proc_lookup(target);
     ErtsProcSysTask *st = NULL;
-    erts_aint32_t prio;
+    erts_aint32_t prio, fail_state = ERTS_PSFLG_EXITING;
     Eterm noproc_res, req_type;
 
-    if (!rp && !is_internal_pid(BIF_ARG_1)) {
-	if (!is_external_pid(BIF_ARG_1))
+    if (!rp && !is_internal_pid(target)) {
+	if (!is_external_pid(target))
 	    goto badarg;
-	if (external_pid_dist_entry(BIF_ARG_1) != erts_this_dist_entry)
+	if (external_pid_dist_entry(target) != erts_this_dist_entry)
 	    goto badarg;
     }
 
-    switch (BIF_ARG_2) {
+    switch (priority) {
     case am_max:	prio = PRIORITY_MAX;	break;
     case am_high:	prio = PRIORITY_HIGH;	break;
     case am_normal:	prio = PRIORITY_NORMAL;	break;
@@ -10519,11 +10622,11 @@ erts_internal_request_system_task_3(BIF_ALIST_3)
     default: goto badarg;
     }
 
-    if (is_not_tuple(BIF_ARG_3))
+    if (is_not_tuple(operation))
 	goto badarg;
     else {
 	int i;
-	Eterm *tp = tuple_val(BIF_ARG_3);
+	Eterm *tp = tuple_val(operation);
 	Uint arity = arityval(*tp);
 	Eterm req_id;
 	Uint req_id_sz;
@@ -10561,7 +10664,7 @@ erts_internal_request_system_task_3(BIF_ALIST_3)
 	ERTS_INIT_OFF_HEAP(&st->off_heap);
 	hp = &st->heap[0];
 
-	st->requester = BIF_P->common.id;
+	st->requester = requester;
 	st->reply_tag = req_type;
 	st->req_id_sz = req_id_sz;
 	st->req_id = req_id_sz == 0 ? req_id : copy_struct(req_id,
@@ -10595,6 +10698,15 @@ erts_internal_request_system_task_3(BIF_ALIST_3)
 	st->type = ERTS_PSTT_CPC;
 	if (!rp)
 	    goto noproc;
+#ifdef ERTS_DIRTY_SCHEDULERS
+	/*
+	 * If the process should start executing dirty
+	 * code it is important that this task is
+	 * aborted. Therefore this strict fail state...
+	 */
+	fail_state |= (ERTS_PSFLG_DIRTY_RUNNING
+		       | ERTS_PSFLG_DIRTY_RUNNING_SYS);
+#endif
 	break;
 
 #ifdef ERTS_NEW_PURGE_STRATEGY
@@ -10612,20 +10724,59 @@ erts_internal_request_system_task_3(BIF_ALIST_3)
 	goto badarg;
     }
 
-    if (!schedule_process_sys_task(rp, prio, st)) {
-    noproc:
-	notify_sys_task_executed(BIF_P, st, noproc_res);
+    if (!schedule_process_sys_task(rp, prio, st, &fail_state)) {
+	Eterm failure;
+	if (fail_state & ERTS_PSFLG_EXITING) {
+	noproc:
+	    failure = noproc_res;
+	}
+#ifdef ERTS_DIRTY_SCHEDULERS
+	else if (fail_state & (ERTS_PSFLG_DIRTY_RUNNING
+			       | ERTS_PSFLG_DIRTY_RUNNING_SYS)) {
+	    ret = dispatch_system_task(c_p, fail_state, st,
+				       target, priority, operation);
+	    goto cleanup_return;
+	}
+#endif
+	else {
+	    ERTS_INTERNAL_ERROR("Unknown failure schedule_process_sys_task()");
+	    failure = am_internal_error;
+	}
+	notify_sys_task_executed(c_p, st, failure);
     }
 
-    BIF_RET(am_ok);
+    ERTS_BIF_PREP_RET(ret, am_ok);
+
+    return ret;
 
 badarg:
 
+    ERTS_BIF_PREP_ERROR(ret, c_p, BADARG);
+
+#ifdef ERTS_DIRTY_SCHEDULERS
+cleanup_return:
+#endif
+
     if (st) {
 	erts_cleanup_offheap(&st->off_heap);
 	erts_free(ERTS_ALC_T_PROC_SYS_TSK, st);
     }
-    BIF_ERROR(BIF_P, BADARG);
+
+    return ret;
+}
+
+BIF_RETTYPE
+erts_internal_request_system_task_3(BIF_ALIST_3)
+{
+    return request_system_task(BIF_P, BIF_P->common.id,
+			       BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
+}
+
+BIF_RETTYPE
+erts_internal_request_system_task_4(BIF_ALIST_4)
+{
+    return request_system_task(BIF_P, BIF_ARG_1,
+			       BIF_ARG_2, BIF_ARG_3, BIF_ARG_4);
 }
 
 static void
@@ -10634,7 +10785,7 @@ erts_schedule_generic_sys_task(Eterm pid, ErtsProcSysTaskType type)
     Process *rp = erts_proc_lookup(pid);
     if (rp) {
 	ErtsProcSysTask *st;
-	erts_aint32_t state;
+	erts_aint32_t state, fail_state;
 	int i;
 
 	st = erts_alloc(ERTS_ALC_T_PROC_SYS_TSK,
@@ -10649,7 +10800,10 @@ erts_schedule_generic_sys_task(Eterm pid, ErtsProcSysTaskType type)
 	ERTS_INIT_OFF_HEAP(&st->off_heap);
 	state = erts_smp_atomic32_read_nob(&rp->state);
 
-	if (!schedule_process_sys_task(rp, ERTS_PSFLGS_GET_USR_PRIO(state), st))
+	fail_state = ERTS_PSFLG_EXITING;
+
+	if (!schedule_process_sys_task(rp, ERTS_PSFLGS_GET_USR_PRIO(state),
+				       st, &fail_state))
 	    erts_free(ERTS_ALC_T_PROC_SYS_TSK, st);
     }
 }
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index d844f9310b..7a00cd8f6e 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -1017,6 +1017,9 @@ extern ErtsLiteralArea *erts_copy_literal_area;
 #ifdef ERTS_NEW_PURGE_STRATEGY
 extern Process *erts_literal_area_collector;
 #endif
+#ifdef ERTS_DIRTY_SCHEDULERS
+extern Process *erts_dirty_process_code_checker;
+#endif
 
 extern Process *erts_code_purger;
 
diff --git a/erts/emulator/test/dirty_nif_SUITE.erl b/erts/emulator/test/dirty_nif_SUITE.erl
index 83b098a704..c2d2e58957 100644
--- a/erts/emulator/test/dirty_nif_SUITE.erl
+++ b/erts/emulator/test/dirty_nif_SUITE.erl
@@ -33,7 +33,8 @@
 	 dirty_nif_exception/1, call_dirty_nif_exception/1,
 	 dirty_scheduler_exit/1, dirty_call_while_terminated/1,
 	 dirty_heap_access/1, dirty_process_info/1,
-	 dirty_process_register/1, dirty_process_trace/1]).
+	 dirty_process_register/1, dirty_process_trace/1,
+	 code_purge/1]).
 
 -define(nif_stub,nif_stub_error(?LINE)).
 
@@ -48,7 +49,8 @@ all() ->
      dirty_heap_access,
      dirty_process_info,
      dirty_process_register,
-     dirty_process_trace].
+     dirty_process_trace,
+     code_purge].
 
 init_per_suite(Config) ->
     try erlang:system_info(dirty_cpu_schedulers) of
@@ -349,6 +351,75 @@ dirty_process_trace(Config) when is_list(Config) ->
 	      ok
       end).
 
+dirty_code_test_code() ->
+    "
+-module(dirty_code_test).
+
+-export([func/1]).
+
+func(Fun) ->
+  Fun(),
+  blipp:blapp().
+
+".
+
+code_purge(Config) when is_list(Config) ->
+    Path = ?config(data_dir, Config),
+    File = filename:join(Path, "dirty_code_test.erl"),
+    ok = file:write_file(File, dirty_code_test_code()),
+    {ok, dirty_code_test, Bin} = compile:file(File, [binary]),
+    {module, dirty_code_test} = erlang:load_module(dirty_code_test, Bin),
+    Start = erlang:monotonic_time(),
+    {Pid1, Mon1} = spawn_monitor(fun () ->
+				       dirty_code_test:func(fun () ->
+								    %% Sleep for 6 seconds
+								    %% in dirty nif...
+								    dirty_sleeper()
+							    end)
+			       end),
+    {module, dirty_code_test} = erlang:load_module(dirty_code_test, Bin),
+    {Pid2, Mon2} = spawn_monitor(fun () ->
+				       dirty_code_test:func(fun () ->
+								    %% Sleep for 6 seconds
+								    %% in dirty nif...
+								    dirty_sleeper()
+							    end)
+				 end),
+    receive
+	{'DOWN', Mon1, process, Pid1, _} ->
+	    ct:fail(premature_death)
+    after 100 ->
+	    ok
+    end,
+    true = erlang:purge_module(dirty_code_test),
+    receive
+	{'DOWN', Mon1, process, Pid1, Reason} ->
+	    killed = Reason
+    end,
+    receive
+	{'DOWN', Mon2, process, Pid2, _} ->
+	    ct:fail(premature_death)
+    after 100 ->
+	    ok
+    end,
+    true = erlang:delete_module(dirty_code_test),
+    receive
+	{'DOWN', Mon2, process, Pid2, _} ->
+	    ct:fail(premature_death)
+    after 100 ->
+	    ok
+    end,
+    true = erlang:purge_module(dirty_code_test),
+    receive
+	{'DOWN', Mon2, process, Pid2, Reason} ->
+	    killed = Reason
+    end,
+    End = erlang:monotonic_time(),
+    Time = erlang:convert_time_unit(End-Start, native, milli_seconds),
+    io:format("Time=~p~n", [Time]),
+    true = Time =< 1000,
+    ok.
+
 %%
 %% Internal...
 %%
diff --git a/erts/preloaded/ebin/erts_dirty_process_code_checker.beam b/erts/preloaded/ebin/erts_dirty_process_code_checker.beam
new file mode 100644
index 0000000000..a7ac116c05
--- /dev/null
+++ b/erts/preloaded/ebin/erts_dirty_process_code_checker.beam
diff --git a/erts/preloaded/ebin/erts_internal.beam b/erts/preloaded/ebin/erts_internal.beam
index 8d4ca152de..22817be8f4 100644
--- a/erts/preloaded/ebin/erts_internal.beam
+++ b/erts/preloaded/ebin/erts_internal.beam
diff --git a/erts/preloaded/src/Makefile b/erts/preloaded/src/Makefile
index df4645070b..2ab9edaf5e 100644
--- a/erts/preloaded/src/Makefile
+++ b/erts/preloaded/src/Makefile
@@ -45,7 +45,8 @@ PRE_LOADED_ERL_MODULES = \
 	erlang \
 	erts_internal \
 	erl_tracer \
-	erts_literal_area_collector
+	erts_literal_area_collector \
+	erts_dirty_process_code_checker
 
 PRE_LOADED_BEAM_MODULES = \
 	prim_eval
diff --git a/erts/preloaded/src/erts_dirty_process_code_checker.erl b/erts/preloaded/src/erts_dirty_process_code_checker.erl
new file mode 100644
index 0000000000..911642082c
--- /dev/null
+++ b/erts/preloaded/src/erts_dirty_process_code_checker.erl
@@ -0,0 +1,82 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2016. All Rights Reserved.
+%%
+%% Licensed under the Apache License, Version 2.0 (the "License");
+%% you may not use this file except in compliance with the License.
+%% You may obtain a copy of the License at
+%%
+%%     http://www.apache.org/licenses/LICENSE-2.0
+%%
+%% Unless required by applicable law or agreed to in writing, software
+%% distributed under the License is distributed on an "AS IS" BASIS,
+%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+%% See the License for the specific language governing permissions and
+%% limitations under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+-module(erts_dirty_process_code_checker).
+
+-export([start/0]).
+
+%%
+%% The erts_dirty_process_code_checker is started at
+%% VM boot by the VM. It is a spawned as a system
+%% process, i.e, the whole VM will terminate if
+%% this process terminates.
+%%
+start() ->
+    process_flag(trap_exit, true),
+    msg_loop().
+
+msg_loop() ->
+    _ = receive
+	    Request ->
+		handle_request(Request)
+	end,
+    msg_loop().
+
+check_process(Requester, Target, ReqId, Module) ->
+    Result = erts_internal:check_dirty_process_code(Target, Module),
+    Requester ! {check_process_code, ReqId, Result}.
+					  
+handle_request({Requester,
+		Target,
+		Prio,
+		{check_process_code,
+		 ReqId,
+		 Module,
+		 _Flags} = Op}) ->
+    %%
+    %% Target may have stopped executing dirty since the
+    %% initial request was made. Check its current state
+    %% and try to send the request if possible; otherwise,
+    %% check the dirty executing process and send the result...
+    %%
+    try
+	case erts_internal:is_process_executing_dirty(Target) of
+	    true ->
+		check_process(Requester, Target, ReqId, Module);
+	    false ->
+		case erts_internal:request_system_task(Requester,
+						       Target,
+						       Prio,
+						       Op) of
+		    ok ->
+			ok;
+		    dirty_execution ->
+			check_process(Requester, Target, ReqId, Module)
+		end
+	end
+    catch
+	_ : _ ->
+	    ok %% Ignore all failures; someone passed us garbage...
+    end;
+handle_request(_Garbage) ->
+    ignore.
+
+		    
+	    
diff --git a/erts/preloaded/src/erts_internal.erl b/erts/preloaded/src/erts_internal.erl
index 2a6d626279..6229754c8c 100644
--- a/erts/preloaded/src/erts_internal.erl
+++ b/erts/preloaded/src/erts_internal.erl
@@ -38,9 +38,11 @@
 -export([system_check/1,
          gather_system_check_result/1]).
 
--export([request_system_task/3]).
+-export([request_system_task/3, request_system_task/4]).
 
 -export([check_process_code/3]).
+-export([check_dirty_process_code/2]).
+-export([is_process_executing_dirty/1]).
 -export([release_literal_area_switch/0]).
 -export([purge_module/2]).
 
@@ -204,12 +206,24 @@ port_info(_Result, _Item) ->
 -spec request_system_task(Pid, Prio, Request) -> 'ok' when
       Prio :: 'max' | 'high' | 'normal' | 'low',
       Request :: {'garbage_collect', term()}
-	       | {'check_process_code', term(), module(), non_neg_integer()},
+	       | {'check_process_code', term(), module(), non_neg_integer()}
+	       | {'copy_literals', term(), boolean()},
       Pid :: pid().
 
 request_system_task(_Pid, _Prio, _Request) ->
     erlang:nif_error(undefined).
 
+-spec request_system_task(RequesterPid, TargetPid, Prio, Request) -> 'ok' | 'dirty_execution' when
+      Prio :: 'max' | 'high' | 'normal' | 'low',
+      Request :: {'garbage_collect', term()}
+	       | {'check_process_code', term(), module(), non_neg_integer()}
+	       | {'copy_literals', term(), boolean()},
+      RequesterPid :: pid(),
+      TargetPid :: pid().
+
+request_system_task(_RequesterPid, _TargetPid, _Prio, _Request) ->
+    erlang:nif_error(undefined).
+
 -define(ERTS_CPC_ALLOW_GC, (1 bsl 0)).
 
 -spec check_process_code(Module, Flags) -> boolean() when
@@ -272,6 +286,17 @@ cpc_flags(OldFlags, Bit, true) ->
 cpc_flags(OldFlags, Bit, false) ->
     OldFlags band (bnot Bit).
 
+-spec check_dirty_process_code(Pid,Module) -> 'true' | 'false' when
+      Pid :: pid(),
+      Module :: module().
+check_dirty_process_code(_Pid,_Module) ->
+    erlang:nif_error(undefined).
+
+-spec is_process_executing_dirty(Pid) -> 'true' | 'false' when
+      Pid :: pid().
+is_process_executing_dirty(_Pid) ->
+    erlang:nif_error(undefined).
+
 -spec release_literal_area_switch() -> 'true' | 'false'.
 
 release_literal_area_switch() ->