erts: Add enif_send with NULL as msg env

This is an optimization for reducing the number of heap fragments
allocated when sending a message where the majority of the
message payload is on the sending process' heap.

2 files changed, 24 insertions, 2 deletions

diff --git a/erts/emulator/test/nif_SUITE.erl b/erts/emulator/test/nif_SUITE.erl
index a185b72341..aa512b2360 100644
--- a/erts/emulator/test/nif_SUITE.erl
+++ b/erts/emulator/test/nif_SUITE.erl
@@ -1282,9 +1282,10 @@ send3_make_blob() ->
             repeat(N bsr 1,
                    fun(_) -> grow_blob(MsgEnv,other_term(),rand:uniform(1 bsl 20))
                    end, void),
-            case (N band 1) of
+            case (N band 3) of
                 0 -> {term,copy_blob(MsgEnv)};
-                1 -> {msgenv,MsgEnv}
+                1 -> {copy,copy_blob(MsgEnv)};
+                _ -> {msgenv,MsgEnv}
             end
     end.
 
@@ -1297,6 +1298,9 @@ send3_send(Pid, Msg) ->
 send3_send_nif(Pid, {term,Blob}) ->
     %%io:format("~p send term nif\n",[self()]),
     send_term(Pid, {blob, Blob}) =:= 1;
+send3_send_nif(Pid, {copy,Blob}) ->
+    %%io:format("~p send term nif\n",[self()]),
+    send_copy_term(Pid, {blob, Blob}) =:= 1;
 send3_send_nif(Pid, {msgenv,MsgEnv}) ->
     %%io:format("~p send blob nif\n",[self()]),   
     send3_blob(MsgEnv, Pid, blob) =:= 1.
@@ -1305,6 +1309,10 @@ send3_send_bang(Pid, {term,Blob}) ->
     %%io:format("~p send term bang\n",[self()]),   
     Pid ! {blob, Blob},
     true;
+send3_send_bang(Pid, {copy,Blob}) ->
+    %%io:format("~p send term bang\n",[self()]),
+    Pid ! {blob, Blob},
+    true;
 send3_send_bang(Pid, {msgenv,MsgEnv}) ->
     %%io:format("~p send blob bang\n",[self()]),   
     Pid ! {blob, copy_blob(MsgEnv)},
@@ -2062,6 +2070,7 @@ send_blob_thread(_,_,_) -> ?nif_stub.
 join_send_thread(_) -> ?nif_stub.
 copy_blob(_) -> ?nif_stub.
 send_term(_,_) -> ?nif_stub.
+send_copy_term(_,_) -> ?nif_stub.
 reverse_list(_) -> ?nif_stub.
 echo_int(_) -> ?nif_stub.
 type_sizes() -> ?nif_stub.
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index b3c6cc5ba3..e369fb3386 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -1466,6 +1466,18 @@ static ERL_NIF_TERM send_term(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[
     return enif_make_int(env, ret);
 }
 
+static ERL_NIF_TERM send_copy_term(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
+{
+    ErlNifEnv* menv;
+    ErlNifPid pid;
+    int ret;
+    if (!enif_get_local_pid(env, argv[0], &pid)) {
+	return enif_make_badarg(env);
+    }
+    ret = enif_send(env, &pid, NULL, argv[1]);
+    return enif_make_int(env, ret);
+}
+
 static ERL_NIF_TERM reverse_list(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
     ERL_NIF_TERM rev_list;
 
@@ -2142,6 +2154,7 @@ static ErlNifFunc nif_funcs[] =
     {"join_send_thread", 1, join_send_thread},
     {"copy_blob", 1, copy_blob},
     {"send_term", 2, send_term},
+    {"send_copy_term", 2, send_copy_term},
     {"reverse_list",1, reverse_list},
     {"echo_int", 1, echo_int},
     {"type_sizes", 0, type_sizes},