From b079018e38272604ffacfece9b97924a9e39df5c Mon Sep 17 00:00:00 2001
From: Rickard Green <rickard@erlang.org>
Date: Mon, 23 Jan 2017 17:10:18 +0100
Subject: Implement magic references

Magic references are *intentionally* indistinguishable from ordinary
references for the Erlang software. Magic references do not change
the language, and are intended as a pure runtime internal optimization.

An ordinary reference is typically used as a key in some table. A
magic reference has a direct pointer to a reference counted magic
binary. This makes it possible to implement various things without
having to do lookups in a table, but instead access the data directly.
Besides very fast lookups this can also improve scalability by
removing a potentially contended table. A couple of examples of
planned future usage of magic references are ETS table identifiers,
and BIF timer identifiers.

Besides future optimizations using magic references it should also
be possible to replace the exposed magic binary cludge with magic
references. That is, magic binaries that are exposed as empty
binaries to the Erlang software.
---
 erts/emulator/test/node_container_SUITE.erl | 41 +++++++++++++++++++++++++++--
 1 file changed, 39 insertions(+), 2 deletions(-)

(limited to 'erts/emulator/test/node_container_SUITE.erl')

diff --git a/erts/emulator/test/node_container_SUITE.erl b/erts/emulator/test/node_container_SUITE.erl
index af18545bff..7356f31b75 100644
--- a/erts/emulator/test/node_container_SUITE.erl
+++ b/erts/emulator/test/node_container_SUITE.erl
@@ -50,7 +50,8 @@
          port_wrap/1,
          bad_nc/1,
          unique_pid/1,
-         iter_max_procs/1]).
+         iter_max_procs/1,
+         magic_ref/1]).
 
 suite() ->
     [{ct_hooks,[ts_install_cth]},
@@ -62,7 +63,7 @@ all() ->
      node_table_gc, dist_link_refc, dist_monitor_refc,
      node_controller_refc, ets_refc, match_spec_refc,
      timer_refc, otp_4715, pid_wrap, port_wrap, bad_nc,
-     unique_pid, iter_max_procs].
+     unique_pid, iter_max_procs, magic_ref].
 
 init_per_suite(Config) ->
     Config.
@@ -889,10 +890,46 @@ chk_max_proc_line_until(NoMoreTests, Res) ->
               chk_max_proc_line_until(NoMoreTests, Res)
     end.
 
+magic_ref(Config) when is_list(Config) ->
+    {MRef0, Addr0} = erts_debug:set_internal_state(make, magic_ref),
+    true = is_reference(MRef0),
+    {Addr0, 1, true} = erts_debug:get_internal_state({magic_ref,MRef0}),
+    MRef1 = binary_to_term(term_to_binary(MRef0)),
+    {Addr0, 2, true} = erts_debug:get_internal_state({magic_ref,MRef1}),
+    MRef0 = MRef1,
+    Me = self(),
+    {Pid, Mon} = spawn_opt(fun () ->
+				   receive
+				       {Me, MRef} ->
+					   Me ! {self(), erts_debug:get_internal_state({magic_ref,MRef})}
+				   end
+			   end,
+			   [link, monitor]),
+    Pid ! {self(), MRef0},
+    receive
+	{Pid, Info} ->
+	    {Addr0, 3, true} = Info
+    end,
+    receive
+	{'DOWN', Mon, process, Pid, _} ->
+	    ok
+    end,
+    {Addr0, 2, true} = erts_debug:get_internal_state({magic_ref,MRef0}),
+    id(MRef0),
+    id(MRef1),
+    MRefExt = term_to_binary(erts_debug:set_internal_state(make, magic_ref)),
+    garbage_collect(),
+    {MRef2, _Addr2} = binary_to_term(MRefExt),
+    true = is_reference(MRef2),
+    true = erts_debug:get_internal_state({magic_ref,MRef2}),
+    ok.
 %%
 %% -- Internal utils ---------------------------------------------------------
 %%
 
+id(X) ->
+    X.
+
 -define(ND_REFS, erts_debug:get_internal_state(node_and_dist_references)).
 
 node_container_refc_check(Node) when is_atom(Node) ->
-- 
cgit v1.2.3


From 7c06ca6231b812965305522284dd9f2653ced98d Mon Sep 17 00:00:00 2001
From: Andrew Dryga <andrew@dryga.com>
Date: Tue, 14 Feb 2017 11:30:41 +0200
Subject: Fixed typos in erts

---
 erts/emulator/test/node_container_SUITE.erl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'erts/emulator/test/node_container_SUITE.erl')

diff --git a/erts/emulator/test/node_container_SUITE.erl b/erts/emulator/test/node_container_SUITE.erl
index 7356f31b75..291d3ee30d 100644
--- a/erts/emulator/test/node_container_SUITE.erl
+++ b/erts/emulator/test/node_container_SUITE.erl
@@ -153,7 +153,7 @@ ttbtteq_do_remote(RNode) ->
 %%
 %% Test case: round_trip_eq
 %%
-%% Tests that node containers that are sent beteen nodes stay equal to themselves.
+%% Tests that node containers that are sent between nodes stay equal to themselves.
 round_trip_eq(Config) when is_list(Config) ->
     ThisNode = {node(), erlang:system_info(creation)},
     NodeFirstName = get_nodefirstname(),
-- 
cgit v1.2.3