erts: Move reason in dist messages to payload

The dist messages EXIT, EXIT2 and MONITOR_DOWN have been
updated with new versions that send the reason term as
part of the payload of the message instead of as part
of the control message.

This allows the decode of the reason to be done by the
receiving process instead of the dist entry which in turn
makes it possible for multiple decodes to be done in
parallel.

This change is done in order to make it easier to fragment
the potentially large payload of EXIT, EXIT2 and MONITOR_DOWN
into multiple distribution messages.

OTP-15611

1 files changed, 32 insertions, 20 deletions

diff --git a/erts/emulator/beam/dist.h b/erts/emulator/beam/dist.h
index a8ccd1eaec..81a09bc69c 100644
--- a/erts/emulator/beam/dist.h
+++ b/erts/emulator/beam/dist.h
@@ -47,6 +47,7 @@
 #define DFLAG_SEND_SENDER         0x80000
 #define DFLAG_BIG_SEQTRACE_LABELS 0x100000
 #define DFLAG_NO_MAGIC            0x200000 /* internal for pending connection */
+#define DFLAG_EXIT_PAYLOAD        0x400000
 
 /* Mandatory flags for distribution */
 #define DFLAG_DIST_MANDATORY (DFLAG_EXTENDED_REFERENCES         \
@@ -75,7 +76,8 @@
                             | DFLAG_MAP_TAG                   \
                             | DFLAG_BIG_CREATION              \
                             | DFLAG_SEND_SENDER               \
-                            | DFLAG_BIG_SEQTRACE_LABELS)
+                            | DFLAG_BIG_SEQTRACE_LABELS       \
+                            | DFLAG_EXIT_PAYLOAD)
 
 /* Flags addable by local distr implementations */
 #define DFLAG_DIST_ADDABLE    DFLAG_DIST_DEFAULT
@@ -99,26 +101,35 @@
                                | DFLAG_BIG_CREATION)
 
 /* opcodes used in distribution messages */
-#define DOP_LINK		1
-#define DOP_SEND		2
-#define DOP_EXIT		3
-#define DOP_UNLINK		4
+enum {
+    DOP_LINK                = 1,
+    DOP_SEND                = 2,
+    DOP_EXIT                = 3,
+    DOP_UNLINK              = 4,
 /* Ancient DOP_NODE_LINK (5) was here, can be reused */
-#define DOP_REG_SEND		6
-#define DOP_GROUP_LEADER	7
-#define DOP_EXIT2		8
-
-#define DOP_SEND_TT		12
-#define DOP_EXIT_TT		13
-#define DOP_REG_SEND_TT		16
-#define DOP_EXIT2_TT		18
-
-#define DOP_MONITOR_P		19
-#define DOP_DEMONITOR_P		20
-#define DOP_MONITOR_P_EXIT	21
-
-#define DOP_SEND_SENDER         22
-#define DOP_SEND_SENDER_TT      23
+    DOP_REG_SEND            = 6,
+    DOP_GROUP_LEADER        = 7,
+    DOP_EXIT2               = 8,
+
+    DOP_SEND_TT             = 12,
+    DOP_EXIT_TT             = 13,
+    DOP_REG_SEND_TT         = 16,
+    DOP_EXIT2_TT            = 18,
+
+    DOP_MONITOR_P           = 19,
+    DOP_DEMONITOR_P         = 20,
+    DOP_MONITOR_P_EXIT      = 21,
+
+    DOP_SEND_SENDER         = 22,
+    DOP_SEND_SENDER_TT      = 23,
+
+    /* These are used when DFLAG_EXIT_PAYLOAD is detected */
+    DOP_PAYLOAD_EXIT           = 24,
+    DOP_PAYLOAD_EXIT_TT        = 25,
+    DOP_PAYLOAD_EXIT2          = 26,
+    DOP_PAYLOAD_EXIT2_TT       = 27,
+    DOP_PAYLOAD_MONITOR_P_EXIT = 28
+};
 
 /* distribution trap functions */
 extern Export* dmonitor_node_trap;
@@ -346,6 +357,7 @@ struct erts_dsig_send_context {
     Eterm ctl;
     Eterm msg;
     int force_busy;
+    int force_encode;
     Uint32 max_finalize_prepend;
     Uint data_size, dhdr_ext_size;
     ErtsAtomCacheMap *acmp;