Option to erlang:garbage_collect to request minor (generational) GC

Note: Minor GC option is a hint, and GC may still decide to run fullsweep.
Test case for major and minor gc on self
Test case for major and minor gs on some other process + async gc test check

docs fix

5 files changed, 41 insertions, 8 deletions

diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index badd69856e..f88aeba49f 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -361,6 +361,7 @@ atom long_schedule
 atom low
 atom Lt='<'
 atom machine
+atom major
 atom match
 atom match_limit
 atom match_limit_recursion
@@ -388,6 +389,7 @@ atom microstate_accounting
 atom milli_seconds
 atom min_heap_size
 atom min_bin_vheap_size
+atom minor
 atom minor_version
 atom Minus='-'
 atom module
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index d9048065c8..84eab5f651 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -3869,7 +3869,24 @@ BIF_RETTYPE garbage_collect_0(BIF_ALIST_0)
 {
     FLAGS(BIF_P) |= F_NEED_FULLSWEEP;
     erts_garbage_collect(BIF_P, 0, NULL, 0);
-    BIF_RET(am_true);
+    return am_true;
+}
+
+/*
+ * Pass atom 'minor' for relaxed generational GC run. This is only
+ * recommendation, major run may still be chosen by VM.
+ * Pass atom 'major' for default behaviour - major GC run (fullsweep)
+ */
+BIF_RETTYPE
+erts_internal_garbage_collect_1(BIF_ALIST_1)
+{
+    switch (BIF_ARG_1) {
+    case am_minor:  break;
+    case am_major:  FLAGS(BIF_P) |= F_NEED_FULLSWEEP; break;
+    default:        BIF_ERROR(BIF_P, BADARG);
+    }
+    erts_garbage_collect(BIF_P, 0, NULL, 0);
+    return am_true;
 }
 
 /**********************************************************************/
diff --git a/erts/emulator/beam/bif.tab b/erts/emulator/beam/bif.tab
index 978bcd4bba..5bb7db5d47 100644
--- a/erts/emulator/beam/bif.tab
+++ b/erts/emulator/beam/bif.tab
@@ -69,6 +69,7 @@ bif erlang:float_to_list/1
 bif erlang:float_to_list/2
 bif erlang:fun_info/2
 bif erlang:garbage_collect/0
+bif erts_internal:garbage_collect/1
 bif erlang:get/0
 bif erlang:get/1
 bif erlang:get_keys/1
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 85c37e08be..a0c5e247d4 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -446,7 +446,8 @@ int erts_system_profile_ts_type = ERTS_TRACE_FLG_NOW_TIMESTAMP;
 #endif
 
 typedef enum {
-    ERTS_PSTT_GC,	/* Garbage Collect */
+    ERTS_PSTT_GC_MAJOR,	/* Garbage Collect: Fullsweep */
+    ERTS_PSTT_GC_MINOR,	/* Garbage Collect: Generational */
     ERTS_PSTT_CPC,	/* Check Process Code */
     ERTS_PSTT_COHMQ,    /* Change off heap message queue */
     ERTS_PSTT_FTMQ      /* Flush trace msg queue */
@@ -10358,7 +10359,8 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds)
 	    break;
 
 	switch (st->type) {
-	case ERTS_PSTT_GC:
+        case ERTS_PSTT_GC_MAJOR:
+        case ERTS_PSTT_GC_MINOR:
 	    if (c_p->flags & F_DISABLE_GC) {
 		save_gc_task(c_p, st, st_prio);
 		st = NULL;
@@ -10366,7 +10368,9 @@ execute_sys_tasks(Process *c_p, erts_aint32_t *statep, int in_reds)
 	    }
 	    else {
 		if (!garbage_collected) {
-		    FLAGS(c_p) |= F_NEED_FULLSWEEP;
+                    if (st->type == ERTS_PSTT_GC_MAJOR) {
+                        FLAGS(c_p) |= F_NEED_FULLSWEEP;
+                    }
 		    reds -= scheduler_gc_proc(c_p, reds);
 		    garbage_collected = 1;
 		}
@@ -10442,7 +10446,8 @@ cleanup_sys_tasks(Process *c_p, erts_aint32_t in_state, int in_reds)
 	    break;
 
 	switch (st->type) {
-	case ERTS_PSTT_GC:
+        case ERTS_PSTT_GC_MAJOR:
+        case ERTS_PSTT_GC_MINOR:
 	    st_res = am_false;
 	    break;
 	case ERTS_PSTT_CPC:
@@ -10555,9 +10560,13 @@ erts_internal_request_system_task_3(BIF_ALIST_3)
     switch (req_type) {
 
     case am_garbage_collect:
-	st->type = ERTS_PSTT_GC;
-	noproc_res = am_false;
-	if (!rp)
+        switch (st->arg[0]) {
+        case am_minor:  st->type = ERTS_PSTT_GC_MINOR; break;
+        case am_major:  st->type = ERTS_PSTT_GC_MAJOR; break;
+        default: goto badarg;
+        }
+        noproc_res = am_false;
+        if (!rp)
 	    goto noproc;
 	break;
 
diff --git a/erts/emulator/beam/ops.tab b/erts/emulator/beam/ops.tab
index 879daaca0a..801d43e957 100644
--- a/erts/emulator/beam/ops.tab
+++ b/erts/emulator/beam/ops.tab
@@ -811,6 +811,10 @@ call_ext u==0 Bif=u$bif:erlang:garbage_collect/0 => i_call_ext Bif
 call_ext_last u==0 Bif=u$bif:erlang:garbage_collect/0 D => i_call_ext_last Bif D
 call_ext_only u==0 Bif=u$bif:erlang:garbage_collect/0 => i_call_ext_only Bif
 
+call_ext u==1 Bif=u$bif:erts_internal:garbage_collect/1 => i_call_ext Bif
+call_ext_last u==1 Bif=u$bif:erts_internal:garbage_collect/1 D => i_call_ext_last Bif D
+call_ext_only u==1 Bif=u$bif:erts_internal:garbage_collect/1 => i_call_ext_only Bif
+
 #
 # put/2 and erase/1 must be able to do garbage collection, so we must call
 # them like functions.