Distinguish between GC disabled by BIFs and other disabled GC

Processes remember heap fragments that are known to be fully
live due to creation in a just called BIF that yields in the
live_hf_end field. This field must not be used if we have not
disabled GC in a BIF. F_DELAY_GC has been introduced in order
to distinguish between to two different scenarios.

- F_DISABLE_GC should *only* be used by BIFs. This when
  the BIF needs to yield while preventig a GC.
- F_DELAY_GC should only be used when GC is temporarily
  disabled while the process is scheduled. A process must
  not be scheduled out while F_DELAY_GC is set.

1 files changed, 12 insertions, 3 deletions

diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 3bb1f601aa..3784367195 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -440,8 +440,15 @@ delay_garbage_collection(Process *p, ErlHeapFragment *live_hf_end, int need)
 
     ERTS_HOLE_CHECK(p);
 
-    if (p->live_hf_end == ERTS_INVALID_HFRAG_PTR)
+    if ((p->flags & F_DISABLE_GC)
+	&& p->live_hf_end == ERTS_INVALID_HFRAG_PTR) {
+	/*
+	 * A BIF yielded with disabled GC. Remember
+	 * heap fragments created by the BIF until we
+	 * do next GC.
+	 */
 	p->live_hf_end = live_hf_end;
+    }
 
     if (need == 0)
 	return 1;
@@ -564,10 +571,12 @@ garbage_collect(Process* p, ErlHeapFragment *live_hf_end,
     DTRACE_CHARBUF(pidbuf, DTRACE_TERM_BUF_SIZE);
 #endif
 
-    if (p->flags & F_DISABLE_GC)
+    if (p->flags & (F_DISABLE_GC|F_DELAY_GC))
 	return delay_garbage_collection(p, live_hf_end, need);
 
-    if (p->live_hf_end != ERTS_INVALID_HFRAG_PTR)
+    if (p->abandoned_heap)
+	live_hf_end = ERTS_INVALID_HFRAG_PTR;
+    else if (p->live_hf_end != ERTS_INVALID_HFRAG_PTR)
 	live_hf_end = p->live_hf_end;
 
     esdp = erts_get_scheduler_data();