Functionality for disabling garbage collection

Being able to disable garbage collection over context
switches vastly simplifies implementation of yielding
native code that builds large or complex data structures
on the heap. This since the heap can be left in an
inconsistent state over the context switch.

1 files changed, 12 insertions, 0 deletions

diff --git a/erts/emulator/beam/beam_bif_load.c b/erts/emulator/beam/beam_bif_load.c
index 5239940a50..3f92c5b025 100644
--- a/erts/emulator/beam/beam_bif_load.c
+++ b/erts/emulator/beam/beam_bif_load.c
@@ -495,6 +495,8 @@ BIF_RETTYPE erts_internal_check_process_code_2(BIF_ALIST_2)
 
     res = erts_check_process_code(BIF_P, BIF_ARG_1, allow_gc, &reds);
 
+    ASSERT(is_value(res));
+
     BIF_RET2(res, reds);
 
 badarg:
@@ -784,6 +786,16 @@ check_process_code(Process* rp, Module* modp, int allow_gc, int *redsp)
 	}
     }
 
+    if (rp->flags & F_DISABLE_GC) {
+	/*
+	 * Cannot proceed. Process has disabled gc in order to
+	 * safely leave inconsistent data on the heap and/or
+	 * off heap lists. Need to wait for gc to be enabled
+	 * again.
+	 */ 
+	return THE_NON_VALUE;
+    }
+
     /*
      * See if there are funs that refer to the old version of the module.
      */