From 6c40a29d5d55c7201e510d94e3ee89983ddfad91 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Fri, 3 Jul 2015 23:27:24 -0400
Subject: [PATCH] Upgrade to major GC if data heap exceeds limit

---
 runtime-main.h |  1 +
 runtime.c      | 10 ++++++++++
 runtime.h      |  1 +
 3 files changed, 12 insertions(+)

diff --git a/runtime-main.h b/runtime-main.h
index ce360427..1071aa58 100644
--- a/runtime-main.h
+++ b/runtime-main.h
@@ -65,6 +65,7 @@ static void main_main (stack_size,heap_size,stack_base)
   alloc_end = allocp + heap_size - 8;
   
   dhallocp = dhbottom = calloc(1, heap_size);
+  dhalloc_limit = dhallocp + (long)((heap_size - 8) * 0.90);
   dhalloc_end = dhallocp + heap_size - 8;
 #if DEBUG_SHOW_DIAG
   printf("main: heap_size=%ld  allocp=%p  alloc_end=%p\n",
diff --git a/runtime.c b/runtime.c
index 690255ed..cb7b6c12 100644
--- a/runtime.c
+++ b/runtime.c
@@ -42,6 +42,7 @@ char *alloc_end;
    copying to occur during GC */
 char *dhbottom; /* Bottom of data heap */
 char *dhallocp; /* Current place in data heap */
+char *dhalloc_limit; /* GC beyond this limit */ 
 char *dhalloc_end;
 long no_gcs = 0; /* Count the number of GC's. */
 long no_major_gcs = 0; /* Count the number of GC's. */
@@ -1674,6 +1675,14 @@ void GC_loop(int major, closure cont, object *ans, int num_ans)
  char *tmp_dhbottom = dhbottom;
  char *tmp_dhallocp = dhallocp;
  char *tmp_dhallocp_end = dhalloc_end;
+
+ if (dhallocp > dhalloc_limit) {
+   // Upgrade to major GC
+   major = 1;
+   no_major_gcs++;
+   no_gcs--;
+ }
+
  if (major) {
     // Initialize new heap (TODO: make a function for this)
     bottom = calloc(1,global_heap_size);
@@ -1684,6 +1693,7 @@ void GC_loop(int major, closure cont, object *ans, int num_ans)
     old_heap_high_limit = tmp_alloc_end;
     
     dhallocp = dhbottom = calloc(1, global_heap_size);
+    dhalloc_limit = dhallocp + (long)((global_heap_size - 8) * 0.90);
     dhalloc_end = dhallocp + global_heap_size - 8;
  }
 
diff --git a/runtime.h b/runtime.h
index 519fdd63..abf75d16 100644
--- a/runtime.h
+++ b/runtime.h
@@ -224,6 +224,7 @@ extern char *alloc_end;
    copying to occur during GC */
 extern char *dhbottom; /* Bottom of data heap */
 extern char *dhallocp; /* Current place in data heap */
+extern char *dhalloc_limit; /* GC beyond this limit */ 
 extern char *dhalloc_end;
 extern long no_gcs; /* Count the number of GC's. */
 extern long no_major_gcs; /* Count the number of GC's. */