From 4bb24a4eddb5b6b944b5bf172adca7a376e62bc2 Mon Sep 17 00:00:00 2001
From: Justin Ethier <justin.ethier@gmail.com>
Date: Thu, 12 Nov 2015 22:33:34 -0500
Subject: [PATCH] Added mutator cooperation function

---
 gc.c                    | 32 ++++++++++++++++----------------
 include/cyclone/types.h |  1 +
 runtime.c               |  5 ++++-
 3 files changed, 21 insertions(+), 17 deletions(-)

diff --git a/gc.c b/gc.c
index 4c0925e4..a35e8554 100644
--- a/gc.c
+++ b/gc.c
@@ -514,25 +514,25 @@ void gc_mut_update()
 // ideally want to do this without needing sync. we need to sync to get markColor in coop, though
 //void gc_mut_create()
 
-// TODO: when is this called, is this good enough, etc??
+// TODO: still need to handle case where a mutator is blocked
 void gc_mut_cooperate(gc_thread_data *thd)
 {
-
-// !!!!
-// TODO: think about what else needs to be done here. for example,
-// would want to reset last read/write at some point, to conserve
-// amount of memory being used by the mark buffers
-
-
-  if (thd->gc_status == gc_status_col) { // TODO: synchronization of var access
-    if (thd->gc_status == STATUS_SYNC2) { // TODO: more sync??
-      // Since everything is on the stack, at this point probably only need
-      // to worry about anything on the stack that is referencing a heap object
-      //  For each x in roots:
-      //  MarkGray(x)
-      thd->gc_alloc_color = ATOMIC_GET(&gc_color_mark); // TODO: synchronization for global??
+  int i, status = ATOMIC_GET(&gc_status_col);
+  if (thd->gc_status != status) {
+    if (thd->gc_status == STATUS_ASYNC) {
+      // Async is done, so clean up old mark data from the last collection
+      thd->last_write = 0;
+      thd->last_read = 0;
     }
-    thd->gc_status = gc_status_col; // TODO: syncronization??
+    else if (thd->gc_status == STATUS_SYNC2) {
+      // Mark thread "roots"
+      gc_mark_gray(thd, thd->gc_cont);
+      for (i = 0; i < thd->gc_num_args; i++) {
+        gc_mark_gray(thd, thd->gc_args[i]);
+      }
+      thd->gc_alloc_color = ATOMIC_GET(&gc_color_mark);
+    }
+    thd->gc_status = status;
   }
 }
 
diff --git a/include/cyclone/types.h b/include/cyclone/types.h
index a1bfc527..4f6a7c1e 100644
--- a/include/cyclone/types.h
+++ b/include/cyclone/types.h
@@ -142,6 +142,7 @@ void gc_thr_add_to_move_buffer(gc_thread_data *d, int *alloci, object obj);
 void gc_thread_data_init(gc_thread_data *thd, int mut_num, char *stack_base, long stack_size);
 void gc_thread_data_free(gc_thread_data *thd);
 // Prototypes for mutator/collector:
+void gc_mut_cooperate(gc_thread_data *thd);
 void gc_mark_gray(gc_thread_data *thd, object obj);
 void gc_collector_trace();
 void gc_mark_black(object obj);
diff --git a/runtime.c b/runtime.c
index c5d7332b..9b2f48c8 100644
--- a/runtime.c
+++ b/runtime.c
@@ -2764,7 +2764,10 @@ void GC(void *data, closure cont, object *args, int num_args)
 //#endif
 //  }
 
-  /* Let it all go, Neo... */
+  // Cooperate with the collector thread
+  gc_mut_cooperate((gc_thread_data *)data);
+
+  // Let it all go, Neo...
   longjmp(*(((gc_thread_data *)data)->jmp_start), 1);
 }