[sgen] Add option for enabling/disabling precleaning

diff --git a/mono/sgen/sgen-gc.c b/mono/sgen/sgen-gc.c
index 1314a8f090044559446639c1ceaf05e415641c9a..e4d787a8bc85eb4c2f5867db98e062a0acd2f075 100644 (file)
--- a/mono/sgen/sgen-gc.c
+++ b/mono/sgen/sgen-gc.c
@@ -245,6 +245,8 @@ static gboolean do_verify_nursery = FALSE;
 static gboolean do_dump_nursery_content = FALSE;
 static gboolean enable_nursery_canaries = FALSE;
 
+static gboolean precleaning_enabled = TRUE;
+
 #ifdef HEAVY_STATISTICS
 guint64 stat_objects_alloced_degraded = 0;
 guint64 stat_bytes_alloced_degraded = 0;
@@ -1788,11 +1790,15 @@ major_copy_or_mark_from_roots (size_t *old_next_pin_slot, CopyOrMarkFromRootsMod
         * collector we start the workers after pinning.
         */
        if (mode == COPY_OR_MARK_FROM_ROOTS_START_CONCURRENT) {
-               ScanJob *sj;
-               /* Mod union preclean job */
-               sj = (ScanJob*)sgen_thread_pool_job_alloc ("preclean mod union cardtable", job_mod_union_preclean, sizeof (ScanJob));
-               sj->ops = object_ops;
-               sgen_workers_start_all_workers (object_ops, &sj->job);
+               if (precleaning_enabled) {
+                       ScanJob *sj;
+                       /* Mod union preclean job */
+                       sj = (ScanJob*)sgen_thread_pool_job_alloc ("preclean mod union cardtable", job_mod_union_preclean, sizeof (ScanJob));
+                       sj->ops = object_ops;
+                       sgen_workers_start_all_workers (object_ops, &sj->job);
+               } else {
+                       sgen_workers_start_all_workers (object_ops, NULL);
+               }
                gray_queue_enable_redirect (WORKERS_DISTRIBUTE_GRAY_QUEUE);
        } else if (mode == COPY_OR_MARK_FROM_ROOTS_FINISH_CONCURRENT) {
                if (sgen_workers_have_idle_work ()) {
@@ -2948,6 +2954,15 @@ sgen_gc_init (void)
                                continue;
                        }
 
+                       if (!strcmp (opt, "precleaning")) {
+                               precleaning_enabled = TRUE;
+                               continue;
+                       }
+                       if (!strcmp (opt, "no-precleaning")) {
+                               precleaning_enabled = FALSE;
+                               continue;
+                       }
+
                        if (major_collector.handle_gc_param && major_collector.handle_gc_param (opt))
                                continue;