[sgen] More information in sweep and world restart DTrace probes.

Pass to the sweep probes whether a full sweep (including memset and resetting
mark bitmaps) was performed.

Pass to the world restart probes the oldest generation collected during
the pause.

data/mono.d

@@ -25,13 +25,13 @@ provider mono {
 	probe gc__concurrent__update__end (int generation);
 	probe gc__concurrent__finish__end (int generation);
 
-	probe gc__sweep__begin (int generation);
-	probe gc__sweep__end (int generation);
+	probe gc__sweep__begin (int generation, int full_sweep);
+	probe gc__sweep__end (int generation, int full_sweep);
 
 	probe gc__world__stop__begin ();
 	probe gc__world__stop__end ();
-	probe gc__world__restart__begin ();
-	probe gc__world__restart__end ();
+	probe gc__world__restart__begin (int generation);
+	probe gc__world__restart__end (int generation);
 
 	probe gc__heap__alloc (uintptr_t addr, uintptr_t len);
 	probe gc__heap__free (uintptr_t addr, uintptr_t len);

mono/metadata/sgen-gc.c

@@ -2963,7 +2963,7 @@ major_finish_collection (const char *reason, int old_next_pin_slot, gboolean sca
 	reset_heap_boundaries ();
 	sgen_update_heap_boundaries ((mword)sgen_get_nursery_start (), (mword)sgen_get_nursery_end ());
 
-	MONO_GC_SWEEP_BEGIN (GENERATION_OLD);
+	MONO_GC_SWEEP_BEGIN (GENERATION_OLD, !major_collector.sweeps_lazily);
 
 	/* sweep the big objects list */
 	prevbo = NULL;
@@ -2998,7 +2998,7 @@ major_finish_collection (const char *reason, int old_next_pin_slot, gboolean sca
 
 	major_collector.sweep ();
 
-	MONO_GC_SWEEP_END (GENERATION_OLD);
+	MONO_GC_SWEEP_END (GENERATION_OLD, !major_collector.sweeps_lazily);
 
 	TV_GETTIME (btv);
 	time_major_sweep += TV_ELAPSED (atv, btv);
@@ -3165,8 +3165,11 @@ sgen_perform_collection (size_t requested_size, int generation_to_collect, const
 	TV_DECLARE (gc_end);
 	GGTimingInfo infos [2];
 	int overflow_generation_to_collect = -1;
+	int oldest_generation_collected = generation_to_collect;
 	const char *overflow_reason = NULL;
 
+	g_assert (generation_to_collect == GENERATION_NURSERY || generation_to_collect == GENERATION_OLD);
+
 	memset (infos, 0, sizeof (infos));
 	mono_profiler_gc_event (MONO_GC_EVENT_START, generation_to_collect);
 
@@ -3180,8 +3183,10 @@ sgen_perform_collection (size_t requested_size, int generation_to_collect, const
 
 	if (concurrent_collection_in_progress) {
 		g_print ("finishing concurrent collection\n");
-		if (major_update_or_finish_concurrent_collection (generation_to_collect == GENERATION_OLD))
+		if (major_update_or_finish_concurrent_collection (generation_to_collect == GENERATION_OLD)) {
+			oldest_generation_collected = GENERATION_OLD;
 			goto done;
+		}
 	}
 
 	//FIXME extract overflow reason
@@ -3233,6 +3238,8 @@ sgen_perform_collection (size_t requested_size, int generation_to_collect, const
 
 		/* keep events symmetric */
 		mono_profiler_gc_event (MONO_GC_EVENT_END, overflow_generation_to_collect);
+
+		oldest_generation_collected = MAX (oldest_generation_collected, overflow_generation_to_collect);
 	}
 
 	SGEN_LOG (2, "Heap size: %lu, LOS size: %lu", (unsigned long)mono_gc_get_heap_size (), (unsigned long)los_memory_usage);
@@ -3249,7 +3256,7 @@ sgen_perform_collection (size_t requested_size, int generation_to_collect, const
 	g_assert (sgen_gray_object_queue_is_empty (&gray_queue));
 	g_assert (sgen_gray_object_queue_is_empty (&remember_major_objects_gray_queue));
 
-	sgen_restart_world (generation_to_collect, infos);
+	sgen_restart_world (oldest_generation_collected, infos);
 
 	mono_profiler_gc_event (MONO_GC_EVENT_END, generation_to_collect);
 }
@@ -4956,7 +4963,7 @@ mono_gc_base_init (void)
 	}
 
 	if (major_collector.post_param_init)
-		major_collector.post_param_init ();
+		major_collector.post_param_init (&major_collector);
 
 	sgen_memgov_init (max_heap, soft_limit, debug_print_allowance, allowance_ratio, save_target);
 

mono/metadata/sgen-gc.h

@@ -671,6 +671,7 @@ struct _SgenMajorCollector {
 	gboolean is_parallel;
 	gboolean is_concurrent;
 	gboolean supports_cardtable;
+	gboolean sweeps_lazily;
 
 	/*
 	 * This is set to TRUE if the sweep for the last major
@@ -713,7 +714,7 @@ struct _SgenMajorCollector {
 	gboolean (*handle_gc_param) (const char *opt);
 	void (*print_gc_param_usage) (void);
 	gboolean (*is_worker_thread) (MonoNativeThreadId thread);
-	void (*post_param_init) (void);
+	void (*post_param_init) (SgenMajorCollector *collector);
 	void* (*alloc_worker_data) (void);
 	void (*init_worker_thread) (void *data);
 	void (*reset_worker_data) (void *data);

mono/metadata/sgen-marksweep.c

@@ -1833,6 +1833,8 @@ major_start_major_collection (void)
 	if (lazy_sweep) {
 		MSBlockInfo **iter;
 
+		MONO_GC_SWEEP_BEGIN (GENERATION_OLD, TRUE);
+
 		iter = &all_blocks;
 		while (*iter) {
 			MSBlockInfo *block = *iter;
@@ -1841,6 +1843,8 @@ major_start_major_collection (void)
 
 			iter = &block->next;
 		}
+
+		MONO_GC_SWEEP_END (GENERATION_OLD, TRUE);
 	}
 }
 
@@ -2290,14 +2294,16 @@ major_reset_worker_data (void *data)
 #undef pthread_create
 
 static void
-post_param_init (void)
+post_param_init (SgenMajorCollector *collector)
 {
 	if (concurrent_sweep) {
 		if (!mono_native_thread_create (&ms_sweep_thread, ms_sweep_thread_func, NULL)) {
 			fprintf (stderr, "Error: Could not create sweep thread.\n");
 			exit (1);
 		}
 	}
+
+	collector->sweeps_lazily = lazy_sweep;
 }
 
 void

mono/metadata/sgen-stw.c

@@ -251,7 +251,7 @@ sgen_restart_world (int generation, GGTimingInfo *timing)
 	if (G_UNLIKELY (mono_profiler_events & MONO_PROFILE_GC_MOVES))
 		sgen_gc_event_moves ();
 	mono_profiler_gc_event (MONO_GC_EVENT_PRE_START_WORLD, generation);
-	MONO_GC_WORLD_RESTART_BEGIN ();
+	MONO_GC_WORLD_RESTART_BEGIN (generation);
 	FOREACH_THREAD (info) {
 		info->stack_start = NULL;
 #ifdef USE_MONO_CTX
@@ -270,7 +270,7 @@ sgen_restart_world (int generation, GGTimingInfo *timing)
 	max_pause_usec = MAX (usec, max_pause_usec);
 	SGEN_LOG (2, "restarted %d thread(s) (pause time: %d usec, max: %d)", count, (int)usec, (int)max_pause_usec);
 	mono_profiler_gc_event (MONO_GC_EVENT_POST_START_WORLD, generation);
-	MONO_GC_WORLD_RESTART_END ();
+	MONO_GC_WORLD_RESTART_END (generation);
 
 	bridge_process (generation);