2 * sgen-marksweep-drain-gray-stack.h: The copy/mark and gray stack
3 * draining functions of the M&S major collector.
5 * Copyright (C) 2014 Xamarin Inc
7 * Licensed under the MIT license. See LICENSE file in the project root for full license information.
11 * COPY_OR_MARK_FUNCTION_NAME must be defined to be the function name of the copy/mark
14 * SCAN_OBJECT_FUNCTION_NAME must be defined to be the function name of the object scanning
17 * DRAIN_GRAY_STACK_FUNCTION_NAME must be defined to be the function name of the gray stack
20 * Define COPY_OR_MARK_WITH_EVACUATION to support evacuation.
23 /* Returns whether the object is still in the nursery. */
24 static inline MONO_ALWAYS_INLINE gboolean
25 COPY_OR_MARK_FUNCTION_NAME (GCObject **ptr, GCObject *obj, SgenGrayQueue *queue)
29 #ifdef HEAVY_STATISTICS
30 ++stat_optimized_copy;
34 if ((forwarded = SGEN_OBJECT_IS_FORWARDED (obj)))
35 desc = sgen_obj_get_descriptor_safe (forwarded);
37 desc = sgen_obj_get_descriptor_safe (obj);
39 sgen_descriptor_count_copied_object (desc);
43 SGEN_ASSERT (9, obj, "null object from pointer %p", ptr);
44 #if !defined(COPY_OR_MARK_CONCURRENT) && !defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
45 SGEN_ASSERT (9, current_collection_generation == GENERATION_OLD, "old gen parallel allocator called from a %d collection", current_collection_generation);
48 if (sgen_ptr_in_nursery (obj)) {
49 #if !defined(COPY_OR_MARK_CONCURRENT) && !defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
51 GCObject *forwarded, *old_obj;
52 mword vtable_word = *(mword*)obj;
54 HEAVY_STAT (++stat_optimized_copy_nursery);
56 #if SGEN_MAX_DEBUG_LEVEL >= 9
57 if (sgen_nursery_is_to_space (obj))
58 SGEN_ASSERT (9, !SGEN_VTABLE_IS_PINNED (vtable_word) && !SGEN_VTABLE_IS_FORWARDED (vtable_word), "To-space object can't be pinned or forwarded.");
61 if (SGEN_VTABLE_IS_PINNED (vtable_word)) {
62 SGEN_ASSERT (9, !SGEN_VTABLE_IS_FORWARDED (vtable_word), "Cannot be both pinned and forwarded.");
63 HEAVY_STAT (++stat_optimized_copy_nursery_pinned);
66 if ((forwarded = (GCObject *)SGEN_VTABLE_IS_FORWARDED (vtable_word))) {
67 HEAVY_STAT (++stat_optimized_copy_nursery_forwarded);
68 SGEN_UPDATE_REFERENCE (ptr, forwarded);
69 return sgen_ptr_in_nursery (forwarded);
72 /* An object in the nursery To Space has already been copied and grayed. Nothing to do. */
73 if (sgen_nursery_is_to_space (obj))
76 #ifdef COPY_OR_MARK_WITH_EVACUATION
80 obj = copy_object_no_checks (obj, queue);
81 if (G_UNLIKELY (old_obj == obj)) {
83 * If we fail to evacuate an object we just stop doing it for a
84 * given block size as all other will surely fail too.
86 /* FIXME: test this case somehow. */
87 if (!sgen_ptr_in_nursery (obj)) {
89 block = MS_BLOCK_FOR_OBJ (obj);
90 size_index = block->obj_size_index;
91 evacuate_block_obj_sizes [size_index] = FALSE;
92 MS_MARK_OBJECT_AND_ENQUEUE (obj, sgen_obj_get_descriptor (obj), block, queue);
97 HEAVY_STAT (++stat_objects_copied_major);
98 SGEN_UPDATE_REFERENCE (ptr, obj);
100 if (sgen_ptr_in_nursery (obj))
104 * FIXME: See comment for copy_object_no_checks(). If
105 * we have that, we can let the allocation function
106 * give us the block info, too, and we won't have to
109 * FIXME (2): We should rework this to avoid all those nursery checks.
112 * For the split nursery allocator the object might
113 * still be in the nursery despite having being
114 * promoted, in which case we can't mark it.
116 block = MS_BLOCK_FOR_OBJ (obj);
117 MS_CALC_MARK_BIT (word, bit, obj);
118 SGEN_ASSERT (9, !MS_MARK_BIT (block, word, bit), "object %p already marked", obj);
119 MS_SET_MARK_BIT (block, word, bit);
120 binary_protocol_mark (obj, (gpointer)LOAD_VTABLE (obj), sgen_safe_object_get_size (obj));
125 mword vtable_word = *(mword*)obj;
129 HEAVY_STAT (++stat_optimized_copy_major);
131 #ifdef COPY_OR_MARK_WITH_EVACUATION
134 if ((forwarded = (GCObject *)SGEN_VTABLE_IS_FORWARDED (vtable_word))) {
135 HEAVY_STAT (++stat_optimized_copy_major_forwarded);
136 SGEN_UPDATE_REFERENCE (ptr, forwarded);
137 SGEN_ASSERT (9, !sgen_ptr_in_nursery (forwarded), "Cannot be forwarded to nursery.");
143 SGEN_ASSERT (9, !SGEN_VTABLE_IS_PINNED (vtable_word), "Pinned object in non-pinned block?");
145 desc = sgen_vtable_get_descriptor ((GCVTable)vtable_word);
146 type = desc & DESC_TYPE_MASK;
148 if (sgen_safe_object_is_small (obj, type)) {
149 #ifdef HEAVY_STATISTICS
150 if (type <= DESC_TYPE_MAX_SMALL_OBJ)
151 ++stat_optimized_copy_major_small_fast;
153 ++stat_optimized_copy_major_small_slow;
156 block = MS_BLOCK_FOR_OBJ (obj);
158 #ifdef COPY_OR_MARK_CONCURRENT_WITH_EVACUATION
159 if (G_UNLIKELY (major_block_is_evacuating (block))) {
161 * We don't copy within the concurrent phase. These objects will
162 * be handled below in the finishing pause, by scanning the mod-union
169 #ifdef COPY_OR_MARK_WITH_EVACUATION
170 if (major_block_is_evacuating (block)) {
171 HEAVY_STAT (++stat_optimized_copy_major_small_evacuate);
176 MS_MARK_OBJECT_AND_ENQUEUE (obj, desc, block, queue);
178 HEAVY_STAT (++stat_optimized_copy_major_large);
180 if (sgen_los_object_is_pinned (obj))
182 binary_protocol_pin (obj, (gpointer)SGEN_LOAD_VTABLE (obj), sgen_safe_object_get_size (obj));
184 sgen_los_pin_object (obj);
185 if (SGEN_OBJECT_HAS_REFERENCES (obj))
186 GRAY_OBJECT_ENQUEUE (queue, obj, sgen_obj_get_descriptor (obj));
195 SCAN_OBJECT_FUNCTION_NAME (GCObject *full_object, SgenDescriptor desc, SgenGrayQueue *queue)
197 char *start = (char*)full_object;
199 #ifdef HEAVY_STATISTICS
200 ++stat_optimized_major_scan;
201 if (!sgen_gc_descr_has_references (desc))
202 ++stat_optimized_major_scan_no_refs;
203 sgen_descriptor_count_scanned_object (desc);
205 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
206 add_scanned_object (start);
209 /* Now scan the object. */
212 #if defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
213 #define HANDLE_PTR(ptr,obj) do { \
214 GCObject *__old = *(ptr); \
215 binary_protocol_scan_process_reference ((full_object), (ptr), __old); \
216 if (__old && !sgen_ptr_in_nursery (__old)) { \
217 if (G_UNLIKELY (!sgen_ptr_in_nursery (ptr) && \
218 sgen_safe_object_is_small (__old, sgen_obj_get_descriptor (__old) & DESC_TYPE_MASK) && \
219 major_block_is_evacuating (MS_BLOCK_FOR_OBJ (__old)))) { \
220 mark_mod_union_card ((full_object), (void**)(ptr), __old); \
222 PREFETCH_READ (__old); \
223 COPY_OR_MARK_FUNCTION_NAME ((ptr), __old, queue); \
226 if (G_UNLIKELY (sgen_ptr_in_nursery (__old) && !sgen_ptr_in_nursery ((ptr)) && !sgen_cement_is_forced (__old))) \
227 mark_mod_union_card ((full_object), (void**)(ptr), __old); \
230 #elif defined(COPY_OR_MARK_CONCURRENT)
231 #define HANDLE_PTR(ptr,obj) do { \
232 GCObject *__old = *(ptr); \
233 binary_protocol_scan_process_reference ((full_object), (ptr), __old); \
234 if (__old && !sgen_ptr_in_nursery (__old)) { \
235 PREFETCH_READ (__old); \
236 COPY_OR_MARK_FUNCTION_NAME ((ptr), __old, queue); \
238 if (G_UNLIKELY (sgen_ptr_in_nursery (__old) && !sgen_ptr_in_nursery ((ptr)) && !sgen_cement_is_forced (__old))) \
239 mark_mod_union_card ((full_object), (void**)(ptr), __old); \
243 #define HANDLE_PTR(ptr,obj) do { \
244 GCObject *__old = *(ptr); \
245 binary_protocol_scan_process_reference ((full_object), (ptr), __old); \
247 gboolean __still_in_nursery = COPY_OR_MARK_FUNCTION_NAME ((ptr), __old, queue); \
248 if (G_UNLIKELY (__still_in_nursery && !sgen_ptr_in_nursery ((ptr)) && !SGEN_OBJECT_IS_CEMENTED (*(ptr)))) { \
249 GCObject *__copy = *(ptr); \
250 sgen_add_to_global_remset ((ptr), __copy); \
256 #define SCAN_OBJECT_PROTOCOL
257 #include "sgen-scan-object.h"
260 #ifdef SCAN_VTYPE_FUNCTION_NAME
262 SCAN_VTYPE_FUNCTION_NAME (GCObject *full_object, char *start, SgenDescriptor desc, SgenGrayQueue *queue BINARY_PROTOCOL_ARG (size_t size))
264 SGEN_OBJECT_LAYOUT_STATISTICS_DECLARE_BITMAP;
266 #ifdef HEAVY_STATISTICS
267 /* FIXME: We're half scanning this object. How do we account for that? */
268 //add_scanned_object (start);
271 /* The descriptors include info about the object header as well */
272 start -= SGEN_CLIENT_OBJECT_HEADER_SIZE;
274 /* We use the same HANDLE_PTR from the obj scan function */
275 #define SCAN_OBJECT_NOVTABLE
276 #define SCAN_OBJECT_PROTOCOL
277 #include "sgen-scan-object.h"
279 SGEN_OBJECT_LAYOUT_STATISTICS_COMMIT_BITMAP;
283 #ifdef SCAN_PTR_FIELD_FUNCTION_NAME
285 SCAN_PTR_FIELD_FUNCTION_NAME (GCObject *full_object, GCObject **ptr, SgenGrayQueue *queue)
287 HANDLE_PTR (ptr, NULL);
292 DRAIN_GRAY_STACK_FUNCTION_NAME (SgenGrayQueue *queue)
294 #if defined(COPY_OR_MARK_CONCURRENT) || defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
296 for (i = 0; i < 32; i++) {
303 HEAVY_STAT (++stat_drain_loops);
305 GRAY_OBJECT_DEQUEUE (queue, &obj, &desc);
309 SCAN_OBJECT_FUNCTION_NAME (obj, desc, queue);
314 #undef COPY_OR_MARK_FUNCTION_NAME
315 #undef COPY_OR_MARK_WITH_EVACUATION
316 #undef COPY_OR_MARK_CONCURRENT
317 #undef COPY_OR_MARK_CONCURRENT_WITH_EVACUATION
318 #undef SCAN_OBJECT_FUNCTION_NAME
319 #undef SCAN_VTYPE_FUNCTION_NAME
320 #undef SCAN_PTR_FIELD_FUNCTION_NAME
321 #undef DRAIN_GRAY_STACK_FUNCTION_NAME