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 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License 2.0 as published by the Free Software Foundation;
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
16 * You should have received a copy of the GNU Library General Public
17 * License 2.0 along with this library; if not, write to the Free
18 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 * COPY_OR_MARK_FUNCTION_NAME must be defined to be the function name of the copy/mark
25 * SCAN_OBJECT_FUNCTION_NAME must be defined to be the function name of the object scanning
28 * DRAIN_GRAY_STACK_FUNCTION_NAME must be defined to be the function name of the gray stack
31 * Define COPY_OR_MARK_WITH_EVACUATION to support evacuation.
34 /* Returns whether the object is still in the nursery. */
35 static inline MONO_ALWAYS_INLINE gboolean
36 COPY_OR_MARK_FUNCTION_NAME (GCObject
**ptr
, GCObject
*obj
, SgenGrayQueue
*queue
)
40 #ifdef HEAVY_STATISTICS
41 ++stat_optimized_copy
;
45 if ((forwarded
= SGEN_OBJECT_IS_FORWARDED (obj
)))
46 desc
= sgen_obj_get_descriptor_safe (forwarded
);
48 desc
= sgen_obj_get_descriptor_safe (obj
);
50 sgen_descriptor_count_copied_object (desc
);
54 SGEN_ASSERT (9, obj
, "null object from pointer %p", ptr
);
55 #if !defined(COPY_OR_MARK_CONCURRENT) && !defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
56 SGEN_ASSERT (9, current_collection_generation
== GENERATION_OLD
, "old gen parallel allocator called from a %d collection", current_collection_generation
);
59 if (sgen_ptr_in_nursery (obj
)) {
60 #if !defined(COPY_OR_MARK_CONCURRENT) && !defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
62 GCObject
*forwarded
, *old_obj
;
63 mword vtable_word
= *(mword
*)obj
;
65 HEAVY_STAT (++stat_optimized_copy_nursery
);
67 #if SGEN_MAX_DEBUG_LEVEL >= 9
68 if (sgen_nursery_is_to_space (obj
))
69 SGEN_ASSERT (9, !SGEN_VTABLE_IS_PINNED (vtable_word
) && !SGEN_VTABLE_IS_FORWARDED (vtable_word
), "To-space object can't be pinned or forwarded.");
72 if (SGEN_VTABLE_IS_PINNED (vtable_word
)) {
73 SGEN_ASSERT (9, !SGEN_VTABLE_IS_FORWARDED (vtable_word
), "Cannot be both pinned and forwarded.");
74 HEAVY_STAT (++stat_optimized_copy_nursery_pinned
);
77 if ((forwarded
= (GCObject
*)SGEN_VTABLE_IS_FORWARDED (vtable_word
))) {
78 HEAVY_STAT (++stat_optimized_copy_nursery_forwarded
);
79 SGEN_UPDATE_REFERENCE (ptr
, forwarded
);
80 return sgen_ptr_in_nursery (forwarded
);
83 /* An object in the nursery To Space has already been copied and grayed. Nothing to do. */
84 if (sgen_nursery_is_to_space (obj
))
87 #ifdef COPY_OR_MARK_WITH_EVACUATION
91 obj
= copy_object_no_checks (obj
, queue
);
92 if (G_UNLIKELY (old_obj
== obj
)) {
94 * If we fail to evacuate an object we just stop doing it for a
95 * given block size as all other will surely fail too.
97 /* FIXME: test this case somehow. */
98 if (!sgen_ptr_in_nursery (obj
)) {
100 block
= MS_BLOCK_FOR_OBJ (obj
);
101 size_index
= block
->obj_size_index
;
102 evacuate_block_obj_sizes
[size_index
] = FALSE
;
103 MS_MARK_OBJECT_AND_ENQUEUE (obj
, sgen_obj_get_descriptor (obj
), block
, queue
);
108 HEAVY_STAT (++stat_objects_copied_major
);
109 SGEN_UPDATE_REFERENCE (ptr
, obj
);
111 if (sgen_ptr_in_nursery (obj
))
115 * FIXME: See comment for copy_object_no_checks(). If
116 * we have that, we can let the allocation function
117 * give us the block info, too, and we won't have to
120 * FIXME (2): We should rework this to avoid all those nursery checks.
123 * For the split nursery allocator the object might
124 * still be in the nursery despite having being
125 * promoted, in which case we can't mark it.
127 block
= MS_BLOCK_FOR_OBJ (obj
);
128 MS_CALC_MARK_BIT (word
, bit
, obj
);
129 SGEN_ASSERT (9, !MS_MARK_BIT (block
, word
, bit
), "object %p already marked", obj
);
130 MS_SET_MARK_BIT (block
, word
, bit
);
131 binary_protocol_mark (obj
, (gpointer
)LOAD_VTABLE (obj
), sgen_safe_object_get_size (obj
));
136 mword vtable_word
= *(mword
*)obj
;
140 HEAVY_STAT (++stat_optimized_copy_major
);
142 #ifdef COPY_OR_MARK_WITH_EVACUATION
145 if ((forwarded
= (GCObject
*)SGEN_VTABLE_IS_FORWARDED (vtable_word
))) {
146 HEAVY_STAT (++stat_optimized_copy_major_forwarded
);
147 SGEN_UPDATE_REFERENCE (ptr
, forwarded
);
148 SGEN_ASSERT (9, !sgen_ptr_in_nursery (forwarded
), "Cannot be forwarded to nursery.");
154 SGEN_ASSERT (9, !SGEN_VTABLE_IS_PINNED (vtable_word
), "Pinned object in non-pinned block?");
156 desc
= sgen_vtable_get_descriptor ((GCVTable
)vtable_word
);
157 type
= desc
& DESC_TYPE_MASK
;
159 if (sgen_safe_object_is_small (obj
, type
)) {
160 #ifdef HEAVY_STATISTICS
161 if (type
<= DESC_TYPE_MAX_SMALL_OBJ
)
162 ++stat_optimized_copy_major_small_fast
;
164 ++stat_optimized_copy_major_small_slow
;
167 block
= MS_BLOCK_FOR_OBJ (obj
);
169 #ifdef COPY_OR_MARK_CONCURRENT_WITH_EVACUATION
170 if (G_UNLIKELY (major_block_is_evacuating (block
))) {
172 * We don't copy within the concurrent phase. These objects will
173 * be handled below in the finishing pause, by scanning the mod-union
180 #ifdef COPY_OR_MARK_WITH_EVACUATION
181 if (major_block_is_evacuating (block
)) {
182 HEAVY_STAT (++stat_optimized_copy_major_small_evacuate
);
187 MS_MARK_OBJECT_AND_ENQUEUE (obj
, desc
, block
, queue
);
189 HEAVY_STAT (++stat_optimized_copy_major_large
);
191 if (sgen_los_object_is_pinned (obj
))
193 binary_protocol_pin (obj
, (gpointer
)SGEN_LOAD_VTABLE (obj
), sgen_safe_object_get_size (obj
));
195 sgen_los_pin_object (obj
);
196 if (SGEN_OBJECT_HAS_REFERENCES (obj
))
197 GRAY_OBJECT_ENQUEUE (queue
, obj
, sgen_obj_get_descriptor (obj
));
206 SCAN_OBJECT_FUNCTION_NAME (GCObject
*full_object
, SgenDescriptor desc
, SgenGrayQueue
*queue
)
208 char *start
= (char*)full_object
;
210 #ifdef HEAVY_STATISTICS
211 ++stat_optimized_major_scan
;
212 if (!sgen_gc_descr_has_references (desc
))
213 ++stat_optimized_major_scan_no_refs
;
214 sgen_descriptor_count_scanned_object (desc
);
216 #ifdef SGEN_HEAVY_BINARY_PROTOCOL
217 add_scanned_object (start
);
220 /* Now scan the object. */
223 #if defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
224 #define HANDLE_PTR(ptr,obj) do { \
225 GCObject *__old = *(ptr); \
226 binary_protocol_scan_process_reference ((full_object), (ptr), __old); \
227 if (__old && !sgen_ptr_in_nursery (__old)) { \
228 if (G_UNLIKELY (!sgen_ptr_in_nursery (ptr) && \
229 sgen_safe_object_is_small (__old, sgen_obj_get_descriptor (__old) & DESC_TYPE_MASK) && \
230 major_block_is_evacuating (MS_BLOCK_FOR_OBJ (__old)))) { \
231 mark_mod_union_card ((full_object), (void**)(ptr), __old); \
233 PREFETCH_READ (__old); \
234 COPY_OR_MARK_FUNCTION_NAME ((ptr), __old, queue); \
237 if (G_UNLIKELY (sgen_ptr_in_nursery (__old) && !sgen_ptr_in_nursery ((ptr)))) \
238 mark_mod_union_card ((full_object), (void**)(ptr), __old); \
241 #elif defined(COPY_OR_MARK_CONCURRENT)
242 #define HANDLE_PTR(ptr,obj) do { \
243 GCObject *__old = *(ptr); \
244 binary_protocol_scan_process_reference ((full_object), (ptr), __old); \
245 if (__old && !sgen_ptr_in_nursery (__old)) { \
246 PREFETCH_READ (__old); \
247 COPY_OR_MARK_FUNCTION_NAME ((ptr), __old, queue); \
249 if (G_UNLIKELY (sgen_ptr_in_nursery (__old) && !sgen_ptr_in_nursery ((ptr)))) \
250 mark_mod_union_card ((full_object), (void**)(ptr), __old); \
254 #define HANDLE_PTR(ptr,obj) do { \
255 GCObject *__old = *(ptr); \
256 binary_protocol_scan_process_reference ((full_object), (ptr), __old); \
258 gboolean __still_in_nursery = COPY_OR_MARK_FUNCTION_NAME ((ptr), __old, queue); \
259 if (G_UNLIKELY (__still_in_nursery && !sgen_ptr_in_nursery ((ptr)) && !SGEN_OBJECT_IS_CEMENTED (*(ptr)))) { \
260 GCObject *__copy = *(ptr); \
261 sgen_add_to_global_remset ((ptr), __copy); \
267 #define SCAN_OBJECT_PROTOCOL
268 #include "sgen-scan-object.h"
272 DRAIN_GRAY_STACK_FUNCTION_NAME (SgenGrayQueue
*queue
)
274 #if defined(COPY_OR_MARK_CONCURRENT) || defined(COPY_OR_MARK_CONCURRENT_WITH_EVACUATION)
276 for (i
= 0; i
< 32; i
++) {
283 HEAVY_STAT (++stat_drain_loops
);
285 GRAY_OBJECT_DEQUEUE (queue
, &obj
, &desc
);
289 SCAN_OBJECT_FUNCTION_NAME (obj
, desc
, queue
);
294 #undef COPY_OR_MARK_FUNCTION_NAME
295 #undef COPY_OR_MARK_WITH_EVACUATION
296 #undef SCAN_OBJECT_FUNCTION_NAME
297 #undef DRAIN_GRAY_STACK_FUNCTION_NAME