Tue, 19 May 2015 15:49:27 +0200
8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before
Summary: added WhiteBox methods to count regions and exact aux data sizes
Reviewed-by: jwilhelm, brutisso
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
28 #include "gc_implementation/g1/concurrentMark.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
31 // Utility routine to set an exclusive range of cards on the given
32 // card liveness bitmap
33 inline void ConcurrentMark::set_card_bitmap_range(BitMap* card_bm,
34 BitMap::idx_t start_idx,
35 BitMap::idx_t end_idx,
36 bool is_par) {
38 // Set the exclusive bit range [start_idx, end_idx).
39 assert((end_idx - start_idx) > 0, "at least one card");
40 assert(end_idx <= card_bm->size(), "sanity");
42 // Silently clip the end index
43 end_idx = MIN2(end_idx, card_bm->size());
45 // For small ranges use a simple loop; otherwise use set_range or
46 // use par_at_put_range (if parallel). The range is made up of the
47 // cards that are spanned by an object/mem region so 8 cards will
48 // allow up to object sizes up to 4K to be handled using the loop.
49 if ((end_idx - start_idx) <= 8) {
50 for (BitMap::idx_t i = start_idx; i < end_idx; i += 1) {
51 if (is_par) {
52 card_bm->par_set_bit(i);
53 } else {
54 card_bm->set_bit(i);
55 }
56 }
57 } else {
58 // Note BitMap::par_at_put_range() and BitMap::set_range() are exclusive.
59 if (is_par) {
60 card_bm->par_at_put_range(start_idx, end_idx, true);
61 } else {
62 card_bm->set_range(start_idx, end_idx);
63 }
64 }
65 }
67 // Returns the index in the liveness accounting card bitmap
68 // for the given address
69 inline BitMap::idx_t ConcurrentMark::card_bitmap_index_for(HeapWord* addr) {
70 // Below, the term "card num" means the result of shifting an address
71 // by the card shift -- address 0 corresponds to card number 0. One
72 // must subtract the card num of the bottom of the heap to obtain a
73 // card table index.
74 intptr_t card_num = intptr_t(uintptr_t(addr) >> CardTableModRefBS::card_shift);
75 return card_num - heap_bottom_card_num();
76 }
78 // Counts the given memory region in the given task/worker
79 // counting data structures.
80 inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr,
81 size_t* marked_bytes_array,
82 BitMap* task_card_bm) {
83 G1CollectedHeap* g1h = _g1h;
84 CardTableModRefBS* ct_bs = g1h->g1_barrier_set();
86 HeapWord* start = mr.start();
87 HeapWord* end = mr.end();
88 size_t region_size_bytes = mr.byte_size();
89 uint index = hr->hrm_index();
91 assert(!hr->continuesHumongous(), "should not be HC region");
92 assert(hr == g1h->heap_region_containing(start), "sanity");
93 assert(hr == g1h->heap_region_containing(mr.last()), "sanity");
94 assert(marked_bytes_array != NULL, "pre-condition");
95 assert(task_card_bm != NULL, "pre-condition");
97 // Add to the task local marked bytes for this region.
98 marked_bytes_array[index] += region_size_bytes;
100 BitMap::idx_t start_idx = card_bitmap_index_for(start);
101 BitMap::idx_t end_idx = card_bitmap_index_for(end);
103 // Note: if we're looking at the last region in heap - end
104 // could be actually just beyond the end of the heap; end_idx
105 // will then correspond to a (non-existent) card that is also
106 // just beyond the heap.
107 if (g1h->is_in_g1_reserved(end) && !ct_bs->is_card_aligned(end)) {
108 // end of region is not card aligned - incremement to cover
109 // all the cards spanned by the region.
110 end_idx += 1;
111 }
112 // The card bitmap is task/worker specific => no need to use
113 // the 'par' BitMap routines.
114 // Set bits in the exclusive bit range [start_idx, end_idx).
115 set_card_bitmap_range(task_card_bm, start_idx, end_idx, false /* is_par */);
116 }
118 // Counts the given memory region in the task/worker counting
119 // data structures for the given worker id.
120 inline void ConcurrentMark::count_region(MemRegion mr,
121 HeapRegion* hr,
122 uint worker_id) {
123 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id);
124 BitMap* task_card_bm = count_card_bitmap_for(worker_id);
125 count_region(mr, hr, marked_bytes_array, task_card_bm);
126 }
128 // Counts the given object in the given task/worker counting data structures.
129 inline void ConcurrentMark::count_object(oop obj,
130 HeapRegion* hr,
131 size_t* marked_bytes_array,
132 BitMap* task_card_bm) {
133 MemRegion mr((HeapWord*)obj, obj->size());
134 count_region(mr, hr, marked_bytes_array, task_card_bm);
135 }
137 // Attempts to mark the given object and, if successful, counts
138 // the object in the given task/worker counting structures.
139 inline bool ConcurrentMark::par_mark_and_count(oop obj,
140 HeapRegion* hr,
141 size_t* marked_bytes_array,
142 BitMap* task_card_bm) {
143 HeapWord* addr = (HeapWord*)obj;
144 if (_nextMarkBitMap->parMark(addr)) {
145 // Update the task specific count data for the object.
146 count_object(obj, hr, marked_bytes_array, task_card_bm);
147 return true;
148 }
149 return false;
150 }
152 // Attempts to mark the given object and, if successful, counts
153 // the object in the task/worker counting structures for the
154 // given worker id.
155 inline bool ConcurrentMark::par_mark_and_count(oop obj,
156 size_t word_size,
157 HeapRegion* hr,
158 uint worker_id) {
159 HeapWord* addr = (HeapWord*)obj;
160 if (_nextMarkBitMap->parMark(addr)) {
161 MemRegion mr(addr, word_size);
162 count_region(mr, hr, worker_id);
163 return true;
164 }
165 return false;
166 }
168 inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) {
169 HeapWord* start_addr = MAX2(startWord(), mr.start());
170 HeapWord* end_addr = MIN2(endWord(), mr.end());
172 if (end_addr > start_addr) {
173 // Right-open interval [start-offset, end-offset).
174 BitMap::idx_t start_offset = heapWordToOffset(start_addr);
175 BitMap::idx_t end_offset = heapWordToOffset(end_addr);
177 start_offset = _bm.get_next_one_offset(start_offset, end_offset);
178 while (start_offset < end_offset) {
179 if (!cl->do_bit(start_offset)) {
180 return false;
181 }
182 HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr);
183 BitMap::idx_t next_offset = heapWordToOffset(next_addr);
184 start_offset = _bm.get_next_one_offset(next_offset, end_offset);
185 }
186 }
187 return true;
188 }
190 inline bool CMBitMapRO::iterate(BitMapClosure* cl) {
191 MemRegion mr(startWord(), sizeInWords());
192 return iterate(cl, mr);
193 }
195 #define check_mark(addr) \
196 assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize), \
197 "outside underlying space?"); \
198 assert(G1CollectedHeap::heap()->is_in_exact(addr), \
199 err_msg("Trying to access not available bitmap "PTR_FORMAT \
200 " corresponding to "PTR_FORMAT" (%u)", \
201 p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr)));
203 inline void CMBitMap::mark(HeapWord* addr) {
204 check_mark(addr);
205 _bm.set_bit(heapWordToOffset(addr));
206 }
208 inline void CMBitMap::clear(HeapWord* addr) {
209 check_mark(addr);
210 _bm.clear_bit(heapWordToOffset(addr));
211 }
213 inline bool CMBitMap::parMark(HeapWord* addr) {
214 check_mark(addr);
215 return _bm.par_set_bit(heapWordToOffset(addr));
216 }
218 inline bool CMBitMap::parClear(HeapWord* addr) {
219 check_mark(addr);
220 return _bm.par_clear_bit(heapWordToOffset(addr));
221 }
223 #undef check_mark
225 inline void CMTask::push(oop obj) {
226 HeapWord* objAddr = (HeapWord*) obj;
227 assert(_g1h->is_in_g1_reserved(objAddr), "invariant");
228 assert(!_g1h->is_on_master_free_list(
229 _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant");
230 assert(!_g1h->is_obj_ill(obj), "invariant");
231 assert(_nextMarkBitMap->isMarked(objAddr), "invariant");
233 if (_cm->verbose_high()) {
234 gclog_or_tty->print_cr("[%u] pushing " PTR_FORMAT, _worker_id, p2i((void*) obj));
235 }
237 if (!_task_queue->push(obj)) {
238 // The local task queue looks full. We need to push some entries
239 // to the global stack.
241 if (_cm->verbose_medium()) {
242 gclog_or_tty->print_cr("[%u] task queue overflow, "
243 "moving entries to the global stack",
244 _worker_id);
245 }
246 move_entries_to_global_stack();
248 // this should succeed since, even if we overflow the global
249 // stack, we should have definitely removed some entries from the
250 // local queue. So, there must be space on it.
251 bool success = _task_queue->push(obj);
252 assert(success, "invariant");
253 }
255 statsOnly( int tmp_size = _task_queue->size();
256 if (tmp_size > _local_max_size) {
257 _local_max_size = tmp_size;
258 }
259 ++_local_pushes );
260 }
262 inline bool CMTask::is_below_finger(oop obj, HeapWord* global_finger) const {
263 // If obj is above the global finger, then the mark bitmap scan
264 // will find it later, and no push is needed. Similarly, if we have
265 // a current region and obj is between the local finger and the
266 // end of the current region, then no push is needed. The tradeoff
267 // of checking both vs only checking the global finger is that the
268 // local check will be more accurate and so result in fewer pushes,
269 // but may also be a little slower.
270 HeapWord* objAddr = (HeapWord*)obj;
271 if (_finger != NULL) {
272 // We have a current region.
274 // Finger and region values are all NULL or all non-NULL. We
275 // use _finger to check since we immediately use its value.
276 assert(_curr_region != NULL, "invariant");
277 assert(_region_limit != NULL, "invariant");
278 assert(_region_limit <= global_finger, "invariant");
280 // True if obj is less than the local finger, or is between
281 // the region limit and the global finger.
282 if (objAddr < _finger) {
283 return true;
284 } else if (objAddr < _region_limit) {
285 return false;
286 } // Else check global finger.
287 }
288 // Check global finger.
289 return objAddr < global_finger;
290 }
292 inline void CMTask::make_reference_grey(oop obj, HeapRegion* hr) {
293 if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) {
295 if (_cm->verbose_high()) {
296 gclog_or_tty->print_cr("[%u] marked object " PTR_FORMAT,
297 _worker_id, p2i(obj));
298 }
300 // No OrderAccess:store_load() is needed. It is implicit in the
301 // CAS done in CMBitMap::parMark() call in the routine above.
302 HeapWord* global_finger = _cm->finger();
304 // We only need to push a newly grey object on the mark
305 // stack if it is in a section of memory the mark bitmap
306 // scan has already examined. Mark bitmap scanning
307 // maintains progress "fingers" for determining that.
308 //
309 // Notice that the global finger might be moving forward
310 // concurrently. This is not a problem. In the worst case, we
311 // mark the object while it is above the global finger and, by
312 // the time we read the global finger, it has moved forward
313 // past this object. In this case, the object will probably
314 // be visited when a task is scanning the region and will also
315 // be pushed on the stack. So, some duplicate work, but no
316 // correctness problems.
317 if (is_below_finger(obj, global_finger)) {
318 if (obj->is_typeArray()) {
319 // Immediately process arrays of primitive types, rather
320 // than pushing on the mark stack. This keeps us from
321 // adding humongous objects to the mark stack that might
322 // be reclaimed before the entry is processed - see
323 // selection of candidates for eager reclaim of humongous
324 // objects. The cost of the additional type test is
325 // mitigated by avoiding a trip through the mark stack,
326 // by only doing a bookkeeping update and avoiding the
327 // actual scan of the object - a typeArray contains no
328 // references, and the metadata is built-in.
329 process_grey_object<false>(obj);
330 } else {
331 if (_cm->verbose_high()) {
332 gclog_or_tty->print_cr("[%u] below a finger (local: " PTR_FORMAT
333 ", global: " PTR_FORMAT ") pushing "
334 PTR_FORMAT " on mark stack",
335 _worker_id, p2i(_finger),
336 p2i(global_finger), p2i(obj));
337 }
338 push(obj);
339 }
340 }
341 }
342 }
344 inline void CMTask::deal_with_reference(oop obj) {
345 if (_cm->verbose_high()) {
346 gclog_or_tty->print_cr("[%u] we're dealing with reference = "PTR_FORMAT,
347 _worker_id, p2i((void*) obj));
348 }
350 increment_refs_reached();
352 HeapWord* objAddr = (HeapWord*) obj;
353 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error");
354 if (_g1h->is_in_g1_reserved(objAddr)) {
355 assert(obj != NULL, "null check is implicit");
356 if (!_nextMarkBitMap->isMarked(objAddr)) {
357 // Only get the containing region if the object is not marked on the
358 // bitmap (otherwise, it's a waste of time since we won't do
359 // anything with it).
360 HeapRegion* hr = _g1h->heap_region_containing_raw(obj);
361 if (!hr->obj_allocated_since_next_marking(obj)) {
362 make_reference_grey(obj, hr);
363 }
364 }
365 }
366 }
368 inline void ConcurrentMark::markPrev(oop p) {
369 assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity");
370 // Note we are overriding the read-only view of the prev map here, via
371 // the cast.
372 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p);
373 }
375 inline void ConcurrentMark::grayRoot(oop obj, size_t word_size,
376 uint worker_id, HeapRegion* hr) {
377 assert(obj != NULL, "pre-condition");
378 HeapWord* addr = (HeapWord*) obj;
379 if (hr == NULL) {
380 hr = _g1h->heap_region_containing_raw(addr);
381 } else {
382 assert(hr->is_in(addr), "pre-condition");
383 }
384 assert(hr != NULL, "sanity");
385 // Given that we're looking for a region that contains an object
386 // header it's impossible to get back a HC region.
387 assert(!hr->continuesHumongous(), "sanity");
389 // We cannot assert that word_size == obj->size() given that obj
390 // might not be in a consistent state (another thread might be in
391 // the process of copying it). So the best thing we can do is to
392 // assert that word_size is under an upper bound which is its
393 // containing region's capacity.
394 assert(word_size * HeapWordSize <= hr->capacity(),
395 err_msg("size: "SIZE_FORMAT" capacity: "SIZE_FORMAT" "HR_FORMAT,
396 word_size * HeapWordSize, hr->capacity(),
397 HR_FORMAT_PARAMS(hr)));
399 if (addr < hr->next_top_at_mark_start()) {
400 if (!_nextMarkBitMap->isMarked(addr)) {
401 par_mark_and_count(obj, word_size, hr, worker_id);
402 }
403 }
404 }
406 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP