52 53 if (TraceBlockOffsetTable) { 54 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: "); 55 gclog_or_tty->print_cr(" " 56 " rs.base(): " PTR_FORMAT 57 " rs.size(): " SIZE_FORMAT 58 " rs end(): " PTR_FORMAT, 59 p2i(bot_reserved.start()), bot_reserved.byte_size(), p2i(bot_reserved.end())); 60 } 61 } 62 63 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { 64 assert(p >= _reserved.start(), "just checking"); 65 size_t delta = pointer_delta(p, _reserved.start()); 66 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; 67 } 68 69 #ifdef ASSERT 70 void G1BlockOffsetSharedArray::check_index(size_t index, const char* msg) const { 71 assert((index) < (_reserved.word_size() >> LogN_words), 72 err_msg("%s - index: " SIZE_FORMAT ", _vs.committed_size: " SIZE_FORMAT, 73 msg, (index), (_reserved.word_size() >> LogN_words))); 74 assert(G1CollectedHeap::heap()->is_in_exact(address_for_index_raw(index)), 75 err_msg("Index " SIZE_FORMAT " corresponding to " PTR_FORMAT 76 " (%u) is not in committed area.", 77 (index), 78 p2i(address_for_index_raw(index)), 79 G1CollectedHeap::heap()->addr_to_region(address_for_index_raw(index)))); 80 } 81 #endif // ASSERT 82 83 ////////////////////////////////////////////////////////////////////// 84 // G1BlockOffsetArray 85 ////////////////////////////////////////////////////////////////////// 86 87 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array, 88 MemRegion mr) : 89 G1BlockOffsetTable(mr.start(), mr.end()), 90 _unallocated_block(_bottom), 91 _array(array), _gsp(NULL) { 92 assert(_bottom <= _end, "arguments out of order"); 93 } 94 95 void G1BlockOffsetArray::set_space(G1OffsetTableContigSpace* sp) { 96 _gsp = sp; 97 } 98 99 // The arguments follow the normal convention of denoting 175 _array->set_offset_array(start_card_for_region, reach, offset); 176 start_card_for_region = reach + 1; 177 } 178 assert(start_card_for_region > end_card, "Sanity check"); 179 DEBUG_ONLY(check_all_cards(start_card, end_card);) 180 } 181 182 // The card-interval [start_card, end_card] is a closed interval; this 183 // is an expensive check -- use with care and only under protection of 184 // suitable flag. 185 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { 186 187 if (end_card < start_card) { 188 return; 189 } 190 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); 191 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { 192 u_char entry = _array->offset_array(c); 193 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) { 194 guarantee(entry > N_words, 195 err_msg("Should be in logarithmic region - " 196 "entry: %u, " 197 "_array->offset_array(c): %u, " 198 "N_words: %u", 199 (uint)entry, (uint)_array->offset_array(c), (uint)N_words)); 200 } 201 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry); 202 size_t landing_card = c - backskip; 203 guarantee(landing_card >= (start_card - 1), "Inv"); 204 if (landing_card >= start_card) { 205 guarantee(_array->offset_array(landing_card) <= entry, 206 err_msg("Monotonicity - landing_card offset: %u, " 207 "entry: %u", 208 (uint)_array->offset_array(landing_card), (uint)entry)); 209 } else { 210 guarantee(landing_card == start_card - 1, "Tautology"); 211 // Note that N_words is the maximum offset value 212 guarantee(_array->offset_array(landing_card) <= N_words, 213 err_msg("landing card offset: %u, " 214 "N_words: %u", 215 (uint)_array->offset_array(landing_card), (uint)N_words)); 216 } 217 } 218 } 219 220 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) { 221 assert(_bottom <= addr && addr < _end, 222 "addr must be covered by this Array"); 223 // Must read this exactly once because it can be modified by parallel 224 // allocation. 225 HeapWord* ub = _unallocated_block; 226 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { 227 assert(ub < _end, "tautology (see above)"); 228 return ub; 229 } 230 // Otherwise, find the block start using the table. 231 HeapWord* q = block_at_or_preceding(addr, false, 0); 232 return forward_to_block_containing_addr(q, addr); 233 } 234 235 // This duplicates a little code from the above: unavoidable. 254 HeapWord* 255 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q, 256 HeapWord* n, 257 const void* addr) { 258 // We're not in the normal case. We need to handle an important subcase 259 // here: LAB allocation. An allocation previously recorded in the 260 // offset table was actually a lab allocation, and was divided into 261 // several objects subsequently. Fix this situation as we answer the 262 // query, by updating entries as we cross them. 263 264 // If the fist object's end q is at the card boundary. Start refining 265 // with the corresponding card (the value of the entry will be basically 266 // set to 0). If the object crosses the boundary -- start from the next card. 267 size_t n_index = _array->index_for(n); 268 size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n); 269 // Calculate a consistent next boundary. If "n" is not at the boundary 270 // already, step to the boundary. 271 HeapWord* next_boundary = _array->address_for_index(n_index) + 272 (n_index == next_index ? 0 : N_words); 273 assert(next_boundary <= _array->_end, 274 err_msg("next_boundary is beyond the end of the covered region " 275 " next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT, 276 p2i(next_boundary), p2i(_array->_end))); 277 if (addr >= gsp()->top()) return gsp()->top(); 278 while (next_boundary < addr) { 279 while (n <= next_boundary) { 280 q = n; 281 oop obj = oop(q); 282 if (obj->klass_or_null() == NULL) return q; 283 n += block_size(q); 284 } 285 assert(q <= next_boundary && n > next_boundary, "Consequence of loop"); 286 // [q, n) is the block that crosses the boundary. 287 alloc_block_work2(&next_boundary, &next_index, q, n); 288 } 289 return forward_to_block_containing_addr_const(q, n, addr); 290 } 291 292 // Note that the committed size of the covered space may have changed, 293 // so the table size might also wish to change. 294 void G1BlockOffsetArray::resize(size_t new_word_size) { 295 HeapWord* new_end = _bottom + new_word_size; 296 _end = new_end; // update _end 348 349 index = end_index + 1; 350 // Calculate threshold_ this way because end_index 351 // may be the last valid index in the covered region. 352 threshold = _array->address_for_index(end_index) + N_words; 353 assert(threshold >= blk_end, "Incorrect offset threshold"); 354 355 // index_ and threshold_ updated here. 356 *threshold_ = threshold; 357 *index_ = index; 358 359 #ifdef ASSERT 360 // The offset can be 0 if the block starts on a boundary. That 361 // is checked by an assertion above. 362 size_t start_index = _array->index_for(blk_start); 363 HeapWord* boundary = _array->address_for_index(start_index); 364 assert((_array->offset_array(orig_index) == 0 && 365 blk_start == boundary) || 366 (_array->offset_array(orig_index) > 0 && 367 _array->offset_array(orig_index) <= N_words), 368 err_msg("offset array should have been set - " 369 "orig_index offset: %u, " 370 "blk_start: " PTR_FORMAT ", " 371 "boundary: " PTR_FORMAT, 372 (uint)_array->offset_array(orig_index), 373 p2i(blk_start), p2i(boundary))); 374 for (size_t j = orig_index + 1; j <= end_index; j++) { 375 assert(_array->offset_array(j) > 0 && 376 _array->offset_array(j) <= 377 (u_char) (N_words+BlockOffsetArray::N_powers-1), 378 err_msg("offset array should have been set - " 379 "%u not > 0 OR %u not <= %u", 380 (uint) _array->offset_array(j), 381 (uint) _array->offset_array(j), 382 (uint) (N_words+BlockOffsetArray::N_powers-1))); 383 } 384 #endif 385 } 386 387 void G1BlockOffsetArray::verify() const { 388 assert(gsp()->bottom() < gsp()->top(), "Only non-empty regions should be verified."); 389 size_t start_card = _array->index_for(gsp()->bottom()); 390 size_t end_card = _array->index_for(gsp()->top() - 1); 391 392 for (size_t current_card = start_card; current_card < end_card; current_card++) { 393 u_char entry = _array->offset_array(current_card); 394 if (entry < N_words) { 395 // The entry should point to an object before the current card. Verify that 396 // it is possible to walk from that object in to the current card by just 397 // iterating over the objects following it. 398 HeapWord* card_address = _array->address_for_index(current_card); 399 HeapWord* obj_end = card_address - entry; 400 while (obj_end < card_address) { 401 HeapWord* obj = obj_end; 402 size_t obj_size = block_size(obj); 403 obj_end = obj + obj_size; 404 guarantee(obj_end > obj && obj_end <= gsp()->top(), 405 err_msg("Invalid object end. obj: " PTR_FORMAT " obj_size: " SIZE_FORMAT " obj_end: " PTR_FORMAT " top: " PTR_FORMAT, 406 p2i(obj), obj_size, p2i(obj_end), p2i(gsp()->top()))); 407 } 408 } else { 409 // Because we refine the BOT based on which cards are dirty there is not much we can verify here. 410 // We need to make sure that we are going backwards and that we don't pass the start of the 411 // corresponding heap region. But that is about all we can verify. 412 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry); 413 guarantee(backskip >= 1, "Must be going back at least one card."); 414 415 size_t max_backskip = current_card - start_card; 416 guarantee(backskip <= max_backskip, 417 err_msg("Going backwards beyond the start_card. start_card: " SIZE_FORMAT " current_card: " SIZE_FORMAT " backskip: " SIZE_FORMAT, 418 start_card, current_card, backskip)); 419 420 HeapWord* backskip_address = _array->address_for_index(current_card - backskip); 421 guarantee(backskip_address >= gsp()->bottom(), 422 err_msg("Going backwards beyond bottom of the region: bottom: " PTR_FORMAT ", backskip_address: " PTR_FORMAT, 423 p2i(gsp()->bottom()), p2i(backskip_address))); 424 } 425 } 426 } 427 428 #ifndef PRODUCT 429 void 430 G1BlockOffsetArray::print_on(outputStream* out) { 431 size_t from_index = _array->index_for(_bottom); 432 size_t to_index = _array->index_for(_end); 433 out->print_cr(">> BOT for area [" PTR_FORMAT "," PTR_FORMAT ") " 434 "cards [" SIZE_FORMAT "," SIZE_FORMAT ")", 435 p2i(_bottom), p2i(_end), from_index, to_index); 436 for (size_t i = from_index; i < to_index; ++i) { 437 out->print_cr(" entry " SIZE_FORMAT_W(8) " | " PTR_FORMAT " : %3u", 438 i, p2i(_array->address_for_index(i)), 439 (uint) _array->offset_array(i)); 440 } 441 } 442 #endif // !PRODUCT 443 | 52 53 if (TraceBlockOffsetTable) { 54 gclog_or_tty->print_cr("G1BlockOffsetSharedArray::G1BlockOffsetSharedArray: "); 55 gclog_or_tty->print_cr(" " 56 " rs.base(): " PTR_FORMAT 57 " rs.size(): " SIZE_FORMAT 58 " rs end(): " PTR_FORMAT, 59 p2i(bot_reserved.start()), bot_reserved.byte_size(), p2i(bot_reserved.end())); 60 } 61 } 62 63 bool G1BlockOffsetSharedArray::is_card_boundary(HeapWord* p) const { 64 assert(p >= _reserved.start(), "just checking"); 65 size_t delta = pointer_delta(p, _reserved.start()); 66 return (delta & right_n_bits(LogN_words)) == (size_t)NoBits; 67 } 68 69 #ifdef ASSERT 70 void G1BlockOffsetSharedArray::check_index(size_t index, const char* msg) const { 71 assert((index) < (_reserved.word_size() >> LogN_words), 72 "%s - index: " SIZE_FORMAT ", _vs.committed_size: " SIZE_FORMAT, 73 msg, (index), (_reserved.word_size() >> LogN_words)); 74 assert(G1CollectedHeap::heap()->is_in_exact(address_for_index_raw(index)), 75 "Index " SIZE_FORMAT " corresponding to " PTR_FORMAT 76 " (%u) is not in committed area.", 77 (index), 78 p2i(address_for_index_raw(index)), 79 G1CollectedHeap::heap()->addr_to_region(address_for_index_raw(index))); 80 } 81 #endif // ASSERT 82 83 ////////////////////////////////////////////////////////////////////// 84 // G1BlockOffsetArray 85 ////////////////////////////////////////////////////////////////////// 86 87 G1BlockOffsetArray::G1BlockOffsetArray(G1BlockOffsetSharedArray* array, 88 MemRegion mr) : 89 G1BlockOffsetTable(mr.start(), mr.end()), 90 _unallocated_block(_bottom), 91 _array(array), _gsp(NULL) { 92 assert(_bottom <= _end, "arguments out of order"); 93 } 94 95 void G1BlockOffsetArray::set_space(G1OffsetTableContigSpace* sp) { 96 _gsp = sp; 97 } 98 99 // The arguments follow the normal convention of denoting 175 _array->set_offset_array(start_card_for_region, reach, offset); 176 start_card_for_region = reach + 1; 177 } 178 assert(start_card_for_region > end_card, "Sanity check"); 179 DEBUG_ONLY(check_all_cards(start_card, end_card);) 180 } 181 182 // The card-interval [start_card, end_card] is a closed interval; this 183 // is an expensive check -- use with care and only under protection of 184 // suitable flag. 185 void G1BlockOffsetArray::check_all_cards(size_t start_card, size_t end_card) const { 186 187 if (end_card < start_card) { 188 return; 189 } 190 guarantee(_array->offset_array(start_card) == N_words, "Wrong value in second card"); 191 for (size_t c = start_card + 1; c <= end_card; c++ /* yeah! */) { 192 u_char entry = _array->offset_array(c); 193 if (c - start_card > BlockOffsetArray::power_to_cards_back(1)) { 194 guarantee(entry > N_words, 195 "Should be in logarithmic region - " 196 "entry: %u, " 197 "_array->offset_array(c): %u, " 198 "N_words: %u", 199 (uint)entry, (uint)_array->offset_array(c), (uint)N_words); 200 } 201 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry); 202 size_t landing_card = c - backskip; 203 guarantee(landing_card >= (start_card - 1), "Inv"); 204 if (landing_card >= start_card) { 205 guarantee(_array->offset_array(landing_card) <= entry, 206 "Monotonicity - landing_card offset: %u, " 207 "entry: %u", 208 (uint)_array->offset_array(landing_card), (uint)entry); 209 } else { 210 guarantee(landing_card == start_card - 1, "Tautology"); 211 // Note that N_words is the maximum offset value 212 guarantee(_array->offset_array(landing_card) <= N_words, 213 "landing card offset: %u, " 214 "N_words: %u", 215 (uint)_array->offset_array(landing_card), (uint)N_words); 216 } 217 } 218 } 219 220 HeapWord* G1BlockOffsetArray::block_start_unsafe(const void* addr) { 221 assert(_bottom <= addr && addr < _end, 222 "addr must be covered by this Array"); 223 // Must read this exactly once because it can be modified by parallel 224 // allocation. 225 HeapWord* ub = _unallocated_block; 226 if (BlockOffsetArrayUseUnallocatedBlock && addr >= ub) { 227 assert(ub < _end, "tautology (see above)"); 228 return ub; 229 } 230 // Otherwise, find the block start using the table. 231 HeapWord* q = block_at_or_preceding(addr, false, 0); 232 return forward_to_block_containing_addr(q, addr); 233 } 234 235 // This duplicates a little code from the above: unavoidable. 254 HeapWord* 255 G1BlockOffsetArray::forward_to_block_containing_addr_slow(HeapWord* q, 256 HeapWord* n, 257 const void* addr) { 258 // We're not in the normal case. We need to handle an important subcase 259 // here: LAB allocation. An allocation previously recorded in the 260 // offset table was actually a lab allocation, and was divided into 261 // several objects subsequently. Fix this situation as we answer the 262 // query, by updating entries as we cross them. 263 264 // If the fist object's end q is at the card boundary. Start refining 265 // with the corresponding card (the value of the entry will be basically 266 // set to 0). If the object crosses the boundary -- start from the next card. 267 size_t n_index = _array->index_for(n); 268 size_t next_index = _array->index_for(n) + !_array->is_card_boundary(n); 269 // Calculate a consistent next boundary. If "n" is not at the boundary 270 // already, step to the boundary. 271 HeapWord* next_boundary = _array->address_for_index(n_index) + 272 (n_index == next_index ? 0 : N_words); 273 assert(next_boundary <= _array->_end, 274 "next_boundary is beyond the end of the covered region " 275 " next_boundary " PTR_FORMAT " _array->_end " PTR_FORMAT, 276 p2i(next_boundary), p2i(_array->_end)); 277 if (addr >= gsp()->top()) return gsp()->top(); 278 while (next_boundary < addr) { 279 while (n <= next_boundary) { 280 q = n; 281 oop obj = oop(q); 282 if (obj->klass_or_null() == NULL) return q; 283 n += block_size(q); 284 } 285 assert(q <= next_boundary && n > next_boundary, "Consequence of loop"); 286 // [q, n) is the block that crosses the boundary. 287 alloc_block_work2(&next_boundary, &next_index, q, n); 288 } 289 return forward_to_block_containing_addr_const(q, n, addr); 290 } 291 292 // Note that the committed size of the covered space may have changed, 293 // so the table size might also wish to change. 294 void G1BlockOffsetArray::resize(size_t new_word_size) { 295 HeapWord* new_end = _bottom + new_word_size; 296 _end = new_end; // update _end 348 349 index = end_index + 1; 350 // Calculate threshold_ this way because end_index 351 // may be the last valid index in the covered region. 352 threshold = _array->address_for_index(end_index) + N_words; 353 assert(threshold >= blk_end, "Incorrect offset threshold"); 354 355 // index_ and threshold_ updated here. 356 *threshold_ = threshold; 357 *index_ = index; 358 359 #ifdef ASSERT 360 // The offset can be 0 if the block starts on a boundary. That 361 // is checked by an assertion above. 362 size_t start_index = _array->index_for(blk_start); 363 HeapWord* boundary = _array->address_for_index(start_index); 364 assert((_array->offset_array(orig_index) == 0 && 365 blk_start == boundary) || 366 (_array->offset_array(orig_index) > 0 && 367 _array->offset_array(orig_index) <= N_words), 368 "offset array should have been set - " 369 "orig_index offset: %u, " 370 "blk_start: " PTR_FORMAT ", " 371 "boundary: " PTR_FORMAT, 372 (uint)_array->offset_array(orig_index), 373 p2i(blk_start), p2i(boundary)); 374 for (size_t j = orig_index + 1; j <= end_index; j++) { 375 assert(_array->offset_array(j) > 0 && 376 _array->offset_array(j) <= 377 (u_char) (N_words+BlockOffsetArray::N_powers-1), 378 "offset array should have been set - " 379 "%u not > 0 OR %u not <= %u", 380 (uint) _array->offset_array(j), 381 (uint) _array->offset_array(j), 382 (uint) (N_words+BlockOffsetArray::N_powers-1)); 383 } 384 #endif 385 } 386 387 void G1BlockOffsetArray::verify() const { 388 assert(gsp()->bottom() < gsp()->top(), "Only non-empty regions should be verified."); 389 size_t start_card = _array->index_for(gsp()->bottom()); 390 size_t end_card = _array->index_for(gsp()->top() - 1); 391 392 for (size_t current_card = start_card; current_card < end_card; current_card++) { 393 u_char entry = _array->offset_array(current_card); 394 if (entry < N_words) { 395 // The entry should point to an object before the current card. Verify that 396 // it is possible to walk from that object in to the current card by just 397 // iterating over the objects following it. 398 HeapWord* card_address = _array->address_for_index(current_card); 399 HeapWord* obj_end = card_address - entry; 400 while (obj_end < card_address) { 401 HeapWord* obj = obj_end; 402 size_t obj_size = block_size(obj); 403 obj_end = obj + obj_size; 404 guarantee(obj_end > obj && obj_end <= gsp()->top(), 405 "Invalid object end. obj: " PTR_FORMAT " obj_size: " SIZE_FORMAT " obj_end: " PTR_FORMAT " top: " PTR_FORMAT, 406 p2i(obj), obj_size, p2i(obj_end), p2i(gsp()->top())); 407 } 408 } else { 409 // Because we refine the BOT based on which cards are dirty there is not much we can verify here. 410 // We need to make sure that we are going backwards and that we don't pass the start of the 411 // corresponding heap region. But that is about all we can verify. 412 size_t backskip = BlockOffsetArray::entry_to_cards_back(entry); 413 guarantee(backskip >= 1, "Must be going back at least one card."); 414 415 size_t max_backskip = current_card - start_card; 416 guarantee(backskip <= max_backskip, 417 "Going backwards beyond the start_card. start_card: " SIZE_FORMAT " current_card: " SIZE_FORMAT " backskip: " SIZE_FORMAT, 418 start_card, current_card, backskip); 419 420 HeapWord* backskip_address = _array->address_for_index(current_card - backskip); 421 guarantee(backskip_address >= gsp()->bottom(), 422 "Going backwards beyond bottom of the region: bottom: " PTR_FORMAT ", backskip_address: " PTR_FORMAT, 423 p2i(gsp()->bottom()), p2i(backskip_address)); 424 } 425 } 426 } 427 428 #ifndef PRODUCT 429 void 430 G1BlockOffsetArray::print_on(outputStream* out) { 431 size_t from_index = _array->index_for(_bottom); 432 size_t to_index = _array->index_for(_end); 433 out->print_cr(">> BOT for area [" PTR_FORMAT "," PTR_FORMAT ") " 434 "cards [" SIZE_FORMAT "," SIZE_FORMAT ")", 435 p2i(_bottom), p2i(_end), from_index, to_index); 436 for (size_t i = from_index; i < to_index; ++i) { 437 out->print_cr(" entry " SIZE_FORMAT_W(8) " | " PTR_FORMAT " : %3u", 438 i, p2i(_array->address_for_index(i)), 439 (uint) _array->offset_array(i)); 440 } 441 } 442 #endif // !PRODUCT 443 |