| /* |
| * Copyright (c) 2007 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| * |
| */ |
| |
| # include "incls/_precompiled.incl" |
| # include "incls/_parCardTableModRefBS.cpp.incl" |
| |
| void CardTableModRefBS::par_non_clean_card_iterate_work(Space* sp, MemRegion mr, |
| DirtyCardToOopClosure* dcto_cl, |
| MemRegionClosure* cl, |
| bool clear, |
| int n_threads) { |
| if (n_threads > 0) { |
| assert(n_threads == (int)ParallelGCThreads, "# worker threads != # requested!"); |
| |
| // Make sure the LNC array is valid for the space. |
| jbyte** lowest_non_clean; |
| uintptr_t lowest_non_clean_base_chunk_index; |
| size_t lowest_non_clean_chunk_size; |
| get_LNC_array_for_space(sp, lowest_non_clean, |
| lowest_non_clean_base_chunk_index, |
| lowest_non_clean_chunk_size); |
| |
| int n_strides = n_threads * StridesPerThread; |
| SequentialSubTasksDone* pst = sp->par_seq_tasks(); |
| pst->set_par_threads(n_threads); |
| pst->set_n_tasks(n_strides); |
| |
| int stride = 0; |
| while (!pst->is_task_claimed(/* reference */ stride)) { |
| process_stride(sp, mr, stride, n_strides, dcto_cl, cl, clear, |
| lowest_non_clean, |
| lowest_non_clean_base_chunk_index, |
| lowest_non_clean_chunk_size); |
| } |
| if (pst->all_tasks_completed()) { |
| // Clear lowest_non_clean array for next time. |
| intptr_t first_chunk_index = addr_to_chunk_index(mr.start()); |
| uintptr_t last_chunk_index = addr_to_chunk_index(mr.last()); |
| for (uintptr_t ch = first_chunk_index; ch <= last_chunk_index; ch++) { |
| intptr_t ind = ch - lowest_non_clean_base_chunk_index; |
| assert(0 <= ind && ind < (intptr_t)lowest_non_clean_chunk_size, |
| "Bounds error"); |
| lowest_non_clean[ind] = NULL; |
| } |
| } |
| } |
| } |
| |
| void |
| CardTableModRefBS:: |
| process_stride(Space* sp, |
| MemRegion used, |
| jint stride, int n_strides, |
| DirtyCardToOopClosure* dcto_cl, |
| MemRegionClosure* cl, |
| bool clear, |
| jbyte** lowest_non_clean, |
| uintptr_t lowest_non_clean_base_chunk_index, |
| size_t lowest_non_clean_chunk_size) { |
| // We don't have to go downwards here; it wouldn't help anyway, |
| // because of parallelism. |
| |
| // Find the first card address of the first chunk in the stride that is |
| // at least "bottom" of the used region. |
| jbyte* start_card = byte_for(used.start()); |
| jbyte* end_card = byte_after(used.last()); |
| uintptr_t start_chunk = addr_to_chunk_index(used.start()); |
| uintptr_t start_chunk_stride_num = start_chunk % n_strides; |
| jbyte* chunk_card_start; |
| |
| if ((uintptr_t)stride >= start_chunk_stride_num) { |
| chunk_card_start = (jbyte*)(start_card + |
| (stride - start_chunk_stride_num) * |
| CardsPerStrideChunk); |
| } else { |
| // Go ahead to the next chunk group boundary, then to the requested stride. |
| chunk_card_start = (jbyte*)(start_card + |
| (n_strides - start_chunk_stride_num + stride) * |
| CardsPerStrideChunk); |
| } |
| |
| while (chunk_card_start < end_card) { |
| // We don't have to go downwards here; it wouldn't help anyway, |
| // because of parallelism. (We take care with "min_done"; see below.) |
| // Invariant: chunk_mr should be fully contained within the "used" region. |
| jbyte* chunk_card_end = chunk_card_start + CardsPerStrideChunk; |
| MemRegion chunk_mr = MemRegion(addr_for(chunk_card_start), |
| chunk_card_end >= end_card ? |
| used.end() : addr_for(chunk_card_end)); |
| assert(chunk_mr.word_size() > 0, "[chunk_card_start > used_end)"); |
| assert(used.contains(chunk_mr), "chunk_mr should be subset of used"); |
| |
| // Process the chunk. |
| process_chunk_boundaries(sp, |
| dcto_cl, |
| chunk_mr, |
| used, |
| lowest_non_clean, |
| lowest_non_clean_base_chunk_index, |
| lowest_non_clean_chunk_size); |
| |
| non_clean_card_iterate_work(chunk_mr, cl, clear); |
| |
| // Find the next chunk of the stride. |
| chunk_card_start += CardsPerStrideChunk * n_strides; |
| } |
| } |
| |
| void |
| CardTableModRefBS:: |
| process_chunk_boundaries(Space* sp, |
| DirtyCardToOopClosure* dcto_cl, |
| MemRegion chunk_mr, |
| MemRegion used, |
| jbyte** lowest_non_clean, |
| uintptr_t lowest_non_clean_base_chunk_index, |
| size_t lowest_non_clean_chunk_size) |
| { |
| // We must worry about the chunk boundaries. |
| |
| // First, set our max_to_do: |
| HeapWord* max_to_do = NULL; |
| uintptr_t cur_chunk_index = addr_to_chunk_index(chunk_mr.start()); |
| cur_chunk_index = cur_chunk_index - lowest_non_clean_base_chunk_index; |
| |
| if (chunk_mr.end() < used.end()) { |
| // This is not the last chunk in the used region. What is the last |
| // object? |
| HeapWord* last_block = sp->block_start(chunk_mr.end()); |
| assert(last_block <= chunk_mr.end(), "In case this property changes."); |
| if (last_block == chunk_mr.end() |
| || !sp->block_is_obj(last_block)) { |
| max_to_do = chunk_mr.end(); |
| |
| } else { |
| // It is an object and starts before the end of the current chunk. |
| // last_obj_card is the card corresponding to the start of the last object |
| // in the chunk. Note that the last object may not start in |
| // the chunk. |
| jbyte* last_obj_card = byte_for(last_block); |
| if (!card_may_have_been_dirty(*last_obj_card)) { |
| // The card containing the head is not dirty. Any marks in |
| // subsequent cards still in this chunk must have been made |
| // precisely; we can cap processing at the end. |
| max_to_do = chunk_mr.end(); |
| } else { |
| // The last object must be considered dirty, and extends onto the |
| // following chunk. Look for a dirty card in that chunk that will |
| // bound our processing. |
| jbyte* limit_card = NULL; |
| size_t last_block_size = sp->block_size(last_block); |
| jbyte* last_card_of_last_obj = |
| byte_for(last_block + last_block_size - 1); |
| jbyte* first_card_of_next_chunk = byte_for(chunk_mr.end()); |
| // This search potentially goes a long distance looking |
| // for the next card that will be scanned. For example, |
| // an object that is an array of primitives will not |
| // have any cards covering regions interior to the array |
| // that will need to be scanned. The scan can be terminated |
| // at the last card of the next chunk. That would leave |
| // limit_card as NULL and would result in "max_to_do" |
| // being set with the LNC value or with the end |
| // of the last block. |
| jbyte* last_card_of_next_chunk = first_card_of_next_chunk + |
| CardsPerStrideChunk; |
| assert(byte_for(chunk_mr.end()) - byte_for(chunk_mr.start()) |
| == CardsPerStrideChunk, "last card of next chunk may be wrong"); |
| jbyte* last_card_to_check = (jbyte*) MIN2(last_card_of_last_obj, |
| last_card_of_next_chunk); |
| for (jbyte* cur = first_card_of_next_chunk; |
| cur <= last_card_to_check; cur++) { |
| if (card_will_be_scanned(*cur)) { |
| limit_card = cur; break; |
| } |
| } |
| assert(0 <= cur_chunk_index+1 && |
| cur_chunk_index+1 < lowest_non_clean_chunk_size, |
| "Bounds error."); |
| // LNC for the next chunk |
| jbyte* lnc_card = lowest_non_clean[cur_chunk_index+1]; |
| if (limit_card == NULL) { |
| limit_card = lnc_card; |
| } |
| if (limit_card != NULL) { |
| if (lnc_card != NULL) { |
| limit_card = (jbyte*)MIN2((intptr_t)limit_card, |
| (intptr_t)lnc_card); |
| } |
| max_to_do = addr_for(limit_card); |
| } else { |
| max_to_do = last_block + last_block_size; |
| } |
| } |
| } |
| assert(max_to_do != NULL, "OOPS!"); |
| } else { |
| max_to_do = used.end(); |
| } |
| // Now we can set the closure we're using so it doesn't to beyond |
| // max_to_do. |
| dcto_cl->set_min_done(max_to_do); |
| #ifndef PRODUCT |
| dcto_cl->set_last_bottom(max_to_do); |
| #endif |
| |
| // Now we set *our" lowest_non_clean entry. |
| // Find the object that spans our boundary, if one exists. |
| // Nothing to do on the first chunk. |
| if (chunk_mr.start() > used.start()) { |
| // first_block is the block possibly spanning the chunk start |
| HeapWord* first_block = sp->block_start(chunk_mr.start()); |
| // Does the block span the start of the chunk and is it |
| // an object? |
| if (first_block < chunk_mr.start() && |
| sp->block_is_obj(first_block)) { |
| jbyte* first_dirty_card = NULL; |
| jbyte* last_card_of_first_obj = |
| byte_for(first_block + sp->block_size(first_block) - 1); |
| jbyte* first_card_of_cur_chunk = byte_for(chunk_mr.start()); |
| jbyte* last_card_of_cur_chunk = byte_for(chunk_mr.last()); |
| jbyte* last_card_to_check = |
| (jbyte*) MIN2((intptr_t) last_card_of_cur_chunk, |
| (intptr_t) last_card_of_first_obj); |
| for (jbyte* cur = first_card_of_cur_chunk; |
| cur <= last_card_to_check; cur++) { |
| if (card_will_be_scanned(*cur)) { |
| first_dirty_card = cur; break; |
| } |
| } |
| if (first_dirty_card != NULL) { |
| assert(0 <= cur_chunk_index && |
| cur_chunk_index < lowest_non_clean_chunk_size, |
| "Bounds error."); |
| lowest_non_clean[cur_chunk_index] = first_dirty_card; |
| } |
| } |
| } |
| } |
| |
| void |
| CardTableModRefBS:: |
| get_LNC_array_for_space(Space* sp, |
| jbyte**& lowest_non_clean, |
| uintptr_t& lowest_non_clean_base_chunk_index, |
| size_t& lowest_non_clean_chunk_size) { |
| |
| int i = find_covering_region_containing(sp->bottom()); |
| MemRegion covered = _covered[i]; |
| size_t n_chunks = chunks_to_cover(covered); |
| |
| // Only the first thread to obtain the lock will resize the |
| // LNC array for the covered region. Any later expansion can't affect |
| // the used_at_save_marks region. |
| // (I observed a bug in which the first thread to execute this would |
| // resize, and then it would cause "expand_and_allocates" that would |
| // Increase the number of chunks in the covered region. Then a second |
| // thread would come and execute this, see that the size didn't match, |
| // and free and allocate again. So the first thread would be using a |
| // freed "_lowest_non_clean" array.) |
| |
| // Do a dirty read here. If we pass the conditional then take the rare |
| // event lock and do the read again in case some other thread had already |
| // succeeded and done the resize. |
| int cur_collection = Universe::heap()->total_collections(); |
| if (_last_LNC_resizing_collection[i] != cur_collection) { |
| MutexLocker x(ParGCRareEvent_lock); |
| if (_last_LNC_resizing_collection[i] != cur_collection) { |
| if (_lowest_non_clean[i] == NULL || |
| n_chunks != _lowest_non_clean_chunk_size[i]) { |
| |
| // Should we delete the old? |
| if (_lowest_non_clean[i] != NULL) { |
| assert(n_chunks != _lowest_non_clean_chunk_size[i], |
| "logical consequence"); |
| FREE_C_HEAP_ARRAY(CardPtr, _lowest_non_clean[i]); |
| _lowest_non_clean[i] = NULL; |
| } |
| // Now allocate a new one if necessary. |
| if (_lowest_non_clean[i] == NULL) { |
| _lowest_non_clean[i] = NEW_C_HEAP_ARRAY(CardPtr, n_chunks); |
| _lowest_non_clean_chunk_size[i] = n_chunks; |
| _lowest_non_clean_base_chunk_index[i] = addr_to_chunk_index(covered.start()); |
| for (int j = 0; j < (int)n_chunks; j++) |
| _lowest_non_clean[i][j] = NULL; |
| } |
| } |
| _last_LNC_resizing_collection[i] = cur_collection; |
| } |
| } |
| // In any case, now do the initialization. |
| lowest_non_clean = _lowest_non_clean[i]; |
| lowest_non_clean_base_chunk_index = _lowest_non_clean_base_chunk_index[i]; |
| lowest_non_clean_chunk_size = _lowest_non_clean_chunk_size[i]; |
| } |
