| /* |
| * Copyright (c) 2005, 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| #include "aot/aotLoader.hpp" |
| #include "classfile/stringTable.hpp" |
| #include "classfile/symbolTable.hpp" |
| #include "classfile/systemDictionary.hpp" |
| #include "code/codeCache.hpp" |
| #include "gc/parallel/gcTaskManager.hpp" |
| #include "gc/parallel/parallelScavengeHeap.inline.hpp" |
| #include "gc/parallel/parMarkBitMap.inline.hpp" |
| #include "gc/parallel/pcTasks.hpp" |
| #include "gc/parallel/psAdaptiveSizePolicy.hpp" |
| #include "gc/parallel/psCompactionManager.inline.hpp" |
| #include "gc/parallel/psMarkSweep.hpp" |
| #include "gc/parallel/psMarkSweepDecorator.hpp" |
| #include "gc/parallel/psOldGen.hpp" |
| #include "gc/parallel/psParallelCompact.inline.hpp" |
| #include "gc/parallel/psPromotionManager.inline.hpp" |
| #include "gc/parallel/psScavenge.hpp" |
| #include "gc/parallel/psYoungGen.hpp" |
| #include "gc/shared/gcCause.hpp" |
| #include "gc/shared/gcHeapSummary.hpp" |
| #include "gc/shared/gcId.hpp" |
| #include "gc/shared/gcLocker.inline.hpp" |
| #include "gc/shared/gcTimer.hpp" |
| #include "gc/shared/gcTrace.hpp" |
| #include "gc/shared/gcTraceTime.inline.hpp" |
| #include "gc/shared/isGCActiveMark.hpp" |
| #include "gc/shared/referencePolicy.hpp" |
| #include "gc/shared/referenceProcessor.hpp" |
| #include "gc/shared/spaceDecorator.hpp" |
| #include "logging/log.hpp" |
| #include "memory/resourceArea.hpp" |
| #include "oops/instanceKlass.inline.hpp" |
| #include "oops/instanceMirrorKlass.inline.hpp" |
| #include "oops/methodData.hpp" |
| #include "oops/objArrayKlass.inline.hpp" |
| #include "oops/oop.inline.hpp" |
| #include "runtime/atomic.hpp" |
| #include "runtime/safepoint.hpp" |
| #include "runtime/vmThread.hpp" |
| #include "services/management.hpp" |
| #include "services/memTracker.hpp" |
| #include "services/memoryService.hpp" |
| #include "utilities/align.hpp" |
| #include "utilities/debug.hpp" |
| #include "utilities/events.hpp" |
| #include "utilities/formatBuffer.hpp" |
| #include "utilities/stack.inline.hpp" |
| |
| #include <math.h> |
| |
| // All sizes are in HeapWords. |
| const size_t ParallelCompactData::Log2RegionSize = 16; // 64K words |
| const size_t ParallelCompactData::RegionSize = (size_t)1 << Log2RegionSize; |
| const size_t ParallelCompactData::RegionSizeBytes = |
| RegionSize << LogHeapWordSize; |
| const size_t ParallelCompactData::RegionSizeOffsetMask = RegionSize - 1; |
| const size_t ParallelCompactData::RegionAddrOffsetMask = RegionSizeBytes - 1; |
| const size_t ParallelCompactData::RegionAddrMask = ~RegionAddrOffsetMask; |
| |
| const size_t ParallelCompactData::Log2BlockSize = 7; // 128 words |
| const size_t ParallelCompactData::BlockSize = (size_t)1 << Log2BlockSize; |
| const size_t ParallelCompactData::BlockSizeBytes = |
| BlockSize << LogHeapWordSize; |
| const size_t ParallelCompactData::BlockSizeOffsetMask = BlockSize - 1; |
| const size_t ParallelCompactData::BlockAddrOffsetMask = BlockSizeBytes - 1; |
| const size_t ParallelCompactData::BlockAddrMask = ~BlockAddrOffsetMask; |
| |
| const size_t ParallelCompactData::BlocksPerRegion = RegionSize / BlockSize; |
| const size_t ParallelCompactData::Log2BlocksPerRegion = |
| Log2RegionSize - Log2BlockSize; |
| |
| const ParallelCompactData::RegionData::region_sz_t |
| ParallelCompactData::RegionData::dc_shift = 27; |
| |
| const ParallelCompactData::RegionData::region_sz_t |
| ParallelCompactData::RegionData::dc_mask = ~0U << dc_shift; |
| |
| const ParallelCompactData::RegionData::region_sz_t |
| ParallelCompactData::RegionData::dc_one = 0x1U << dc_shift; |
| |
| const ParallelCompactData::RegionData::region_sz_t |
| ParallelCompactData::RegionData::los_mask = ~dc_mask; |
| |
| const ParallelCompactData::RegionData::region_sz_t |
| ParallelCompactData::RegionData::dc_claimed = 0x8U << dc_shift; |
| |
| const ParallelCompactData::RegionData::region_sz_t |
| ParallelCompactData::RegionData::dc_completed = 0xcU << dc_shift; |
| |
| SpaceInfo PSParallelCompact::_space_info[PSParallelCompact::last_space_id]; |
| |
| ReferenceProcessor* PSParallelCompact::_ref_processor = NULL; |
| |
| double PSParallelCompact::_dwl_mean; |
| double PSParallelCompact::_dwl_std_dev; |
| double PSParallelCompact::_dwl_first_term; |
| double PSParallelCompact::_dwl_adjustment; |
| #ifdef ASSERT |
| bool PSParallelCompact::_dwl_initialized = false; |
| #endif // #ifdef ASSERT |
| |
| void SplitInfo::record(size_t src_region_idx, size_t partial_obj_size, |
| HeapWord* destination) |
| { |
| assert(src_region_idx != 0, "invalid src_region_idx"); |
| assert(partial_obj_size != 0, "invalid partial_obj_size argument"); |
| assert(destination != NULL, "invalid destination argument"); |
| |
| _src_region_idx = src_region_idx; |
| _partial_obj_size = partial_obj_size; |
| _destination = destination; |
| |
| // These fields may not be updated below, so make sure they're clear. |
| assert(_dest_region_addr == NULL, "should have been cleared"); |
| assert(_first_src_addr == NULL, "should have been cleared"); |
| |
| // Determine the number of destination regions for the partial object. |
| HeapWord* const last_word = destination + partial_obj_size - 1; |
| const ParallelCompactData& sd = PSParallelCompact::summary_data(); |
| HeapWord* const beg_region_addr = sd.region_align_down(destination); |
| HeapWord* const end_region_addr = sd.region_align_down(last_word); |
| |
| if (beg_region_addr == end_region_addr) { |
| // One destination region. |
| _destination_count = 1; |
| if (end_region_addr == destination) { |
| // The destination falls on a region boundary, thus the first word of the |
| // partial object will be the first word copied to the destination region. |
| _dest_region_addr = end_region_addr; |
| _first_src_addr = sd.region_to_addr(src_region_idx); |
| } |
| } else { |
| // Two destination regions. When copied, the partial object will cross a |
| // destination region boundary, so a word somewhere within the partial |
| // object will be the first word copied to the second destination region. |
| _destination_count = 2; |
| _dest_region_addr = end_region_addr; |
| const size_t ofs = pointer_delta(end_region_addr, destination); |
| assert(ofs < _partial_obj_size, "sanity"); |
| _first_src_addr = sd.region_to_addr(src_region_idx) + ofs; |
| } |
| } |
| |
| void SplitInfo::clear() |
| { |
| _src_region_idx = 0; |
| _partial_obj_size = 0; |
| _destination = NULL; |
| _destination_count = 0; |
| _dest_region_addr = NULL; |
| _first_src_addr = NULL; |
| assert(!is_valid(), "sanity"); |
| } |
| |
| #ifdef ASSERT |
| void SplitInfo::verify_clear() |
| { |
| assert(_src_region_idx == 0, "not clear"); |
| assert(_partial_obj_size == 0, "not clear"); |
| assert(_destination == NULL, "not clear"); |
| assert(_destination_count == 0, "not clear"); |
| assert(_dest_region_addr == NULL, "not clear"); |
| assert(_first_src_addr == NULL, "not clear"); |
| } |
| #endif // #ifdef ASSERT |
| |
| |
| void PSParallelCompact::print_on_error(outputStream* st) { |
| _mark_bitmap.print_on_error(st); |
| } |
| |
| #ifndef PRODUCT |
| const char* PSParallelCompact::space_names[] = { |
| "old ", "eden", "from", "to " |
| }; |
| |
| void PSParallelCompact::print_region_ranges() { |
| if (!log_develop_is_enabled(Trace, gc, compaction)) { |
| return; |
| } |
| Log(gc, compaction) log; |
| ResourceMark rm; |
| LogStream ls(log.trace()); |
| Universe::print_on(&ls); |
| log.trace("space bottom top end new_top"); |
| log.trace("------ ---------- ---------- ---------- ----------"); |
| |
| for (unsigned int id = 0; id < last_space_id; ++id) { |
| const MutableSpace* space = _space_info[id].space(); |
| log.trace("%u %s " |
| SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " " |
| SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " ", |
| id, space_names[id], |
| summary_data().addr_to_region_idx(space->bottom()), |
| summary_data().addr_to_region_idx(space->top()), |
| summary_data().addr_to_region_idx(space->end()), |
| summary_data().addr_to_region_idx(_space_info[id].new_top())); |
| } |
| } |
| |
| void |
| print_generic_summary_region(size_t i, const ParallelCompactData::RegionData* c) |
| { |
| #define REGION_IDX_FORMAT SIZE_FORMAT_W(7) |
| #define REGION_DATA_FORMAT SIZE_FORMAT_W(5) |
| |
| ParallelCompactData& sd = PSParallelCompact::summary_data(); |
| size_t dci = c->destination() ? sd.addr_to_region_idx(c->destination()) : 0; |
| log_develop_trace(gc, compaction)( |
| REGION_IDX_FORMAT " " PTR_FORMAT " " |
| REGION_IDX_FORMAT " " PTR_FORMAT " " |
| REGION_DATA_FORMAT " " REGION_DATA_FORMAT " " |
| REGION_DATA_FORMAT " " REGION_IDX_FORMAT " %d", |
| i, p2i(c->data_location()), dci, p2i(c->destination()), |
| c->partial_obj_size(), c->live_obj_size(), |
| c->data_size(), c->source_region(), c->destination_count()); |
| |
| #undef REGION_IDX_FORMAT |
| #undef REGION_DATA_FORMAT |
| } |
| |
| void |
| print_generic_summary_data(ParallelCompactData& summary_data, |
| HeapWord* const beg_addr, |
| HeapWord* const end_addr) |
| { |
| size_t total_words = 0; |
| size_t i = summary_data.addr_to_region_idx(beg_addr); |
| const size_t last = summary_data.addr_to_region_idx(end_addr); |
| HeapWord* pdest = 0; |
| |
| while (i < last) { |
| ParallelCompactData::RegionData* c = summary_data.region(i); |
| if (c->data_size() != 0 || c->destination() != pdest) { |
| print_generic_summary_region(i, c); |
| total_words += c->data_size(); |
| pdest = c->destination(); |
| } |
| ++i; |
| } |
| |
| log_develop_trace(gc, compaction)("summary_data_bytes=" SIZE_FORMAT, total_words * HeapWordSize); |
| } |
| |
| void |
| PSParallelCompact::print_generic_summary_data(ParallelCompactData& summary_data, |
| HeapWord* const beg_addr, |
| HeapWord* const end_addr) { |
| ::print_generic_summary_data(summary_data,beg_addr, end_addr); |
| } |
| |
| void |
| print_generic_summary_data(ParallelCompactData& summary_data, |
| SpaceInfo* space_info) |
| { |
| if (!log_develop_is_enabled(Trace, gc, compaction)) { |
| return; |
| } |
| |
| for (unsigned int id = 0; id < PSParallelCompact::last_space_id; ++id) { |
| const MutableSpace* space = space_info[id].space(); |
| print_generic_summary_data(summary_data, space->bottom(), |
| MAX2(space->top(), space_info[id].new_top())); |
| } |
| } |
| |
| void |
| print_initial_summary_data(ParallelCompactData& summary_data, |
| const MutableSpace* space) { |
| if (space->top() == space->bottom()) { |
| return; |
| } |
| |
| const size_t region_size = ParallelCompactData::RegionSize; |
| typedef ParallelCompactData::RegionData RegionData; |
| HeapWord* const top_aligned_up = summary_data.region_align_up(space->top()); |
| const size_t end_region = summary_data.addr_to_region_idx(top_aligned_up); |
| const RegionData* c = summary_data.region(end_region - 1); |
| HeapWord* end_addr = c->destination() + c->data_size(); |
| const size_t live_in_space = pointer_delta(end_addr, space->bottom()); |
| |
| // Print (and count) the full regions at the beginning of the space. |
| size_t full_region_count = 0; |
| size_t i = summary_data.addr_to_region_idx(space->bottom()); |
| while (i < end_region && summary_data.region(i)->data_size() == region_size) { |
| ParallelCompactData::RegionData* c = summary_data.region(i); |
| log_develop_trace(gc, compaction)( |
| SIZE_FORMAT_W(5) " " PTR_FORMAT " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d", |
| i, p2i(c->destination()), |
| c->partial_obj_size(), c->live_obj_size(), |
| c->data_size(), c->source_region(), c->destination_count()); |
| ++full_region_count; |
| ++i; |
| } |
| |
| size_t live_to_right = live_in_space - full_region_count * region_size; |
| |
| double max_reclaimed_ratio = 0.0; |
| size_t max_reclaimed_ratio_region = 0; |
| size_t max_dead_to_right = 0; |
| size_t max_live_to_right = 0; |
| |
| // Print the 'reclaimed ratio' for regions while there is something live in |
| // the region or to the right of it. The remaining regions are empty (and |
| // uninteresting), and computing the ratio will result in division by 0. |
| while (i < end_region && live_to_right > 0) { |
| c = summary_data.region(i); |
| HeapWord* const region_addr = summary_data.region_to_addr(i); |
| const size_t used_to_right = pointer_delta(space->top(), region_addr); |
| const size_t dead_to_right = used_to_right - live_to_right; |
| const double reclaimed_ratio = double(dead_to_right) / live_to_right; |
| |
| if (reclaimed_ratio > max_reclaimed_ratio) { |
| max_reclaimed_ratio = reclaimed_ratio; |
| max_reclaimed_ratio_region = i; |
| max_dead_to_right = dead_to_right; |
| max_live_to_right = live_to_right; |
| } |
| |
| ParallelCompactData::RegionData* c = summary_data.region(i); |
| log_develop_trace(gc, compaction)( |
| SIZE_FORMAT_W(5) " " PTR_FORMAT " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d" |
| "%12.10f " SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10), |
| i, p2i(c->destination()), |
| c->partial_obj_size(), c->live_obj_size(), |
| c->data_size(), c->source_region(), c->destination_count(), |
| reclaimed_ratio, dead_to_right, live_to_right); |
| |
| |
| live_to_right -= c->data_size(); |
| ++i; |
| } |
| |
| // Any remaining regions are empty. Print one more if there is one. |
| if (i < end_region) { |
| ParallelCompactData::RegionData* c = summary_data.region(i); |
| log_develop_trace(gc, compaction)( |
| SIZE_FORMAT_W(5) " " PTR_FORMAT " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d", |
| i, p2i(c->destination()), |
| c->partial_obj_size(), c->live_obj_size(), |
| c->data_size(), c->source_region(), c->destination_count()); |
| } |
| |
| log_develop_trace(gc, compaction)("max: " SIZE_FORMAT_W(4) " d2r=" SIZE_FORMAT_W(10) " l2r=" SIZE_FORMAT_W(10) " max_ratio=%14.12f", |
| max_reclaimed_ratio_region, max_dead_to_right, max_live_to_right, max_reclaimed_ratio); |
| } |
| |
| void |
| print_initial_summary_data(ParallelCompactData& summary_data, |
| SpaceInfo* space_info) { |
| if (!log_develop_is_enabled(Trace, gc, compaction)) { |
| return; |
| } |
| |
| unsigned int id = PSParallelCompact::old_space_id; |
| const MutableSpace* space; |
| do { |
| space = space_info[id].space(); |
| print_initial_summary_data(summary_data, space); |
| } while (++id < PSParallelCompact::eden_space_id); |
| |
| do { |
| space = space_info[id].space(); |
| print_generic_summary_data(summary_data, space->bottom(), space->top()); |
| } while (++id < PSParallelCompact::last_space_id); |
| } |
| #endif // #ifndef PRODUCT |
| |
| #ifdef ASSERT |
| size_t add_obj_count; |
| size_t add_obj_size; |
| size_t mark_bitmap_count; |
| size_t mark_bitmap_size; |
| #endif // #ifdef ASSERT |
| |
| ParallelCompactData::ParallelCompactData() |
| { |
| _region_start = 0; |
| |
| _region_vspace = 0; |
| _reserved_byte_size = 0; |
| _region_data = 0; |
| _region_count = 0; |
| |
| _block_vspace = 0; |
| _block_data = 0; |
| _block_count = 0; |
| } |
| |
| bool ParallelCompactData::initialize(MemRegion covered_region) |
| { |
| _region_start = covered_region.start(); |
| const size_t region_size = covered_region.word_size(); |
| DEBUG_ONLY(_region_end = _region_start + region_size;) |
| |
| assert(region_align_down(_region_start) == _region_start, |
| "region start not aligned"); |
| assert((region_size & RegionSizeOffsetMask) == 0, |
| "region size not a multiple of RegionSize"); |
| |
| bool result = initialize_region_data(region_size) && initialize_block_data(); |
| return result; |
| } |
| |
| PSVirtualSpace* |
| ParallelCompactData::create_vspace(size_t count, size_t element_size) |
| { |
| const size_t raw_bytes = count * element_size; |
| const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10); |
| const size_t granularity = os::vm_allocation_granularity(); |
| _reserved_byte_size = align_up(raw_bytes, MAX2(page_sz, granularity)); |
| |
| const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 : |
| MAX2(page_sz, granularity); |
| ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0); |
| os::trace_page_sizes("Parallel Compact Data", raw_bytes, raw_bytes, page_sz, rs.base(), |
| rs.size()); |
| |
| MemTracker::record_virtual_memory_type((address)rs.base(), mtGC); |
| |
| PSVirtualSpace* vspace = new PSVirtualSpace(rs, page_sz); |
| if (vspace != 0) { |
| if (vspace->expand_by(_reserved_byte_size)) { |
| return vspace; |
| } |
| delete vspace; |
| // Release memory reserved in the space. |
| rs.release(); |
| } |
| |
| return 0; |
| } |
| |
| bool ParallelCompactData::initialize_region_data(size_t region_size) |
| { |
| const size_t count = (region_size + RegionSizeOffsetMask) >> Log2RegionSize; |
| _region_vspace = create_vspace(count, sizeof(RegionData)); |
| if (_region_vspace != 0) { |
| _region_data = (RegionData*)_region_vspace->reserved_low_addr(); |
| _region_count = count; |
| return true; |
| } |
| return false; |
| } |
| |
| bool ParallelCompactData::initialize_block_data() |
| { |
| assert(_region_count != 0, "region data must be initialized first"); |
| const size_t count = _region_count << Log2BlocksPerRegion; |
| _block_vspace = create_vspace(count, sizeof(BlockData)); |
| if (_block_vspace != 0) { |
| _block_data = (BlockData*)_block_vspace->reserved_low_addr(); |
| _block_count = count; |
| return true; |
| } |
| return false; |
| } |
| |
| void ParallelCompactData::clear() |
| { |
| memset(_region_data, 0, _region_vspace->committed_size()); |
| memset(_block_data, 0, _block_vspace->committed_size()); |
| } |
| |
| void ParallelCompactData::clear_range(size_t beg_region, size_t end_region) { |
| assert(beg_region <= _region_count, "beg_region out of range"); |
| assert(end_region <= _region_count, "end_region out of range"); |
| assert(RegionSize % BlockSize == 0, "RegionSize not a multiple of BlockSize"); |
| |
| const size_t region_cnt = end_region - beg_region; |
| memset(_region_data + beg_region, 0, region_cnt * sizeof(RegionData)); |
| |
| const size_t beg_block = beg_region * BlocksPerRegion; |
| const size_t block_cnt = region_cnt * BlocksPerRegion; |
| memset(_block_data + beg_block, 0, block_cnt * sizeof(BlockData)); |
| } |
| |
| HeapWord* ParallelCompactData::partial_obj_end(size_t region_idx) const |
| { |
| const RegionData* cur_cp = region(region_idx); |
| const RegionData* const end_cp = region(region_count() - 1); |
| |
| HeapWord* result = region_to_addr(region_idx); |
| if (cur_cp < end_cp) { |
| do { |
| result += cur_cp->partial_obj_size(); |
| } while (cur_cp->partial_obj_size() == RegionSize && ++cur_cp < end_cp); |
| } |
| return result; |
| } |
| |
| void ParallelCompactData::add_obj(HeapWord* addr, size_t len) |
| { |
| const size_t obj_ofs = pointer_delta(addr, _region_start); |
| const size_t beg_region = obj_ofs >> Log2RegionSize; |
| const size_t end_region = (obj_ofs + len - 1) >> Log2RegionSize; |
| |
| DEBUG_ONLY(Atomic::inc_ptr(&add_obj_count);) |
| DEBUG_ONLY(Atomic::add_ptr(len, &add_obj_size);) |
| |
| if (beg_region == end_region) { |
| // All in one region. |
| _region_data[beg_region].add_live_obj(len); |
| return; |
| } |
| |
| // First region. |
| const size_t beg_ofs = region_offset(addr); |
| _region_data[beg_region].add_live_obj(RegionSize - beg_ofs); |
| |
| Klass* klass = ((oop)addr)->klass(); |
| // Middle regions--completely spanned by this object. |
| for (size_t region = beg_region + 1; region < end_region; ++region) { |
| _region_data[region].set_partial_obj_size(RegionSize); |
| _region_data[region].set_partial_obj_addr(addr); |
| } |
| |
| // Last region. |
| const size_t end_ofs = region_offset(addr + len - 1); |
| _region_data[end_region].set_partial_obj_size(end_ofs + 1); |
| _region_data[end_region].set_partial_obj_addr(addr); |
| } |
| |
| void |
| ParallelCompactData::summarize_dense_prefix(HeapWord* beg, HeapWord* end) |
| { |
| assert(region_offset(beg) == 0, "not RegionSize aligned"); |
| assert(region_offset(end) == 0, "not RegionSize aligned"); |
| |
| size_t cur_region = addr_to_region_idx(beg); |
| const size_t end_region = addr_to_region_idx(end); |
| HeapWord* addr = beg; |
| while (cur_region < end_region) { |
| _region_data[cur_region].set_destination(addr); |
| _region_data[cur_region].set_destination_count(0); |
| _region_data[cur_region].set_source_region(cur_region); |
| _region_data[cur_region].set_data_location(addr); |
| |
| // Update live_obj_size so the region appears completely full. |
| size_t live_size = RegionSize - _region_data[cur_region].partial_obj_size(); |
| _region_data[cur_region].set_live_obj_size(live_size); |
| |
| ++cur_region; |
| addr += RegionSize; |
| } |
| } |
| |
| // Find the point at which a space can be split and, if necessary, record the |
| // split point. |
| // |
| // If the current src region (which overflowed the destination space) doesn't |
| // have a partial object, the split point is at the beginning of the current src |
| // region (an "easy" split, no extra bookkeeping required). |
| // |
| // If the current src region has a partial object, the split point is in the |
| // region where that partial object starts (call it the split_region). If |
| // split_region has a partial object, then the split point is just after that |
| // partial object (a "hard" split where we have to record the split data and |
| // zero the partial_obj_size field). With a "hard" split, we know that the |
| // partial_obj ends within split_region because the partial object that caused |
| // the overflow starts in split_region. If split_region doesn't have a partial |
| // obj, then the split is at the beginning of split_region (another "easy" |
| // split). |
| HeapWord* |
| ParallelCompactData::summarize_split_space(size_t src_region, |
| SplitInfo& split_info, |
| HeapWord* destination, |
| HeapWord* target_end, |
| HeapWord** target_next) |
| { |
| assert(destination <= target_end, "sanity"); |
| assert(destination + _region_data[src_region].data_size() > target_end, |
| "region should not fit into target space"); |
| assert(is_region_aligned(target_end), "sanity"); |
| |
| size_t split_region = src_region; |
| HeapWord* split_destination = destination; |
| size_t partial_obj_size = _region_data[src_region].partial_obj_size(); |
| |
| if (destination + partial_obj_size > target_end) { |
| // The split point is just after the partial object (if any) in the |
| // src_region that contains the start of the object that overflowed the |
| // destination space. |
| // |
| // Find the start of the "overflow" object and set split_region to the |
| // region containing it. |
| HeapWord* const overflow_obj = _region_data[src_region].partial_obj_addr(); |
| split_region = addr_to_region_idx(overflow_obj); |
| |
| // Clear the source_region field of all destination regions whose first word |
| // came from data after the split point (a non-null source_region field |
| // implies a region must be filled). |
| // |
| // An alternative to the simple loop below: clear during post_compact(), |
| // which uses memcpy instead of individual stores, and is easy to |
| // parallelize. (The downside is that it clears the entire RegionData |
| // object as opposed to just one field.) |
| // |
| // post_compact() would have to clear the summary data up to the highest |
| // address that was written during the summary phase, which would be |
| // |
| // max(top, max(new_top, clear_top)) |
| // |
| // where clear_top is a new field in SpaceInfo. Would have to set clear_top |
| // to target_end. |
| const RegionData* const sr = region(split_region); |
| const size_t beg_idx = |
| addr_to_region_idx(region_align_up(sr->destination() + |
| sr->partial_obj_size())); |
| const size_t end_idx = addr_to_region_idx(target_end); |
| |
| log_develop_trace(gc, compaction)("split: clearing source_region field in [" SIZE_FORMAT ", " SIZE_FORMAT ")", beg_idx, end_idx); |
| for (size_t idx = beg_idx; idx < end_idx; ++idx) { |
| _region_data[idx].set_source_region(0); |
| } |
| |
| // Set split_destination and partial_obj_size to reflect the split region. |
| split_destination = sr->destination(); |
| partial_obj_size = sr->partial_obj_size(); |
| } |
| |
| // The split is recorded only if a partial object extends onto the region. |
| if (partial_obj_size != 0) { |
| _region_data[split_region].set_partial_obj_size(0); |
| split_info.record(split_region, partial_obj_size, split_destination); |
| } |
| |
| // Setup the continuation addresses. |
| *target_next = split_destination + partial_obj_size; |
| HeapWord* const source_next = region_to_addr(split_region) + partial_obj_size; |
| |
| if (log_develop_is_enabled(Trace, gc, compaction)) { |
| const char * split_type = partial_obj_size == 0 ? "easy" : "hard"; |
| log_develop_trace(gc, compaction)("%s split: src=" PTR_FORMAT " src_c=" SIZE_FORMAT " pos=" SIZE_FORMAT, |
| split_type, p2i(source_next), split_region, partial_obj_size); |
| log_develop_trace(gc, compaction)("%s split: dst=" PTR_FORMAT " dst_c=" SIZE_FORMAT " tn=" PTR_FORMAT, |
| split_type, p2i(split_destination), |
| addr_to_region_idx(split_destination), |
| p2i(*target_next)); |
| |
| if (partial_obj_size != 0) { |
| HeapWord* const po_beg = split_info.destination(); |
| HeapWord* const po_end = po_beg + split_info.partial_obj_size(); |
| log_develop_trace(gc, compaction)("%s split: po_beg=" PTR_FORMAT " " SIZE_FORMAT " po_end=" PTR_FORMAT " " SIZE_FORMAT, |
| split_type, |
| p2i(po_beg), addr_to_region_idx(po_beg), |
| p2i(po_end), addr_to_region_idx(po_end)); |
| } |
| } |
| |
| return source_next; |
| } |
| |
| bool ParallelCompactData::summarize(SplitInfo& split_info, |
| HeapWord* source_beg, HeapWord* source_end, |
| HeapWord** source_next, |
| HeapWord* target_beg, HeapWord* target_end, |
| HeapWord** target_next) |
| { |
| HeapWord* const source_next_val = source_next == NULL ? NULL : *source_next; |
| log_develop_trace(gc, compaction)( |
| "sb=" PTR_FORMAT " se=" PTR_FORMAT " sn=" PTR_FORMAT |
| "tb=" PTR_FORMAT " te=" PTR_FORMAT " tn=" PTR_FORMAT, |
| p2i(source_beg), p2i(source_end), p2i(source_next_val), |
| p2i(target_beg), p2i(target_end), p2i(*target_next)); |
| |
| size_t cur_region = addr_to_region_idx(source_beg); |
| const size_t end_region = addr_to_region_idx(region_align_up(source_end)); |
| |
| HeapWord *dest_addr = target_beg; |
| while (cur_region < end_region) { |
| // The destination must be set even if the region has no data. |
| _region_data[cur_region].set_destination(dest_addr); |
| |
| size_t words = _region_data[cur_region].data_size(); |
| if (words > 0) { |
| // If cur_region does not fit entirely into the target space, find a point |
| // at which the source space can be 'split' so that part is copied to the |
| // target space and the rest is copied elsewhere. |
| if (dest_addr + words > target_end) { |
| assert(source_next != NULL, "source_next is NULL when splitting"); |
| *source_next = summarize_split_space(cur_region, split_info, dest_addr, |
| target_end, target_next); |
| return false; |
| } |
| |
| // Compute the destination_count for cur_region, and if necessary, update |
| // source_region for a destination region. The source_region field is |
| // updated if cur_region is the first (left-most) region to be copied to a |
| // destination region. |
| // |
| // The destination_count calculation is a bit subtle. A region that has |
| // data that compacts into itself does not count itself as a destination. |
| // This maintains the invariant that a zero count means the region is |
| // available and can be claimed and then filled. |
| uint destination_count = 0; |
| if (split_info.is_split(cur_region)) { |
| // The current region has been split: the partial object will be copied |
| // to one destination space and the remaining data will be copied to |
| // another destination space. Adjust the initial destination_count and, |
| // if necessary, set the source_region field if the partial object will |
| // cross a destination region boundary. |
| destination_count = split_info.destination_count(); |
| if (destination_count == 2) { |
| size_t dest_idx = addr_to_region_idx(split_info.dest_region_addr()); |
| _region_data[dest_idx].set_source_region(cur_region); |
| } |
| } |
| |
| HeapWord* const last_addr = dest_addr + words - 1; |
| const size_t dest_region_1 = addr_to_region_idx(dest_addr); |
| const size_t dest_region_2 = addr_to_region_idx(last_addr); |
| |
| // Initially assume that the destination regions will be the same and |
| // adjust the value below if necessary. Under this assumption, if |
| // cur_region == dest_region_2, then cur_region will be compacted |
| // completely into itself. |
| destination_count += cur_region == dest_region_2 ? 0 : 1; |
| if (dest_region_1 != dest_region_2) { |
| // Destination regions differ; adjust destination_count. |
| destination_count += 1; |
| // Data from cur_region will be copied to the start of dest_region_2. |
| _region_data[dest_region_2].set_source_region(cur_region); |
| } else if (region_offset(dest_addr) == 0) { |
| // Data from cur_region will be copied to the start of the destination |
| // region. |
| _region_data[dest_region_1].set_source_region(cur_region); |
| } |
| |
| _region_data[cur_region].set_destination_count(destination_count); |
| _region_data[cur_region].set_data_location(region_to_addr(cur_region)); |
| dest_addr += words; |
| } |
| |
| ++cur_region; |
| } |
| |
| *target_next = dest_addr; |
| return true; |
| } |
| |
| HeapWord* ParallelCompactData::calc_new_pointer(HeapWord* addr, ParCompactionManager* cm) { |
| assert(addr != NULL, "Should detect NULL oop earlier"); |
| assert(ParallelScavengeHeap::heap()->is_in(addr), "not in heap"); |
| assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "not marked"); |
| |
| // Region covering the object. |
| RegionData* const region_ptr = addr_to_region_ptr(addr); |
| HeapWord* result = region_ptr->destination(); |
| |
| // If the entire Region is live, the new location is region->destination + the |
| // offset of the object within in the Region. |
| |
| // Run some performance tests to determine if this special case pays off. It |
| // is worth it for pointers into the dense prefix. If the optimization to |
| // avoid pointer updates in regions that only point to the dense prefix is |
| // ever implemented, this should be revisited. |
| if (region_ptr->data_size() == RegionSize) { |
| result += region_offset(addr); |
| return result; |
| } |
| |
| // Otherwise, the new location is region->destination + block offset + the |
| // number of live words in the Block that are (a) to the left of addr and (b) |
| // due to objects that start in the Block. |
| |
| // Fill in the block table if necessary. This is unsynchronized, so multiple |
| // threads may fill the block table for a region (harmless, since it is |
| // idempotent). |
| if (!region_ptr->blocks_filled()) { |
| PSParallelCompact::fill_blocks(addr_to_region_idx(addr)); |
| region_ptr->set_blocks_filled(); |
| } |
| |
| HeapWord* const search_start = block_align_down(addr); |
| const size_t block_offset = addr_to_block_ptr(addr)->offset(); |
| |
| const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap(); |
| const size_t live = bitmap->live_words_in_range(cm, search_start, oop(addr)); |
| result += block_offset + live; |
| DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result)); |
| return result; |
| } |
| |
| #ifdef ASSERT |
| void ParallelCompactData::verify_clear(const PSVirtualSpace* vspace) |
| { |
| const size_t* const beg = (const size_t*)vspace->committed_low_addr(); |
| const size_t* const end = (const size_t*)vspace->committed_high_addr(); |
| for (const size_t* p = beg; p < end; ++p) { |
| assert(*p == 0, "not zero"); |
| } |
| } |
| |
| void ParallelCompactData::verify_clear() |
| { |
| verify_clear(_region_vspace); |
| verify_clear(_block_vspace); |
| } |
| #endif // #ifdef ASSERT |
| |
| STWGCTimer PSParallelCompact::_gc_timer; |
| ParallelOldTracer PSParallelCompact::_gc_tracer; |
| elapsedTimer PSParallelCompact::_accumulated_time; |
| unsigned int PSParallelCompact::_total_invocations = 0; |
| unsigned int PSParallelCompact::_maximum_compaction_gc_num = 0; |
| jlong PSParallelCompact::_time_of_last_gc = 0; |
| CollectorCounters* PSParallelCompact::_counters = NULL; |
| ParMarkBitMap PSParallelCompact::_mark_bitmap; |
| ParallelCompactData PSParallelCompact::_summary_data; |
| |
| PSParallelCompact::IsAliveClosure PSParallelCompact::_is_alive_closure; |
| |
| bool PSParallelCompact::IsAliveClosure::do_object_b(oop p) { return mark_bitmap()->is_marked(p); } |
| |
| void PSParallelCompact::AdjustKlassClosure::do_klass(Klass* klass) { |
| PSParallelCompact::AdjustPointerClosure closure(_cm); |
| klass->oops_do(&closure); |
| } |
| |
| void PSParallelCompact::post_initialize() { |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| MemRegion mr = heap->reserved_region(); |
| _ref_processor = |
| new ReferenceProcessor(mr, // span |
| ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing |
| ParallelGCThreads, // mt processing degree |
| true, // mt discovery |
| ParallelGCThreads, // mt discovery degree |
| true, // atomic_discovery |
| &_is_alive_closure); // non-header is alive closure |
| _counters = new CollectorCounters("PSParallelCompact", 1); |
| |
| // Initialize static fields in ParCompactionManager. |
| ParCompactionManager::initialize(mark_bitmap()); |
| } |
| |
| bool PSParallelCompact::initialize() { |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| MemRegion mr = heap->reserved_region(); |
| |
| // Was the old gen get allocated successfully? |
| if (!heap->old_gen()->is_allocated()) { |
| return false; |
| } |
| |
| initialize_space_info(); |
| initialize_dead_wood_limiter(); |
| |
| if (!_mark_bitmap.initialize(mr)) { |
| vm_shutdown_during_initialization( |
| err_msg("Unable to allocate " SIZE_FORMAT "KB bitmaps for parallel " |
| "garbage collection for the requested " SIZE_FORMAT "KB heap.", |
| _mark_bitmap.reserved_byte_size()/K, mr.byte_size()/K)); |
| return false; |
| } |
| |
| if (!_summary_data.initialize(mr)) { |
| vm_shutdown_during_initialization( |
| err_msg("Unable to allocate " SIZE_FORMAT "KB card tables for parallel " |
| "garbage collection for the requested " SIZE_FORMAT "KB heap.", |
| _summary_data.reserved_byte_size()/K, mr.byte_size()/K)); |
| return false; |
| } |
| |
| return true; |
| } |
| |
| void PSParallelCompact::initialize_space_info() |
| { |
| memset(&_space_info, 0, sizeof(_space_info)); |
| |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| PSYoungGen* young_gen = heap->young_gen(); |
| |
| _space_info[old_space_id].set_space(heap->old_gen()->object_space()); |
| _space_info[eden_space_id].set_space(young_gen->eden_space()); |
| _space_info[from_space_id].set_space(young_gen->from_space()); |
| _space_info[to_space_id].set_space(young_gen->to_space()); |
| |
| _space_info[old_space_id].set_start_array(heap->old_gen()->start_array()); |
| } |
| |
| void PSParallelCompact::initialize_dead_wood_limiter() |
| { |
| const size_t max = 100; |
| _dwl_mean = double(MIN2(ParallelOldDeadWoodLimiterMean, max)) / 100.0; |
| _dwl_std_dev = double(MIN2(ParallelOldDeadWoodLimiterStdDev, max)) / 100.0; |
| _dwl_first_term = 1.0 / (sqrt(2.0 * M_PI) * _dwl_std_dev); |
| DEBUG_ONLY(_dwl_initialized = true;) |
| _dwl_adjustment = normal_distribution(1.0); |
| } |
| |
| void |
| PSParallelCompact::clear_data_covering_space(SpaceId id) |
| { |
| // At this point, top is the value before GC, new_top() is the value that will |
| // be set at the end of GC. The marking bitmap is cleared to top; nothing |
| // should be marked above top. The summary data is cleared to the larger of |
| // top & new_top. |
| MutableSpace* const space = _space_info[id].space(); |
| HeapWord* const bot = space->bottom(); |
| HeapWord* const top = space->top(); |
| HeapWord* const max_top = MAX2(top, _space_info[id].new_top()); |
| |
| const idx_t beg_bit = _mark_bitmap.addr_to_bit(bot); |
| const idx_t end_bit = BitMap::word_align_up(_mark_bitmap.addr_to_bit(top)); |
| _mark_bitmap.clear_range(beg_bit, end_bit); |
| |
| const size_t beg_region = _summary_data.addr_to_region_idx(bot); |
| const size_t end_region = |
| _summary_data.addr_to_region_idx(_summary_data.region_align_up(max_top)); |
| _summary_data.clear_range(beg_region, end_region); |
| |
| // Clear the data used to 'split' regions. |
| SplitInfo& split_info = _space_info[id].split_info(); |
| if (split_info.is_valid()) { |
| split_info.clear(); |
| } |
| DEBUG_ONLY(split_info.verify_clear();) |
| } |
| |
| void PSParallelCompact::pre_compact() |
| { |
| // Update the from & to space pointers in space_info, since they are swapped |
| // at each young gen gc. Do the update unconditionally (even though a |
| // promotion failure does not swap spaces) because an unknown number of young |
| // collections will have swapped the spaces an unknown number of times. |
| GCTraceTime(Debug, gc, phases) tm("Pre Compact", &_gc_timer); |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| _space_info[from_space_id].set_space(heap->young_gen()->from_space()); |
| _space_info[to_space_id].set_space(heap->young_gen()->to_space()); |
| |
| DEBUG_ONLY(add_obj_count = add_obj_size = 0;) |
| DEBUG_ONLY(mark_bitmap_count = mark_bitmap_size = 0;) |
| |
| // Increment the invocation count |
| heap->increment_total_collections(true); |
| |
| // We need to track unique mark sweep invocations as well. |
| _total_invocations++; |
| |
| heap->print_heap_before_gc(); |
| heap->trace_heap_before_gc(&_gc_tracer); |
| |
| // Fill in TLABs |
| heap->accumulate_statistics_all_tlabs(); |
| heap->ensure_parsability(true); // retire TLABs |
| |
| if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { |
| HandleMark hm; // Discard invalid handles created during verification |
| Universe::verify("Before GC"); |
| } |
| |
| // Verify object start arrays |
| if (VerifyObjectStartArray && |
| VerifyBeforeGC) { |
| heap->old_gen()->verify_object_start_array(); |
| } |
| |
| DEBUG_ONLY(mark_bitmap()->verify_clear();) |
| DEBUG_ONLY(summary_data().verify_clear();) |
| |
| // Have worker threads release resources the next time they run a task. |
| gc_task_manager()->release_all_resources(); |
| |
| ParCompactionManager::reset_all_bitmap_query_caches(); |
| } |
| |
| void PSParallelCompact::post_compact() |
| { |
| GCTraceTime(Info, gc, phases) tm("Post Compact", &_gc_timer); |
| |
| for (unsigned int id = old_space_id; id < last_space_id; ++id) { |
| // Clear the marking bitmap, summary data and split info. |
| clear_data_covering_space(SpaceId(id)); |
| // Update top(). Must be done after clearing the bitmap and summary data. |
| _space_info[id].publish_new_top(); |
| } |
| |
| MutableSpace* const eden_space = _space_info[eden_space_id].space(); |
| MutableSpace* const from_space = _space_info[from_space_id].space(); |
| MutableSpace* const to_space = _space_info[to_space_id].space(); |
| |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| bool eden_empty = eden_space->is_empty(); |
| if (!eden_empty) { |
| eden_empty = absorb_live_data_from_eden(heap->size_policy(), |
| heap->young_gen(), heap->old_gen()); |
| } |
| |
| // Update heap occupancy information which is used as input to the soft ref |
| // clearing policy at the next gc. |
| Universe::update_heap_info_at_gc(); |
| |
| bool young_gen_empty = eden_empty && from_space->is_empty() && |
| to_space->is_empty(); |
| |
| ModRefBarrierSet* modBS = barrier_set_cast<ModRefBarrierSet>(heap->barrier_set()); |
| MemRegion old_mr = heap->old_gen()->reserved(); |
| if (young_gen_empty) { |
| modBS->clear(MemRegion(old_mr.start(), old_mr.end())); |
| } else { |
| modBS->invalidate(MemRegion(old_mr.start(), old_mr.end())); |
| } |
| |
| // Delete metaspaces for unloaded class loaders and clean up loader_data graph |
| ClassLoaderDataGraph::purge(); |
| MetaspaceAux::verify_metrics(); |
| |
| CodeCache::gc_epilogue(); |
| JvmtiExport::gc_epilogue(); |
| |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| DerivedPointerTable::update_pointers(); |
| #endif |
| |
| ReferenceProcessorPhaseTimes pt(&_gc_timer, ref_processor()->num_q()); |
| |
| ref_processor()->enqueue_discovered_references(NULL, &pt); |
| |
| pt.print_enqueue_phase(); |
| |
| if (ZapUnusedHeapArea) { |
| heap->gen_mangle_unused_area(); |
| } |
| |
| // Update time of last GC |
| reset_millis_since_last_gc(); |
| } |
| |
| HeapWord* |
| PSParallelCompact::compute_dense_prefix_via_density(const SpaceId id, |
| bool maximum_compaction) |
| { |
| const size_t region_size = ParallelCompactData::RegionSize; |
| const ParallelCompactData& sd = summary_data(); |
| |
| const MutableSpace* const space = _space_info[id].space(); |
| HeapWord* const top_aligned_up = sd.region_align_up(space->top()); |
| const RegionData* const beg_cp = sd.addr_to_region_ptr(space->bottom()); |
| const RegionData* const end_cp = sd.addr_to_region_ptr(top_aligned_up); |
| |
| // Skip full regions at the beginning of the space--they are necessarily part |
| // of the dense prefix. |
| size_t full_count = 0; |
| const RegionData* cp; |
| for (cp = beg_cp; cp < end_cp && cp->data_size() == region_size; ++cp) { |
| ++full_count; |
| } |
| |
| assert(total_invocations() >= _maximum_compaction_gc_num, "sanity"); |
| const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num; |
| const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval; |
| if (maximum_compaction || cp == end_cp || interval_ended) { |
| _maximum_compaction_gc_num = total_invocations(); |
| return sd.region_to_addr(cp); |
| } |
| |
| HeapWord* const new_top = _space_info[id].new_top(); |
| const size_t space_live = pointer_delta(new_top, space->bottom()); |
| const size_t space_used = space->used_in_words(); |
| const size_t space_capacity = space->capacity_in_words(); |
| |
| const double cur_density = double(space_live) / space_capacity; |
| const double deadwood_density = |
| (1.0 - cur_density) * (1.0 - cur_density) * cur_density * cur_density; |
| const size_t deadwood_goal = size_t(space_capacity * deadwood_density); |
| |
| if (TraceParallelOldGCDensePrefix) { |
| tty->print_cr("cur_dens=%5.3f dw_dens=%5.3f dw_goal=" SIZE_FORMAT, |
| cur_density, deadwood_density, deadwood_goal); |
| tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " " |
| "space_cap=" SIZE_FORMAT, |
| space_live, space_used, |
| space_capacity); |
| } |
| |
| // XXX - Use binary search? |
| HeapWord* dense_prefix = sd.region_to_addr(cp); |
| const RegionData* full_cp = cp; |
| const RegionData* const top_cp = sd.addr_to_region_ptr(space->top() - 1); |
| while (cp < end_cp) { |
| HeapWord* region_destination = cp->destination(); |
| const size_t cur_deadwood = pointer_delta(dense_prefix, region_destination); |
| if (TraceParallelOldGCDensePrefix && Verbose) { |
| tty->print_cr("c#=" SIZE_FORMAT_W(4) " dst=" PTR_FORMAT " " |
| "dp=" PTR_FORMAT " " "cdw=" SIZE_FORMAT_W(8), |
| sd.region(cp), p2i(region_destination), |
| p2i(dense_prefix), cur_deadwood); |
| } |
| |
| if (cur_deadwood >= deadwood_goal) { |
| // Found the region that has the correct amount of deadwood to the left. |
| // This typically occurs after crossing a fairly sparse set of regions, so |
| // iterate backwards over those sparse regions, looking for the region |
| // that has the lowest density of live objects 'to the right.' |
| size_t space_to_left = sd.region(cp) * region_size; |
| size_t live_to_left = space_to_left - cur_deadwood; |
| size_t space_to_right = space_capacity - space_to_left; |
| size_t live_to_right = space_live - live_to_left; |
| double density_to_right = double(live_to_right) / space_to_right; |
| while (cp > full_cp) { |
| --cp; |
| const size_t prev_region_live_to_right = live_to_right - |
| cp->data_size(); |
| const size_t prev_region_space_to_right = space_to_right + region_size; |
| double prev_region_density_to_right = |
| double(prev_region_live_to_right) / prev_region_space_to_right; |
| if (density_to_right <= prev_region_density_to_right) { |
| return dense_prefix; |
| } |
| if (TraceParallelOldGCDensePrefix && Verbose) { |
| tty->print_cr("backing up from c=" SIZE_FORMAT_W(4) " d2r=%10.8f " |
| "pc_d2r=%10.8f", sd.region(cp), density_to_right, |
| prev_region_density_to_right); |
| } |
| dense_prefix -= region_size; |
| live_to_right = prev_region_live_to_right; |
| space_to_right = prev_region_space_to_right; |
| density_to_right = prev_region_density_to_right; |
| } |
| return dense_prefix; |
| } |
| |
| dense_prefix += region_size; |
| ++cp; |
| } |
| |
| return dense_prefix; |
| } |
| |
| #ifndef PRODUCT |
| void PSParallelCompact::print_dense_prefix_stats(const char* const algorithm, |
| const SpaceId id, |
| const bool maximum_compaction, |
| HeapWord* const addr) |
| { |
| const size_t region_idx = summary_data().addr_to_region_idx(addr); |
| RegionData* const cp = summary_data().region(region_idx); |
| const MutableSpace* const space = _space_info[id].space(); |
| HeapWord* const new_top = _space_info[id].new_top(); |
| |
| const size_t space_live = pointer_delta(new_top, space->bottom()); |
| const size_t dead_to_left = pointer_delta(addr, cp->destination()); |
| const size_t space_cap = space->capacity_in_words(); |
| const double dead_to_left_pct = double(dead_to_left) / space_cap; |
| const size_t live_to_right = new_top - cp->destination(); |
| const size_t dead_to_right = space->top() - addr - live_to_right; |
| |
| tty->print_cr("%s=" PTR_FORMAT " dpc=" SIZE_FORMAT_W(5) " " |
| "spl=" SIZE_FORMAT " " |
| "d2l=" SIZE_FORMAT " d2l%%=%6.4f " |
| "d2r=" SIZE_FORMAT " l2r=" SIZE_FORMAT |
| " ratio=%10.8f", |
| algorithm, p2i(addr), region_idx, |
| space_live, |
| dead_to_left, dead_to_left_pct, |
| dead_to_right, live_to_right, |
| double(dead_to_right) / live_to_right); |
| } |
| #endif // #ifndef PRODUCT |
| |
| // Return a fraction indicating how much of the generation can be treated as |
| // "dead wood" (i.e., not reclaimed). The function uses a normal distribution |
| // based on the density of live objects in the generation to determine a limit, |
| // which is then adjusted so the return value is min_percent when the density is |
| // 1. |
| // |
| // The following table shows some return values for a different values of the |
| // standard deviation (ParallelOldDeadWoodLimiterStdDev); the mean is 0.5 and |
| // min_percent is 1. |
| // |
| // fraction allowed as dead wood |
| // ----------------------------------------------------------------- |
| // density std_dev=70 std_dev=75 std_dev=80 std_dev=85 std_dev=90 std_dev=95 |
| // ------- ---------- ---------- ---------- ---------- ---------- ---------- |
| // 0.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 |
| // 0.05000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941 |
| // 0.10000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272 |
| // 0.15000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066 |
| // 0.20000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975 |
| // 0.25000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313 |
| // 0.30000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132 |
| // 0.35000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289 |
| // 0.40000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500 |
| // 0.45000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386 |
| // 0.50000 0.13832410 0.11599237 0.09847664 0.08456518 0.07338887 0.06431510 |
| // 0.55000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386 |
| // 0.60000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500 |
| // 0.65000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289 |
| // 0.70000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132 |
| // 0.75000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313 |
| // 0.80000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975 |
| // 0.85000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066 |
| // 0.90000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272 |
| // 0.95000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941 |
| // 1.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 |
| |
| double PSParallelCompact::dead_wood_limiter(double density, size_t min_percent) |
| { |
| assert(_dwl_initialized, "uninitialized"); |
| |
| // The raw limit is the value of the normal distribution at x = density. |
| const double raw_limit = normal_distribution(density); |
| |
| // Adjust the raw limit so it becomes the minimum when the density is 1. |
| // |
| // First subtract the adjustment value (which is simply the precomputed value |
| // normal_distribution(1.0)); this yields a value of 0 when the density is 1. |
| // Then add the minimum value, so the minimum is returned when the density is |
| // 1. Finally, prevent negative values, which occur when the mean is not 0.5. |
| const double min = double(min_percent) / 100.0; |
| const double limit = raw_limit - _dwl_adjustment + min; |
| return MAX2(limit, 0.0); |
| } |
| |
| ParallelCompactData::RegionData* |
| PSParallelCompact::first_dead_space_region(const RegionData* beg, |
| const RegionData* end) |
| { |
| const size_t region_size = ParallelCompactData::RegionSize; |
| ParallelCompactData& sd = summary_data(); |
| size_t left = sd.region(beg); |
| size_t right = end > beg ? sd.region(end) - 1 : left; |
| |
| // Binary search. |
| while (left < right) { |
| // Equivalent to (left + right) / 2, but does not overflow. |
| const size_t middle = left + (right - left) / 2; |
| RegionData* const middle_ptr = sd.region(middle); |
| HeapWord* const dest = middle_ptr->destination(); |
| HeapWord* const addr = sd.region_to_addr(middle); |
| assert(dest != NULL, "sanity"); |
| assert(dest <= addr, "must move left"); |
| |
| if (middle > left && dest < addr) { |
| right = middle - 1; |
| } else if (middle < right && middle_ptr->data_size() == region_size) { |
| left = middle + 1; |
| } else { |
| return middle_ptr; |
| } |
| } |
| return sd.region(left); |
| } |
| |
| ParallelCompactData::RegionData* |
| PSParallelCompact::dead_wood_limit_region(const RegionData* beg, |
| const RegionData* end, |
| size_t dead_words) |
| { |
| ParallelCompactData& sd = summary_data(); |
| size_t left = sd.region(beg); |
| size_t right = end > beg ? sd.region(end) - 1 : left; |
| |
| // Binary search. |
| while (left < right) { |
| // Equivalent to (left + right) / 2, but does not overflow. |
| const size_t middle = left + (right - left) / 2; |
| RegionData* const middle_ptr = sd.region(middle); |
| HeapWord* const dest = middle_ptr->destination(); |
| HeapWord* const addr = sd.region_to_addr(middle); |
| assert(dest != NULL, "sanity"); |
| assert(dest <= addr, "must move left"); |
| |
| const size_t dead_to_left = pointer_delta(addr, dest); |
| if (middle > left && dead_to_left > dead_words) { |
| right = middle - 1; |
| } else if (middle < right && dead_to_left < dead_words) { |
| left = middle + 1; |
| } else { |
| return middle_ptr; |
| } |
| } |
| return sd.region(left); |
| } |
| |
| // The result is valid during the summary phase, after the initial summarization |
| // of each space into itself, and before final summarization. |
| inline double |
| PSParallelCompact::reclaimed_ratio(const RegionData* const cp, |
| HeapWord* const bottom, |
| HeapWord* const top, |
| HeapWord* const new_top) |
| { |
| ParallelCompactData& sd = summary_data(); |
| |
| assert(cp != NULL, "sanity"); |
| assert(bottom != NULL, "sanity"); |
| assert(top != NULL, "sanity"); |
| assert(new_top != NULL, "sanity"); |
| assert(top >= new_top, "summary data problem?"); |
| assert(new_top > bottom, "space is empty; should not be here"); |
| assert(new_top >= cp->destination(), "sanity"); |
| assert(top >= sd.region_to_addr(cp), "sanity"); |
| |
| HeapWord* const destination = cp->destination(); |
| const size_t dense_prefix_live = pointer_delta(destination, bottom); |
| const size_t compacted_region_live = pointer_delta(new_top, destination); |
| const size_t compacted_region_used = pointer_delta(top, |
| sd.region_to_addr(cp)); |
| const size_t reclaimable = compacted_region_used - compacted_region_live; |
| |
| const double divisor = dense_prefix_live + 1.25 * compacted_region_live; |
| return double(reclaimable) / divisor; |
| } |
| |
| // Return the address of the end of the dense prefix, a.k.a. the start of the |
| // compacted region. The address is always on a region boundary. |
| // |
| // Completely full regions at the left are skipped, since no compaction can |
| // occur in those regions. Then the maximum amount of dead wood to allow is |
| // computed, based on the density (amount live / capacity) of the generation; |
| // the region with approximately that amount of dead space to the left is |
| // identified as the limit region. Regions between the last completely full |
| // region and the limit region are scanned and the one that has the best |
| // (maximum) reclaimed_ratio() is selected. |
| HeapWord* |
| PSParallelCompact::compute_dense_prefix(const SpaceId id, |
| bool maximum_compaction) |
| { |
| const size_t region_size = ParallelCompactData::RegionSize; |
| const ParallelCompactData& sd = summary_data(); |
| |
| const MutableSpace* const space = _space_info[id].space(); |
| HeapWord* const top = space->top(); |
| HeapWord* const top_aligned_up = sd.region_align_up(top); |
| HeapWord* const new_top = _space_info[id].new_top(); |
| HeapWord* const new_top_aligned_up = sd.region_align_up(new_top); |
| HeapWord* const bottom = space->bottom(); |
| const RegionData* const beg_cp = sd.addr_to_region_ptr(bottom); |
| const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up); |
| const RegionData* const new_top_cp = |
| sd.addr_to_region_ptr(new_top_aligned_up); |
| |
| // Skip full regions at the beginning of the space--they are necessarily part |
| // of the dense prefix. |
| const RegionData* const full_cp = first_dead_space_region(beg_cp, new_top_cp); |
| assert(full_cp->destination() == sd.region_to_addr(full_cp) || |
| space->is_empty(), "no dead space allowed to the left"); |
| assert(full_cp->data_size() < region_size || full_cp == new_top_cp - 1, |
| "region must have dead space"); |
| |
| // The gc number is saved whenever a maximum compaction is done, and used to |
| // determine when the maximum compaction interval has expired. This avoids |
| // successive max compactions for different reasons. |
| assert(total_invocations() >= _maximum_compaction_gc_num, "sanity"); |
| const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num; |
| const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval || |
| total_invocations() == HeapFirstMaximumCompactionCount; |
| if (maximum_compaction || full_cp == top_cp || interval_ended) { |
| _maximum_compaction_gc_num = total_invocations(); |
| return sd.region_to_addr(full_cp); |
| } |
| |
| const size_t space_live = pointer_delta(new_top, bottom); |
| const size_t space_used = space->used_in_words(); |
| const size_t space_capacity = space->capacity_in_words(); |
| |
| const double density = double(space_live) / double(space_capacity); |
| const size_t min_percent_free = MarkSweepDeadRatio; |
| const double limiter = dead_wood_limiter(density, min_percent_free); |
| const size_t dead_wood_max = space_used - space_live; |
| const size_t dead_wood_limit = MIN2(size_t(space_capacity * limiter), |
| dead_wood_max); |
| |
| if (TraceParallelOldGCDensePrefix) { |
| tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " " |
| "space_cap=" SIZE_FORMAT, |
| space_live, space_used, |
| space_capacity); |
| tty->print_cr("dead_wood_limiter(%6.4f, " SIZE_FORMAT ")=%6.4f " |
| "dead_wood_max=" SIZE_FORMAT " dead_wood_limit=" SIZE_FORMAT, |
| density, min_percent_free, limiter, |
| dead_wood_max, dead_wood_limit); |
| } |
| |
| // Locate the region with the desired amount of dead space to the left. |
| const RegionData* const limit_cp = |
| dead_wood_limit_region(full_cp, top_cp, dead_wood_limit); |
| |
| // Scan from the first region with dead space to the limit region and find the |
| // one with the best (largest) reclaimed ratio. |
| double best_ratio = 0.0; |
| const RegionData* best_cp = full_cp; |
| for (const RegionData* cp = full_cp; cp < limit_cp; ++cp) { |
| double tmp_ratio = reclaimed_ratio(cp, bottom, top, new_top); |
| if (tmp_ratio > best_ratio) { |
| best_cp = cp; |
| best_ratio = tmp_ratio; |
| } |
| } |
| |
| return sd.region_to_addr(best_cp); |
| } |
| |
| void PSParallelCompact::summarize_spaces_quick() |
| { |
| for (unsigned int i = 0; i < last_space_id; ++i) { |
| const MutableSpace* space = _space_info[i].space(); |
| HeapWord** nta = _space_info[i].new_top_addr(); |
| bool result = _summary_data.summarize(_space_info[i].split_info(), |
| space->bottom(), space->top(), NULL, |
| space->bottom(), space->end(), nta); |
| assert(result, "space must fit into itself"); |
| _space_info[i].set_dense_prefix(space->bottom()); |
| } |
| } |
| |
| void PSParallelCompact::fill_dense_prefix_end(SpaceId id) |
| { |
| HeapWord* const dense_prefix_end = dense_prefix(id); |
| const RegionData* region = _summary_data.addr_to_region_ptr(dense_prefix_end); |
| const idx_t dense_prefix_bit = _mark_bitmap.addr_to_bit(dense_prefix_end); |
| if (dead_space_crosses_boundary(region, dense_prefix_bit)) { |
| // Only enough dead space is filled so that any remaining dead space to the |
| // left is larger than the minimum filler object. (The remainder is filled |
| // during the copy/update phase.) |
| // |
| // The size of the dead space to the right of the boundary is not a |
| // concern, since compaction will be able to use whatever space is |
| // available. |
| // |
| // Here '||' is the boundary, 'x' represents a don't care bit and a box |
| // surrounds the space to be filled with an object. |
| // |
| // In the 32-bit VM, each bit represents two 32-bit words: |
| // +---+ |
| // a) beg_bits: ... x x x | 0 | || 0 x x ... |
| // end_bits: ... x x x | 0 | || 0 x x ... |
| // +---+ |
| // |
| // In the 64-bit VM, each bit represents one 64-bit word: |
| // +------------+ |
| // b) beg_bits: ... x x x | 0 || 0 | x x ... |
| // end_bits: ... x x 1 | 0 || 0 | x x ... |
| // +------------+ |
| // +-------+ |
| // c) beg_bits: ... x x | 0 0 | || 0 x x ... |
| // end_bits: ... x 1 | 0 0 | || 0 x x ... |
| // +-------+ |
| // +-----------+ |
| // d) beg_bits: ... x | 0 0 0 | || 0 x x ... |
| // end_bits: ... 1 | 0 0 0 | || 0 x x ... |
| // +-----------+ |
| // +-------+ |
| // e) beg_bits: ... 0 0 | 0 0 | || 0 x x ... |
| // end_bits: ... 0 0 | 0 0 | || 0 x x ... |
| // +-------+ |
| |
| // Initially assume case a, c or e will apply. |
| size_t obj_len = CollectedHeap::min_fill_size(); |
| HeapWord* obj_beg = dense_prefix_end - obj_len; |
| |
| #ifdef _LP64 |
| if (MinObjAlignment > 1) { // object alignment > heap word size |
| // Cases a, c or e. |
| } else if (_mark_bitmap.is_obj_end(dense_prefix_bit - 2)) { |
| // Case b above. |
| obj_beg = dense_prefix_end - 1; |
| } else if (!_mark_bitmap.is_obj_end(dense_prefix_bit - 3) && |
| _mark_bitmap.is_obj_end(dense_prefix_bit - 4)) { |
| // Case d above. |
| obj_beg = dense_prefix_end - 3; |
| obj_len = 3; |
| } |
| #endif // #ifdef _LP64 |
| |
| CollectedHeap::fill_with_object(obj_beg, obj_len); |
| _mark_bitmap.mark_obj(obj_beg, obj_len); |
| _summary_data.add_obj(obj_beg, obj_len); |
| assert(start_array(id) != NULL, "sanity"); |
| start_array(id)->allocate_block(obj_beg); |
| } |
| } |
| |
| void |
| PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction) |
| { |
| assert(id < last_space_id, "id out of range"); |
| assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom(), |
| "should have been reset in summarize_spaces_quick()"); |
| |
| const MutableSpace* space = _space_info[id].space(); |
| if (_space_info[id].new_top() != space->bottom()) { |
| HeapWord* dense_prefix_end = compute_dense_prefix(id, maximum_compaction); |
| _space_info[id].set_dense_prefix(dense_prefix_end); |
| |
| #ifndef PRODUCT |
| if (TraceParallelOldGCDensePrefix) { |
| print_dense_prefix_stats("ratio", id, maximum_compaction, |
| dense_prefix_end); |
| HeapWord* addr = compute_dense_prefix_via_density(id, maximum_compaction); |
| print_dense_prefix_stats("density", id, maximum_compaction, addr); |
| } |
| #endif // #ifndef PRODUCT |
| |
| // Recompute the summary data, taking into account the dense prefix. If |
| // every last byte will be reclaimed, then the existing summary data which |
| // compacts everything can be left in place. |
| if (!maximum_compaction && dense_prefix_end != space->bottom()) { |
| // If dead space crosses the dense prefix boundary, it is (at least |
| // partially) filled with a dummy object, marked live and added to the |
| // summary data. This simplifies the copy/update phase and must be done |
| // before the final locations of objects are determined, to prevent |
| // leaving a fragment of dead space that is too small to fill. |
| fill_dense_prefix_end(id); |
| |
| // Compute the destination of each Region, and thus each object. |
| _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end); |
| _summary_data.summarize(_space_info[id].split_info(), |
| dense_prefix_end, space->top(), NULL, |
| dense_prefix_end, space->end(), |
| _space_info[id].new_top_addr()); |
| } |
| } |
| |
| if (log_develop_is_enabled(Trace, gc, compaction)) { |
| const size_t region_size = ParallelCompactData::RegionSize; |
| HeapWord* const dense_prefix_end = _space_info[id].dense_prefix(); |
| const size_t dp_region = _summary_data.addr_to_region_idx(dense_prefix_end); |
| const size_t dp_words = pointer_delta(dense_prefix_end, space->bottom()); |
| HeapWord* const new_top = _space_info[id].new_top(); |
| const HeapWord* nt_aligned_up = _summary_data.region_align_up(new_top); |
| const size_t cr_words = pointer_delta(nt_aligned_up, dense_prefix_end); |
| log_develop_trace(gc, compaction)( |
| "id=%d cap=" SIZE_FORMAT " dp=" PTR_FORMAT " " |
| "dp_region=" SIZE_FORMAT " " "dp_count=" SIZE_FORMAT " " |
| "cr_count=" SIZE_FORMAT " " "nt=" PTR_FORMAT, |
| id, space->capacity_in_words(), p2i(dense_prefix_end), |
| dp_region, dp_words / region_size, |
| cr_words / region_size, p2i(new_top)); |
| } |
| } |
| |
| #ifndef PRODUCT |
| void PSParallelCompact::summary_phase_msg(SpaceId dst_space_id, |
| HeapWord* dst_beg, HeapWord* dst_end, |
| SpaceId src_space_id, |
| HeapWord* src_beg, HeapWord* src_end) |
| { |
| log_develop_trace(gc, compaction)( |
| "Summarizing %d [%s] into %d [%s]: " |
| "src=" PTR_FORMAT "-" PTR_FORMAT " " |
| SIZE_FORMAT "-" SIZE_FORMAT " " |
| "dst=" PTR_FORMAT "-" PTR_FORMAT " " |
| SIZE_FORMAT "-" SIZE_FORMAT, |
| src_space_id, space_names[src_space_id], |
| dst_space_id, space_names[dst_space_id], |
| p2i(src_beg), p2i(src_end), |
| _summary_data.addr_to_region_idx(src_beg), |
| _summary_data.addr_to_region_idx(src_end), |
| p2i(dst_beg), p2i(dst_end), |
| _summary_data.addr_to_region_idx(dst_beg), |
| _summary_data.addr_to_region_idx(dst_end)); |
| } |
| #endif // #ifndef PRODUCT |
| |
| void PSParallelCompact::summary_phase(ParCompactionManager* cm, |
| bool maximum_compaction) |
| { |
| GCTraceTime(Info, gc, phases) tm("Summary Phase", &_gc_timer); |
| |
| #ifdef ASSERT |
| if (TraceParallelOldGCMarkingPhase) { |
| tty->print_cr("add_obj_count=" SIZE_FORMAT " " |
| "add_obj_bytes=" SIZE_FORMAT, |
| add_obj_count, add_obj_size * HeapWordSize); |
| tty->print_cr("mark_bitmap_count=" SIZE_FORMAT " " |
| "mark_bitmap_bytes=" SIZE_FORMAT, |
| mark_bitmap_count, mark_bitmap_size * HeapWordSize); |
| } |
| #endif // #ifdef ASSERT |
| |
| // Quick summarization of each space into itself, to see how much is live. |
| summarize_spaces_quick(); |
| |
| log_develop_trace(gc, compaction)("summary phase: after summarizing each space to self"); |
| NOT_PRODUCT(print_region_ranges()); |
| NOT_PRODUCT(print_initial_summary_data(_summary_data, _space_info)); |
| |
| // The amount of live data that will end up in old space (assuming it fits). |
| size_t old_space_total_live = 0; |
| for (unsigned int id = old_space_id; id < last_space_id; ++id) { |
| old_space_total_live += pointer_delta(_space_info[id].new_top(), |
| _space_info[id].space()->bottom()); |
| } |
| |
| MutableSpace* const old_space = _space_info[old_space_id].space(); |
| const size_t old_capacity = old_space->capacity_in_words(); |
| if (old_space_total_live > old_capacity) { |
| // XXX - should also try to expand |
| maximum_compaction = true; |
| } |
| |
| // Old generations. |
| summarize_space(old_space_id, maximum_compaction); |
| |
| // Summarize the remaining spaces in the young gen. The initial target space |
| // is the old gen. If a space does not fit entirely into the target, then the |
| // remainder is compacted into the space itself and that space becomes the new |
| // target. |
| SpaceId dst_space_id = old_space_id; |
| HeapWord* dst_space_end = old_space->end(); |
| HeapWord** new_top_addr = _space_info[dst_space_id].new_top_addr(); |
| for (unsigned int id = eden_space_id; id < last_space_id; ++id) { |
| const MutableSpace* space = _space_info[id].space(); |
| const size_t live = pointer_delta(_space_info[id].new_top(), |
| space->bottom()); |
| const size_t available = pointer_delta(dst_space_end, *new_top_addr); |
| |
| NOT_PRODUCT(summary_phase_msg(dst_space_id, *new_top_addr, dst_space_end, |
| SpaceId(id), space->bottom(), space->top());) |
| if (live > 0 && live <= available) { |
| // All the live data will fit. |
| bool done = _summary_data.summarize(_space_info[id].split_info(), |
| space->bottom(), space->top(), |
| NULL, |
| *new_top_addr, dst_space_end, |
| new_top_addr); |
| assert(done, "space must fit into old gen"); |
| |
| // Reset the new_top value for the space. |
| _space_info[id].set_new_top(space->bottom()); |
| } else if (live > 0) { |
| // Attempt to fit part of the source space into the target space. |
| HeapWord* next_src_addr = NULL; |
| bool done = _summary_data.summarize(_space_info[id].split_info(), |
| space->bottom(), space->top(), |
| &next_src_addr, |
| *new_top_addr, dst_space_end, |
| new_top_addr); |
| assert(!done, "space should not fit into old gen"); |
| assert(next_src_addr != NULL, "sanity"); |
| |
| // The source space becomes the new target, so the remainder is compacted |
| // within the space itself. |
| dst_space_id = SpaceId(id); |
| dst_space_end = space->end(); |
| new_top_addr = _space_info[id].new_top_addr(); |
| NOT_PRODUCT(summary_phase_msg(dst_space_id, |
| space->bottom(), dst_space_end, |
| SpaceId(id), next_src_addr, space->top());) |
| done = _summary_data.summarize(_space_info[id].split_info(), |
| next_src_addr, space->top(), |
| NULL, |
| space->bottom(), dst_space_end, |
| new_top_addr); |
| assert(done, "space must fit when compacted into itself"); |
| assert(*new_top_addr <= space->top(), "usage should not grow"); |
| } |
| } |
| |
| log_develop_trace(gc, compaction)("Summary_phase: after final summarization"); |
| NOT_PRODUCT(print_region_ranges()); |
| NOT_PRODUCT(print_initial_summary_data(_summary_data, _space_info)); |
| } |
| |
| // This method should contain all heap-specific policy for invoking a full |
| // collection. invoke_no_policy() will only attempt to compact the heap; it |
| // will do nothing further. If we need to bail out for policy reasons, scavenge |
| // before full gc, or any other specialized behavior, it needs to be added here. |
| // |
| // Note that this method should only be called from the vm_thread while at a |
| // safepoint. |
| // |
| // Note that the all_soft_refs_clear flag in the collector policy |
| // may be true because this method can be called without intervening |
| // activity. For example when the heap space is tight and full measure |
| // are being taken to free space. |
| void PSParallelCompact::invoke(bool maximum_heap_compaction) { |
| assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
| assert(Thread::current() == (Thread*)VMThread::vm_thread(), |
| "should be in vm thread"); |
| |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| GCCause::Cause gc_cause = heap->gc_cause(); |
| assert(!heap->is_gc_active(), "not reentrant"); |
| |
| PSAdaptiveSizePolicy* policy = heap->size_policy(); |
| IsGCActiveMark mark; |
| |
| if (ScavengeBeforeFullGC) { |
| PSScavenge::invoke_no_policy(); |
| } |
| |
| const bool clear_all_soft_refs = |
| heap->collector_policy()->should_clear_all_soft_refs(); |
| |
| PSParallelCompact::invoke_no_policy(clear_all_soft_refs || |
| maximum_heap_compaction); |
| } |
| |
| // This method contains no policy. You should probably |
| // be calling invoke() instead. |
| bool PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) { |
| assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); |
| assert(ref_processor() != NULL, "Sanity"); |
| |
| if (GCLocker::check_active_before_gc()) { |
| return false; |
| } |
| |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| |
| GCIdMark gc_id_mark; |
| _gc_timer.register_gc_start(); |
| _gc_tracer.report_gc_start(heap->gc_cause(), _gc_timer.gc_start()); |
| |
| TimeStamp marking_start; |
| TimeStamp compaction_start; |
| TimeStamp collection_exit; |
| |
| GCCause::Cause gc_cause = heap->gc_cause(); |
| PSYoungGen* young_gen = heap->young_gen(); |
| PSOldGen* old_gen = heap->old_gen(); |
| PSAdaptiveSizePolicy* size_policy = heap->size_policy(); |
| |
| // The scope of casr should end after code that can change |
| // CollectorPolicy::_should_clear_all_soft_refs. |
| ClearedAllSoftRefs casr(maximum_heap_compaction, |
| heap->collector_policy()); |
| |
| if (ZapUnusedHeapArea) { |
| // Save information needed to minimize mangling |
| heap->record_gen_tops_before_GC(); |
| } |
| |
| // Make sure data structures are sane, make the heap parsable, and do other |
| // miscellaneous bookkeeping. |
| pre_compact(); |
| |
| PreGCValues pre_gc_values(heap); |
| |
| // Get the compaction manager reserved for the VM thread. |
| ParCompactionManager* const vmthread_cm = |
| ParCompactionManager::manager_array(gc_task_manager()->workers()); |
| |
| { |
| ResourceMark rm; |
| HandleMark hm; |
| |
| // Set the number of GC threads to be used in this collection |
| gc_task_manager()->set_active_gang(); |
| gc_task_manager()->task_idle_workers(); |
| |
| GCTraceCPUTime tcpu; |
| GCTraceTime(Info, gc) tm("Pause Full", NULL, gc_cause, true); |
| |
| heap->pre_full_gc_dump(&_gc_timer); |
| |
| TraceCollectorStats tcs(counters()); |
| TraceMemoryManagerStats tms(true /* Full GC */,gc_cause); |
| |
| if (TraceOldGenTime) accumulated_time()->start(); |
| |
| // Let the size policy know we're starting |
| size_policy->major_collection_begin(); |
| |
| CodeCache::gc_prologue(); |
| |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| DerivedPointerTable::clear(); |
| #endif |
| |
| ref_processor()->enable_discovery(); |
| ref_processor()->setup_policy(maximum_heap_compaction); |
| |
| bool marked_for_unloading = false; |
| |
| marking_start.update(); |
| marking_phase(vmthread_cm, maximum_heap_compaction, &_gc_tracer); |
| |
| bool max_on_system_gc = UseMaximumCompactionOnSystemGC |
| && GCCause::is_user_requested_gc(gc_cause); |
| summary_phase(vmthread_cm, maximum_heap_compaction || max_on_system_gc); |
| |
| #if defined(COMPILER2) || INCLUDE_JVMCI |
| assert(DerivedPointerTable::is_active(), "Sanity"); |
| DerivedPointerTable::set_active(false); |
| #endif |
| |
| // adjust_roots() updates Universe::_intArrayKlassObj which is |
| // needed by the compaction for filling holes in the dense prefix. |
| adjust_roots(vmthread_cm); |
| |
| compaction_start.update(); |
| compact(); |
| |
| // Reset the mark bitmap, summary data, and do other bookkeeping. Must be |
| // done before resizing. |
| post_compact(); |
| |
| // Let the size policy know we're done |
| size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); |
| |
| if (UseAdaptiveSizePolicy) { |
| log_debug(gc, ergo)("AdaptiveSizeStart: collection: %d ", heap->total_collections()); |
| log_trace(gc, ergo)("old_gen_capacity: " SIZE_FORMAT " young_gen_capacity: " SIZE_FORMAT, |
| old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes()); |
| |
| // Don't check if the size_policy is ready here. Let |
| // the size_policy check that internally. |
| if (UseAdaptiveGenerationSizePolicyAtMajorCollection && |
| AdaptiveSizePolicy::should_update_promo_stats(gc_cause)) { |
| // Swap the survivor spaces if from_space is empty. The |
| // resize_young_gen() called below is normally used after |
| // a successful young GC and swapping of survivor spaces; |
| // otherwise, it will fail to resize the young gen with |
| // the current implementation. |
| if (young_gen->from_space()->is_empty()) { |
| young_gen->from_space()->clear(SpaceDecorator::Mangle); |
| young_gen->swap_spaces(); |
| } |
| |
| // Calculate optimal free space amounts |
| assert(young_gen->max_size() > |
| young_gen->from_space()->capacity_in_bytes() + |
| young_gen->to_space()->capacity_in_bytes(), |
| "Sizes of space in young gen are out-of-bounds"); |
| |
| size_t young_live = young_gen->used_in_bytes(); |
| size_t eden_live = young_gen->eden_space()->used_in_bytes(); |
| size_t old_live = old_gen->used_in_bytes(); |
| size_t cur_eden = young_gen->eden_space()->capacity_in_bytes(); |
| size_t max_old_gen_size = old_gen->max_gen_size(); |
| size_t max_eden_size = young_gen->max_size() - |
| young_gen->from_space()->capacity_in_bytes() - |
| young_gen->to_space()->capacity_in_bytes(); |
| |
| // Used for diagnostics |
| size_policy->clear_generation_free_space_flags(); |
| |
| size_policy->compute_generations_free_space(young_live, |
| eden_live, |
| old_live, |
| cur_eden, |
| max_old_gen_size, |
| max_eden_size, |
| true /* full gc*/); |
| |
| size_policy->check_gc_overhead_limit(young_live, |
| eden_live, |
| max_old_gen_size, |
| max_eden_size, |
| true /* full gc*/, |
| gc_cause, |
| heap->collector_policy()); |
| |
| size_policy->decay_supplemental_growth(true /* full gc*/); |
| |
| heap->resize_old_gen( |
| size_policy->calculated_old_free_size_in_bytes()); |
| |
| heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(), |
| size_policy->calculated_survivor_size_in_bytes()); |
| } |
| |
| log_debug(gc, ergo)("AdaptiveSizeStop: collection: %d ", heap->total_collections()); |
| } |
| |
| if (UsePerfData) { |
| PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters(); |
| counters->update_counters(); |
| counters->update_old_capacity(old_gen->capacity_in_bytes()); |
| counters->update_young_capacity(young_gen->capacity_in_bytes()); |
| } |
| |
| heap->resize_all_tlabs(); |
| |
| // Resize the metaspace capacity after a collection |
| MetaspaceGC::compute_new_size(); |
| |
| if (TraceOldGenTime) { |
| accumulated_time()->stop(); |
| } |
| |
| young_gen->print_used_change(pre_gc_values.young_gen_used()); |
| old_gen->print_used_change(pre_gc_values.old_gen_used()); |
| MetaspaceAux::print_metaspace_change(pre_gc_values.metadata_used()); |
| |
| // Track memory usage and detect low memory |
| MemoryService::track_memory_usage(); |
| heap->update_counters(); |
| gc_task_manager()->release_idle_workers(); |
| |
| heap->post_full_gc_dump(&_gc_timer); |
| } |
| |
| #ifdef ASSERT |
| for (size_t i = 0; i < ParallelGCThreads + 1; ++i) { |
| ParCompactionManager* const cm = |
| ParCompactionManager::manager_array(int(i)); |
| assert(cm->marking_stack()->is_empty(), "should be empty"); |
| assert(cm->region_stack()->is_empty(), "Region stack " SIZE_FORMAT " is not empty", i); |
| } |
| #endif // ASSERT |
| |
| if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { |
| HandleMark hm; // Discard invalid handles created during verification |
| Universe::verify("After GC"); |
| } |
| |
| // Re-verify object start arrays |
| if (VerifyObjectStartArray && |
| VerifyAfterGC) { |
| old_gen->verify_object_start_array(); |
| } |
| |
| if (ZapUnusedHeapArea) { |
| old_gen->object_space()->check_mangled_unused_area_complete(); |
| } |
| |
| NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
| |
| collection_exit.update(); |
| |
| heap->print_heap_after_gc(); |
| heap->trace_heap_after_gc(&_gc_tracer); |
| |
| log_debug(gc, task, time)("VM-Thread " JLONG_FORMAT " " JLONG_FORMAT " " JLONG_FORMAT, |
| marking_start.ticks(), compaction_start.ticks(), |
| collection_exit.ticks()); |
| gc_task_manager()->print_task_time_stamps(); |
| |
| #ifdef TRACESPINNING |
| ParallelTaskTerminator::print_termination_counts(); |
| #endif |
| |
| AdaptiveSizePolicyOutput::print(size_policy, heap->total_collections()); |
| |
| _gc_timer.register_gc_end(); |
| |
| _gc_tracer.report_dense_prefix(dense_prefix(old_space_id)); |
| _gc_tracer.report_gc_end(_gc_timer.gc_end(), _gc_timer.time_partitions()); |
| |
| return true; |
| } |
| |
| bool PSParallelCompact::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, |
| PSYoungGen* young_gen, |
| PSOldGen* old_gen) { |
| MutableSpace* const eden_space = young_gen->eden_space(); |
| assert(!eden_space->is_empty(), "eden must be non-empty"); |
| assert(young_gen->virtual_space()->alignment() == |
| old_gen->virtual_space()->alignment(), "alignments do not match"); |
| |
| if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { |
| return false; |
| } |
| |
| // Both generations must be completely committed. |
| if (young_gen->virtual_space()->uncommitted_size() != 0) { |
| return false; |
| } |
| if (old_gen->virtual_space()->uncommitted_size() != 0) { |
| return false; |
| } |
| |
| // Figure out how much to take from eden. Include the average amount promoted |
| // in the total; otherwise the next young gen GC will simply bail out to a |
| // full GC. |
| const size_t alignment = old_gen->virtual_space()->alignment(); |
| const size_t eden_used = eden_space->used_in_bytes(); |
| const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); |
| const size_t absorb_size = align_up(eden_used + promoted, alignment); |
| const size_t eden_capacity = eden_space->capacity_in_bytes(); |
| |
| if (absorb_size >= eden_capacity) { |
| return false; // Must leave some space in eden. |
| } |
| |
| const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; |
| if (new_young_size < young_gen->min_gen_size()) { |
| return false; // Respect young gen minimum size. |
| } |
| |
| log_trace(heap, ergo)(" absorbing " SIZE_FORMAT "K: " |
| "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " |
| "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " |
| "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", |
| absorb_size / K, |
| eden_capacity / K, (eden_capacity - absorb_size) / K, |
| young_gen->from_space()->used_in_bytes() / K, |
| young_gen->to_space()->used_in_bytes() / K, |
| young_gen->capacity_in_bytes() / K, new_young_size / K); |
| |
| // Fill the unused part of the old gen. |
| MutableSpace* const old_space = old_gen->object_space(); |
| HeapWord* const unused_start = old_space->top(); |
| size_t const unused_words = pointer_delta(old_space->end(), unused_start); |
| |
| if (unused_words > 0) { |
| if (unused_words < CollectedHeap::min_fill_size()) { |
| return false; // If the old gen cannot be filled, must give up. |
| } |
| CollectedHeap::fill_with_objects(unused_start, unused_words); |
| } |
| |
| // Take the live data from eden and set both top and end in the old gen to |
| // eden top. (Need to set end because reset_after_change() mangles the region |
| // from end to virtual_space->high() in debug builds). |
| HeapWord* const new_top = eden_space->top(); |
| old_gen->virtual_space()->expand_into(young_gen->virtual_space(), |
| absorb_size); |
| young_gen->reset_after_change(); |
| old_space->set_top(new_top); |
| old_space->set_end(new_top); |
| old_gen->reset_after_change(); |
| |
| // Update the object start array for the filler object and the data from eden. |
| ObjectStartArray* const start_array = old_gen->start_array(); |
| for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { |
| start_array->allocate_block(p); |
| } |
| |
| // Could update the promoted average here, but it is not typically updated at |
| // full GCs and the value to use is unclear. Something like |
| // |
| // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. |
| |
| size_policy->set_bytes_absorbed_from_eden(absorb_size); |
| return true; |
| } |
| |
| GCTaskManager* const PSParallelCompact::gc_task_manager() { |
| assert(ParallelScavengeHeap::gc_task_manager() != NULL, |
| "shouldn't return NULL"); |
| return ParallelScavengeHeap::gc_task_manager(); |
| } |
| |
| void PSParallelCompact::marking_phase(ParCompactionManager* cm, |
| bool maximum_heap_compaction, |
| ParallelOldTracer *gc_tracer) { |
| // Recursively traverse all live objects and mark them |
| GCTraceTime(Info, gc, phases) tm("Marking Phase", &_gc_timer); |
| |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| uint parallel_gc_threads = heap->gc_task_manager()->workers(); |
| uint active_gc_threads = heap->gc_task_manager()->active_workers(); |
| TaskQueueSetSuper* qset = ParCompactionManager::stack_array(); |
| ParallelTaskTerminator terminator(active_gc_threads, qset); |
| |
| ParCompactionManager::MarkAndPushClosure mark_and_push_closure(cm); |
| ParCompactionManager::FollowStackClosure follow_stack_closure(cm); |
| |
| // Need new claim bits before marking starts. |
| ClassLoaderDataGraph::clear_claimed_marks(); |
| |
| { |
| GCTraceTime(Debug, gc, phases) tm("Par Mark", &_gc_timer); |
| |
| ParallelScavengeHeap::ParStrongRootsScope psrs; |
| |
| GCTaskQueue* q = GCTaskQueue::create(); |
| |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::universe)); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jni_handles)); |
| // We scan the thread roots in parallel |
| Threads::create_thread_roots_marking_tasks(q); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::object_synchronizer)); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::management)); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::system_dictionary)); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::class_loader_data)); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jvmti)); |
| q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::code_cache)); |
| |
| if (active_gc_threads > 1) { |
| for (uint j = 0; j < active_gc_threads; j++) { |
| q->enqueue(new StealMarkingTask(&terminator)); |
| } |
| } |
| |
| gc_task_manager()->execute_and_wait(q); |
| } |
| |
| // Process reference objects found during marking |
| { |
| GCTraceTime(Debug, gc, phases) tm("Reference Processing", &_gc_timer); |
| |
| ReferenceProcessorStats stats; |
| ReferenceProcessorPhaseTimes pt(&_gc_timer, ref_processor()->num_q()); |
| if (ref_processor()->processing_is_mt()) { |
| RefProcTaskExecutor task_executor; |
| stats = ref_processor()->process_discovered_references( |
| is_alive_closure(), &mark_and_push_closure, &follow_stack_closure, |
| &task_executor, &pt); |
| } else { |
| stats = ref_processor()->process_discovered_references( |
| is_alive_closure(), &mark_and_push_closure, &follow_stack_closure, NULL, |
| &pt); |
| } |
| |
| gc_tracer->report_gc_reference_stats(stats); |
| pt.print_all_references(); |
| } |
| |
| // This is the point where the entire marking should have completed. |
| assert(cm->marking_stacks_empty(), "Marking should have completed"); |
| |
| { |
| GCTraceTime(Debug, gc, phases) tm_m("Class Unloading", &_gc_timer); |
| |
| // Follow system dictionary roots and unload classes. |
| bool purged_class = SystemDictionary::do_unloading(is_alive_closure(), &_gc_timer); |
| |
| // Unload nmethods. |
| CodeCache::do_unloading(is_alive_closure(), purged_class); |
| |
| // Prune dead klasses from subklass/sibling/implementor lists. |
| Klass::clean_weak_klass_links(is_alive_closure()); |
| } |
| |
| { |
| GCTraceTime(Debug, gc, phases) t("Scrub String Table", &_gc_timer); |
| // Delete entries for dead interned strings. |
| StringTable::unlink(is_alive_closure()); |
| } |
| |
| { |
| GCTraceTime(Debug, gc, phases) t("Scrub Symbol Table", &_gc_timer); |
| // Clean up unreferenced symbols in symbol table. |
| SymbolTable::unlink(); |
| } |
| |
| _gc_tracer.report_object_count_after_gc(is_alive_closure()); |
| } |
| |
| void PSParallelCompact::adjust_roots(ParCompactionManager* cm) { |
| // Adjust the pointers to reflect the new locations |
| GCTraceTime(Info, gc, phases) tm("Adjust Roots", &_gc_timer); |
| |
| // Need new claim bits when tracing through and adjusting pointers. |
| ClassLoaderDataGraph::clear_claimed_marks(); |
| |
| PSParallelCompact::AdjustPointerClosure oop_closure(cm); |
| PSParallelCompact::AdjustKlassClosure klass_closure(cm); |
| |
| // General strong roots. |
| Universe::oops_do(&oop_closure); |
| JNIHandles::oops_do(&oop_closure); // Global (strong) JNI handles |
| Threads::oops_do(&oop_closure, NULL); |
| ObjectSynchronizer::oops_do(&oop_closure); |
| Management::oops_do(&oop_closure); |
| JvmtiExport::oops_do(&oop_closure); |
| SystemDictionary::oops_do(&oop_closure); |
| ClassLoaderDataGraph::oops_do(&oop_closure, &klass_closure, true); |
| |
| // Now adjust pointers in remaining weak roots. (All of which should |
| // have been cleared if they pointed to non-surviving objects.) |
| // Global (weak) JNI handles |
| JNIHandles::weak_oops_do(&oop_closure); |
| |
| CodeBlobToOopClosure adjust_from_blobs(&oop_closure, CodeBlobToOopClosure::FixRelocations); |
| CodeCache::blobs_do(&adjust_from_blobs); |
| AOTLoader::oops_do(&oop_closure); |
| StringTable::oops_do(&oop_closure); |
| ref_processor()->weak_oops_do(&oop_closure); |
| // Roots were visited so references into the young gen in roots |
| // may have been scanned. Process them also. |
| // Should the reference processor have a span that excludes |
| // young gen objects? |
| PSScavenge::reference_processor()->weak_oops_do(&oop_closure); |
| } |
| |
| // Helper class to print 8 region numbers per line and then print the total at the end. |
| class FillableRegionLogger : public StackObj { |
| private: |
| Log(gc, compaction) log; |
| static const int LineLength = 8; |
| size_t _regions[LineLength]; |
| int _next_index; |
| bool _enabled; |
| size_t _total_regions; |
| public: |
| FillableRegionLogger() : _next_index(0), _total_regions(0), _enabled(log_develop_is_enabled(Trace, gc, compaction)) { } |
| ~FillableRegionLogger() { |
| log.trace(SIZE_FORMAT " initially fillable regions", _total_regions); |
| } |
| |
| void print_line() { |
| if (!_enabled || _next_index == 0) { |
| return; |
| } |
| FormatBuffer<> line("Fillable: "); |
| for (int i = 0; i < _next_index; i++) { |
| line.append(" " SIZE_FORMAT_W(7), _regions[i]); |
| } |
| log.trace("%s", line.buffer()); |
| _next_index = 0; |
| } |
| |
| void handle(size_t region) { |
| if (!_enabled) { |
| return; |
| } |
| _regions[_next_index++] = region; |
| if (_next_index == LineLength) { |
| print_line(); |
| } |
| _total_regions++; |
| } |
| }; |
| |
| void PSParallelCompact::prepare_region_draining_tasks(GCTaskQueue* q, |
| uint parallel_gc_threads) |
| { |
| GCTraceTime(Trace, gc, phases) tm("Drain Task Setup", &_gc_timer); |
| |
| // Find the threads that are active |
| unsigned int which = 0; |
| |
| // Find all regions that are available (can be filled immediately) and |
| // distribute them to the thread stacks. The iteration is done in reverse |
| // order (high to low) so the regions will be removed in ascending order. |
| |
| const ParallelCompactData& sd = PSParallelCompact::summary_data(); |
| |
| which = 0; |
| // id + 1 is used to test termination so unsigned can |
| // be used with an old_space_id == 0. |
| FillableRegionLogger region_logger; |
| for (unsigned int id = to_space_id; id + 1 > old_space_id; --id) { |
| SpaceInfo* const space_info = _space_info + id; |
| MutableSpace* const space = space_info->space(); |
| HeapWord* const new_top = space_info->new_top(); |
| |
| const size_t beg_region = sd.addr_to_region_idx(space_info->dense_prefix()); |
| const size_t end_region = |
| sd.addr_to_region_idx(sd.region_align_up(new_top)); |
| |
| for (size_t cur = end_region - 1; cur + 1 > beg_region; --cur) { |
| if (sd.region(cur)->claim_unsafe()) { |
| ParCompactionManager* cm = ParCompactionManager::manager_array(which); |
| cm->region_stack()->push(cur); |
| region_logger.handle(cur); |
| // Assign regions to tasks in round-robin fashion. |
| if (++which == parallel_gc_threads) { |
| which = 0; |
| } |
| } |
| } |
| region_logger.print_line(); |
| } |
| } |
| |
| #define PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING 4 |
| |
| void PSParallelCompact::enqueue_dense_prefix_tasks(GCTaskQueue* q, |
| uint parallel_gc_threads) { |
| GCTraceTime(Trace, gc, phases) tm("Dense Prefix Task Setup", &_gc_timer); |
| |
| ParallelCompactData& sd = PSParallelCompact::summary_data(); |
| |
| // Iterate over all the spaces adding tasks for updating |
| // regions in the dense prefix. Assume that 1 gc thread |
| // will work on opening the gaps and the remaining gc threads |
| // will work on the dense prefix. |
| unsigned int space_id; |
| for (space_id = old_space_id; space_id < last_space_id; ++ space_id) { |
| HeapWord* const dense_prefix_end = _space_info[space_id].dense_prefix(); |
| const MutableSpace* const space = _space_info[space_id].space(); |
| |
| if (dense_prefix_end == space->bottom()) { |
| // There is no dense prefix for this space. |
| continue; |
| } |
| |
| // The dense prefix is before this region. |
| size_t region_index_end_dense_prefix = |
| sd.addr_to_region_idx(dense_prefix_end); |
| RegionData* const dense_prefix_cp = |
| sd.region(region_index_end_dense_prefix); |
| assert(dense_prefix_end == space->end() || |
| dense_prefix_cp->available() || |
| dense_prefix_cp->claimed(), |
| "The region after the dense prefix should always be ready to fill"); |
| |
| size_t region_index_start = sd.addr_to_region_idx(space->bottom()); |
| |
| // Is there dense prefix work? |
| size_t total_dense_prefix_regions = |
| region_index_end_dense_prefix - region_index_start; |
| // How many regions of the dense prefix should be given to |
| // each thread? |
| if (total_dense_prefix_regions > 0) { |
| uint tasks_for_dense_prefix = 1; |
| if (total_dense_prefix_regions <= |
| (parallel_gc_threads * PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING)) { |
| // Don't over partition. This assumes that |
| // PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING is a small integer value |
| // so there are not many regions to process. |
| tasks_for_dense_prefix = parallel_gc_threads; |
| } else { |
| // Over partition |
| tasks_for_dense_prefix = parallel_gc_threads * |
| PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING; |
| } |
| size_t regions_per_thread = total_dense_prefix_regions / |
| tasks_for_dense_prefix; |
| // Give each thread at least 1 region. |
| if (regions_per_thread == 0) { |
| regions_per_thread = 1; |
| } |
| |
| for (uint k = 0; k < tasks_for_dense_prefix; k++) { |
| if (region_index_start >= region_index_end_dense_prefix) { |
| break; |
| } |
| // region_index_end is not processed |
| size_t region_index_end = MIN2(region_index_start + regions_per_thread, |
| region_index_end_dense_prefix); |
| q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id), |
| region_index_start, |
| region_index_end)); |
| region_index_start = region_index_end; |
| } |
| } |
| // This gets any part of the dense prefix that did not |
| // fit evenly. |
| if (region_index_start < region_index_end_dense_prefix) { |
| q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id), |
| region_index_start, |
| region_index_end_dense_prefix)); |
| } |
| } |
| } |
| |
| void PSParallelCompact::enqueue_region_stealing_tasks( |
| GCTaskQueue* q, |
| ParallelTaskTerminator* terminator_ptr, |
| uint parallel_gc_threads) { |
| GCTraceTime(Trace, gc, phases) tm("Steal Task Setup", &_gc_timer); |
| |
| // Once a thread has drained it's stack, it should try to steal regions from |
| // other threads. |
| for (uint j = 0; j < parallel_gc_threads; j++) { |
| q->enqueue(new CompactionWithStealingTask(terminator_ptr)); |
| } |
| } |
| |
| #ifdef ASSERT |
| // Write a histogram of the number of times the block table was filled for a |
| // region. |
| void PSParallelCompact::write_block_fill_histogram() |
| { |
| if (!log_develop_is_enabled(Trace, gc, compaction)) { |
| return; |
| } |
| |
| Log(gc, compaction) log; |
| ResourceMark rm; |
| LogStream ls(log.trace()); |
| outputStream* out = &ls; |
| |
| typedef ParallelCompactData::RegionData rd_t; |
| ParallelCompactData& sd = summary_data(); |
| |
| for (unsigned int id = old_space_id; id < last_space_id; ++id) { |
| MutableSpace* const spc = _space_info[id].space(); |
| if (spc->bottom() != spc->top()) { |
| const rd_t* const beg = sd.addr_to_region_ptr(spc->bottom()); |
| HeapWord* const top_aligned_up = sd.region_align_up(spc->top()); |
| const rd_t* const end = sd.addr_to_region_ptr(top_aligned_up); |
| |
| size_t histo[5] = { 0, 0, 0, 0, 0 }; |
| const size_t histo_len = sizeof(histo) / sizeof(size_t); |
| const size_t region_cnt = pointer_delta(end, beg, sizeof(rd_t)); |
| |
| for (const rd_t* cur = beg; cur < end; ++cur) { |
| ++histo[MIN2(cur->blocks_filled_count(), histo_len - 1)]; |
| } |
| out->print("Block fill histogram: %u %-4s" SIZE_FORMAT_W(5), id, space_names[id], region_cnt); |
| for (size_t i = 0; i < histo_len; ++i) { |
| out->print(" " SIZE_FORMAT_W(5) " %5.1f%%", |
| histo[i], 100.0 * histo[i] / region_cnt); |
| } |
| out->cr(); |
| } |
| } |
| } |
| #endif // #ifdef ASSERT |
| |
| void PSParallelCompact::compact() { |
| GCTraceTime(Info, gc, phases) tm("Compaction Phase", &_gc_timer); |
| |
| ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); |
| PSOldGen* old_gen = heap->old_gen(); |
| old_gen->start_array()->reset(); |
| uint parallel_gc_threads = heap->gc_task_manager()->workers(); |
| uint active_gc_threads = heap->gc_task_manager()->active_workers(); |
| TaskQueueSetSuper* qset = ParCompactionManager::region_array(); |
| ParallelTaskTerminator terminator(active_gc_threads, qset); |
| |
| GCTaskQueue* q = GCTaskQueue::create(); |
| prepare_region_draining_tasks(q, active_gc_threads); |
| enqueue_dense_prefix_tasks(q, active_gc_threads); |
| enqueue_region_stealing_tasks(q, &terminator, active_gc_threads); |
| |
| { |
| GCTraceTime(Trace, gc, phases) tm("Par Compact", &_gc_timer); |
| |
| gc_task_manager()->execute_and_wait(q); |
| |
| #ifdef ASSERT |
| // Verify that all regions have been processed before the deferred updates. |
| for (unsigned int id = old_space_id; id < last_space_id; ++id) { |
| verify_complete(SpaceId(id)); |
| } |
| #endif |
| } |
| |
| { |
| // Update the deferred objects, if any. Any compaction manager can be used. |
| GCTraceTime(Trace, gc, phases) tm("Deferred Updates", &_gc_timer); |
| ParCompactionManager* cm = ParCompactionManager::manager_array(0); |
| for (unsigned int id = old_space_id; id < last_space_id; ++id) { |
| update_deferred_objects(cm, SpaceId(id)); |
| } |
| } |
| |
| DEBUG_ONLY(write_block_fill_histogram()); |
| } |
| |
| #ifdef ASSERT |
| void PSParallelCompact::verify_complete(SpaceId space_id) { |
| // All Regions between space bottom() to new_top() should be marked as filled |
| // and all Regions between new_top() and top() should be available (i.e., |
| // should have been emptied). |
| ParallelCompactData& sd = summary_data(); |
| SpaceInfo si = _space_info[space_id]; |
| HeapWord* new_top_addr = sd.region_align_up(si.new_top()); |
| HeapWord* old_top_addr = sd.region_align_up(si.space()->top()); |
| const size_t beg_region = sd.addr_to_region_idx(si.space()->bottom()); |
| const size_t new_top_region = sd.addr_to_region_idx(new_top_addr); |
| const size_t old_top_region = sd.addr_to_region_idx(old_top_addr); |
| |
| bool issued_a_warning = false; |
| |
| size_t cur_region; |
| for (cur_region = beg_region; cur_region < new_top_region; ++cur_region) { |
| const RegionData* const c = sd.region(cur_region); |
| if (!c->completed()) { |
| log_warning(gc)("region " SIZE_FORMAT " not filled: destination_count=%u", |
| cur_region, c->destination_count()); |
| issued_a_warning = true; |
| } |
| } |
| |
| for (cur_region = new_top_region; cur_region < old_top_region; ++cur_region) { |
| const RegionData* const c = sd.region(cur_region); |
| if (!c->available()) { |
| log_warning(gc)("region " SIZE_FORMAT " not empty: destination_count=%u", |
| cur_region, c->destination_count()); |
| issued_a_warning = true; |
| } |
| } |
| |
| if (issued_a_warning) { |
| print_region_ranges(); |
| } |
| } |
| #endif // #ifdef ASSERT |
| |
| inline void UpdateOnlyClosure::do_addr(HeapWord* addr) { |
| _start_array->allocate_block(addr); |
| compaction_manager()->update_contents(oop(addr)); |
| } |
| |
| // Update interior oops in the ranges of regions [beg_region, end_region). |
| void |
| PSParallelCompact::update_and_deadwood_in_dense_prefix(ParCompactionManager* cm, |
| SpaceId space_id, |
| size_t beg_region, |
| size_t end_region) { |
| ParallelCompactData& sd = summary_data(); |
| ParMarkBitMap* const mbm = mark_bitmap(); |
| |
| HeapWord* beg_addr = sd.region_to_addr(beg_region); |
| HeapWord* const end_addr = sd.region_to_addr(end_region); |
| assert(beg_region <= end_region, "bad region range"); |
| assert(end_addr <= dense_prefix(space_id), "not in the dense prefix"); |
| |
| #ifdef ASSERT |
| // Claim the regions to avoid triggering an assert when they are marked as |
| // filled. |
| for (size_t claim_region = beg_region; claim_region < end_region; ++claim_region) { |
| assert(sd.region(claim_region)->claim_unsafe(), "claim() failed"); |
| } |
| #endif // #ifdef ASSERT |
| |
| if (beg_addr != space(space_id)->bottom()) { |
| // Find the first live object or block of dead space that *starts* in this |
| // range of regions. If a partial object crosses onto the region, skip it; |
| // it will be marked for 'deferred update' when the object head is |
| // processed. If dead space crosses onto the region, it is also skipped; it |
| // will be filled when the prior region is processed. If neither of those |
| // apply, the first word in the region is the start of a live object or dead |
| // space. |
| assert(beg_addr > space(space_id)->bottom(), "sanity"); |
| const RegionData* const cp = sd.region(beg_region); |
| if (cp->partial_obj_size() != 0) { |
| beg_addr = sd.partial_obj_end(beg_region); |
| } else if (dead_space_crosses_boundary(cp, mbm->addr_to_bit(beg_addr))) { |
| beg_addr = mbm->find_obj_beg(beg_addr, end_addr); |
| } |
| } |
| |
| if (beg_addr < end_addr) { |
| // A live object or block of dead space starts in this range of Regions. |
| HeapWord* const dense_prefix_end = dense_prefix(space_id); |
| |
| // Create closures and iterate. |
| UpdateOnlyClosure update_closure(mbm, cm, space_id); |
| FillClosure fill_closure(cm, space_id); |
| ParMarkBitMap::IterationStatus status; |
| status = mbm->iterate(&update_closure, &fill_closure, beg_addr, end_addr, |
| dense_prefix_end); |
| if (status == ParMarkBitMap::incomplete) { |
| update_closure.do_addr(update_closure.source()); |
| } |
| } |
| |
| // Mark the regions as filled. |
| RegionData* const beg_cp = sd.region(beg_region); |
| RegionData* const end_cp = sd.region(end_region); |
| for (RegionData* cp = beg_cp; cp < end_cp; ++cp) { |
| cp->set_completed(); |
| } |
| } |
| |
| // Return the SpaceId for the space containing addr. If addr is not in the |
| // heap, last_space_id is returned. In debug mode it expects the address to be |
| // in the heap and asserts such. |
| PSParallelCompact::SpaceId PSParallelCompact::space_id(HeapWord* addr) { |
| assert(ParallelScavengeHeap::heap()->is_in_reserved(addr), "addr not in the heap"); |
| |
| for (unsigned int id = old_space_id; id < last_space_id; ++id) { |
| if (_space_info[id].space()->contains(addr)) { |
| return SpaceId(id); |
| } |
| } |
| |
| assert(false, "no space contains the addr"); |
| return last_space_id; |
| } |
| |
| void PSParallelCompact::update_deferred_objects(ParCompactionManager* cm, |
| SpaceId id) { |
| assert(id < last_space_id, "bad space id"); |
| |
| ParallelCompactData& sd = summary_data(); |
| const SpaceInfo* const space_info = _space_info + id; |
| ObjectStartArray* const start_array = space_info->start_array(); |
| |
| const MutableSpace* const space = space_info->space(); |
| assert(space_info->dense_prefix() >= space->bottom(), "dense_prefix not set"); |
| HeapWord* const beg_addr = space_info->dense_prefix(); |
| HeapWord* const end_addr = sd.region_align_up(space_info->new_top()); |
| |
| const RegionData* const beg_region = sd.addr_to_region_ptr(beg_addr); |
| const RegionData* const end_region = sd.addr_to_region_ptr(end_addr); |
| const RegionData* cur_region; |
| for (cur_region = beg_region; cur_region < end_region; ++cur_region) { |
| HeapWord* const addr = cur_region->deferred_obj_addr(); |
| if (addr != NULL) { |
| if (start_array != NULL) { |
| start_array->allocate_block(addr); |
| } |
| cm->update_contents(oop(addr)); |
| assert(oopDesc::is_oop_or_null(oop(addr)), "Expected an oop or NULL at " PTR_FORMAT, p2i(oop(addr))); |
| } |
| } |
| } |
| |
| // Skip over count live words starting from beg, and return the address of the |
| // next live word. Unless marked, the word corresponding to beg is assumed to |
| // be dead. Callers must either ensure beg does not correspond to the middle of |
| // an object, or account for those live words in some other way. Callers must |
| // also ensure that there are enough live words in the range [beg, end) to skip. |
| HeapWord* |
| PSParallelCompact::skip_live_words(HeapWord* beg, HeapWord* end, size_t count) |
| { |
| assert(count > 0, "sanity"); |
| |
| ParMarkBitMap* m = mark_bitmap(); |
| idx_t bits_to_skip = m->words_to_bits(count); |
| idx_t cur_beg = m->addr_to_bit(beg); |
| const idx_t search_end = BitMap::word_align_up(m->addr_to_bit(end)); |
| |
| do { |
| cur_beg = m->find_obj_beg(cur_beg, search_end); |
| idx_t cur_end = m->find_obj_end(cur_beg, search_end); |
| const size_t obj_bits = cur_end - cur_beg + 1; |
| if (obj_bits > bits_to_skip) { |
| return m->bit_to_addr(cur_beg + bits_to_skip); |
| } |
| bits_to_skip -= obj_bits; |
| cur_beg = cur_end + 1; |
| } while (bits_to_skip > 0); |
| |
| // Skipping the desired number of words landed just past the end of an object. |
| // Find the start of the next object. |
| cur_beg = m->find_obj_beg(cur_beg, search_end); |
| assert(cur_beg < m->addr_to_bit(end), "not enough live words to skip"); |
| return m->bit_to_addr(cur_beg); |
| } |
| |
| HeapWord* PSParallelCompact::first_src_addr(HeapWord* const dest_addr, |
| SpaceId src_space_id, |
| size_t src_region_idx) |
| { |
| assert(summary_data().is_region_aligned(dest_addr), "not aligned"); |
| |
| const SplitInfo& split_info = _space_info[src_space_id].split_info(); |
| if (split_info.dest_region_addr() == dest_addr) { |
| // The partial object ending at the split point contains the first word to |
| // be copied to dest_addr. |
| return split_info.first_src_addr(); |
| } |
| |
| const ParallelCompactData& sd = summary_data(); |
| ParMarkBitMap* const bitmap = mark_bitmap(); |
| const size_t RegionSize = ParallelCompactData::RegionSize; |
| |
| assert(sd.is_region_aligned(dest_addr), "not aligned"); |
| const RegionData* const src_region_ptr = sd.region(src_region_idx); |
| const size_t partial_obj_size = src_region_ptr->partial_obj_size(); |
| HeapWord* const src_region_destination = src_region_ptr->destination(); |
| |
| assert(dest_addr >= src_region_destination, "wrong src region"); |
| assert(src_region_ptr->data_size() > 0, "src region cannot be empty"); |
| |
| HeapWord* const src_region_beg = sd.region_to_addr(src_region_idx); |
| HeapWord* const src_region_end = src_region_beg + RegionSize; |
| |
| HeapWord* addr = src_region_beg; |
| if (dest_addr == src_region_destination) { |
| // Return the first live word in the source region. |
| if (partial_obj_size == 0) { |
| addr = bitmap->find_obj_beg(addr, src_region_end); |
| assert(addr < src_region_end, "no objects start in src region"); |
| } |
| return addr; |
| } |
| |
| // Must skip some live data. |
| size_t words_to_skip = dest_addr - src_region_destination; |
| assert(src_region_ptr->data_size() > words_to_skip, "wrong src region"); |
| |
| if (partial_obj_size >= words_to_skip) { |
| // All the live words to skip are part of the partial object. |
| addr += words_to_skip; |
| if (partial_obj_size == words_to_skip) { |
| // Find the first live word past the partial object. |
| addr = bitmap->find_obj_beg(addr, src_region_end); |
| assert(addr < src_region_end, "wrong src region"); |
| } |
| return addr; |
| } |
| |
| // Skip over the partial object (if any). |
| if (partial_obj_size != 0) { |
| words_to_skip -= partial_obj_size; |
| addr += partial_obj_size; |
| } |
| |
| // Skip over live words due to objects that start in the region. |
| addr = skip_live_words(addr, src_region_end, words_to_skip); |
| assert(addr < src_region_end, "wrong src region"); |
| return addr; |
| } |
| |
| void PSParallelCompact::decrement_destination_counts(ParCompactionManager* cm, |
| SpaceId src_space_id, |
| size_t beg_region, |
| HeapWord* end_addr) |
| { |
| ParallelCompactData& sd = summary_data(); |
| |
| #ifdef ASSERT |
| MutableSpace* const src_space = _space_info[src_space_id].space(); |
| HeapWord* const beg_addr = sd.region_to_addr(beg_region); |
| assert(src_space->contains(beg_addr) || beg_addr == src_space->end(), |
| "src_space_id does not match beg_addr"); |
| assert(src_space->contains(end_addr) || end_addr == src_space->end(), |
| "src_space_id does not match end_addr"); |
| #endif // #ifdef ASSERT |
| |
| RegionData* const beg = sd.region(beg_region); |
| RegionData* const end = sd.addr_to_region_ptr(sd.region_align_up(end_addr)); |
| |
| // Regions up to new_top() are enqueued if they become available. |
| HeapWord* const new_top = _space_info[src_space_id].new_top(); |
| RegionData* const enqueue_end = |
| sd.addr_to_region_ptr(sd.region_align_up(new_top)); |
| |
| for (RegionData* cur = beg; cur < end; ++cur) { |
| assert(cur->data_size() > 0, "region must have live data"); |
| cur->decrement_destination_count(); |
| if (cur < enqueue_end && cur->available() && cur->claim()) { |
| cm->push_region(sd.region(cur)); |
| } |
| } |
| } |
| |
| size_t PSParallelCompact::next_src_region(MoveAndUpdateClosure& closure, |
| SpaceId& src_space_id, |
| HeapWord*& src_space_top, |
| HeapWord* end_addr) |
| { |
| typedef ParallelCompactData::RegionData RegionData; |
| |
| ParallelCompactData& sd = PSParallelCompact::summary_data(); |
| const size_t region_size = ParallelCompactData::RegionSize; |
| |
| size_t src_region_idx = 0; |
| |
| // Skip empty regions (if any) up to the top of the space. |
| HeapWord* const src_aligned_up = sd.region_align_up(end_addr); |
| RegionData* src_region_ptr = sd.addr_to_region_ptr(src_aligned_up); |
| HeapWord* const top_aligned_up = sd.region_align_up(src_space_top); |
| const RegionData* const top_region_ptr = |
| sd.addr_to_region_ptr(top_aligned_up); |
| while (src_region_ptr < top_region_ptr && src_region_ptr->data_size() == 0) { |
| ++src_region_ptr; |
| } |
| |
| if (src_region_ptr < top_region_ptr) { |
| // The next source region is in the current space. Update src_region_idx |
| // and the source address to match src_region_ptr. |
| src_region_idx = sd.region(src_region_ptr); |
| HeapWord* const src_region_addr = sd.region_to_addr(src_region_idx); |
| if (src_region_addr > closure.source()) { |
| closure.set_source(src_region_addr); |
| } |
| return src_region_idx; |
| } |
| |
| // Switch to a new source space and find the first non-empty region. |
| unsigned int space_id = src_space_id + 1; |
| assert(space_id < last_space_id, "not enough spaces"); |
| |
| HeapWord* const destination = closure.destination(); |
| |
| do { |
| MutableSpace* space = _space_info[space_id].space(); |
| HeapWord* const bottom = space->bottom(); |
| const RegionData* const bottom_cp = sd.addr_to_region_ptr(bottom); |
| |
| // Iterate over the spaces that do not compact into themselves. |
| if (bottom_cp->destination() != bottom) { |
| HeapWord* const top_aligned_up = sd.region_align_up(space->top()); |
| const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up); |
| |
| for (const RegionData* src_cp = bottom_cp; src_cp < top_cp; ++src_cp) { |
| if (src_cp->live_obj_size() > 0) { |
| // Found it. |
| assert(src_cp->destination() == destination, |
| "first live obj in the space must match the destination"); |
| assert(src_cp->partial_obj_size() == 0, |
| "a space cannot begin with a partial obj"); |
| |
| src_space_id = SpaceId(space_id); |
| src_space_top = space->top(); |
| const size_t src_region_idx = sd.region(src_cp); |
| closure.set_source(sd.region_to_addr(src_region_idx)); |
| return src_region_idx; |
| } else { |
| assert(src_cp->data_size() == 0, "sanity"); |
| } |
| } |
| } |
| } while (++space_id < last_space_id); |
| |
| assert(false, "no source region was found"); |
| return 0; |
| } |
| |
| void PSParallelCompact::fill_region(ParCompactionManager* cm, size_t region_idx) |
| { |
| typedef ParMarkBitMap::IterationStatus IterationStatus; |
| const size_t RegionSize = ParallelCompactData::RegionSize; |
| ParMarkBitMap* const bitmap = mark_bitmap(); |
| ParallelCompactData& sd = summary_data(); |
| RegionData* const region_ptr = sd.region(region_idx); |
| |
| // Get the items needed to construct the closure. |
| HeapWord* dest_addr = sd.region_to_addr(region_idx); |
| SpaceId dest_space_id = space_id(dest_addr); |
| ObjectStartArray* start_array = _space_info[dest_space_id].start_array(); |
| HeapWord* new_top = _space_info[dest_space_id].new_top(); |
| assert(dest_addr < new_top, "sanity"); |
| const size_t words = MIN2(pointer_delta(new_top, dest_addr), RegionSize); |
| |
| // Get the source region and related info. |
| size_t src_region_idx = region_ptr->source_region(); |
| SpaceId src_space_id = space_id(sd.region_to_addr(src_region_idx)); |
| HeapWord* src_space_top = _space_info[src_space_id].space()->top(); |
| |
| MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words); |
| closure.set_source(first_src_addr(dest_addr, src_space_id, src_region_idx)); |
| |
| // Adjust src_region_idx to prepare for decrementing destination counts (the |
| // destination count is not decremented when a region is copied to itself). |
| if (src_region_idx == region_idx) { |
| src_region_idx += 1; |
| } |
| |
| if (bitmap->is_unmarked(closure.source())) { |
| // The first source word is in the middle of an object; copy the remainder |
| // of the object or as much as will fit. The fact that pointer updates were |
| // deferred will be noted when the object header is processed. |
| HeapWord* const old_src_addr = closure.source(); |
| closure.copy_partial_obj(); |
| if (closure.is_full()) { |
| decrement_destination_counts(cm, src_space_id, src_region_idx, |
| closure.source()); |
| region_ptr->set_deferred_obj_addr(NULL); |
| region_ptr->set_completed(); |
| return; |
| } |
| |
| HeapWord* const end_addr = sd.region_align_down(closure.source()); |
| if (sd.region_align_down(old_src_addr) != end_addr) { |
| // The partial object was copied from more than one source region. |
| decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr); |
| |
| // Move to the next source region, possibly switching spaces as well. All |
| // args except end_addr may be modified. |
| src_region_idx = next_src_region(closure, src_space_id, src_space_top, |
| end_addr); |
| } |
| } |
| |
| do { |
| HeapWord* const cur_addr = closure.source(); |
| HeapWord* const end_addr = MIN2(sd.region_align_up(cur_addr + 1), |
| src_space_top); |
| IterationStatus status = bitmap->iterate(&closure, cur_addr, end_addr); |
| |
| if (status == ParMarkBitMap::incomplete) { |
| // The last obj that starts in the source region does not end in the |
| // region. |
| assert(closure.source() < end_addr, "sanity"); |
| HeapWord* const obj_beg = closure.source(); |
| HeapWord* const range_end = MIN2(obj_beg + closure.words_remaining(), |
| src_space_top); |
| HeapWord* const obj_end = bitmap->find_obj_end(obj_beg, range_end); |
| if (obj_end < range_end) { |
| // The end was found; the entire object will fit. |
| status = closure.do_addr(obj_beg, bitmap->obj_size(obj_beg, obj_end)); |
| assert(status != ParMarkBitMap::would_overflow, "sanity"); |
| } else { |
| // The end was not found; the object will not fit. |
| assert(range_end < src_space_top, "obj cannot cross space boundary"); |
| status = ParMarkBitMap::would_overflow; |
| } |
| } |
| |
| if (status == ParMarkBitMap::would_overflow) { |
| // The last object did not fit. Note that interior oop updates were |
| // deferred, then copy enough of the object to fill the region. |
| region_ptr->set_deferred_obj_addr(closure.destination()); |
| status = closure.copy_until_full(); // copies from closure.source() |
| |
| decrement_destination_counts(cm, src_space_id, src_region_idx, |
| closure.source()); |
| region_ptr->set_completed(); |
| return; |
| } |
| |
| if (status == ParMarkBitMap::full) { |
| decrement_destination_counts(cm, src_space_id, src_region_idx, |
| closure.source()); |
| region_ptr->set_deferred_obj_addr(NULL); |
| region_ptr->set_completed(); |
| return; |
| } |
| |
| decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr); |
| |
| // Move to the next source region, possibly switching spaces as well. All |
| // args except end_addr may be modified. |
| src_region_idx = next_src_region(closure, src_space_id, src_space_top, |
| end_addr); |
| } while (true); |
| } |
| |
| void PSParallelCompact::fill_blocks(size_t region_idx) |
| { |
| // Fill in the block table elements for the specified region. Each block |
| // table element holds the number of live words in the region that are to the |
| // left of the first object that starts in the block. Thus only blocks in |
| // which an object starts need to be filled. |
| // |
| // The algorithm scans the section of the bitmap that corresponds to the |
| // region, keeping a running total of the live words. When an object start is |
| // found, if it's the first to start in the block that contains it, the |
| // current total is written to the block table element. |
| const size_t Log2BlockSize = ParallelCompactData::Log2BlockSize; |
| const size_t Log2RegionSize = ParallelCompactData::Log2RegionSize; |
| const size_t RegionSize = ParallelCompactData::RegionSize; |
| |
| ParallelCompactData& sd = summary_data(); |
| const size_t partial_obj_size = sd.region(region_idx)->partial_obj_size(); |
| if (partial_obj_size >= RegionSize) { |
| return; // No objects start in this region. |
| } |
| |
| // Ensure the first loop iteration decides that the block has changed. |
| size_t cur_block = sd.block_count(); |
| |
| const ParMarkBitMap* const bitmap = mark_bitmap(); |
| |
| const size_t Log2BitsPerBlock = Log2BlockSize - LogMinObjAlignment; |
| assert((size_t)1 << Log2BitsPerBlock == |
| bitmap->words_to_bits(ParallelCompactData::BlockSize), "sanity"); |
| |
| size_t beg_bit = bitmap->words_to_bits(region_idx << Log2RegionSize); |
| const size_t range_end = beg_bit + bitmap->words_to_bits(RegionSize); |
| size_t live_bits = bitmap->words_to_bits(partial_obj_size); |
| beg_bit = bitmap->find_obj_beg(beg_bit + live_bits, range_end); |
| while (beg_bit < range_end) { |
| const size_t new_block = beg_bit >> Log2BitsPerBlock; |
| if (new_block != cur_block) { |
| cur_block = new_block; |
| sd.block(cur_block)->set_offset(bitmap->bits_to_words(live_bits)); |
| } |
| |
| const size_t end_bit = bitmap->find_obj_end(beg_bit, range_end); |
| if (end_bit < range_end - 1) { |
| live_bits += end_bit - beg_bit + 1; |
| beg_bit = bitmap->find_obj_beg(end_bit + 1, range_end); |
| } else { |
| return; |
| } |
| } |
| } |
| |
| void |
| PSParallelCompact::move_and_update(ParCompactionManager* cm, SpaceId space_id) { |
| const MutableSpace* sp = space(space_id); |
| if (sp->is_empty()) { |
| return; |
| } |
| |
| ParallelCompactData& sd = PSParallelCompact::summary_data(); |
| ParMarkBitMap* const bitmap = mark_bitmap(); |
| HeapWord* const dp_addr = dense_prefix(space_id); |
| HeapWord* beg_addr = sp->bottom(); |
| HeapWord* end_addr = sp->top(); |
| |
| assert(beg_addr <= dp_addr && dp_addr <= end_addr, "bad dense prefix"); |
| |
| const size_t beg_region = sd.addr_to_region_idx(beg_addr); |
| const size_t dp_region = sd.addr_to_region_idx(dp_addr); |
| if (beg_region < dp_region) { |
| update_and_deadwood_in_dense_prefix(cm, space_id, beg_region, dp_region); |
| } |
| |
| // The destination of the first live object that starts in the region is one |
| // past the end of the partial object entering the region (if any). |
| HeapWord* const dest_addr = sd.partial_obj_end(dp_region); |
| HeapWord* const new_top = _space_info[space_id].new_top(); |
| assert(new_top >= dest_addr, "bad new_top value"); |
| const size_t words = pointer_delta(new_top, dest_addr); |
| |
| if (words > 0) { |
| ObjectStartArray* start_array = _space_info[space_id].start_array(); |
| MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words); |
| |
| ParMarkBitMap::IterationStatus status; |
| status = bitmap->iterate(&closure, dest_addr, end_addr); |
| assert(status == ParMarkBitMap::full, "iteration not complete"); |
| assert(bitmap->find_obj_beg(closure.source(), end_addr) == end_addr, |
| "live objects skipped because closure is full"); |
| } |
| } |
| |
| jlong PSParallelCompact::millis_since_last_gc() { |
| // We need a monotonically non-decreasing time in ms but |
| // os::javaTimeMillis() does not guarantee monotonicity. |
| jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; |
| jlong ret_val = now - _time_of_last_gc; |
| // XXX See note in genCollectedHeap::millis_since_last_gc(). |
| if (ret_val < 0) { |
| NOT_PRODUCT(log_warning(gc)("time warp: " JLONG_FORMAT, ret_val);) |
| return 0; |
| } |
| return ret_val; |
| } |
| |
| void PSParallelCompact::reset_millis_since_last_gc() { |
| // We need a monotonically non-decreasing time in ms but |
| // os::javaTimeMillis() does not guarantee monotonicity. |
| _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC; |
| } |
| |
| ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full() |
| { |
| if (source() != destination()) { |
| DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());) |
| Copy::aligned_conjoint_words(source(), destination(), words_remaining()); |
| } |
| update_state(words_remaining()); |
| assert(is_full(), "sanity"); |
| return ParMarkBitMap::full; |
| } |
| |
| void MoveAndUpdateClosure::copy_partial_obj() |
| { |
| size_t words = words_remaining(); |
| |
| HeapWord* const range_end = MIN2(source() + words, bitmap()->region_end()); |
| HeapWord* const end_addr = bitmap()->find_obj_end(source(), range_end); |
| if (end_addr < range_end) { |
| words = bitmap()->obj_size(source(), end_addr); |
| } |
| |
| // This test is necessary; if omitted, the pointer updates to a partial object |
| // that crosses the dense prefix boundary could be overwritten. |
| if (source() != destination()) { |
| DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());) |
| Copy::aligned_conjoint_words(source(), destination(), words); |
| } |
| update_state(words); |
| } |
| |
| void InstanceKlass::oop_pc_update_pointers(oop obj, ParCompactionManager* cm) { |
| PSParallelCompact::AdjustPointerClosure closure(cm); |
| oop_oop_iterate_oop_maps<true>(obj, &closure); |
| } |
| |
| void InstanceMirrorKlass::oop_pc_update_pointers(oop obj, ParCompactionManager* cm) { |
| InstanceKlass::oop_pc_update_pointers(obj, cm); |
| |
| PSParallelCompact::AdjustPointerClosure closure(cm); |
| oop_oop_iterate_statics<true>(obj, &closure); |
| } |
| |
| void InstanceClassLoaderKlass::oop_pc_update_pointers(oop obj, ParCompactionManager* cm) { |
| InstanceKlass::oop_pc_update_pointers(obj, cm); |
| } |
| |
| #ifdef ASSERT |
| template <class T> static void trace_reference_gc(const char *s, oop obj, |
| T* referent_addr, |
| T* next_addr, |
| T* discovered_addr) { |
| log_develop_trace(gc, ref)("%s obj " PTR_FORMAT, s, p2i(obj)); |
| log_develop_trace(gc, ref)(" referent_addr/* " PTR_FORMAT " / " PTR_FORMAT, |
| p2i(referent_addr), referent_addr ? p2i(oopDesc::load_decode_heap_oop(referent_addr)) : NULL); |
| log_develop_trace(gc, ref)(" next_addr/* " PTR_FORMAT " / " PTR_FORMAT, |
| p2i(next_addr), next_addr ? p2i(oopDesc::load_decode_heap_oop(next_addr)) : NULL); |
| log_develop_trace(gc, ref)(" discovered_addr/* " PTR_FORMAT " / " PTR_FORMAT, |
| p2i(discovered_addr), discovered_addr ? p2i(oopDesc::load_decode_heap_oop(discovered_addr)) : NULL); |
| } |
| #endif |
| |
| template <class T> |
| static void oop_pc_update_pointers_specialized(oop obj, ParCompactionManager* cm) { |
| T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj); |
| PSParallelCompact::adjust_pointer(referent_addr, cm); |
| T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj); |
| PSParallelCompact::adjust_pointer(next_addr, cm); |
| T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj); |
| PSParallelCompact::adjust_pointer(discovered_addr, cm); |
| debug_only(trace_reference_gc("InstanceRefKlass::oop_update_ptrs", obj, |
| referent_addr, next_addr, discovered_addr);) |
| } |
| |
| void InstanceRefKlass::oop_pc_update_pointers(oop obj, ParCompactionManager* cm) { |
| InstanceKlass::oop_pc_update_pointers(obj, cm); |
| |
| if (UseCompressedOops) { |
| oop_pc_update_pointers_specialized<narrowOop>(obj, cm); |
| } else { |
| oop_pc_update_pointers_specialized<oop>(obj, cm); |
| } |
| } |
| |
| void ObjArrayKlass::oop_pc_update_pointers(oop obj, ParCompactionManager* cm) { |
| assert(obj->is_objArray(), "obj must be obj array"); |
| PSParallelCompact::AdjustPointerClosure closure(cm); |
| oop_oop_iterate_elements<true>(objArrayOop(obj), &closure); |
| } |
| |
| void TypeArrayKlass::oop_pc_update_pointers(oop obj, ParCompactionManager* cm) { |
| assert(obj->is_typeArray(),"must be a type array"); |
| } |
| |
| ParMarkBitMapClosure::IterationStatus |
| MoveAndUpdateClosure::do_addr(HeapWord* addr, size_t words) { |
| assert(destination() != NULL, "sanity"); |
| assert(bitmap()->obj_size(addr) == words, "bad size"); |
| |
| _source = addr; |
| assert(PSParallelCompact::summary_data().calc_new_pointer(source(), compaction_manager()) == |
| destination(), "wrong destination"); |
| |
| if (words > words_remaining()) { |
| return ParMarkBitMap::would_overflow; |
| } |
| |
| // The start_array must be updated even if the object is not moving. |
| if (_start_array != NULL) { |
| _start_array->allocate_block(destination()); |
| } |
| |
| if (destination() != source()) { |
| DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());) |
| Copy::aligned_conjoint_words(source(), destination(), words); |
| } |
| |
| oop moved_oop = (oop) destination(); |
| compaction_manager()->update_contents(moved_oop); |
| assert(oopDesc::is_oop_or_null(moved_oop), "Expected an oop or NULL at " PTR_FORMAT, p2i(moved_oop)); |
| |
| update_state(words); |
| assert(destination() == (HeapWord*)moved_oop + moved_oop->size(), "sanity"); |
| return is_full() ? ParMarkBitMap::full : ParMarkBitMap::incomplete; |
| } |
| |
| UpdateOnlyClosure::UpdateOnlyClosure(ParMarkBitMap* mbm, |
| ParCompactionManager* cm, |
| PSParallelCompact::SpaceId space_id) : |
| ParMarkBitMapClosure(mbm, cm), |
| _space_id(space_id), |
| _start_array(PSParallelCompact::start_array(space_id)) |
| { |
| } |
| |
| // Updates the references in the object to their new values. |
| ParMarkBitMapClosure::IterationStatus |
| UpdateOnlyClosure::do_addr(HeapWord* addr, size_t words) { |
| do_addr(addr); |
| return ParMarkBitMap::incomplete; |
| } |
| |
| FillClosure::FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) : |
| ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm), |
| _start_array(PSParallelCompact::start_array(space_id)) |
| { |
| assert(space_id == PSParallelCompact::old_space_id, |
| "cannot use FillClosure in the young gen"); |
| } |
| |
| ParMarkBitMapClosure::IterationStatus |
| FillClosure::do_addr(HeapWord* addr, size_t size) { |
| CollectedHeap::fill_with_objects(addr, size); |
| HeapWord* const end = addr + size; |
| do { |
| _start_array->allocate_block(addr); |
| addr += oop(addr)->size(); |
| } while (addr < end); |
| return ParMarkBitMap::incomplete; |
| } |