--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,3752 @@
+/*
+ * Copyright 2005-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+#include "incls/_precompiled.incl"
+#include "incls/_psParallelCompact.cpp.incl"
+
+#include <math.h>
+
+// All sizes are in HeapWords.
+const size_t ParallelCompactData::Log2ChunkSize = 9; // 512 words
+const size_t ParallelCompactData::ChunkSize = (size_t)1 << Log2ChunkSize;
+const size_t ParallelCompactData::ChunkSizeBytes = ChunkSize << LogHeapWordSize;
+const size_t ParallelCompactData::ChunkSizeOffsetMask = ChunkSize - 1;
+const size_t ParallelCompactData::ChunkAddrOffsetMask = ChunkSizeBytes - 1;
+const size_t ParallelCompactData::ChunkAddrMask = ~ChunkAddrOffsetMask;
+
+// 32-bit: 128 words covers 4 bitmap words
+// 64-bit: 128 words covers 2 bitmap words
+const size_t ParallelCompactData::Log2BlockSize = 7; // 128 words
+const size_t ParallelCompactData::BlockSize = (size_t)1 << Log2BlockSize;
+const size_t ParallelCompactData::BlockOffsetMask = BlockSize - 1;
+const size_t ParallelCompactData::BlockMask = ~BlockOffsetMask;
+
+const size_t ParallelCompactData::BlocksPerChunk = ChunkSize / BlockSize;
+
+const ParallelCompactData::ChunkData::chunk_sz_t
+ParallelCompactData::ChunkData::dc_shift = 27;
+
+const ParallelCompactData::ChunkData::chunk_sz_t
+ParallelCompactData::ChunkData::dc_mask = ~0U << dc_shift;
+
+const ParallelCompactData::ChunkData::chunk_sz_t
+ParallelCompactData::ChunkData::dc_one = 0x1U << dc_shift;
+
+const ParallelCompactData::ChunkData::chunk_sz_t
+ParallelCompactData::ChunkData::los_mask = ~dc_mask;
+
+const ParallelCompactData::ChunkData::chunk_sz_t
+ParallelCompactData::ChunkData::dc_claimed = 0x8U << dc_shift;
+
+const ParallelCompactData::ChunkData::chunk_sz_t
+ParallelCompactData::ChunkData::dc_completed = 0xcU << dc_shift;
+
+#ifdef ASSERT
+short ParallelCompactData::BlockData::_cur_phase = 0;
+#endif
+
+SpaceInfo PSParallelCompact::_space_info[PSParallelCompact::last_space_id];
+bool PSParallelCompact::_print_phases = false;
+
+ReferenceProcessor* PSParallelCompact::_ref_processor = NULL;
+klassOop PSParallelCompact::_updated_int_array_klass_obj = 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
+
+#ifdef VALIDATE_MARK_SWEEP
+GrowableArray<oop*>* PSParallelCompact::_root_refs_stack = NULL;
+GrowableArray<oop> * PSParallelCompact::_live_oops = NULL;
+GrowableArray<oop> * PSParallelCompact::_live_oops_moved_to = NULL;
+GrowableArray<size_t>* PSParallelCompact::_live_oops_size = NULL;
+size_t PSParallelCompact::_live_oops_index = 0;
+size_t PSParallelCompact::_live_oops_index_at_perm = 0;
+GrowableArray<oop*>* PSParallelCompact::_other_refs_stack = NULL;
+GrowableArray<oop*>* PSParallelCompact::_adjusted_pointers = NULL;
+bool PSParallelCompact::_pointer_tracking = false;
+bool PSParallelCompact::_root_tracking = true;
+
+GrowableArray<HeapWord*>* PSParallelCompact::_cur_gc_live_oops = NULL;
+GrowableArray<HeapWord*>* PSParallelCompact::_cur_gc_live_oops_moved_to = NULL;
+GrowableArray<size_t> * PSParallelCompact::_cur_gc_live_oops_size = NULL;
+GrowableArray<HeapWord*>* PSParallelCompact::_last_gc_live_oops = NULL;
+GrowableArray<HeapWord*>* PSParallelCompact::_last_gc_live_oops_moved_to = NULL;
+GrowableArray<size_t> * PSParallelCompact::_last_gc_live_oops_size = NULL;
+#endif
+
+// XXX beg - verification code; only works while we also mark in object headers
+static void
+verify_mark_bitmap(ParMarkBitMap& _mark_bitmap)
+{
+ ParallelScavengeHeap* heap = PSParallelCompact::gc_heap();
+
+ PSPermGen* perm_gen = heap->perm_gen();
+ PSOldGen* old_gen = heap->old_gen();
+ PSYoungGen* young_gen = heap->young_gen();
+
+ MutableSpace* perm_space = perm_gen->object_space();
+ MutableSpace* old_space = old_gen->object_space();
+ MutableSpace* eden_space = young_gen->eden_space();
+ MutableSpace* from_space = young_gen->from_space();
+ MutableSpace* to_space = young_gen->to_space();
+
+ // 'from_space' here is the survivor space at the lower address.
+ if (to_space->bottom() < from_space->bottom()) {
+ from_space = to_space;
+ to_space = young_gen->from_space();
+ }
+
+ HeapWord* boundaries[12];
+ unsigned int bidx = 0;
+ const unsigned int bidx_max = sizeof(boundaries) / sizeof(boundaries[0]);
+
+ boundaries[0] = perm_space->bottom();
+ boundaries[1] = perm_space->top();
+ boundaries[2] = old_space->bottom();
+ boundaries[3] = old_space->top();
+ boundaries[4] = eden_space->bottom();
+ boundaries[5] = eden_space->top();
+ boundaries[6] = from_space->bottom();
+ boundaries[7] = from_space->top();
+ boundaries[8] = to_space->bottom();
+ boundaries[9] = to_space->top();
+ boundaries[10] = to_space->end();
+ boundaries[11] = to_space->end();
+
+ BitMap::idx_t beg_bit = 0;
+ BitMap::idx_t end_bit;
+ BitMap::idx_t tmp_bit;
+ const BitMap::idx_t last_bit = _mark_bitmap.size();
+ do {
+ HeapWord* addr = _mark_bitmap.bit_to_addr(beg_bit);
+ if (_mark_bitmap.is_marked(beg_bit)) {
+ oop obj = (oop)addr;
+ assert(obj->is_gc_marked(), "obj header is not marked");
+ end_bit = _mark_bitmap.find_obj_end(beg_bit, last_bit);
+ const size_t size = _mark_bitmap.obj_size(beg_bit, end_bit);
+ assert(size == (size_t)obj->size(), "end bit wrong?");
+ beg_bit = _mark_bitmap.find_obj_beg(beg_bit + 1, last_bit);
+ assert(beg_bit > end_bit, "bit set in middle of an obj");
+ } else {
+ if (addr >= boundaries[bidx] && addr < boundaries[bidx + 1]) {
+ // a dead object in the current space.
+ oop obj = (oop)addr;
+ end_bit = _mark_bitmap.addr_to_bit(addr + obj->size());
+ assert(!obj->is_gc_marked(), "obj marked in header, not in bitmap");
+ tmp_bit = beg_bit + 1;
+ beg_bit = _mark_bitmap.find_obj_beg(tmp_bit, end_bit);
+ assert(beg_bit == end_bit, "beg bit set in unmarked obj");
+ beg_bit = _mark_bitmap.find_obj_end(tmp_bit, end_bit);
+ assert(beg_bit == end_bit, "end bit set in unmarked obj");
+ } else if (addr < boundaries[bidx + 2]) {
+ // addr is between top in the current space and bottom in the next.
+ end_bit = beg_bit + pointer_delta(boundaries[bidx + 2], addr);
+ tmp_bit = beg_bit;
+ beg_bit = _mark_bitmap.find_obj_beg(tmp_bit, end_bit);
+ assert(beg_bit == end_bit, "beg bit set above top");
+ beg_bit = _mark_bitmap.find_obj_end(tmp_bit, end_bit);
+ assert(beg_bit == end_bit, "end bit set above top");
+ bidx += 2;
+ } else if (bidx < bidx_max - 2) {
+ bidx += 2; // ???
+ } else {
+ tmp_bit = beg_bit;
+ beg_bit = _mark_bitmap.find_obj_beg(tmp_bit, last_bit);
+ assert(beg_bit == last_bit, "beg bit set outside heap");
+ beg_bit = _mark_bitmap.find_obj_end(tmp_bit, last_bit);
+ assert(beg_bit == last_bit, "end bit set outside heap");
+ }
+ }
+ } while (beg_bit < last_bit);
+}
+// XXX end - verification code; only works while we also mark in object headers
+
+#ifndef PRODUCT
+const char* PSParallelCompact::space_names[] = {
+ "perm", "old ", "eden", "from", "to "
+};
+
+void PSParallelCompact::print_chunk_ranges()
+{
+ tty->print_cr("space bottom top end new_top");
+ tty->print_cr("------ ---------- ---------- ---------- ----------");
+
+ for (unsigned int id = 0; id < last_space_id; ++id) {
+ const MutableSpace* space = _space_info[id].space();
+ tty->print_cr("%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_chunk_idx(space->bottom()),
+ summary_data().addr_to_chunk_idx(space->top()),
+ summary_data().addr_to_chunk_idx(space->end()),
+ summary_data().addr_to_chunk_idx(_space_info[id].new_top()));
+ }
+}
+
+void
+print_generic_summary_chunk(size_t i, const ParallelCompactData::ChunkData* c)
+{
+#define CHUNK_IDX_FORMAT SIZE_FORMAT_W("7")
+#define CHUNK_DATA_FORMAT SIZE_FORMAT_W("5")
+
+ ParallelCompactData& sd = PSParallelCompact::summary_data();
+ size_t dci = c->destination() ? sd.addr_to_chunk_idx(c->destination()) : 0;
+ tty->print_cr(CHUNK_IDX_FORMAT " " PTR_FORMAT " "
+ CHUNK_IDX_FORMAT " " PTR_FORMAT " "
+ CHUNK_DATA_FORMAT " " CHUNK_DATA_FORMAT " "
+ CHUNK_DATA_FORMAT " " CHUNK_IDX_FORMAT " %d",
+ i, c->data_location(), dci, c->destination(),
+ c->partial_obj_size(), c->live_obj_size(),
+ c->data_size(), c->source_chunk(), c->destination_count());
+
+#undef CHUNK_IDX_FORMAT
+#undef CHUNK_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_chunk_idx(beg_addr);
+ const size_t last = summary_data.addr_to_chunk_idx(end_addr);
+ HeapWord* pdest = 0;
+
+ while (i <= last) {
+ ParallelCompactData::ChunkData* c = summary_data.chunk(i);
+ if (c->data_size() != 0 || c->destination() != pdest) {
+ print_generic_summary_chunk(i, c);
+ total_words += c->data_size();
+ pdest = c->destination();
+ }
+ ++i;
+ }
+
+ tty->print_cr("summary_data_bytes=" SIZE_FORMAT, total_words * HeapWordSize);
+}
+
+void
+print_generic_summary_data(ParallelCompactData& summary_data,
+ SpaceInfo* space_info)
+{
+ 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_chunk(size_t i,
+ const ParallelCompactData::ChunkData* c,
+ bool newline = true)
+{
+ tty->print(SIZE_FORMAT_W("5") " " PTR_FORMAT " "
+ SIZE_FORMAT_W("5") " " SIZE_FORMAT_W("5") " "
+ SIZE_FORMAT_W("5") " " SIZE_FORMAT_W("5") " %d",
+ i, c->destination(),
+ c->partial_obj_size(), c->live_obj_size(),
+ c->data_size(), c->source_chunk(), c->destination_count());
+ if (newline) tty->cr();
+}
+
+void
+print_initial_summary_data(ParallelCompactData& summary_data,
+ const MutableSpace* space) {
+ if (space->top() == space->bottom()) {
+ return;
+ }
+
+ const size_t chunk_size = ParallelCompactData::ChunkSize;
+ HeapWord* const top_aligned_up = summary_data.chunk_align_up(space->top());
+ const size_t end_chunk = summary_data.addr_to_chunk_idx(top_aligned_up);
+ const ParallelCompactData::ChunkData* c = summary_data.chunk(end_chunk - 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 chunks at the beginning of the space.
+ size_t full_chunk_count = 0;
+ size_t i = summary_data.addr_to_chunk_idx(space->bottom());
+ while (i < end_chunk && summary_data.chunk(i)->data_size() == chunk_size) {
+ print_initial_summary_chunk(i, summary_data.chunk(i));
+ ++full_chunk_count;
+ ++i;
+ }
+
+ size_t live_to_right = live_in_space - full_chunk_count * chunk_size;
+
+ double max_reclaimed_ratio = 0.0;
+ size_t max_reclaimed_ratio_chunk = 0;
+ size_t max_dead_to_right = 0;
+ size_t max_live_to_right = 0;
+
+ // Print the 'reclaimed ratio' for chunks while there is something live in the
+ // chunk or to the right of it. The remaining chunks are empty (and
+ // uninteresting), and computing the ratio will result in division by 0.
+ while (i < end_chunk && live_to_right > 0) {
+ c = summary_data.chunk(i);
+ HeapWord* const chunk_addr = summary_data.chunk_to_addr(i);
+ const size_t used_to_right = pointer_delta(space->top(), chunk_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_chunk = i;
+ max_dead_to_right = dead_to_right;
+ max_live_to_right = live_to_right;
+ }
+
+ print_initial_summary_chunk(i, c, false);
+ tty->print_cr(" %12.10f " SIZE_FORMAT_W("10") " " SIZE_FORMAT_W("10"),
+ reclaimed_ratio, dead_to_right, live_to_right);
+
+ live_to_right -= c->data_size();
+ ++i;
+ }
+
+ // Any remaining chunks are empty. Print one more if there is one.
+ if (i < end_chunk) {
+ print_initial_summary_chunk(i, summary_data.chunk(i));
+ }
+
+ tty->print_cr("max: " SIZE_FORMAT_W("4") " d2r=" SIZE_FORMAT_W("10") " "
+ "l2r=" SIZE_FORMAT_W("10") " max_ratio=%14.12f",
+ max_reclaimed_ratio_chunk, max_dead_to_right,
+ max_live_to_right, max_reclaimed_ratio);
+}
+
+void
+print_initial_summary_data(ParallelCompactData& summary_data,
+ SpaceInfo* space_info) {
+ unsigned int id = PSParallelCompact::perm_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;
+
+ _chunk_vspace = 0;
+ _chunk_data = 0;
+ _chunk_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(chunk_align_down(_region_start) == _region_start,
+ "region start not aligned");
+ assert((region_size & ChunkSizeOffsetMask) == 0,
+ "region size not a multiple of ChunkSize");
+
+ bool result = initialize_chunk_data(region_size);
+
+ // Initialize the block data if it will be used for updating pointers, or if
+ // this is a debug build.
+ if (!UseParallelOldGCChunkPointerCalc || trueInDebug) {
+ result = result && initialize_block_data(region_size);
+ }
+
+ 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(raw_bytes, raw_bytes, 10);
+ const size_t granularity = os::vm_allocation_granularity();
+ const size_t bytes = align_size_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(bytes, rs_align, false);
+ os::trace_page_sizes("par compact", raw_bytes, raw_bytes, page_sz, rs.base(),
+ rs.size());
+ PSVirtualSpace* vspace = new PSVirtualSpace(rs, page_sz);
+ if (vspace != 0) {
+ if (vspace->expand_by(bytes)) {
+ return vspace;
+ }
+ delete vspace;
+ }
+
+ return 0;
+}
+
+bool ParallelCompactData::initialize_chunk_data(size_t region_size)
+{
+ const size_t count = (region_size + ChunkSizeOffsetMask) >> Log2ChunkSize;
+ _chunk_vspace = create_vspace(count, sizeof(ChunkData));
+ if (_chunk_vspace != 0) {
+ _chunk_data = (ChunkData*)_chunk_vspace->reserved_low_addr();
+ _chunk_count = count;
+ return true;
+ }
+ return false;
+}
+
+bool ParallelCompactData::initialize_block_data(size_t region_size)
+{
+ const size_t count = (region_size + BlockOffsetMask) >> Log2BlockSize;
+ _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()
+{
+ if (_block_data) {
+ memset(_block_data, 0, _block_vspace->committed_size());
+ }
+ memset(_chunk_data, 0, _chunk_vspace->committed_size());
+}
+
+void ParallelCompactData::clear_range(size_t beg_chunk, size_t end_chunk) {
+ assert(beg_chunk <= _chunk_count, "beg_chunk out of range");
+ assert(end_chunk <= _chunk_count, "end_chunk out of range");
+ assert(ChunkSize % BlockSize == 0, "ChunkSize not a multiple of BlockSize");
+
+ const size_t chunk_cnt = end_chunk - beg_chunk;
+
+ if (_block_data) {
+ const size_t blocks_per_chunk = ChunkSize / BlockSize;
+ const size_t beg_block = beg_chunk * blocks_per_chunk;
+ const size_t block_cnt = chunk_cnt * blocks_per_chunk;
+ memset(_block_data + beg_block, 0, block_cnt * sizeof(BlockData));
+ }
+ memset(_chunk_data + beg_chunk, 0, chunk_cnt * sizeof(ChunkData));
+}
+
+HeapWord* ParallelCompactData::partial_obj_end(size_t chunk_idx) const
+{
+ const ChunkData* cur_cp = chunk(chunk_idx);
+ const ChunkData* const end_cp = chunk(chunk_count() - 1);
+
+ HeapWord* result = chunk_to_addr(chunk_idx);
+ if (cur_cp < end_cp) {
+ do {
+ result += cur_cp->partial_obj_size();
+ } while (cur_cp->partial_obj_size() == ChunkSize && ++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_chunk = obj_ofs >> Log2ChunkSize;
+ const size_t end_chunk = (obj_ofs + len - 1) >> Log2ChunkSize;
+
+ DEBUG_ONLY(Atomic::inc_ptr(&add_obj_count);)
+ DEBUG_ONLY(Atomic::add_ptr(len, &add_obj_size);)
+
+ if (beg_chunk == end_chunk) {
+ // All in one chunk.
+ _chunk_data[beg_chunk].add_live_obj(len);
+ return;
+ }
+
+ // First chunk.
+ const size_t beg_ofs = chunk_offset(addr);
+ _chunk_data[beg_chunk].add_live_obj(ChunkSize - beg_ofs);
+
+ klassOop klass = ((oop)addr)->klass();
+ // Middle chunks--completely spanned by this object.
+ for (size_t chunk = beg_chunk + 1; chunk < end_chunk; ++chunk) {
+ _chunk_data[chunk].set_partial_obj_size(ChunkSize);
+ _chunk_data[chunk].set_partial_obj_addr(addr);
+ }
+
+ // Last chunk.
+ const size_t end_ofs = chunk_offset(addr + len - 1);
+ _chunk_data[end_chunk].set_partial_obj_size(end_ofs + 1);
+ _chunk_data[end_chunk].set_partial_obj_addr(addr);
+}
+
+void
+ParallelCompactData::summarize_dense_prefix(HeapWord* beg, HeapWord* end)
+{
+ assert(chunk_offset(beg) == 0, "not ChunkSize aligned");
+ assert(chunk_offset(end) == 0, "not ChunkSize aligned");
+
+ size_t cur_chunk = addr_to_chunk_idx(beg);
+ const size_t end_chunk = addr_to_chunk_idx(end);
+ HeapWord* addr = beg;
+ while (cur_chunk < end_chunk) {
+ _chunk_data[cur_chunk].set_destination(addr);
+ _chunk_data[cur_chunk].set_destination_count(0);
+ _chunk_data[cur_chunk].set_source_chunk(cur_chunk);
+ _chunk_data[cur_chunk].set_data_location(addr);
+
+ // Update live_obj_size so the chunk appears completely full.
+ size_t live_size = ChunkSize - _chunk_data[cur_chunk].partial_obj_size();
+ _chunk_data[cur_chunk].set_live_obj_size(live_size);
+
+ ++cur_chunk;
+ addr += ChunkSize;
+ }
+}
+
+bool ParallelCompactData::summarize(HeapWord* target_beg, HeapWord* target_end,
+ HeapWord* source_beg, HeapWord* source_end,
+ HeapWord** target_next,
+ HeapWord** source_next) {
+ // This is too strict.
+ // assert(chunk_offset(source_beg) == 0, "not ChunkSize aligned");
+
+ if (TraceParallelOldGCSummaryPhase) {
+ tty->print_cr("tb=" PTR_FORMAT " te=" PTR_FORMAT " "
+ "sb=" PTR_FORMAT " se=" PTR_FORMAT " "
+ "tn=" PTR_FORMAT " sn=" PTR_FORMAT,
+ target_beg, target_end,
+ source_beg, source_end,
+ target_next != 0 ? *target_next : (HeapWord*) 0,
+ source_next != 0 ? *source_next : (HeapWord*) 0);
+ }
+
+ size_t cur_chunk = addr_to_chunk_idx(source_beg);
+ const size_t end_chunk = addr_to_chunk_idx(chunk_align_up(source_end));
+
+ HeapWord *dest_addr = target_beg;
+ while (cur_chunk < end_chunk) {
+ size_t words = _chunk_data[cur_chunk].data_size();
+
+#if 1
+ assert(pointer_delta(target_end, dest_addr) >= words,
+ "source region does not fit into target region");
+#else
+ // XXX - need some work on the corner cases here. If the chunk does not
+ // fit, then must either make sure any partial_obj from the chunk fits, or
+ // 'undo' the initial part of the partial_obj that is in the previous chunk.
+ if (dest_addr + words >= target_end) {
+ // Let the caller know where to continue.
+ *target_next = dest_addr;
+ *source_next = chunk_to_addr(cur_chunk);
+ return false;
+ }
+#endif // #if 1
+
+ _chunk_data[cur_chunk].set_destination(dest_addr);
+
+ // Set the destination_count for cur_chunk, and if necessary, update
+ // source_chunk for a destination chunk. The source_chunk field is updated
+ // if cur_chunk is the first (left-most) chunk to be copied to a destination
+ // chunk.
+ //
+ // The destination_count calculation is a bit subtle. A chunk that has data
+ // that compacts into itself does not count itself as a destination. This
+ // maintains the invariant that a zero count means the chunk is available
+ // and can be claimed and then filled.
+ if (words > 0) {
+ HeapWord* const last_addr = dest_addr + words - 1;
+ const size_t dest_chunk_1 = addr_to_chunk_idx(dest_addr);
+ const size_t dest_chunk_2 = addr_to_chunk_idx(last_addr);
+#if 0
+ // Initially assume that the destination chunks will be the same and
+ // adjust the value below if necessary. Under this assumption, if
+ // cur_chunk == dest_chunk_2, then cur_chunk will be compacted completely
+ // into itself.
+ uint destination_count = cur_chunk == dest_chunk_2 ? 0 : 1;
+ if (dest_chunk_1 != dest_chunk_2) {
+ // Destination chunks differ; adjust destination_count.
+ destination_count += 1;
+ // Data from cur_chunk will be copied to the start of dest_chunk_2.
+ _chunk_data[dest_chunk_2].set_source_chunk(cur_chunk);
+ } else if (chunk_offset(dest_addr) == 0) {
+ // Data from cur_chunk will be copied to the start of the destination
+ // chunk.
+ _chunk_data[dest_chunk_1].set_source_chunk(cur_chunk);
+ }
+#else
+ // Initially assume that the destination chunks will be different and
+ // adjust the value below if necessary. Under this assumption, if
+ // cur_chunk == dest_chunk2, then cur_chunk will be compacted partially
+ // into dest_chunk_1 and partially into itself.
+ uint destination_count = cur_chunk == dest_chunk_2 ? 1 : 2;
+ if (dest_chunk_1 != dest_chunk_2) {
+ // Data from cur_chunk will be copied to the start of dest_chunk_2.
+ _chunk_data[dest_chunk_2].set_source_chunk(cur_chunk);
+ } else {
+ // Destination chunks are the same; adjust destination_count.
+ destination_count -= 1;
+ if (chunk_offset(dest_addr) == 0) {
+ // Data from cur_chunk will be copied to the start of the destination
+ // chunk.
+ _chunk_data[dest_chunk_1].set_source_chunk(cur_chunk);
+ }
+ }
+#endif // #if 0
+
+ _chunk_data[cur_chunk].set_destination_count(destination_count);
+ _chunk_data[cur_chunk].set_data_location(chunk_to_addr(cur_chunk));
+ dest_addr += words;
+ }
+
+ ++cur_chunk;
+ }
+
+ *target_next = dest_addr;
+ return true;
+}
+
+bool ParallelCompactData::partial_obj_ends_in_block(size_t block_index) {
+ HeapWord* block_addr = block_to_addr(block_index);
+ HeapWord* block_end_addr = block_addr + BlockSize;
+ size_t chunk_index = addr_to_chunk_idx(block_addr);
+ HeapWord* partial_obj_end_addr = partial_obj_end(chunk_index);
+
+ // An object that ends at the end of the block, ends
+ // in the block (the last word of the object is to
+ // the left of the end).
+ if ((block_addr < partial_obj_end_addr) &&
+ (partial_obj_end_addr <= block_end_addr)) {
+ return true;
+ }
+
+ return false;
+}
+
+HeapWord* ParallelCompactData::calc_new_pointer(HeapWord* addr) {
+ HeapWord* result = NULL;
+ if (UseParallelOldGCChunkPointerCalc) {
+ result = chunk_calc_new_pointer(addr);
+ } else {
+ result = block_calc_new_pointer(addr);
+ }
+ return result;
+}
+
+// This method is overly complicated (expensive) to be called
+// for every reference.
+// Try to restructure this so that a NULL is returned if
+// the object is dead. But don't wast the cycles to explicitly check
+// that it is dead since only live objects should be passed in.
+
+HeapWord* ParallelCompactData::chunk_calc_new_pointer(HeapWord* addr) {
+ assert(addr != NULL, "Should detect NULL oop earlier");
+ assert(PSParallelCompact::gc_heap()->is_in(addr), "addr not in heap");
+#ifdef ASSERT
+ if (PSParallelCompact::mark_bitmap()->is_unmarked(addr)) {
+ gclog_or_tty->print_cr("calc_new_pointer:: addr " PTR_FORMAT, addr);
+ }
+#endif
+ assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "obj not marked");
+
+ // Chunk covering the object.
+ size_t chunk_index = addr_to_chunk_idx(addr);
+ const ChunkData* const chunk_ptr = chunk(chunk_index);
+ HeapWord* const chunk_addr = chunk_align_down(addr);
+
+ assert(addr < chunk_addr + ChunkSize, "Chunk does not cover object");
+ assert(addr_to_chunk_ptr(chunk_addr) == chunk_ptr, "sanity check");
+
+ HeapWord* result = chunk_ptr->destination();
+
+ // If all the data in the chunk is live, then the new location of the object
+ // can be calculated from the destination of the chunk plus the offset of the
+ // object in the chunk.
+ if (chunk_ptr->data_size() == ChunkSize) {
+ result += pointer_delta(addr, chunk_addr);
+ return result;
+ }
+
+ // The new location of the object is
+ // chunk destination +
+ // size of the partial object extending onto the chunk +
+ // sizes of the live objects in the Chunk that are to the left of addr
+ const size_t partial_obj_size = chunk_ptr->partial_obj_size();
+ HeapWord* const search_start = chunk_addr + partial_obj_size;
+
+ const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap();
+ size_t live_to_left = bitmap->live_words_in_range(search_start, oop(addr));
+
+ result += partial_obj_size + live_to_left;
+ assert(result <= addr, "object cannot move to the right");
+ return result;
+}
+
+HeapWord* ParallelCompactData::block_calc_new_pointer(HeapWord* addr) {
+ assert(addr != NULL, "Should detect NULL oop earlier");
+ assert(PSParallelCompact::gc_heap()->is_in(addr), "addr not in heap");
+#ifdef ASSERT
+ if (PSParallelCompact::mark_bitmap()->is_unmarked(addr)) {
+ gclog_or_tty->print_cr("calc_new_pointer:: addr " PTR_FORMAT, addr);
+ }
+#endif
+ assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "obj not marked");
+
+ // Chunk covering the object.
+ size_t chunk_index = addr_to_chunk_idx(addr);
+ const ChunkData* const chunk_ptr = chunk(chunk_index);
+ HeapWord* const chunk_addr = chunk_align_down(addr);
+
+ assert(addr < chunk_addr + ChunkSize, "Chunk does not cover object");
+ assert(addr_to_chunk_ptr(chunk_addr) == chunk_ptr, "sanity check");
+
+ HeapWord* result = chunk_ptr->destination();
+
+ // If all the data in the chunk is live, then the new location of the object
+ // can be calculated from the destination of the chunk plus the offset of the
+ // object in the chunk.
+ if (chunk_ptr->data_size() == ChunkSize) {
+ result += pointer_delta(addr, chunk_addr);
+ return result;
+ }
+
+ // The new location of the object is
+ // chunk destination +
+ // block offset +
+ // sizes of the live objects in the Block that are to the left of addr
+ const size_t block_offset = addr_to_block_ptr(addr)->offset();
+ HeapWord* const search_start = chunk_addr + block_offset;
+
+ const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap();
+ size_t live_to_left = bitmap->live_words_in_range(search_start, oop(addr));
+
+ result += block_offset + live_to_left;
+ assert(result <= addr, "object cannot move to the right");
+ assert(result == chunk_calc_new_pointer(addr), "Should match");
+ return result;
+}
+
+klassOop ParallelCompactData::calc_new_klass(klassOop old_klass) {
+ klassOop updated_klass;
+ if (PSParallelCompact::should_update_klass(old_klass)) {
+ updated_klass = (klassOop) calc_new_pointer(old_klass);
+ } else {
+ updated_klass = old_klass;
+ }
+
+ return updated_klass;
+}
+
+#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(_chunk_vspace);
+ verify_clear(_block_vspace);
+}
+#endif // #ifdef ASSERT
+
+#ifdef NOT_PRODUCT
+ParallelCompactData::ChunkData* debug_chunk(size_t chunk_index) {
+ ParallelCompactData& sd = PSParallelCompact::summary_data();
+ return sd.chunk(chunk_index);
+}
+#endif
+
+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;
+PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_root_pointer_closure(true);
+PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_pointer_closure(false);
+
+void PSParallelCompact::KeepAliveClosure::do_oop(oop* p) {
+#ifdef VALIDATE_MARK_SWEEP
+ if (ValidateMarkSweep) {
+ if (!Universe::heap()->is_in_reserved(p)) {
+ _root_refs_stack->push(p);
+ } else {
+ _other_refs_stack->push(p);
+ }
+ }
+#endif
+ mark_and_push(_compaction_manager, p);
+}
+
+void PSParallelCompact::mark_and_follow(ParCompactionManager* cm,
+ oop* p) {
+ assert(Universe::heap()->is_in_reserved(p),
+ "we should only be traversing objects here");
+ oop m = *p;
+ if (m != NULL && mark_bitmap()->is_unmarked(m)) {
+ if (mark_obj(m)) {
+ m->follow_contents(cm); // Follow contents of the marked object
+ }
+ }
+}
+
+// Anything associated with this variable is temporary.
+
+void PSParallelCompact::mark_and_push_internal(ParCompactionManager* cm,
+ oop* p) {
+ // Push marked object, contents will be followed later
+ oop m = *p;
+ if (mark_obj(m)) {
+ // This thread marked the object and
+ // owns the subsequent processing of it.
+ cm->save_for_scanning(m);
+ }
+}
+
+void PSParallelCompact::post_initialize() {
+ ParallelScavengeHeap* heap = gc_heap();
+ assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+
+ MemRegion mr = heap->reserved_region();
+ _ref_processor = ReferenceProcessor::create_ref_processor(
+ mr, // span
+ true, // atomic_discovery
+ true, // mt_discovery
+ &_is_alive_closure,
+ ParallelGCThreads,
+ ParallelRefProcEnabled);
+ _counters = new CollectorCounters("PSParallelCompact", 1);
+
+ // Initialize static fields in ParCompactionManager.
+ ParCompactionManager::initialize(mark_bitmap());
+}
+
+bool PSParallelCompact::initialize() {
+ ParallelScavengeHeap* heap = gc_heap();
+ assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+ 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("Unable to allocate bit map for "
+ "parallel garbage collection for the requested heap size.");
+ return false;
+ }
+
+ if (!_summary_data.initialize(mr)) {
+ vm_shutdown_during_initialization("Unable to allocate tables for "
+ "parallel garbage collection for the requested heap size.");
+ return false;
+ }
+
+ return true;
+}
+
+void PSParallelCompact::initialize_space_info()
+{
+ memset(&_space_info, 0, sizeof(_space_info));
+
+ ParallelScavengeHeap* heap = gc_heap();
+ PSYoungGen* young_gen = heap->young_gen();
+ MutableSpace* perm_space = heap->perm_gen()->object_space();
+
+ _space_info[perm_space_id].set_space(perm_space);
+ _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[perm_space_id].set_start_array(heap->perm_gen()->start_array());
+ _space_info[old_space_id].set_start_array(heap->old_gen()->start_array());
+
+ _space_info[perm_space_id].set_min_dense_prefix(perm_space->top());
+ if (TraceParallelOldGCDensePrefix) {
+ tty->print_cr("perm min_dense_prefix=" PTR_FORMAT,
+ _space_info[perm_space_id].min_dense_prefix());
+ }
+}
+
+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);
+}
+
+// Simple class for storing info about the heap at the start of GC, to be used
+// after GC for comparison/printing.
+class PreGCValues {
+public:
+ PreGCValues() { }
+ PreGCValues(ParallelScavengeHeap* heap) { fill(heap); }
+
+ void fill(ParallelScavengeHeap* heap) {
+ _heap_used = heap->used();
+ _young_gen_used = heap->young_gen()->used_in_bytes();
+ _old_gen_used = heap->old_gen()->used_in_bytes();
+ _perm_gen_used = heap->perm_gen()->used_in_bytes();
+ };
+
+ size_t heap_used() const { return _heap_used; }
+ size_t young_gen_used() const { return _young_gen_used; }
+ size_t old_gen_used() const { return _old_gen_used; }
+ size_t perm_gen_used() const { return _perm_gen_used; }
+
+private:
+ size_t _heap_used;
+ size_t _young_gen_used;
+ size_t _old_gen_used;
+ size_t _perm_gen_used;
+};
+
+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_chunk = _summary_data.addr_to_chunk_idx(bot);
+ const size_t end_chunk =
+ _summary_data.addr_to_chunk_idx(_summary_data.chunk_align_up(max_top));
+ _summary_data.clear_range(beg_chunk, end_chunk);
+}
+
+void PSParallelCompact::pre_compact(PreGCValues* pre_gc_values)
+{
+ // 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 minor
+ // collections will have swapped the spaces an unknown number of times.
+ TraceTime tm("pre compact", print_phases(), true, gclog_or_tty);
+ ParallelScavengeHeap* heap = gc_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());
+
+ pre_gc_values->fill(heap);
+
+ ParCompactionManager::reset();
+ NOT_PRODUCT(_mark_bitmap.reset_counters());
+ 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();
+
+ // We need to track unique mark sweep invocations as well.
+ _total_invocations++;
+
+ if (PrintHeapAtGC) {
+ Universe::print_heap_before_gc();
+ }
+
+ // 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
+ gclog_or_tty->print(" VerifyBeforeGC:");
+ Universe::verify(true);
+ }
+
+ // Verify object start arrays
+ if (VerifyObjectStartArray &&
+ VerifyBeforeGC) {
+ heap->old_gen()->verify_object_start_array();
+ heap->perm_gen()->verify_object_start_array();
+ }
+
+ DEBUG_ONLY(mark_bitmap()->verify_clear();)
+ DEBUG_ONLY(summary_data().verify_clear();)
+}
+
+void PSParallelCompact::post_compact()
+{
+ TraceTime tm("post compact", print_phases(), true, gclog_or_tty);
+
+ // Clear the marking bitmap and summary data and update top() in each space.
+ for (unsigned int id = perm_space_id; id < last_space_id; ++id) {
+ clear_data_covering_space(SpaceId(id));
+ _space_info[id].space()->set_top(_space_info[id].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 = gc_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();
+
+ BarrierSet* bs = heap->barrier_set();
+ if (bs->is_a(BarrierSet::ModRef)) {
+ ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
+ MemRegion old_mr = heap->old_gen()->reserved();
+ MemRegion perm_mr = heap->perm_gen()->reserved();
+ assert(perm_mr.end() <= old_mr.start(), "Generations out of order");
+
+ if (young_gen_empty) {
+ modBS->clear(MemRegion(perm_mr.start(), old_mr.end()));
+ } else {
+ modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end()));
+ }
+ }
+
+ Threads::gc_epilogue();
+ CodeCache::gc_epilogue();
+
+ COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
+
+ ref_processor()->enqueue_discovered_references(NULL);
+
+ // 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 chunk_size = ParallelCompactData::ChunkSize;
+ const ParallelCompactData& sd = summary_data();
+
+ const MutableSpace* const space = _space_info[id].space();
+ HeapWord* const top_aligned_up = sd.chunk_align_up(space->top());
+ const ChunkData* const beg_cp = sd.addr_to_chunk_ptr(space->bottom());
+ const ChunkData* const end_cp = sd.addr_to_chunk_ptr(top_aligned_up);
+
+ // Skip full chunks at the beginning of the space--they are necessarily part
+ // of the dense prefix.
+ size_t full_count = 0;
+ const ChunkData* cp;
+ for (cp = beg_cp; cp < end_cp && cp->data_size() == chunk_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.chunk_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.chunk_to_addr(cp);
+ const ChunkData* full_cp = cp;
+ const ChunkData* const top_cp = sd.addr_to_chunk_ptr(space->top() - 1);
+ while (cp < end_cp) {
+ HeapWord* chunk_destination = cp->destination();
+ const size_t cur_deadwood = pointer_delta(dense_prefix, chunk_destination);
+ if (TraceParallelOldGCDensePrefix && Verbose) {
+ tty->print_cr("c#=" SIZE_FORMAT_W("04") " dst=" PTR_FORMAT " "
+ "dp=" SIZE_FORMAT_W("08") " " "cdw=" SIZE_FORMAT_W("08"),
+ sd.chunk(cp), chunk_destination,
+ dense_prefix, cur_deadwood);
+ }
+
+ if (cur_deadwood >= deadwood_goal) {
+ // Found the chunk that has the correct amount of deadwood to the left.
+ // This typically occurs after crossing a fairly sparse set of chunks, so
+ // iterate backwards over those sparse chunks, looking for the chunk that
+ // has the lowest density of live objects 'to the right.'
+ size_t space_to_left = sd.chunk(cp) * chunk_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_chunk_live_to_right = live_to_right - cp->data_size();
+ const size_t prev_chunk_space_to_right = space_to_right + chunk_size;
+ double prev_chunk_density_to_right =
+ double(prev_chunk_live_to_right) / prev_chunk_space_to_right;
+ if (density_to_right <= prev_chunk_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.chunk(cp), density_to_right,
+ prev_chunk_density_to_right);
+ }
+ dense_prefix -= chunk_size;
+ live_to_right = prev_chunk_live_to_right;
+ space_to_right = prev_chunk_space_to_right;
+ density_to_right = prev_chunk_density_to_right;
+ }
+ return dense_prefix;
+ }
+
+ dense_prefix += chunk_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 chunk_idx = summary_data().addr_to_chunk_idx(addr);
+ ChunkData* const cp = summary_data().chunk(chunk_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("05") " "
+ "spl=" SIZE_FORMAT " "
+ "d2l=" SIZE_FORMAT " d2l%%=%6.4f "
+ "d2r=" SIZE_FORMAT " l2r=" SIZE_FORMAT
+ " ratio=%10.8f",
+ algorithm, addr, chunk_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::ChunkData*
+PSParallelCompact::first_dead_space_chunk(const ChunkData* beg,
+ const ChunkData* end)
+{
+ const size_t chunk_size = ParallelCompactData::ChunkSize;
+ ParallelCompactData& sd = summary_data();
+ size_t left = sd.chunk(beg);
+ size_t right = end > beg ? sd.chunk(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;
+ ChunkData* const middle_ptr = sd.chunk(middle);
+ HeapWord* const dest = middle_ptr->destination();
+ HeapWord* const addr = sd.chunk_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() == chunk_size) {
+ left = middle + 1;
+ } else {
+ return middle_ptr;
+ }
+ }
+ return sd.chunk(left);
+}
+
+ParallelCompactData::ChunkData*
+PSParallelCompact::dead_wood_limit_chunk(const ChunkData* beg,
+ const ChunkData* end,
+ size_t dead_words)
+{
+ ParallelCompactData& sd = summary_data();
+ size_t left = sd.chunk(beg);
+ size_t right = end > beg ? sd.chunk(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;
+ ChunkData* const middle_ptr = sd.chunk(middle);
+ HeapWord* const dest = middle_ptr->destination();
+ HeapWord* const addr = sd.chunk_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.chunk(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 ChunkData* 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.chunk_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.chunk_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 chunk boundary.
+//
+// Completely full chunks at the left are skipped, since no compaction can occur
+// in those chunks. Then the maximum amount of dead wood to allow is computed,
+// based on the density (amount live / capacity) of the generation; the chunk
+// with approximately that amount of dead space to the left is identified as the
+// limit chunk. Chunks between the last completely full chunk and the limit
+// chunk 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 chunk_size = ParallelCompactData::ChunkSize;
+ const ParallelCompactData& sd = summary_data();
+
+ const MutableSpace* const space = _space_info[id].space();
+ HeapWord* const top = space->top();
+ HeapWord* const top_aligned_up = sd.chunk_align_up(top);
+ HeapWord* const new_top = _space_info[id].new_top();
+ HeapWord* const new_top_aligned_up = sd.chunk_align_up(new_top);
+ HeapWord* const bottom = space->bottom();
+ const ChunkData* const beg_cp = sd.addr_to_chunk_ptr(bottom);
+ const ChunkData* const top_cp = sd.addr_to_chunk_ptr(top_aligned_up);
+ const ChunkData* const new_top_cp = sd.addr_to_chunk_ptr(new_top_aligned_up);
+
+ // Skip full chunks at the beginning of the space--they are necessarily part
+ // of the dense prefix.
+ const ChunkData* const full_cp = first_dead_space_chunk(beg_cp, new_top_cp);
+ assert(full_cp->destination() == sd.chunk_to_addr(full_cp) ||
+ space->is_empty(), "no dead space allowed to the left");
+ assert(full_cp->data_size() < chunk_size || full_cp == new_top_cp - 1,
+ "chunk 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.chunk_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 =
+ id == perm_space_id ? PermMarkSweepDeadRatio : 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, %d)=%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 chunk with the desired amount of dead space to the left.
+ const ChunkData* const limit_cp =
+ dead_wood_limit_chunk(full_cp, top_cp, dead_wood_limit);
+
+ // Scan from the first chunk with dead space to the limit chunk and find the
+ // one with the best (largest) reclaimed ratio.
+ double best_ratio = 0.0;
+ const ChunkData* best_cp = full_cp;
+ for (const ChunkData* 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;
+ }
+ }
+
+#if 0
+ // Something to consider: if the chunk with the best ratio is 'close to' the
+ // first chunk w/free space, choose the first chunk with free space
+ // ("first-free"). The first-free chunk is usually near the start of the
+ // heap, which means we are copying most of the heap already, so copy a bit
+ // more to get complete compaction.
+ if (pointer_delta(best_cp, full_cp, sizeof(ChunkData)) < 4) {
+ _maximum_compaction_gc_num = total_invocations();
+ best_cp = full_cp;
+ }
+#endif // #if 0
+
+ return sd.chunk_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();
+ bool result = _summary_data.summarize(space->bottom(), space->end(),
+ space->bottom(), space->top(),
+ _space_info[i].new_top_addr());
+ assert(result, "should never fail");
+ _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 ChunkData* chunk = _summary_data.addr_to_chunk_ptr(dense_prefix_end);
+ const idx_t dense_prefix_bit = _mark_bitmap.addr_to_bit(dense_prefix_end);
+ if (dead_space_crosses_boundary(chunk, 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 = (size_t)oopDesc::header_size();
+ HeapWord* obj_beg = dense_prefix_end - obj_len;
+
+#ifdef _LP64
+ 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
+
+ MemRegion region(obj_beg, obj_len);
+ SharedHeap::fill_region_with_object(region);
+ _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");
+
+ const MutableSpace* space = _space_info[id].space();
+ HeapWord** new_top_addr = _space_info[id].new_top_addr();
+
+ 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
+
+ // 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 with an object.
+ if (!maximum_compaction && dense_prefix_end != space->bottom()) {
+ fill_dense_prefix_end(id);
+ }
+
+ // Compute the destination of each Chunk, and thus each object.
+ _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
+ _summary_data.summarize(dense_prefix_end, space->end(),
+ dense_prefix_end, space->top(),
+ new_top_addr);
+
+ if (TraceParallelOldGCSummaryPhase) {
+ const size_t chunk_size = ParallelCompactData::ChunkSize;
+ const size_t dp_chunk = _summary_data.addr_to_chunk_idx(dense_prefix_end);
+ const size_t dp_words = pointer_delta(dense_prefix_end, space->bottom());
+ const HeapWord* nt_aligned_up = _summary_data.chunk_align_up(*new_top_addr);
+ const size_t cr_words = pointer_delta(nt_aligned_up, dense_prefix_end);
+ tty->print_cr("id=%d cap=" SIZE_FORMAT " dp=" PTR_FORMAT " "
+ "dp_chunk=" SIZE_FORMAT " " "dp_count=" SIZE_FORMAT " "
+ "cr_count=" SIZE_FORMAT " " "nt=" PTR_FORMAT,
+ id, space->capacity_in_words(), dense_prefix_end,
+ dp_chunk, dp_words / chunk_size,
+ cr_words / chunk_size, *new_top_addr);
+ }
+}
+
+void PSParallelCompact::summary_phase(ParCompactionManager* cm,
+ bool maximum_compaction)
+{
+ EventMark m("2 summarize");
+ TraceTime tm("summary phase", print_phases(), true, gclog_or_tty);
+ // trace("2");
+
+#ifdef ASSERT
+ if (VerifyParallelOldWithMarkSweep &&
+ (PSParallelCompact::total_invocations() %
+ VerifyParallelOldWithMarkSweepInterval) == 0) {
+ verify_mark_bitmap(_mark_bitmap);
+ }
+ 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();
+
+ if (TraceParallelOldGCSummaryPhase) {
+ tty->print_cr("summary_phase: after summarizing each space to self");
+ Universe::print();
+ NOT_PRODUCT(print_chunk_ranges());
+ if (Verbose) {
+ 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;
+ unsigned int id;
+ for (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());
+ }
+
+ const MutableSpace* old_space = _space_info[old_space_id].space();
+ if (old_space_total_live > old_space->capacity_in_words()) {
+ // XXX - should also try to expand
+ maximum_compaction = true;
+ } else if (!UseParallelOldGCDensePrefix) {
+ maximum_compaction = true;
+ }
+
+ // Permanent and Old generations.
+ summarize_space(perm_space_id, maximum_compaction);
+ summarize_space(old_space_id, maximum_compaction);
+
+ // Summarize the remaining spaces (those in the young gen) into old space. If
+ // the live data from a space doesn't fit, the existing summarization is left
+ // intact, so the data is compacted down within the space itself.
+ HeapWord** new_top_addr = _space_info[old_space_id].new_top_addr();
+ HeapWord* const target_space_end = old_space->end();
+ for (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(target_space_end, *new_top_addr);
+ if (live <= available) {
+ // All the live data will fit.
+ if (TraceParallelOldGCSummaryPhase) {
+ tty->print_cr("summarizing %d into old_space @ " PTR_FORMAT,
+ id, *new_top_addr);
+ }
+ _summary_data.summarize(*new_top_addr, target_space_end,
+ space->bottom(), space->top(),
+ new_top_addr);
+
+ // Reset the new_top value for the space.
+ _space_info[id].set_new_top(space->bottom());
+
+ // Clear the source_chunk field for each chunk in the space.
+ ChunkData* beg_chunk = _summary_data.addr_to_chunk_ptr(space->bottom());
+ ChunkData* end_chunk = _summary_data.addr_to_chunk_ptr(space->top() - 1);
+ while (beg_chunk <= end_chunk) {
+ beg_chunk->set_source_chunk(0);
+ ++beg_chunk;
+ }
+ }
+ }
+
+ // Fill in the block data after any changes to the chunks have
+ // been made.
+#ifdef ASSERT
+ summarize_blocks(cm, perm_space_id);
+ summarize_blocks(cm, old_space_id);
+#else
+ if (!UseParallelOldGCChunkPointerCalc) {
+ summarize_blocks(cm, perm_space_id);
+ summarize_blocks(cm, old_space_id);
+ }
+#endif
+
+ if (TraceParallelOldGCSummaryPhase) {
+ tty->print_cr("summary_phase: after final summarization");
+ Universe::print();
+ NOT_PRODUCT(print_chunk_ranges());
+ if (Verbose) {
+ NOT_PRODUCT(print_generic_summary_data(_summary_data, _space_info));
+ }
+ }
+}
+
+// Fill in the BlockData.
+// Iterate over the spaces and within each space iterate over
+// the chunks and fill in the BlockData for each chunk.
+
+void PSParallelCompact::summarize_blocks(ParCompactionManager* cm,
+ SpaceId first_compaction_space_id) {
+#if 0
+ DEBUG_ONLY(ParallelCompactData::BlockData::set_cur_phase(1);)
+ for (SpaceId cur_space_id = first_compaction_space_id;
+ cur_space_id != last_space_id;
+ cur_space_id = next_compaction_space_id(cur_space_id)) {
+ // Iterate over the chunks in the space
+ size_t start_chunk_index =
+ _summary_data.addr_to_chunk_idx(space(cur_space_id)->bottom());
+ BitBlockUpdateClosure bbu(mark_bitmap(),
+ cm,
+ start_chunk_index);
+ // Iterate over blocks.
+ for (size_t chunk_index = start_chunk_index;
+ chunk_index < _summary_data.chunk_count() &&
+ _summary_data.chunk_to_addr(chunk_index) < space(cur_space_id)->top();
+ chunk_index++) {
+
+ // Reset the closure for the new chunk. Note that the closure
+ // maintains some data that does not get reset for each chunk
+ // so a new instance of the closure is no appropriate.
+ bbu.reset_chunk(chunk_index);
+
+ // Start the iteration with the first live object. This
+ // may return the end of the chunk. That is acceptable since
+ // it will properly limit the iterations.
+ ParMarkBitMap::idx_t left_offset = mark_bitmap()->addr_to_bit(
+ _summary_data.first_live_or_end_in_chunk(chunk_index));
+
+ // End the iteration at the end of the chunk.
+ HeapWord* chunk_addr = _summary_data.chunk_to_addr(chunk_index);
+ HeapWord* chunk_end = chunk_addr + ParallelCompactData::ChunkSize;
+ ParMarkBitMap::idx_t right_offset =
+ mark_bitmap()->addr_to_bit(chunk_end);
+
+ // Blocks that have not objects starting in them can be
+ // skipped because their data will never be used.
+ if (left_offset < right_offset) {
+
+ // Iterate through the objects in the chunk.
+ ParMarkBitMap::idx_t last_offset =
+ mark_bitmap()->pair_iterate(&bbu, left_offset, right_offset);
+
+ // If last_offset is less than right_offset, then the iterations
+ // terminated while it was looking for an end bit. "last_offset"
+ // is then the offset for the last start bit. In this situation
+ // the "offset" field for the next block to the right (_cur_block + 1)
+ // will not have been update although there may be live data
+ // to the left of the chunk.
+
+ size_t cur_block_plus_1 = bbu.cur_block() + 1;
+ HeapWord* cur_block_plus_1_addr =
+ _summary_data.block_to_addr(bbu.cur_block()) +
+ ParallelCompactData::BlockSize;
+ HeapWord* last_offset_addr = mark_bitmap()->bit_to_addr(last_offset);
+ #if 1 // This code works. The else doesn't but should. Why does it?
+ // The current block (cur_block()) has already been updated.
+ // The last block that may need to be updated is either the
+ // next block (current block + 1) or the block where the
+ // last object starts (which can be greater than the
+ // next block if there were no objects found in intervening
+ // blocks).
+ size_t last_block =
+ MAX2(bbu.cur_block() + 1,
+ _summary_data.addr_to_block_idx(last_offset_addr));
+ #else
+ // The current block has already been updated. The only block
+ // that remains to be updated is the block where the last
+ // object in the chunk starts.
+ size_t last_block = _summary_data.addr_to_block_idx(last_offset_addr);
+ #endif
+ assert_bit_is_start(last_offset);
+ assert((last_block == _summary_data.block_count()) ||
+ (_summary_data.block(last_block)->raw_offset() == 0),
+ "Should not have been set");
+ // Is the last block still in the current chunk? If still
+ // in this chunk, update the last block (the counting that
+ // included the current block is meant for the offset of the last
+ // block). If not in this chunk, do nothing. Should not
+ // update a block in the next chunk.
+ if (ParallelCompactData::chunk_contains_block(bbu.chunk_index(),
+ last_block)) {
+ if (last_offset < right_offset) {
+ // The last object started in this chunk but ends beyond
+ // this chunk. Update the block for this last object.
+ assert(mark_bitmap()->is_marked(last_offset), "Should be marked");
+ // No end bit was found. The closure takes care of
+ // the cases where
+ // an objects crosses over into the next block
+ // an objects starts and ends in the next block
+ // It does not handle the case where an object is
+ // the first object in a later block and extends
+ // past the end of the chunk (i.e., the closure
+ // only handles complete objects that are in the range
+ // it is given). That object is handed back here
+ // for any special consideration necessary.
+ //
+ // Is the first bit in the last block a start or end bit?
+ //
+ // If the partial object ends in the last block L,
+ // then the 1st bit in L may be an end bit.
+ //
+ // Else does the last object start in a block after the current
+ // block? A block AA will already have been updated if an
+ // object ends in the next block AA+1. An object found to end in
+ // the AA+1 is the trigger that updates AA. Objects are being
+ // counted in the current block for updaing a following
+ // block. An object may start in later block
+ // block but may extend beyond the last block in the chunk.
+ // Updates are only done when the end of an object has been
+ // found. If the last object (covered by block L) starts
+ // beyond the current block, then no object ends in L (otherwise
+ // L would be the current block). So the first bit in L is
+ // a start bit.
+ //
+ // Else the last objects start in the current block and ends
+ // beyond the chunk. The current block has already been
+ // updated and there is no later block (with an object
+ // starting in it) that needs to be updated.
+ //
+ if (_summary_data.partial_obj_ends_in_block(last_block)) {
+ _summary_data.block(last_block)->set_end_bit_offset(
+ bbu.live_data_left());
+ } else if (last_offset_addr >= cur_block_plus_1_addr) {
+ // The start of the object is on a later block
+ // (to the right of the current block and there are no
+ // complete live objects to the left of this last object
+ // within the chunk.
+ // The first bit in the block is for the start of the
+ // last object.
+ _summary_data.block(last_block)->set_start_bit_offset(
+ bbu.live_data_left());
+ } else {
+ // The start of the last object was found in
+ // the current chunk (which has already
+ // been updated).
+ assert(bbu.cur_block() ==
+ _summary_data.addr_to_block_idx(last_offset_addr),
+ "Should be a block already processed");
+ }
+#ifdef ASSERT
+ // Is there enough block information to find this object?
+ // The destination of the chunk has not been set so the
+ // values returned by calc_new_pointer() and
+ // block_calc_new_pointer() will only be
+ // offsets. But they should agree.
+ HeapWord* moved_obj_with_chunks =
+ _summary_data.chunk_calc_new_pointer(last_offset_addr);
+ HeapWord* moved_obj_with_blocks =
+ _summary_data.calc_new_pointer(last_offset_addr);
+ assert(moved_obj_with_chunks == moved_obj_with_blocks,
+ "Block calculation is wrong");
+#endif
+ } else if (last_block < _summary_data.block_count()) {
+ // Iterations ended looking for a start bit (but
+ // did not run off the end of the block table).
+ _summary_data.block(last_block)->set_start_bit_offset(
+ bbu.live_data_left());
+ }
+ }
+#ifdef ASSERT
+ // Is there enough block information to find this object?
+ HeapWord* left_offset_addr = mark_bitmap()->bit_to_addr(left_offset);
+ HeapWord* moved_obj_with_chunks =
+ _summary_data.calc_new_pointer(left_offset_addr);
+ HeapWord* moved_obj_with_blocks =
+ _summary_data.calc_new_pointer(left_offset_addr);
+ assert(moved_obj_with_chunks == moved_obj_with_blocks,
+ "Block calculation is wrong");
+#endif
+
+ // Is there another block after the end of this chunk?
+#ifdef ASSERT
+ if (last_block < _summary_data.block_count()) {
+ // No object may have been found in a block. If that
+ // block is at the end of the chunk, the iteration will
+ // terminate without incrementing the current block so
+ // that the current block is not the last block in the
+ // chunk. That situation precludes asserting that the
+ // current block is the last block in the chunk. Assert
+ // the lesser condition that the current block does not
+ // exceed the chunk.
+ assert(_summary_data.block_to_addr(last_block) <=
+ (_summary_data.chunk_to_addr(chunk_index) +
+ ParallelCompactData::ChunkSize),
+ "Chunk and block inconsistency");
+ assert(last_offset <= right_offset, "Iteration over ran end");
+ }
+#endif
+ }
+#ifdef ASSERT
+ if (PrintGCDetails && Verbose) {
+ if (_summary_data.chunk(chunk_index)->partial_obj_size() == 1) {
+ size_t first_block =
+ chunk_index / ParallelCompactData::BlocksPerChunk;
+ gclog_or_tty->print_cr("first_block " PTR_FORMAT
+ " _offset " PTR_FORMAT
+ "_first_is_start_bit %d",
+ first_block,
+ _summary_data.block(first_block)->raw_offset(),
+ _summary_data.block(first_block)->first_is_start_bit());
+ }
+ }
+#endif
+ }
+ }
+ DEBUG_ONLY(ParallelCompactData::BlockData::set_cur_phase(16);)
+#endif // #if 0
+}
+
+// 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.
+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 = gc_heap();
+ GCCause::Cause gc_cause = heap->gc_cause();
+ assert(!heap->is_gc_active(), "not reentrant");
+
+ PSAdaptiveSizePolicy* policy = heap->size_policy();
+
+ // Before each allocation/collection attempt, find out from the
+ // policy object if GCs are, on the whole, taking too long. If so,
+ // bail out without attempting a collection. The exceptions are
+ // for explicitly requested GC's.
+ if (!policy->gc_time_limit_exceeded() ||
+ GCCause::is_user_requested_gc(gc_cause) ||
+ GCCause::is_serviceability_requested_gc(gc_cause)) {
+ IsGCActiveMark mark;
+
+ if (ScavengeBeforeFullGC) {
+ PSScavenge::invoke_no_policy();
+ }
+
+ PSParallelCompact::invoke_no_policy(maximum_heap_compaction);
+ }
+}
+
+bool ParallelCompactData::chunk_contains(size_t chunk_index, HeapWord* addr) {
+ size_t addr_chunk_index = addr_to_chunk_idx(addr);
+ return chunk_index == addr_chunk_index;
+}
+
+bool ParallelCompactData::chunk_contains_block(size_t chunk_index,
+ size_t block_index) {
+ size_t first_block_in_chunk = chunk_index * BlocksPerChunk;
+ size_t last_block_in_chunk = (chunk_index + 1) * BlocksPerChunk - 1;
+
+ return (first_block_in_chunk <= block_index) &&
+ (block_index <= last_block_in_chunk);
+}
+
+// This method contains no policy. You should probably
+// be calling invoke() instead.
+void PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
+ assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
+ assert(ref_processor() != NULL, "Sanity");
+
+ if (GC_locker::is_active()) {
+ return;
+ }
+
+ TimeStamp marking_start;
+ TimeStamp compaction_start;
+ TimeStamp collection_exit;
+
+ // "serial_CM" is needed until the parallel implementation
+ // of the move and update is done.
+ ParCompactionManager* serial_CM = new ParCompactionManager();
+ // Don't initialize more than once.
+ // serial_CM->initialize(&summary_data(), mark_bitmap());
+
+ ParallelScavengeHeap* heap = gc_heap();
+ GCCause::Cause gc_cause = heap->gc_cause();
+ PSYoungGen* young_gen = heap->young_gen();
+ PSOldGen* old_gen = heap->old_gen();
+ PSPermGen* perm_gen = heap->perm_gen();
+ PSAdaptiveSizePolicy* size_policy = heap->size_policy();
+
+ _print_phases = PrintGCDetails && PrintParallelOldGCPhaseTimes;
+
+ // Make sure data structures are sane, make the heap parsable, and do other
+ // miscellaneous bookkeeping.
+ PreGCValues pre_gc_values;
+ pre_compact(&pre_gc_values);
+
+ // Place after pre_compact() where the number of invocations is incremented.
+ AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
+
+ {
+ ResourceMark rm;
+ HandleMark hm;
+
+ const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc;
+
+ // This is useful for debugging but don't change the output the
+ // the customer sees.
+ const char* gc_cause_str = "Full GC";
+ if (is_system_gc && PrintGCDetails) {
+ gc_cause_str = "Full GC (System)";
+ }
+ gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
+ TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
+ TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty);
+ TraceCollectorStats tcs(counters());
+ TraceMemoryManagerStats tms(true /* Full GC */);
+
+ if (TraceGen1Time) accumulated_time()->start();
+
+ // Let the size policy know we're starting
+ size_policy->major_collection_begin();
+
+ // When collecting the permanent generation methodOops may be moving,
+ // so we either have to flush all bcp data or convert it into bci.
+ CodeCache::gc_prologue();
+ Threads::gc_prologue();
+
+ NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
+ COMPILER2_PRESENT(DerivedPointerTable::clear());
+
+ ref_processor()->enable_discovery();
+
+ bool marked_for_unloading = false;
+
+ marking_start.update();
+ marking_phase(serial_CM, maximum_heap_compaction);
+
+#ifndef PRODUCT
+ if (TraceParallelOldGCMarkingPhase) {
+ gclog_or_tty->print_cr("marking_phase: cas_tries %d cas_retries %d "
+ "cas_by_another %d",
+ mark_bitmap()->cas_tries(), mark_bitmap()->cas_retries(),
+ mark_bitmap()->cas_by_another());
+ }
+#endif // #ifndef PRODUCT
+
+#ifdef ASSERT
+ if (VerifyParallelOldWithMarkSweep &&
+ (PSParallelCompact::total_invocations() %
+ VerifyParallelOldWithMarkSweepInterval) == 0) {
+ gclog_or_tty->print_cr("Verify marking with mark_sweep_phase1()");
+ if (PrintGCDetails && Verbose) {
+ gclog_or_tty->print_cr("mark_sweep_phase1:");
+ }
+ // Clear the discovered lists so that discovered objects
+ // don't look like they have been discovered twice.
+ ref_processor()->clear_discovered_references();
+
+ PSMarkSweep::allocate_stacks();
+ MemRegion mr = Universe::heap()->reserved_region();
+ PSMarkSweep::ref_processor()->enable_discovery();
+ PSMarkSweep::mark_sweep_phase1(maximum_heap_compaction);
+ }
+#endif
+
+ bool max_on_system_gc = UseMaximumCompactionOnSystemGC && is_system_gc;
+ summary_phase(serial_CM, maximum_heap_compaction || max_on_system_gc);
+
+#ifdef ASSERT
+ if (VerifyParallelOldWithMarkSweep &&
+ (PSParallelCompact::total_invocations() %
+ VerifyParallelOldWithMarkSweepInterval) == 0) {
+ if (PrintGCDetails && Verbose) {
+ gclog_or_tty->print_cr("mark_sweep_phase2:");
+ }
+ PSMarkSweep::mark_sweep_phase2();
+ }
+#endif
+
+ COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
+ COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
+
+ // adjust_roots() updates Universe::_intArrayKlassObj which is
+ // needed by the compaction for filling holes in the dense prefix.
+ adjust_roots();
+
+#ifdef ASSERT
+ if (VerifyParallelOldWithMarkSweep &&
+ (PSParallelCompact::total_invocations() %
+ VerifyParallelOldWithMarkSweepInterval) == 0) {
+ // Do a separate verify phase so that the verify
+ // code can use the the forwarding pointers to
+ // check the new pointer calculation. The restore_marks()
+ // has to be done before the real compact.
+ serial_CM->set_action(ParCompactionManager::VerifyUpdate);
+ compact_perm(serial_CM);
+ compact_serial(serial_CM);
+ serial_CM->set_action(ParCompactionManager::ResetObjects);
+ compact_perm(serial_CM);
+ compact_serial(serial_CM);
+ serial_CM->set_action(ParCompactionManager::UpdateAndCopy);
+
+ // For debugging only
+ PSMarkSweep::restore_marks();
+ PSMarkSweep::deallocate_stacks();
+ }
+#endif
+
+ compaction_start.update();
+ // Does the perm gen always have to be done serially because
+ // klasses are used in the update of an object?
+ compact_perm(serial_CM);
+
+ if (UseParallelOldGCCompacting) {
+ compact();
+ } else {
+ compact_serial(serial_CM);
+ }
+
+ delete serial_CM;
+
+ // 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) {
+ if (PrintAdaptiveSizePolicy) {
+ gclog_or_tty->print("AdaptiveSizeStart: ");
+ gclog_or_tty->stamp();
+ gclog_or_tty->print_cr(" collection: %d ",
+ heap->total_collections());
+ if (Verbose) {
+ gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
+ " perm_gen_capacity: %d ",
+ old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
+ perm_gen->capacity_in_bytes());
+ }
+ }
+
+ // Don't check if the size_policy is ready here. Let
+ // the size_policy check that internally.
+ if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
+ ((gc_cause != GCCause::_java_lang_system_gc) ||
+ UseAdaptiveSizePolicyWithSystemGC)) {
+ // 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 max_eden_size = young_gen->max_size() -
+ young_gen->from_space()->capacity_in_bytes() -
+ young_gen->to_space()->capacity_in_bytes();
+ size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
+ young_gen->eden_space()->used_in_bytes(),
+ old_gen->used_in_bytes(),
+ perm_gen->used_in_bytes(),
+ young_gen->eden_space()->capacity_in_bytes(),
+ old_gen->max_gen_size(),
+ max_eden_size,
+ true /* full gc*/,
+ gc_cause);
+
+ heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
+
+ // Don't resize the young generation at an major collection. A
+ // desired young generation size may have been calculated but
+ // resizing the young generation complicates the code because the
+ // resizing of the old generation may have moved the boundary
+ // between the young generation and the old generation. Let the
+ // young generation resizing happen at the minor collections.
+ }
+ if (PrintAdaptiveSizePolicy) {
+ gclog_or_tty->print_cr("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();
+
+ // We collected the perm gen, so we'll resize it here.
+ perm_gen->compute_new_size(pre_gc_values.perm_gen_used());
+
+ if (TraceGen1Time) accumulated_time()->stop();
+
+ if (PrintGC) {
+ if (PrintGCDetails) {
+ // No GC timestamp here. This is after GC so it would be confusing.
+ young_gen->print_used_change(pre_gc_values.young_gen_used());
+ old_gen->print_used_change(pre_gc_values.old_gen_used());
+ heap->print_heap_change(pre_gc_values.heap_used());
+ // Print perm gen last (print_heap_change() excludes the perm gen).
+ perm_gen->print_used_change(pre_gc_values.perm_gen_used());
+ } else {
+ heap->print_heap_change(pre_gc_values.heap_used());
+ }
+ }
+
+ // Track memory usage and detect low memory
+ MemoryService::track_memory_usage();
+ heap->update_counters();
+
+ if (PrintGCDetails) {
+ if (size_policy->print_gc_time_limit_would_be_exceeded()) {
+ if (size_policy->gc_time_limit_exceeded()) {
+ gclog_or_tty->print_cr(" GC time is exceeding GCTimeLimit "
+ "of %d%%", GCTimeLimit);
+ } else {
+ gclog_or_tty->print_cr(" GC time would exceed GCTimeLimit "
+ "of %d%%", GCTimeLimit);
+ }
+ }
+ size_policy->set_print_gc_time_limit_would_be_exceeded(false);
+ }
+ }
+
+ if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
+ HandleMark hm; // Discard invalid handles created during verification
+ gclog_or_tty->print(" VerifyAfterGC:");
+ Universe::verify(false);
+ }
+
+ // Re-verify object start arrays
+ if (VerifyObjectStartArray &&
+ VerifyAfterGC) {
+ old_gen->verify_object_start_array();
+ perm_gen->verify_object_start_array();
+ }
+
+ NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
+
+ collection_exit.update();
+
+ if (PrintHeapAtGC) {
+ Universe::print_heap_after_gc();
+ }
+ if (PrintGCTaskTimeStamps) {
+ gclog_or_tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " "
+ INT64_FORMAT,
+ marking_start.ticks(), compaction_start.ticks(),
+ collection_exit.ticks());
+ gc_task_manager()->print_task_time_stamps();
+ }
+}
+
+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_size_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.
+ }
+
+ if (TraceAdaptiveGCBoundary && Verbose) {
+ gclog_or_tty->print(" 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();
+ MemRegion old_gen_unused(old_space->top(), old_space->end());
+ if (!old_gen_unused.is_empty()) {
+ SharedHeap::fill_region_with_object(old_gen_unused);
+ }
+
+ // 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();
+ HeapWord* const start = old_gen_unused.start();
+ for (HeapWord* addr = start; addr < new_top; addr += oop(addr)->size()) {
+ start_array->allocate_block(addr);
+ }
+
+ // 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) {
+ // Recursively traverse all live objects and mark them
+ EventMark m("1 mark object");
+ TraceTime tm("marking phase", print_phases(), true, gclog_or_tty);
+
+ ParallelScavengeHeap* heap = gc_heap();
+ uint parallel_gc_threads = heap->gc_task_manager()->workers();
+ TaskQueueSetSuper* qset = ParCompactionManager::chunk_array();
+ ParallelTaskTerminator terminator(parallel_gc_threads, qset);
+
+ PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
+ PSParallelCompact::FollowStackClosure follow_stack_closure(cm);
+
+ {
+ TraceTime tm_m("par mark", print_phases(), true, gclog_or_tty);
+
+ 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::flat_profiler));
+ q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::management));
+ q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::system_dictionary));
+ q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jvmti));
+ q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::vm_symbols));
+
+ if (parallel_gc_threads > 1) {
+ for (uint j = 0; j < parallel_gc_threads; j++) {
+ q->enqueue(new StealMarkingTask(&terminator));
+ }
+ }
+
+ WaitForBarrierGCTask* fin = WaitForBarrierGCTask::create();
+ q->enqueue(fin);
+
+ gc_task_manager()->add_list(q);
+
+ fin->wait_for();
+
+ // We have to release the barrier tasks!
+ WaitForBarrierGCTask::destroy(fin);
+ }
+
+ // Process reference objects found during marking
+ {
+ TraceTime tm_r("reference processing", print_phases(), true, gclog_or_tty);
+ ReferencePolicy *soft_ref_policy;
+ if (maximum_heap_compaction) {
+ soft_ref_policy = new AlwaysClearPolicy();
+ } else {
+#ifdef COMPILER2
+ soft_ref_policy = new LRUMaxHeapPolicy();
+#else
+ soft_ref_policy = new LRUCurrentHeapPolicy();
+#endif // COMPILER2
+ }
+ assert(soft_ref_policy != NULL, "No soft reference policy");
+ if (ref_processor()->processing_is_mt()) {
+ RefProcTaskExecutor task_executor;
+ ref_processor()->process_discovered_references(
+ soft_ref_policy, is_alive_closure(), &mark_and_push_closure,
+ &follow_stack_closure, &task_executor);
+ } else {
+ ref_processor()->process_discovered_references(
+ soft_ref_policy, is_alive_closure(), &mark_and_push_closure,
+ &follow_stack_closure, NULL);
+ }
+ }
+
+ TraceTime tm_c("class unloading", print_phases(), true, gclog_or_tty);
+ // Follow system dictionary roots and unload classes.
+ bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
+
+ // Follow code cache roots.
+ CodeCache::do_unloading(is_alive_closure(), &mark_and_push_closure,
+ purged_class);
+ follow_stack(cm); // Flush marking stack.
+
+ // Update subklass/sibling/implementor links of live klasses
+ // revisit_klass_stack is used in follow_weak_klass_links().
+ follow_weak_klass_links(cm);
+
+ // Visit symbol and interned string tables and delete unmarked oops
+ SymbolTable::unlink(is_alive_closure());
+ StringTable::unlink(is_alive_closure());
+
+ assert(cm->marking_stack()->size() == 0, "stack should be empty by now");
+ assert(cm->overflow_stack()->is_empty(), "stack should be empty by now");
+}
+
+// This should be moved to the shared markSweep code!
+class PSAlwaysTrueClosure: public BoolObjectClosure {
+public:
+ void do_object(oop p) { ShouldNotReachHere(); }
+ bool do_object_b(oop p) { return true; }
+};
+static PSAlwaysTrueClosure always_true;
+
+void PSParallelCompact::adjust_roots() {
+ // Adjust the pointers to reflect the new locations
+ EventMark m("3 adjust roots");
+ TraceTime tm("adjust roots", print_phases(), true, gclog_or_tty);
+
+ // General strong roots.
+ Universe::oops_do(adjust_root_pointer_closure());
+ ReferenceProcessor::oops_do(adjust_root_pointer_closure());
+ JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
+ Threads::oops_do(adjust_root_pointer_closure());
+ ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
+ FlatProfiler::oops_do(adjust_root_pointer_closure());
+ Management::oops_do(adjust_root_pointer_closure());
+ JvmtiExport::oops_do(adjust_root_pointer_closure());
+ // SO_AllClasses
+ SystemDictionary::oops_do(adjust_root_pointer_closure());
+ vmSymbols::oops_do(adjust_root_pointer_closure());
+
+ // 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(&always_true, adjust_root_pointer_closure());
+
+ CodeCache::oops_do(adjust_pointer_closure());
+ SymbolTable::oops_do(adjust_root_pointer_closure());
+ StringTable::oops_do(adjust_root_pointer_closure());
+ ref_processor()->weak_oops_do(adjust_root_pointer_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(
+ adjust_root_pointer_closure());
+}
+
+void PSParallelCompact::compact_perm(ParCompactionManager* cm) {
+ EventMark m("4 compact perm");
+ TraceTime tm("compact perm gen", print_phases(), true, gclog_or_tty);
+ // trace("4");
+
+ gc_heap()->perm_gen()->start_array()->reset();
+ move_and_update(cm, perm_space_id);
+}
+
+void PSParallelCompact::enqueue_chunk_draining_tasks(GCTaskQueue* q,
+ uint parallel_gc_threads) {
+ TraceTime tm("drain task setup", print_phases(), true, gclog_or_tty);
+
+ const unsigned int task_count = MAX2(parallel_gc_threads, 1U);
+ for (unsigned int j = 0; j < task_count; j++) {
+ q->enqueue(new DrainStacksCompactionTask());
+ }
+
+ // Find all chunks 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 chunks will be removed in ascending order.
+
+ const ParallelCompactData& sd = PSParallelCompact::summary_data();
+
+ size_t fillable_chunks = 0; // A count for diagnostic purposes.
+ unsigned int which = 0; // The worker thread number.
+
+ for (unsigned int id = to_space_id; id > perm_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_chunk = sd.addr_to_chunk_idx(space_info->dense_prefix());
+ const size_t end_chunk = sd.addr_to_chunk_idx(sd.chunk_align_up(new_top));
+ assert(end_chunk > 0, "perm gen cannot be empty");
+
+ for (size_t cur = end_chunk - 1; cur >= beg_chunk; --cur) {
+ if (sd.chunk(cur)->claim_unsafe()) {
+ ParCompactionManager* cm = ParCompactionManager::manager_array(which);
+ cm->save_for_processing(cur);
+
+ if (TraceParallelOldGCCompactionPhase && Verbose) {
+ const size_t count_mod_8 = fillable_chunks & 7;
+ if (count_mod_8 == 0) gclog_or_tty->print("fillable: ");
+ gclog_or_tty->print(" " SIZE_FORMAT_W("7"), cur);
+ if (count_mod_8 == 7) gclog_or_tty->cr();
+ }
+
+ NOT_PRODUCT(++fillable_chunks;)
+
+ // Assign chunks to threads in round-robin fashion.
+ if (++which == task_count) {
+ which = 0;
+ }
+ }
+ }
+ }
+
+ if (TraceParallelOldGCCompactionPhase) {
+ if (Verbose && (fillable_chunks & 7) != 0) gclog_or_tty->cr();
+ gclog_or_tty->print_cr("%u initially fillable chunks", fillable_chunks);
+ }
+}
+
+#define PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING 4
+
+void PSParallelCompact::enqueue_dense_prefix_tasks(GCTaskQueue* q,
+ uint parallel_gc_threads) {
+ TraceTime tm("dense prefix task setup", print_phases(), true, gclog_or_tty);
+
+ ParallelCompactData& sd = PSParallelCompact::summary_data();
+
+ // Iterate over all the spaces adding tasks for updating
+ // chunks 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.
+ SpaceId space_id = old_space_id;
+ while (space_id != last_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.
+ space_id = next_compaction_space_id(space_id);
+ continue;
+ }
+
+ // The dense prefix is before this chunk.
+ size_t chunk_index_end_dense_prefix =
+ sd.addr_to_chunk_idx(dense_prefix_end);
+ ChunkData* const dense_prefix_cp = sd.chunk(chunk_index_end_dense_prefix);
+ assert(dense_prefix_end == space->end() ||
+ dense_prefix_cp->available() ||
+ dense_prefix_cp->claimed(),
+ "The chunk after the dense prefix should always be ready to fill");
+
+ size_t chunk_index_start = sd.addr_to_chunk_idx(space->bottom());
+
+ // Is there dense prefix work?
+ size_t total_dense_prefix_chunks =
+ chunk_index_end_dense_prefix - chunk_index_start;
+ // How many chunks of the dense prefix should be given to
+ // each thread?
+ if (total_dense_prefix_chunks > 0) {
+ uint tasks_for_dense_prefix = 1;
+ if (UseParallelDensePrefixUpdate) {
+ if (total_dense_prefix_chunks <=
+ (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 chunks 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 chunks_per_thread = total_dense_prefix_chunks /
+ tasks_for_dense_prefix;
+ // Give each thread at least 1 chunk.
+ if (chunks_per_thread == 0) {
+ chunks_per_thread = 1;
+ }
+
+ for (uint k = 0; k < tasks_for_dense_prefix; k++) {
+ if (chunk_index_start >= chunk_index_end_dense_prefix) {
+ break;
+ }
+ // chunk_index_end is not processed
+ size_t chunk_index_end = MIN2(chunk_index_start + chunks_per_thread,
+ chunk_index_end_dense_prefix);
+ q->enqueue(new UpdateDensePrefixTask(
+ space_id,
+ chunk_index_start,
+ chunk_index_end));
+ chunk_index_start = chunk_index_end;
+ }
+ }
+ // This gets any part of the dense prefix that did not
+ // fit evenly.
+ if (chunk_index_start < chunk_index_end_dense_prefix) {
+ q->enqueue(new UpdateDensePrefixTask(
+ space_id,
+ chunk_index_start,
+ chunk_index_end_dense_prefix));
+ }
+ space_id = next_compaction_space_id(space_id);
+ } // End tasks for dense prefix
+}
+
+void PSParallelCompact::enqueue_chunk_stealing_tasks(
+ GCTaskQueue* q,
+ ParallelTaskTerminator* terminator_ptr,
+ uint parallel_gc_threads) {
+ TraceTime tm("steal task setup", print_phases(), true, gclog_or_tty);
+
+ // Once a thread has drained it's stack, it should try to steal chunks from
+ // other threads.
+ if (parallel_gc_threads > 1) {
+ for (uint j = 0; j < parallel_gc_threads; j++) {
+ q->enqueue(new StealChunkCompactionTask(terminator_ptr));
+ }
+ }
+}
+
+void PSParallelCompact::compact() {
+ EventMark m("5 compact");
+ // trace("5");
+ TraceTime tm("compaction phase", print_phases(), true, gclog_or_tty);
+
+ ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+ assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+ PSOldGen* old_gen = heap->old_gen();
+ old_gen->start_array()->reset();
+ uint parallel_gc_threads = heap->gc_task_manager()->workers();
+ TaskQueueSetSuper* qset = ParCompactionManager::chunk_array();
+ ParallelTaskTerminator terminator(parallel_gc_threads, qset);
+
+ GCTaskQueue* q = GCTaskQueue::create();
+ enqueue_chunk_draining_tasks(q, parallel_gc_threads);
+ enqueue_dense_prefix_tasks(q, parallel_gc_threads);
+ enqueue_chunk_stealing_tasks(q, &terminator, parallel_gc_threads);
+
+ {
+ TraceTime tm_pc("par compact", print_phases(), true, gclog_or_tty);
+
+ WaitForBarrierGCTask* fin = WaitForBarrierGCTask::create();
+ q->enqueue(fin);
+
+ gc_task_manager()->add_list(q);
+
+ fin->wait_for();
+
+ // We have to release the barrier tasks!
+ WaitForBarrierGCTask::destroy(fin);
+
+#ifdef ASSERT
+ // Verify that all chunks have been processed before the deferred updates.
+ // Note that perm_space_id is skipped; this type of verification is not
+ // valid until the perm gen is compacted by chunks.
+ 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.
+ TraceTime tm_du("deferred updates", print_phases(), true, gclog_or_tty);
+ ParCompactionManager* cm = ParCompactionManager::manager_array(0);
+ for (unsigned int id = old_space_id; id < last_space_id; ++id) {
+ update_deferred_objects(cm, SpaceId(id));
+ }
+ }
+}
+
+#ifdef ASSERT
+void PSParallelCompact::verify_complete(SpaceId space_id) {
+ // All Chunks between space bottom() to new_top() should be marked as filled
+ // and all Chunks 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.chunk_align_up(si.new_top());
+ HeapWord* old_top_addr = sd.chunk_align_up(si.space()->top());
+ const size_t beg_chunk = sd.addr_to_chunk_idx(si.space()->bottom());
+ const size_t new_top_chunk = sd.addr_to_chunk_idx(new_top_addr);
+ const size_t old_top_chunk = sd.addr_to_chunk_idx(old_top_addr);
+
+ bool issued_a_warning = false;
+
+ size_t cur_chunk;
+ for (cur_chunk = beg_chunk; cur_chunk < new_top_chunk; ++cur_chunk) {
+ const ChunkData* const c = sd.chunk(cur_chunk);
+ if (!c->completed()) {
+ warning("chunk " SIZE_FORMAT " not filled: "
+ "destination_count=" SIZE_FORMAT,
+ cur_chunk, c->destination_count());
+ issued_a_warning = true;
+ }
+ }
+
+ for (cur_chunk = new_top_chunk; cur_chunk < old_top_chunk; ++cur_chunk) {
+ const ChunkData* const c = sd.chunk(cur_chunk);
+ if (!c->available()) {
+ warning("chunk " SIZE_FORMAT " not empty: "
+ "destination_count=" SIZE_FORMAT,
+ cur_chunk, c->destination_count());
+ issued_a_warning = true;
+ }
+ }
+
+ if (issued_a_warning) {
+ print_chunk_ranges();
+ }
+}
+#endif // #ifdef ASSERT
+
+void PSParallelCompact::compact_serial(ParCompactionManager* cm) {
+ EventMark m("5 compact serial");
+ TraceTime tm("compact serial", print_phases(), true, gclog_or_tty);
+
+ ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
+ assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
+
+ PSYoungGen* young_gen = heap->young_gen();
+ PSOldGen* old_gen = heap->old_gen();
+
+ old_gen->start_array()->reset();
+ old_gen->move_and_update(cm);
+ young_gen->move_and_update(cm);
+}
+
+void PSParallelCompact::follow_root(ParCompactionManager* cm, oop* p) {
+ assert(!Universe::heap()->is_in_reserved(p),
+ "roots shouldn't be things within the heap");
+#ifdef VALIDATE_MARK_SWEEP
+ if (ValidateMarkSweep) {
+ guarantee(!_root_refs_stack->contains(p), "should only be in here once");
+ _root_refs_stack->push(p);
+ }
+#endif
+ oop m = *p;
+ if (m != NULL && mark_bitmap()->is_unmarked(m)) {
+ if (mark_obj(m)) {
+ m->follow_contents(cm); // Follow contents of the marked object
+ }
+ }
+ follow_stack(cm);
+}
+
+void PSParallelCompact::follow_stack(ParCompactionManager* cm) {
+ while(!cm->overflow_stack()->is_empty()) {
+ oop obj = cm->overflow_stack()->pop();
+ obj->follow_contents(cm);
+ }
+
+ oop obj;
+ // obj is a reference!!!
+ while (cm->marking_stack()->pop_local(obj)) {
+ // It would be nice to assert about the type of objects we might
+ // pop, but they can come from anywhere, unfortunately.
+ obj->follow_contents(cm);
+ }
+}
+
+void
+PSParallelCompact::follow_weak_klass_links(ParCompactionManager* serial_cm) {
+ // All klasses on the revisit stack are marked at this point.
+ // Update and follow all subklass, sibling and implementor links.
+ for (uint i = 0; i < ParallelGCThreads+1; i++) {
+ ParCompactionManager* cm = ParCompactionManager::manager_array(i);
+ KeepAliveClosure keep_alive_closure(cm);
+ for (int i = 0; i < cm->revisit_klass_stack()->length(); i++) {
+ cm->revisit_klass_stack()->at(i)->follow_weak_klass_links(
+ is_alive_closure(),
+ &keep_alive_closure);
+ }
+ follow_stack(cm);
+ }
+}
+
+void
+PSParallelCompact::revisit_weak_klass_link(ParCompactionManager* cm, Klass* k) {
+ cm->revisit_klass_stack()->push(k);
+}
+
+#ifdef VALIDATE_MARK_SWEEP
+
+void PSParallelCompact::track_adjusted_pointer(oop* p, oop newobj, bool isroot) {
+ if (!ValidateMarkSweep)
+ return;
+
+ if (!isroot) {
+ if (_pointer_tracking) {
+ guarantee(_adjusted_pointers->contains(p), "should have seen this pointer");
+ _adjusted_pointers->remove(p);
+ }
+ } else {
+ ptrdiff_t index = _root_refs_stack->find(p);
+ if (index != -1) {
+ int l = _root_refs_stack->length();
+ if (l > 0 && l - 1 != index) {
+ oop* last = _root_refs_stack->pop();
+ assert(last != p, "should be different");
+ _root_refs_stack->at_put(index, last);
+ } else {
+ _root_refs_stack->remove(p);
+ }
+ }
+ }
+}
+
+
+void PSParallelCompact::check_adjust_pointer(oop* p) {
+ _adjusted_pointers->push(p);
+}
+
+
+class AdjusterTracker: public OopClosure {
+ public:
+ AdjusterTracker() {};
+ void do_oop(oop* o) { PSParallelCompact::check_adjust_pointer(o); }
+};
+
+
+void PSParallelCompact::track_interior_pointers(oop obj) {
+ if (ValidateMarkSweep) {
+ _adjusted_pointers->clear();
+ _pointer_tracking = true;
+
+ AdjusterTracker checker;
+ obj->oop_iterate(&checker);
+ }
+}
+
+
+void PSParallelCompact::check_interior_pointers() {
+ if (ValidateMarkSweep) {
+ _pointer_tracking = false;
+ guarantee(_adjusted_pointers->length() == 0, "should have processed the same pointers");
+ }
+}
+
+
+void PSParallelCompact::reset_live_oop_tracking(bool at_perm) {
+ if (ValidateMarkSweep) {
+ guarantee((size_t)_live_oops->length() == _live_oops_index, "should be at end of live oops");
+ _live_oops_index = at_perm ? _live_oops_index_at_perm : 0;
+ }
+}
+
+
+void PSParallelCompact::register_live_oop(oop p, size_t size) {
+ if (ValidateMarkSweep) {
+ _live_oops->push(p);
+ _live_oops_size->push(size);
+ _live_oops_index++;
+ }
+}
+
+void PSParallelCompact::validate_live_oop(oop p, size_t size) {
+ if (ValidateMarkSweep) {
+ oop obj = _live_oops->at((int)_live_oops_index);
+ guarantee(obj == p, "should be the same object");
+ guarantee(_live_oops_size->at((int)_live_oops_index) == size, "should be the same size");
+ _live_oops_index++;
+ }
+}
+
+void PSParallelCompact::live_oop_moved_to(HeapWord* q, size_t size,
+ HeapWord* compaction_top) {
+ assert(oop(q)->forwardee() == NULL || oop(q)->forwardee() == oop(compaction_top),
+ "should be moved to forwarded location");
+ if (ValidateMarkSweep) {
+ PSParallelCompact::validate_live_oop(oop(q), size);
+ _live_oops_moved_to->push(oop(compaction_top));
+ }
+ if (RecordMarkSweepCompaction) {
+ _cur_gc_live_oops->push(q);
+ _cur_gc_live_oops_moved_to->push(compaction_top);
+ _cur_gc_live_oops_size->push(size);
+ }
+}
+
+
+void PSParallelCompact::compaction_complete() {
+ if (RecordMarkSweepCompaction) {
+ GrowableArray<HeapWord*>* _tmp_live_oops = _cur_gc_live_oops;
+ GrowableArray<HeapWord*>* _tmp_live_oops_moved_to = _cur_gc_live_oops_moved_to;
+ GrowableArray<size_t> * _tmp_live_oops_size = _cur_gc_live_oops_size;
+
+ _cur_gc_live_oops = _last_gc_live_oops;
+ _cur_gc_live_oops_moved_to = _last_gc_live_oops_moved_to;
+ _cur_gc_live_oops_size = _last_gc_live_oops_size;
+ _last_gc_live_oops = _tmp_live_oops;
+ _last_gc_live_oops_moved_to = _tmp_live_oops_moved_to;
+ _last_gc_live_oops_size = _tmp_live_oops_size;
+ }
+}
+
+
+void PSParallelCompact::print_new_location_of_heap_address(HeapWord* q) {
+ if (!RecordMarkSweepCompaction) {
+ tty->print_cr("Requires RecordMarkSweepCompaction to be enabled");
+ return;
+ }
+
+ if (_last_gc_live_oops == NULL) {
+ tty->print_cr("No compaction information gathered yet");
+ return;
+ }
+
+ for (int i = 0; i < _last_gc_live_oops->length(); i++) {
+ HeapWord* old_oop = _last_gc_live_oops->at(i);
+ size_t sz = _last_gc_live_oops_size->at(i);
+ if (old_oop <= q && q < (old_oop + sz)) {
+ HeapWord* new_oop = _last_gc_live_oops_moved_to->at(i);
+ size_t offset = (q - old_oop);
+ tty->print_cr("Address " PTR_FORMAT, q);
+ tty->print_cr(" Was in oop " PTR_FORMAT ", size %d, at offset %d", old_oop, sz, offset);
+ tty->print_cr(" Now in oop " PTR_FORMAT ", actual address " PTR_FORMAT, new_oop, new_oop + offset);
+ return;
+ }
+ }
+
+ tty->print_cr("Address " PTR_FORMAT " not found in live oop information from last GC", q);
+}
+#endif //VALIDATE_MARK_SWEEP
+
+void PSParallelCompact::adjust_pointer(oop* p, bool isroot) {
+ oop obj = *p;
+ VALIDATE_MARK_SWEEP_ONLY(oop saved_new_pointer = NULL);
+ if (obj != NULL) {
+ oop new_pointer = (oop) summary_data().calc_new_pointer(obj);
+ assert(new_pointer != NULL || // is forwarding ptr?
+ obj->is_shared(), // never forwarded?
+ "should have a new location");
+ // Just always do the update unconditionally?
+ if (new_pointer != NULL) {
+ *p = new_pointer;
+ assert(Universe::heap()->is_in_reserved(new_pointer),
+ "should be in object space");
+ VALIDATE_MARK_SWEEP_ONLY(saved_new_pointer = new_pointer);
+ }
+ }
+ VALIDATE_MARK_SWEEP_ONLY(track_adjusted_pointer(p, saved_new_pointer, isroot));
+}
+
+// Update interior oops in the ranges of chunks [beg_chunk, end_chunk).
+void
+PSParallelCompact::update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
+ SpaceId space_id,
+ size_t beg_chunk,
+ size_t end_chunk) {
+ ParallelCompactData& sd = summary_data();
+ ParMarkBitMap* const mbm = mark_bitmap();
+
+ HeapWord* beg_addr = sd.chunk_to_addr(beg_chunk);
+ HeapWord* const end_addr = sd.chunk_to_addr(end_chunk);
+ assert(beg_chunk <= end_chunk, "bad chunk range");
+ assert(end_addr <= dense_prefix(space_id), "not in the dense prefix");
+
+#ifdef ASSERT
+ // Claim the chunks to avoid triggering an assert when they are marked as
+ // filled.
+ for (size_t claim_chunk = beg_chunk; claim_chunk < end_chunk; ++claim_chunk) {
+ assert(sd.chunk(claim_chunk)->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 chunks. If a partial object crosses onto the chunk, skip it; it
+ // will be marked for 'deferred update' when the object head is processed.
+ // If dead space crosses onto the chunk, it is also skipped; it will be
+ // filled when the prior chunk is processed. If neither of those apply, the
+ // first word in the chunk is the start of a live object or dead space.
+ assert(beg_addr > space(space_id)->bottom(), "sanity");
+ const ChunkData* const cp = sd.chunk(beg_chunk);
+ if (cp->partial_obj_size() != 0) {
+ beg_addr = sd.partial_obj_end(beg_chunk);
+ } 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 Chunks.
+ 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 chunks as filled.
+ ChunkData* const beg_cp = sd.chunk(beg_chunk);
+ ChunkData* const end_cp = sd.chunk(end_chunk);
+ for (ChunkData* 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(Universe::heap()->is_in_reserved(addr), "addr not in the heap");
+
+ for (unsigned int id = perm_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.chunk_align_up(space_info->new_top());
+
+ const ChunkData* const beg_chunk = sd.addr_to_chunk_ptr(beg_addr);
+ const ChunkData* const end_chunk = sd.addr_to_chunk_ptr(end_addr);
+ const ChunkData* cur_chunk;
+ for (cur_chunk = beg_chunk; cur_chunk < end_chunk; ++cur_chunk) {
+ HeapWord* const addr = cur_chunk->deferred_obj_addr();
+ if (addr != NULL) {
+ if (start_array != NULL) {
+ start_array->allocate_block(addr);
+ }
+ oop(addr)->update_contents(cm);
+ assert(oop(addr)->is_oop_or_null(), "should be an oop now");
+ }
+ }
+}
+
+// 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,
+ size_t src_chunk_idx)
+{
+ ParMarkBitMap* const bitmap = mark_bitmap();
+ const ParallelCompactData& sd = summary_data();
+ const size_t ChunkSize = ParallelCompactData::ChunkSize;
+
+ assert(sd.is_chunk_aligned(dest_addr), "not aligned");
+
+ const ChunkData* const src_chunk_ptr = sd.chunk(src_chunk_idx);
+ const size_t partial_obj_size = src_chunk_ptr->partial_obj_size();
+ HeapWord* const src_chunk_destination = src_chunk_ptr->destination();
+
+ assert(dest_addr >= src_chunk_destination, "wrong src chunk");
+ assert(src_chunk_ptr->data_size() > 0, "src chunk cannot be empty");
+
+ HeapWord* const src_chunk_beg = sd.chunk_to_addr(src_chunk_idx);
+ HeapWord* const src_chunk_end = src_chunk_beg + ChunkSize;
+
+ HeapWord* addr = src_chunk_beg;
+ if (dest_addr == src_chunk_destination) {
+ // Return the first live word in the source chunk.
+ if (partial_obj_size == 0) {
+ addr = bitmap->find_obj_beg(addr, src_chunk_end);
+ assert(addr < src_chunk_end, "no objects start in src chunk");
+ }
+ return addr;
+ }
+
+ // Must skip some live data.
+ size_t words_to_skip = dest_addr - src_chunk_destination;
+ assert(src_chunk_ptr->data_size() > words_to_skip, "wrong src chunk");
+
+ 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_chunk_end);
+ assert(addr < src_chunk_end, "wrong src chunk");
+ }
+ 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 chunk.
+ addr = skip_live_words(addr, src_chunk_end, words_to_skip);
+ assert(addr < src_chunk_end, "wrong src chunk");
+ return addr;
+}
+
+void PSParallelCompact::decrement_destination_counts(ParCompactionManager* cm,
+ size_t beg_chunk,
+ HeapWord* end_addr)
+{
+ ParallelCompactData& sd = summary_data();
+ ChunkData* const beg = sd.chunk(beg_chunk);
+ HeapWord* const end_addr_aligned_up = sd.chunk_align_up(end_addr);
+ ChunkData* const end = sd.addr_to_chunk_ptr(end_addr_aligned_up);
+ size_t cur_idx = beg_chunk;
+ for (ChunkData* cur = beg; cur < end; ++cur, ++cur_idx) {
+ assert(cur->data_size() > 0, "chunk must have live data");
+ cur->decrement_destination_count();
+ if (cur_idx <= cur->source_chunk() && cur->available() && cur->claim()) {
+ cm->save_for_processing(cur_idx);
+ }
+ }
+}
+
+size_t PSParallelCompact::next_src_chunk(MoveAndUpdateClosure& closure,
+ SpaceId& src_space_id,
+ HeapWord*& src_space_top,
+ HeapWord* end_addr)
+{
+ typedef ParallelCompactData::ChunkData ChunkData;
+
+ ParallelCompactData& sd = PSParallelCompact::summary_data();
+ const size_t chunk_size = ParallelCompactData::ChunkSize;
+
+ size_t src_chunk_idx = 0;
+
+ // Skip empty chunks (if any) up to the top of the space.
+ HeapWord* const src_aligned_up = sd.chunk_align_up(end_addr);
+ ChunkData* src_chunk_ptr = sd.addr_to_chunk_ptr(src_aligned_up);
+ HeapWord* const top_aligned_up = sd.chunk_align_up(src_space_top);
+ const ChunkData* const top_chunk_ptr = sd.addr_to_chunk_ptr(top_aligned_up);
+ while (src_chunk_ptr < top_chunk_ptr && src_chunk_ptr->data_size() == 0) {
+ ++src_chunk_ptr;
+ }
+
+ if (src_chunk_ptr < top_chunk_ptr) {
+ // The next source chunk is in the current space. Update src_chunk_idx and
+ // the source address to match src_chunk_ptr.
+ src_chunk_idx = sd.chunk(src_chunk_ptr);
+ HeapWord* const src_chunk_addr = sd.chunk_to_addr(src_chunk_idx);
+ if (src_chunk_addr > closure.source()) {
+ closure.set_source(src_chunk_addr);
+ }
+ return src_chunk_idx;
+ }
+
+ // Switch to a new source space and find the first non-empty chunk.
+ 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 ChunkData* const bottom_cp = sd.addr_to_chunk_ptr(bottom);
+
+ // Iterate over the spaces that do not compact into themselves.
+ if (bottom_cp->destination() != bottom) {
+ HeapWord* const top_aligned_up = sd.chunk_align_up(space->top());
+ const ChunkData* const top_cp = sd.addr_to_chunk_ptr(top_aligned_up);
+
+ for (const ChunkData* 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_chunk_idx = sd.chunk(src_cp);
+ closure.set_source(sd.chunk_to_addr(src_chunk_idx));
+ return src_chunk_idx;
+ } else {
+ assert(src_cp->data_size() == 0, "sanity");
+ }
+ }
+ }
+ } while (++space_id < last_space_id);
+
+ assert(false, "no source chunk was found");
+ return 0;
+}
+
+void PSParallelCompact::fill_chunk(ParCompactionManager* cm, size_t chunk_idx)
+{
+ typedef ParMarkBitMap::IterationStatus IterationStatus;
+ const size_t ChunkSize = ParallelCompactData::ChunkSize;
+ ParMarkBitMap* const bitmap = mark_bitmap();
+ ParallelCompactData& sd = summary_data();
+ ChunkData* const chunk_ptr = sd.chunk(chunk_idx);
+
+ // Get the items needed to construct the closure.
+ HeapWord* dest_addr = sd.chunk_to_addr(chunk_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), ChunkSize);
+
+ // Get the source chunk and related info.
+ size_t src_chunk_idx = chunk_ptr->source_chunk();
+ SpaceId src_space_id = space_id(sd.chunk_to_addr(src_chunk_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_chunk_idx));
+
+ // Adjust src_chunk_idx to prepare for decrementing destination counts (the
+ // destination count is not decremented when a chunk is copied to itself).
+ if (src_chunk_idx == chunk_idx) {
+ src_chunk_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_chunk_idx, closure.source());
+ chunk_ptr->set_deferred_obj_addr(NULL);
+ chunk_ptr->set_completed();
+ return;
+ }
+
+ HeapWord* const end_addr = sd.chunk_align_down(closure.source());
+ if (sd.chunk_align_down(old_src_addr) != end_addr) {
+ // The partial object was copied from more than one source chunk.
+ decrement_destination_counts(cm, src_chunk_idx, end_addr);
+
+ // Move to the next source chunk, possibly switching spaces as well. All
+ // args except end_addr may be modified.
+ src_chunk_idx = next_src_chunk(closure, src_space_id, src_space_top,
+ end_addr);
+ }
+ }
+
+ do {
+ HeapWord* const cur_addr = closure.source();
+ HeapWord* const end_addr = MIN2(sd.chunk_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 chunk does not end in the chunk.
+ 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 chunk.
+ chunk_ptr->set_deferred_obj_addr(closure.destination());
+ status = closure.copy_until_full(); // copies from closure.source()
+
+ decrement_destination_counts(cm, src_chunk_idx, closure.source());
+ chunk_ptr->set_completed();
+ return;
+ }
+
+ if (status == ParMarkBitMap::full) {
+ decrement_destination_counts(cm, src_chunk_idx, closure.source());
+ chunk_ptr->set_deferred_obj_addr(NULL);
+ chunk_ptr->set_completed();
+ return;
+ }
+
+ decrement_destination_counts(cm, src_chunk_idx, end_addr);
+
+ // Move to the next source chunk, possibly switching spaces as well. All
+ // args except end_addr may be modified.
+ src_chunk_idx = next_src_chunk(closure, src_space_id, src_space_top,
+ end_addr);
+ } while (true);
+}
+
+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();
+
+#ifdef ASSERT
+ assert(beg_addr <= dp_addr && dp_addr <= end_addr, "bad dense prefix");
+ if (cm->should_verify_only()) {
+ VerifyUpdateClosure verify_update(cm, sp);
+ bitmap->iterate(&verify_update, beg_addr, end_addr);
+ return;
+ }
+
+ if (cm->should_reset_only()) {
+ ResetObjectsClosure reset_objects(cm);
+ bitmap->iterate(&reset_objects, beg_addr, end_addr);
+ return;
+ }
+#endif
+
+ const size_t beg_chunk = sd.addr_to_chunk_idx(beg_addr);
+ const size_t dp_chunk = sd.addr_to_chunk_idx(dp_addr);
+ if (beg_chunk < dp_chunk) {
+ update_and_deadwood_in_dense_prefix(cm, space_id, beg_chunk, dp_chunk);
+ }
+
+ // The destination of the first live object that starts in the chunk is one
+ // past the end of the partial object entering the chunk (if any).
+ HeapWord* const dest_addr = sd.partial_obj_end(dp_chunk);
+ 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() {
+ jlong ret_val = os::javaTimeMillis() - _time_of_last_gc;
+ // XXX See note in genCollectedHeap::millis_since_last_gc().
+ if (ret_val < 0) {
+ NOT_PRODUCT(warning("time warp: %d", ret_val);)
+ return 0;
+ }
+ return ret_val;
+}
+
+void PSParallelCompact::reset_millis_since_last_gc() {
+ _time_of_last_gc = os::javaTimeMillis();
+}
+
+ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full()
+{
+ if (source() != destination()) {
+ assert(source() > destination(), "must copy to the left");
+ 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()) {
+ assert(source() > destination(), "must copy to the left");
+ Copy::aligned_conjoint_words(source(), destination(), words);
+ }
+ update_state(words);
+}
+
+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()) ==
+ 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()) {
+ assert(destination() < source(), "must copy to the left");
+ Copy::aligned_conjoint_words(source(), destination(), words);
+ }
+
+ oop moved_oop = (oop) destination();
+ moved_oop->update_contents(compaction_manager());
+ assert(moved_oop->is_oop_or_null(), "Object should be whole at this point");
+
+ 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;
+}
+
+BitBlockUpdateClosure::BitBlockUpdateClosure(ParMarkBitMap* mbm,
+ ParCompactionManager* cm,
+ size_t chunk_index) :
+ ParMarkBitMapClosure(mbm, cm),
+ _live_data_left(0),
+ _cur_block(0) {
+ _chunk_start =
+ PSParallelCompact::summary_data().chunk_to_addr(chunk_index);
+ _chunk_end =
+ PSParallelCompact::summary_data().chunk_to_addr(chunk_index) +
+ ParallelCompactData::ChunkSize;
+ _chunk_index = chunk_index;
+ _cur_block =
+ PSParallelCompact::summary_data().addr_to_block_idx(_chunk_start);
+}
+
+bool BitBlockUpdateClosure::chunk_contains_cur_block() {
+ return ParallelCompactData::chunk_contains_block(_chunk_index, _cur_block);
+}
+
+void BitBlockUpdateClosure::reset_chunk(size_t chunk_index) {
+ DEBUG_ONLY(ParallelCompactData::BlockData::set_cur_phase(7);)
+ ParallelCompactData& sd = PSParallelCompact::summary_data();
+ _chunk_index = chunk_index;
+ _live_data_left = 0;
+ _chunk_start = sd.chunk_to_addr(chunk_index);
+ _chunk_end = sd.chunk_to_addr(chunk_index) + ParallelCompactData::ChunkSize;
+
+ // The first block in this chunk
+ size_t first_block = sd.addr_to_block_idx(_chunk_start);
+ size_t partial_live_size = sd.chunk(chunk_index)->partial_obj_size();
+
+ // Set the offset to 0. By definition it should have that value
+ // but it may have been written while processing an earlier chunk.
+ if (partial_live_size == 0) {
+ // No live object extends onto the chunk. The first bit
+ // in the bit map for the first chunk must be a start bit.
+ // Although there may not be any marked bits, it is safe
+ // to set it as a start bit.
+ sd.block(first_block)->set_start_bit_offset(0);
+ sd.block(first_block)->set_first_is_start_bit(true);
+ } else if (sd.partial_obj_ends_in_block(first_block)) {
+ sd.block(first_block)->set_end_bit_offset(0);
+ sd.block(first_block)->set_first_is_start_bit(false);
+ } else {
+ // The partial object extends beyond the first block.
+ // There is no object starting in the first block
+ // so the offset and bit parity are not needed.
+ // Set the the bit parity to start bit so assertions
+ // work when not bit is found.
+ sd.block(first_block)->set_end_bit_offset(0);
+ sd.block(first_block)->set_first_is_start_bit(false);
+ }
+ _cur_block = first_block;
+#ifdef ASSERT
+ if (sd.block(first_block)->first_is_start_bit()) {
+ assert(!sd.partial_obj_ends_in_block(first_block),
+ "Partial object cannot end in first block");
+ }
+
+ if (PrintGCDetails && Verbose) {
+ if (partial_live_size == 1) {
+ gclog_or_tty->print_cr("first_block " PTR_FORMAT
+ " _offset " PTR_FORMAT
+ " _first_is_start_bit %d",
+ first_block,
+ sd.block(first_block)->raw_offset(),
+ sd.block(first_block)->first_is_start_bit());
+ }
+ }
+#endif
+ DEBUG_ONLY(ParallelCompactData::BlockData::set_cur_phase(17);)
+}
+
+// This method is called when a object has been found (both beginning
+// and end of the object) in the range of iteration. This method is
+// calculating the words of live data to the left of a block. That live
+// data includes any object starting to the left of the block (i.e.,
+// the live-data-to-the-left of block AAA will include the full size
+// of any object entering AAA).
+
+ParMarkBitMapClosure::IterationStatus
+BitBlockUpdateClosure::do_addr(HeapWord* addr, size_t words) {
+ // add the size to the block data.
+ HeapWord* obj = addr;
+ ParallelCompactData& sd = PSParallelCompact::summary_data();
+
+ assert(bitmap()->obj_size(obj) == words, "bad size");
+ assert(_chunk_start <= obj, "object is not in chunk");
+ assert(obj + words <= _chunk_end, "object is not in chunk");
+
+ // Update the live data to the left
+ size_t prev_live_data_left = _live_data_left;
+ _live_data_left = _live_data_left + words;
+
+ // Is this object in the current block.
+ size_t block_of_obj = sd.addr_to_block_idx(obj);
+ size_t block_of_obj_last = sd.addr_to_block_idx(obj + words - 1);
+ HeapWord* block_of_obj_last_addr = sd.block_to_addr(block_of_obj_last);
+ if (_cur_block < block_of_obj) {
+
+ //
+ // No object crossed the block boundary and this object was found
+ // on the other side of the block boundary. Update the offset for
+ // the new block with the data size that does not include this object.
+ //
+ // The first bit in block_of_obj is a start bit except in the
+ // case where the partial object for the chunk extends into
+ // this block.
+ if (sd.partial_obj_ends_in_block(block_of_obj)) {
+ sd.block(block_of_obj)->set_end_bit_offset(prev_live_data_left);
+ } else {
+ sd.block(block_of_obj)->set_start_bit_offset(prev_live_data_left);
+ }
+
+ // Does this object pass beyond the its block?
+ if (block_of_obj < block_of_obj_last) {
+ // Object crosses block boundary. Two blocks need to be udpated:
+ // the current block where the object started
+ // the block where the object ends
+ //
+ // The offset for blocks with no objects starting in them
+ // (e.g., blocks between _cur_block and block_of_obj_last)
+ // should not be needed.
+ // Note that block_of_obj_last may be in another chunk. If so,
+ // it should be overwritten later. This is a problem (writting
+ // into a block in a later chunk) for parallel execution.
+ assert(obj < block_of_obj_last_addr,
+ "Object should start in previous block");
+
+ // obj is crossing into block_of_obj_last so the first bit
+ // is and end bit.
+ sd.block(block_of_obj_last)->set_end_bit_offset(_live_data_left);
+
+ _cur_block = block_of_obj_last;
+ } else {
+ // _first_is_start_bit has already been set correctly
+ // in the if-then-else above so don't reset it here.
+ _cur_block = block_of_obj;
+ }
+ } else {
+ // The current block only changes if the object extends beyound
+ // the block it starts in.
+ //
+ // The object starts in the current block.
+ // Does this object pass beyond the end of it?
+ if (block_of_obj < block_of_obj_last) {
+ // Object crosses block boundary.
+ // See note above on possible blocks between block_of_obj and
+ // block_of_obj_last
+ assert(obj < block_of_obj_last_addr,
+ "Object should start in previous block");
+
+ sd.block(block_of_obj_last)->set_end_bit_offset(_live_data_left);
+
+ _cur_block = block_of_obj_last;
+ }
+ }
+
+ // Return incomplete if there are more blocks to be done.
+ if (chunk_contains_cur_block()) {
+ return ParMarkBitMap::incomplete;
+ }
+ return ParMarkBitMap::complete;
+}
+
+// Verify the new location using the forwarding pointer
+// from MarkSweep::mark_sweep_phase2(). Set the mark_word
+// to the initial value.
+ParMarkBitMapClosure::IterationStatus
+PSParallelCompact::VerifyUpdateClosure::do_addr(HeapWord* addr, size_t words) {
+ // The second arg (words) is not used.
+ oop obj = (oop) addr;
+ HeapWord* forwarding_ptr = (HeapWord*) obj->mark()->decode_pointer();
+ HeapWord* new_pointer = summary_data().calc_new_pointer(obj);
+ if (forwarding_ptr == NULL) {
+ // The object is dead or not moving.
+ assert(bitmap()->is_unmarked(obj) || (new_pointer == (HeapWord*) obj),
+ "Object liveness is wrong.");
+ return ParMarkBitMap::incomplete;
+ }
+ assert(UseParallelOldGCDensePrefix ||
+ (HeapMaximumCompactionInterval > 1) ||
+ (MarkSweepAlwaysCompactCount > 1) ||
+ (forwarding_ptr == new_pointer),
+ "Calculation of new location is incorrect");
+ return ParMarkBitMap::incomplete;
+}
+
+// Reset objects modified for debug checking.
+ParMarkBitMapClosure::IterationStatus
+PSParallelCompact::ResetObjectsClosure::do_addr(HeapWord* addr, size_t words) {
+ // The second arg (words) is not used.
+ oop obj = (oop) addr;
+ obj->init_mark();
+ return ParMarkBitMap::incomplete;
+}
+
+// Prepare for compaction. This method is executed once
+// (i.e., by a single thread) before compaction.
+// Save the updated location of the intArrayKlassObj for
+// filling holes in the dense prefix.
+void PSParallelCompact::compact_prologue() {
+ _updated_int_array_klass_obj = (klassOop)
+ summary_data().calc_new_pointer(Universe::intArrayKlassObj());
+}
+
+// The initial implementation of this method created a field
+// _next_compaction_space_id in SpaceInfo and initialized
+// that field in SpaceInfo::initialize_space_info(). That
+// required that _next_compaction_space_id be declared a
+// SpaceId in SpaceInfo and that would have required that
+// either SpaceId be declared in a separate class or that
+// it be declared in SpaceInfo. It didn't seem consistent
+// to declare it in SpaceInfo (didn't really fit logically).
+// Alternatively, defining a separate class to define SpaceId
+// seem excessive. This implementation is simple and localizes
+// the knowledge.
+
+PSParallelCompact::SpaceId
+PSParallelCompact::next_compaction_space_id(SpaceId id) {
+ assert(id < last_space_id, "id out of range");
+ switch (id) {
+ case perm_space_id :
+ return last_space_id;
+ case old_space_id :
+ return eden_space_id;
+ case eden_space_id :
+ return from_space_id;
+ case from_space_id :
+ return to_space_id;
+ case to_space_id :
+ return last_space_id;
+ default:
+ assert(false, "Bad space id");
+ return last_space_id;
+ }
+}
+
+// Here temporarily for debugging
+#ifdef ASSERT
+ size_t ParallelCompactData::block_idx(BlockData* block) {
+ size_t index = pointer_delta(block,
+ PSParallelCompact::summary_data()._block_data, sizeof(BlockData));
+ return index;
+ }
+#endif