| /* |
| * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #include "precompiled.hpp" |
| |
| #include "gc/shenandoah/shenandoahCollectionSet.hpp" |
| #include "gc/shenandoah/shenandoahHeap.inline.hpp" |
| #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" |
| #include "gc/shenandoah/shenandoahUtils.hpp" |
| #include "runtime/atomic.hpp" |
| #include "services/memTracker.hpp" |
| #include "utilities/copy.hpp" |
| |
| ShenandoahCollectionSet::ShenandoahCollectionSet(ShenandoahHeap* heap, char* heap_base, size_t size) : |
| _map_size(heap->num_regions()), |
| _region_size_bytes_shift(ShenandoahHeapRegion::region_size_bytes_shift()), |
| _map_space(align_up(((uintx)heap_base + size) >> _region_size_bytes_shift, os::vm_allocation_granularity())), |
| _cset_map(_map_space.base() + ((uintx)heap_base >> _region_size_bytes_shift)), |
| _biased_cset_map(_map_space.base()), |
| _heap(heap), |
| _garbage(0), |
| _live_data(0), |
| _used(0), |
| _region_count(0), |
| _current_index(0) { |
| |
| // The collection set map is reserved to cover the entire heap *and* zero addresses. |
| // This is needed to accept in-cset checks for both heap oops and NULLs, freeing |
| // high-performance code from checking for NULL first. |
| // |
| // Since heap_base can be far away, committing the entire map would waste memory. |
| // Therefore, we only commit the parts that are needed to operate: the heap view, |
| // and the zero page. |
| // |
| // Note: we could instead commit the entire map, and piggyback on OS virtual memory |
| // subsystem for mapping not-yet-written-to pages to a single physical backing page, |
| // but this is not guaranteed, and would confuse NMT and other memory accounting tools. |
| |
| MemTracker::record_virtual_memory_type(_map_space.base(), mtGC); |
| |
| size_t page_size = (size_t)os::vm_page_size(); |
| |
| if (!_map_space.special()) { |
| // Commit entire pages that cover the heap cset map. |
| char* bot_addr = align_down(_cset_map, page_size); |
| char* top_addr = align_up(_cset_map + _map_size, page_size); |
| os::commit_memory_or_exit(bot_addr, pointer_delta(top_addr, bot_addr, 1), false, |
| "Unable to commit collection set bitmap: heap"); |
| |
| // Commit the zero page, if not yet covered by heap cset map. |
| if (bot_addr != _biased_cset_map) { |
| os::commit_memory_or_exit(_biased_cset_map, page_size, false, |
| "Unable to commit collection set bitmap: zero page"); |
| } |
| } |
| |
| Copy::zero_to_bytes(_cset_map, _map_size); |
| Copy::zero_to_bytes(_biased_cset_map, page_size); |
| } |
| |
| void ShenandoahCollectionSet::add_region(ShenandoahHeapRegion* r) { |
| assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); |
| assert(Thread::current()->is_VM_thread(), "Must be VMThread"); |
| assert(!is_in(r), "Already in collection set"); |
| _cset_map[r->region_number()] = 1; |
| _region_count ++; |
| _garbage += r->garbage(); |
| _live_data += r->get_live_data_bytes(); |
| _used += r->used(); |
| } |
| |
| bool ShenandoahCollectionSet::add_region_check_for_duplicates(ShenandoahHeapRegion* r) { |
| if (!is_in(r)) { |
| add_region(r); |
| return true; |
| } else { |
| return false; |
| } |
| } |
| |
| void ShenandoahCollectionSet::remove_region(ShenandoahHeapRegion* r) { |
| assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); |
| assert(Thread::current()->is_VM_thread(), "Must be VMThread"); |
| assert(is_in(r), "Not in collection set"); |
| _cset_map[r->region_number()] = 0; |
| _region_count --; |
| } |
| |
| void ShenandoahCollectionSet::update_region_status() { |
| for (size_t index = 0; index < _heap->num_regions(); index ++) { |
| ShenandoahHeapRegion* r = _heap->get_region(index); |
| if (is_in(r)) { |
| r->make_cset(); |
| } else { |
| assert (!r->is_cset(), "should not be cset"); |
| } |
| } |
| } |
| |
| void ShenandoahCollectionSet::clear() { |
| assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); |
| Copy::zero_to_bytes(_cset_map, _map_size); |
| |
| #ifdef ASSERT |
| for (size_t index = 0; index < _heap->num_regions(); index ++) { |
| assert (!_heap->get_region(index)->is_cset(), "should have been cleared before"); |
| } |
| #endif |
| |
| _garbage = 0; |
| _live_data = 0; |
| _used = 0; |
| |
| _region_count = 0; |
| _current_index = 0; |
| } |
| |
| ShenandoahHeapRegion* ShenandoahCollectionSet::claim_next() { |
| size_t num_regions = _heap->num_regions(); |
| if (_current_index >= (jint)num_regions) { |
| return NULL; |
| } |
| |
| jint saved_current = _current_index; |
| size_t index = (size_t)saved_current; |
| |
| while(index < num_regions) { |
| if (is_in(index)) { |
| jint cur = Atomic::cmpxchg((jint)(index + 1), &_current_index, saved_current); |
| assert(cur >= (jint)saved_current, "Must move forward"); |
| if (cur == saved_current) { |
| assert(is_in(index), "Invariant"); |
| return _heap->get_region(index); |
| } else { |
| index = (size_t)cur; |
| saved_current = cur; |
| } |
| } else { |
| index ++; |
| } |
| } |
| return NULL; |
| } |
| |
| ShenandoahHeapRegion* ShenandoahCollectionSet::next() { |
| assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Must be at a safepoint"); |
| assert(Thread::current()->is_VM_thread(), "Must be VMThread"); |
| size_t num_regions = _heap->num_regions(); |
| for (size_t index = (size_t)_current_index; index < num_regions; index ++) { |
| if (is_in(index)) { |
| _current_index = (jint)(index + 1); |
| return _heap->get_region(index); |
| } |
| } |
| |
| return NULL; |
| } |
| |
| void ShenandoahCollectionSet::print_on(outputStream* out) const { |
| out->print_cr("Collection Set : " SIZE_FORMAT "", count()); |
| |
| debug_only(size_t regions = 0;) |
| for (size_t index = 0; index < _heap->num_regions(); index ++) { |
| if (is_in(index)) { |
| _heap->get_region(index)->print_on(out); |
| debug_only(regions ++;) |
| } |
| } |
| assert(regions == count(), "Must match"); |
| } |