| /* |
| * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_COLLECTIONSETCHOOSER_HPP |
| #define SHARE_VM_GC_IMPLEMENTATION_G1_COLLECTIONSETCHOOSER_HPP |
| |
| #include "gc_implementation/g1/heapRegion.hpp" |
| #include "utilities/growableArray.hpp" |
| |
| class CollectionSetChooser: public CHeapObj<mtGC> { |
| |
| GrowableArray<HeapRegion*> _regions; |
| |
| // Unfortunately, GrowableArray uses ints for length and indexes. To |
| // avoid excessive casting in the rest of the class the following |
| // wrapper methods are provided that use uints. |
| |
| uint regions_length() { return (uint) _regions.length(); } |
| HeapRegion* regions_at(uint i) { return _regions.at((int) i); } |
| void regions_at_put(uint i, HeapRegion* hr) { |
| _regions.at_put((int) i, hr); |
| } |
| void regions_at_put_grow(uint i, HeapRegion* hr) { |
| _regions.at_put_grow((int) i, hr); |
| } |
| void regions_trunc_to(uint i) { _regions.trunc_to((uint) i); } |
| |
| // The index of the next candidate old region to be considered for |
| // addition to the CSet. |
| uint _curr_index; |
| |
| // The number of candidate old regions added to the CSet chooser. |
| uint _length; |
| |
| // Keeps track of the start of the next array chunk to be claimed by |
| // parallel GC workers. |
| uint _first_par_unreserved_idx; |
| |
| // If a region has more live bytes than this threshold, it will not |
| // be added to the CSet chooser and will not be a candidate for |
| // collection. |
| size_t _region_live_threshold_bytes; |
| |
| // The sum of reclaimable bytes over all the regions in the CSet chooser. |
| size_t _remaining_reclaimable_bytes; |
| |
| public: |
| |
| // Return the current candidate region to be considered for |
| // collection without removing it from the CSet chooser. |
| HeapRegion* peek() { |
| HeapRegion* res = NULL; |
| if (_curr_index < _length) { |
| res = regions_at(_curr_index); |
| assert(res != NULL, |
| err_msg("Unexpected NULL hr in _regions at index %u", |
| _curr_index)); |
| } |
| return res; |
| } |
| |
| // Remove the given region from the CSet chooser and move to the |
| // next one. The given region should be the current candidate region |
| // in the CSet chooser. |
| void remove_and_move_to_next(HeapRegion* hr) { |
| assert(hr != NULL, "pre-condition"); |
| assert(_curr_index < _length, "pre-condition"); |
| assert(regions_at(_curr_index) == hr, "pre-condition"); |
| regions_at_put(_curr_index, NULL); |
| assert(hr->reclaimable_bytes() <= _remaining_reclaimable_bytes, |
| err_msg("remaining reclaimable bytes inconsistent " |
| "from region: "SIZE_FORMAT" remaining: "SIZE_FORMAT, |
| hr->reclaimable_bytes(), _remaining_reclaimable_bytes)); |
| _remaining_reclaimable_bytes -= hr->reclaimable_bytes(); |
| _curr_index += 1; |
| } |
| |
| CollectionSetChooser(); |
| |
| void sort_regions(); |
| |
| // Determine whether to add the given region to the CSet chooser or |
| // not. Currently, we skip humongous regions (we never add them to |
| // the CSet, we only reclaim them during cleanup) and regions whose |
| // live bytes are over the threshold. |
| bool should_add(HeapRegion* hr) { |
| assert(hr->is_marked(), "pre-condition"); |
| assert(!hr->is_young(), "should never consider young regions"); |
| return !hr->isHumongous() && |
| hr->live_bytes() < _region_live_threshold_bytes; |
| } |
| |
| // Calculate the minimum number of old regions we'll add to the CSet |
| // during a mixed GC. |
| uint calc_min_old_cset_length(); |
| |
| // Calculate the maximum number of old regions we'll add to the CSet |
| // during a mixed GC. |
| uint calc_max_old_cset_length(); |
| |
| // Serial version. |
| void add_region(HeapRegion *hr); |
| |
| // Must be called before calls to claim_array_chunk(). |
| // n_regions is the number of regions, chunk_size the chunk size. |
| void prepare_for_par_region_addition(uint n_regions, uint chunk_size); |
| // Returns the first index in a contiguous chunk of chunk_size indexes |
| // that the calling thread has reserved. These must be set by the |
| // calling thread using set_region() (to NULL if necessary). |
| uint claim_array_chunk(uint chunk_size); |
| // Set the marked array entry at index to hr. Careful to claim the index |
| // first if in parallel. |
| void set_region(uint index, HeapRegion* hr); |
| // Atomically increment the number of added regions by region_num |
| // and the amount of reclaimable bytes by reclaimable_bytes. |
| void update_totals(uint region_num, size_t reclaimable_bytes); |
| |
| void clear(); |
| |
| // Return the number of candidate regions that remain to be collected. |
| uint remaining_regions() { return _length - _curr_index; } |
| |
| // Determine whether the CSet chooser has more candidate regions or not. |
| bool is_empty() { return remaining_regions() == 0; } |
| |
| // Return the reclaimable bytes that remain to be collected on |
| // all the candidate regions in the CSet chooser. |
| size_t remaining_reclaimable_bytes() { return _remaining_reclaimable_bytes; } |
| |
| // Returns true if the used portion of "_regions" is properly |
| // sorted, otherwise asserts false. |
| void verify() PRODUCT_RETURN; |
| }; |
| |
| class CSetChooserParUpdater : public StackObj { |
| private: |
| CollectionSetChooser* _chooser; |
| bool _parallel; |
| uint _chunk_size; |
| uint _cur_chunk_idx; |
| uint _cur_chunk_end; |
| uint _regions_added; |
| size_t _reclaimable_bytes_added; |
| |
| public: |
| CSetChooserParUpdater(CollectionSetChooser* chooser, |
| bool parallel, uint chunk_size) : |
| _chooser(chooser), _parallel(parallel), _chunk_size(chunk_size), |
| _cur_chunk_idx(0), _cur_chunk_end(0), |
| _regions_added(0), _reclaimable_bytes_added(0) { } |
| |
| ~CSetChooserParUpdater() { |
| if (_parallel && _regions_added > 0) { |
| _chooser->update_totals(_regions_added, _reclaimable_bytes_added); |
| } |
| } |
| |
| void add_region(HeapRegion* hr) { |
| if (_parallel) { |
| if (_cur_chunk_idx == _cur_chunk_end) { |
| _cur_chunk_idx = _chooser->claim_array_chunk(_chunk_size); |
| _cur_chunk_end = _cur_chunk_idx + _chunk_size; |
| } |
| assert(_cur_chunk_idx < _cur_chunk_end, "invariant"); |
| _chooser->set_region(_cur_chunk_idx, hr); |
| _cur_chunk_idx += 1; |
| } else { |
| _chooser->add_region(hr); |
| } |
| _regions_added += 1; |
| _reclaimable_bytes_added += hr->reclaimable_bytes(); |
| } |
| |
| bool should_add(HeapRegion* hr) { return _chooser->should_add(hr); } |
| }; |
| |
| #endif // SHARE_VM_GC_IMPLEMENTATION_G1_COLLECTIONSETCHOOSER_HPP |
| |