Mercurial > hg > truffle
view src/share/vm/gc_implementation/g1/collectionSetChooser.hpp @ 17677:51e1bb81df86 jdk8u20-b03
Merge
author | amurillo |
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date | Tue, 25 Feb 2014 13:02:52 -0800 |
parents | 55fb97c4c58d |
children | 4ca6dc0799b6 |
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/* * Copyright (c) 2001, 2013, 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. // Note: this is not updated when removing a region using // remove_and_move_to_next() below. 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; } // Returns the number candidate old regions added uint length() { return _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