ysr@777: /*
mikael@6198:  * Copyright (c) 2001, 2013, Oracle and/or its affiliates. All rights reserved.
ysr@777:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
ysr@777:  *
ysr@777:  * This code is free software; you can redistribute it and/or modify it
ysr@777:  * under the terms of the GNU General Public License version 2 only, as
ysr@777:  * published by the Free Software Foundation.
ysr@777:  *
ysr@777:  * This code is distributed in the hope that it will be useful, but WITHOUT
ysr@777:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
ysr@777:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
ysr@777:  * version 2 for more details (a copy is included in the LICENSE file that
ysr@777:  * accompanied this code).
ysr@777:  *
ysr@777:  * You should have received a copy of the GNU General Public License version
ysr@777:  * 2 along with this work; if not, write to the Free Software Foundation,
ysr@777:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
ysr@777:  *
trims@1907:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
trims@1907:  * or visit www.oracle.com if you need additional information or have any
trims@1907:  * questions.
ysr@777:  *
ysr@777:  */
ysr@777: 
stefank@2314: #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_COLLECTIONSETCHOOSER_HPP
stefank@2314: #define SHARE_VM_GC_IMPLEMENTATION_G1_COLLECTIONSETCHOOSER_HPP
stefank@2314: 
stefank@2314: #include "gc_implementation/g1/heapRegion.hpp"
stefank@2314: #include "utilities/growableArray.hpp"
stefank@2314: 
zgu@3900: class CollectionSetChooser: public CHeapObj<mtGC> {
ysr@777: 
tonyp@3714:   GrowableArray<HeapRegion*> _regions;
tonyp@3714: 
tonyp@3714:   // Unfortunately, GrowableArray uses ints for length and indexes. To
tonyp@3714:   // avoid excessive casting in the rest of the class the following
tonyp@3714:   // wrapper methods are provided that use uints.
tonyp@3714: 
tonyp@3714:   uint regions_length()          { return (uint) _regions.length(); }
tonyp@3714:   HeapRegion* regions_at(uint i) { return _regions.at((int) i);     }
tonyp@3714:   void regions_at_put(uint i, HeapRegion* hr) {
tonyp@3714:     _regions.at_put((int) i, hr);
tonyp@3714:   }
tonyp@3714:   void regions_at_put_grow(uint i, HeapRegion* hr) {
tonyp@3714:     _regions.at_put_grow((int) i, hr);
tonyp@3714:   }
tonyp@3714:   void regions_trunc_to(uint i)  { _regions.trunc_to((uint) i); }
tonyp@3539: 
tonyp@3539:   // The index of the next candidate old region to be considered for
tonyp@3539:   // addition to the CSet.
tonyp@3714:   uint _curr_index;
tonyp@3539: 
tonyp@3539:   // The number of candidate old regions added to the CSet chooser.
johnc@4681:   // Note: this is not updated when removing a region using
johnc@4681:   // remove_and_move_to_next() below.
tonyp@3714:   uint _length;
tonyp@3539: 
tonyp@3714:   // Keeps track of the start of the next array chunk to be claimed by
tonyp@3714:   // parallel GC workers.
tonyp@3714:   uint _first_par_unreserved_idx;
ysr@777: 
tonyp@3539:   // If a region has more live bytes than this threshold, it will not
tonyp@3539:   // be added to the CSet chooser and will not be a candidate for
tonyp@3539:   // collection.
tonyp@3714:   size_t _region_live_threshold_bytes;
ysr@777: 
tonyp@3539:   // The sum of reclaimable bytes over all the regions in the CSet chooser.
tonyp@3714:   size_t _remaining_reclaimable_bytes;
ysr@777: 
ysr@777: public:
ysr@777: 
tonyp@3539:   // Return the current candidate region to be considered for
tonyp@3539:   // collection without removing it from the CSet chooser.
tonyp@3539:   HeapRegion* peek() {
tonyp@3539:     HeapRegion* res = NULL;
tonyp@3539:     if (_curr_index < _length) {
tonyp@3714:       res = regions_at(_curr_index);
tonyp@3539:       assert(res != NULL,
tonyp@3714:              err_msg("Unexpected NULL hr in _regions at index %u",
tonyp@3539:                      _curr_index));
tonyp@3539:     }
tonyp@3539:     return res;
tonyp@3539:   }
tonyp@3539: 
tonyp@3539:   // Remove the given region from the CSet chooser and move to the
tonyp@3539:   // next one. The given region should be the current candidate region
tonyp@3539:   // in the CSet chooser.
tonyp@3539:   void remove_and_move_to_next(HeapRegion* hr) {
tonyp@3539:     assert(hr != NULL, "pre-condition");
tonyp@3539:     assert(_curr_index < _length, "pre-condition");
tonyp@3714:     assert(regions_at(_curr_index) == hr, "pre-condition");
tonyp@3714:     regions_at_put(_curr_index, NULL);
tonyp@3714:     assert(hr->reclaimable_bytes() <= _remaining_reclaimable_bytes,
tonyp@3539:            err_msg("remaining reclaimable bytes inconsistent "
kevinw@9327:                    "from region: " SIZE_FORMAT " remaining: " SIZE_FORMAT,
tonyp@3714:                    hr->reclaimable_bytes(), _remaining_reclaimable_bytes));
tonyp@3714:     _remaining_reclaimable_bytes -= hr->reclaimable_bytes();
tonyp@3539:     _curr_index += 1;
tonyp@3539:   }
ysr@777: 
ysr@777:   CollectionSetChooser();
ysr@777: 
tonyp@3714:   void sort_regions();
tonyp@3539: 
tonyp@3539:   // Determine whether to add the given region to the CSet chooser or
tonyp@3539:   // not. Currently, we skip humongous regions (we never add them to
tonyp@3539:   // the CSet, we only reclaim them during cleanup) and regions whose
tonyp@3539:   // live bytes are over the threshold.
tonyp@3714:   bool should_add(HeapRegion* hr) {
tonyp@3539:     assert(hr->is_marked(), "pre-condition");
tonyp@3539:     assert(!hr->is_young(), "should never consider young regions");
tonyp@3539:     return !hr->isHumongous() &&
tonyp@3714:             hr->live_bytes() < _region_live_threshold_bytes;
tonyp@3539:   }
tonyp@3539: 
johnc@4681:   // Returns the number candidate old regions added
johnc@4681:   uint length() { return _length; }
tonyp@3539: 
tonyp@3539:   // Serial version.
tonyp@3714:   void add_region(HeapRegion *hr);
ysr@777: 
tonyp@3714:   // Must be called before calls to claim_array_chunk().
tonyp@3714:   // n_regions is the number of regions, chunk_size the chunk size.
tonyp@3714:   void prepare_for_par_region_addition(uint n_regions, uint chunk_size);
tonyp@3714:   // Returns the first index in a contiguous chunk of chunk_size indexes
ysr@777:   // that the calling thread has reserved.  These must be set by the
tonyp@3714:   // calling thread using set_region() (to NULL if necessary).
tonyp@3714:   uint claim_array_chunk(uint chunk_size);
ysr@777:   // Set the marked array entry at index to hr.  Careful to claim the index
ysr@777:   // first if in parallel.
tonyp@3714:   void set_region(uint index, HeapRegion* hr);
tonyp@3539:   // Atomically increment the number of added regions by region_num
tonyp@3539:   // and the amount of reclaimable bytes by reclaimable_bytes.
tonyp@3714:   void update_totals(uint region_num, size_t reclaimable_bytes);
ysr@777: 
tonyp@3714:   void clear();
ysr@777: 
tonyp@3539:   // Return the number of candidate regions that remain to be collected.
tonyp@3714:   uint remaining_regions() { return _length - _curr_index; }
ysr@777: 
tonyp@3539:   // Determine whether the CSet chooser has more candidate regions or not.
tonyp@3714:   bool is_empty() { return remaining_regions() == 0; }
tonyp@3539: 
tonyp@3539:   // Return the reclaimable bytes that remain to be collected on
tonyp@3539:   // all the candidate regions in the CSet chooser.
tonyp@3714:   size_t remaining_reclaimable_bytes() { return _remaining_reclaimable_bytes; }
ysr@777: 
tonyp@3714:   // Returns true if the used portion of "_regions" is properly
ysr@777:   // sorted, otherwise asserts false.
tonyp@3714:   void verify() PRODUCT_RETURN;
ysr@777: };
stefank@2314: 
tonyp@3957: class CSetChooserParUpdater : public StackObj {
tonyp@3957: private:
tonyp@3957:   CollectionSetChooser* _chooser;
tonyp@3957:   bool _parallel;
tonyp@3957:   uint _chunk_size;
tonyp@3957:   uint _cur_chunk_idx;
tonyp@3957:   uint _cur_chunk_end;
tonyp@3957:   uint _regions_added;
tonyp@3957:   size_t _reclaimable_bytes_added;
tonyp@3957: 
tonyp@3957: public:
tonyp@3957:   CSetChooserParUpdater(CollectionSetChooser* chooser,
tonyp@3957:                         bool parallel, uint chunk_size) :
tonyp@3957:     _chooser(chooser), _parallel(parallel), _chunk_size(chunk_size),
tonyp@3957:     _cur_chunk_idx(0), _cur_chunk_end(0),
tonyp@3957:     _regions_added(0), _reclaimable_bytes_added(0) { }
tonyp@3957: 
tonyp@3957:   ~CSetChooserParUpdater() {
tonyp@3957:     if (_parallel && _regions_added > 0) {
tonyp@3957:       _chooser->update_totals(_regions_added, _reclaimable_bytes_added);
tonyp@3957:     }
tonyp@3957:   }
tonyp@3957: 
tonyp@3957:   void add_region(HeapRegion* hr) {
tonyp@3957:     if (_parallel) {
tonyp@3957:       if (_cur_chunk_idx == _cur_chunk_end) {
tonyp@3957:         _cur_chunk_idx = _chooser->claim_array_chunk(_chunk_size);
tonyp@3957:         _cur_chunk_end = _cur_chunk_idx + _chunk_size;
tonyp@3957:       }
tonyp@3957:       assert(_cur_chunk_idx < _cur_chunk_end, "invariant");
tonyp@3957:       _chooser->set_region(_cur_chunk_idx, hr);
tonyp@3957:       _cur_chunk_idx += 1;
tonyp@3957:     } else {
tonyp@3957:       _chooser->add_region(hr);
tonyp@3957:     }
tonyp@3957:     _regions_added += 1;
tonyp@3957:     _reclaimable_bytes_added += hr->reclaimable_bytes();
tonyp@3957:   }
tonyp@3957: 
tonyp@3957:   bool should_add(HeapRegion* hr) { return _chooser->should_add(hr); }
tonyp@3957: };
tonyp@3957: 
stefank@2314: #endif // SHARE_VM_GC_IMPLEMENTATION_G1_COLLECTIONSETCHOOSER_HPP
tonyp@3957: