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view src/share/vm/gc_implementation/g1/heapRegionSeq.hpp @ 17374:9928ad27a80e
OopRecorder should check for duplicates
author | Tom Rodriguez <tom.rodriguez@oracle.com> |
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date | Wed, 08 Oct 2014 11:48:00 -0700 |
parents | 4ca6dc0799b6 |
children | 89152779163c |
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/* * 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_HEAPREGIONSEQ_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP #include "gc_implementation/g1/g1BiasedArray.hpp" class HeapRegion; class HeapRegionClosure; class FreeRegionList; class G1HeapRegionTable : public G1BiasedMappedArray<HeapRegion*> { protected: virtual HeapRegion* default_value() const { return NULL; } }; // This class keeps track of the region metadata (i.e., HeapRegion // instances). They are kept in the _regions array in address // order. A region's index in the array corresponds to its index in // the heap (i.e., 0 is the region at the bottom of the heap, 1 is // the one after it, etc.). Two regions that are consecutive in the // array should also be adjacent in the address space (i.e., // region(i).end() == region(i+1).bottom(). // // We create a HeapRegion when we commit the region's address space // for the first time. When we uncommit the address space of a // region we retain the HeapRegion to be able to re-use it in the // future (in case we recommit it). // // We keep track of three lengths: // // * _committed_length (returned by length()) is the number of currently // committed regions. // * _allocated_length (not exposed outside this class) is the // number of regions for which we have HeapRegions. // * max_length() returns the maximum number of regions the heap can have. // // and maintain that: _committed_length <= _allocated_length <= max_length() class HeapRegionSeq: public CHeapObj<mtGC> { friend class VMStructs; G1HeapRegionTable _regions; // The number of regions committed in the heap. uint _committed_length; // A hint for which index to start searching from for humongous // allocations. uint _next_search_index; // The number of regions for which we have allocated HeapRegions for. uint _allocated_length; // Find a contiguous set of empty regions of length num, starting // from the given index. uint find_contiguous_from(uint from, uint num); void increment_allocated_length() { assert(_allocated_length < max_length(), "pre-condition"); _allocated_length++; } void increment_length() { assert(length() < max_length(), "pre-condition"); _committed_length++; } void decrement_length() { assert(length() > 0, "pre-condition"); _committed_length--; } HeapWord* heap_bottom() const { return _regions.bottom_address_mapped(); } HeapWord* heap_end() const {return _regions.end_address_mapped(); } public: // Empty contructor, we'll initialize it with the initialize() method. HeapRegionSeq() : _regions(), _committed_length(0), _next_search_index(0), _allocated_length(0) { } void initialize(HeapWord* bottom, HeapWord* end); // Return the HeapRegion at the given index. Assume that the index // is valid. inline HeapRegion* at(uint index) const; // If addr is within the committed space return its corresponding // HeapRegion, otherwise return NULL. inline HeapRegion* addr_to_region(HeapWord* addr) const; // Return the HeapRegion that corresponds to the given // address. Assume the address is valid. inline HeapRegion* addr_to_region_unsafe(HeapWord* addr) const; // Return the number of regions that have been committed in the heap. uint length() const { return _committed_length; } // Return the maximum number of regions in the heap. uint max_length() const { return (uint)_regions.length(); } // Expand the sequence to reflect that the heap has grown from // old_end to new_end. Either create new HeapRegions, or re-use // existing ones, and return them in the given list. Returns the // memory region that covers the newly-created regions. If a // HeapRegion allocation fails, the result memory region might be // smaller than the desired one. MemRegion expand_by(HeapWord* old_end, HeapWord* new_end, FreeRegionList* list); // Return the number of contiguous regions at the end of the sequence // that are available for allocation. uint free_suffix(); // Find a contiguous set of empty regions of length num and return // the index of the first region or G1_NULL_HRS_INDEX if the // search was unsuccessful. uint find_contiguous(uint num); // Apply blk->doHeapRegion() on all committed regions in address order, // terminating the iteration early if doHeapRegion() returns true. void iterate(HeapRegionClosure* blk) const; // As above, but start the iteration from hr and loop around. If hr // is NULL, we start from the first region in the heap. void iterate_from(HeapRegion* hr, HeapRegionClosure* blk) const; // Tag as uncommitted as many regions that are completely free as // possible, up to num_regions_to_remove, from the suffix of the committed // sequence. Return the actual number of removed regions. uint shrink_by(uint num_regions_to_remove); // Do some sanity checking. void verify_optional() PRODUCT_RETURN; }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONSEQ_HPP