| /* |
| * 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_MEMORY_GENREMSET_HPP |
| #define SHARE_VM_MEMORY_GENREMSET_HPP |
| |
| #include "oops/oop.hpp" |
| |
| // A GenRemSet provides ways of iterating over pointers accross generations. |
| // (This is especially useful for older-to-younger.) |
| |
| class Generation; |
| class BarrierSet; |
| class OopsInGenClosure; |
| class CardTableRS; |
| |
| // Helper to remember modified oops in all klasses. |
| class KlassRemSet { |
| bool _accumulate_modified_oops; |
| public: |
| KlassRemSet() : _accumulate_modified_oops(false) {} |
| void set_accumulate_modified_oops(bool value) { _accumulate_modified_oops = value; } |
| bool accumulate_modified_oops() { return _accumulate_modified_oops; } |
| bool mod_union_is_clear(); |
| void clear_mod_union(); |
| }; |
| |
| class GenRemSet: public CHeapObj<mtGC> { |
| friend class Generation; |
| |
| BarrierSet* _bs; |
| KlassRemSet _klass_rem_set; |
| |
| public: |
| enum Name { |
| CardTable, |
| Other |
| }; |
| |
| GenRemSet(BarrierSet * bs) : _bs(bs) {} |
| GenRemSet() : _bs(NULL) {} |
| |
| virtual Name rs_kind() = 0; |
| |
| // These are for dynamic downcasts. Unfortunately that it names the |
| // possible subtypes (but not that they are subtypes!) Return NULL if |
| // the cast is invalide. |
| virtual CardTableRS* as_CardTableRS() { return NULL; } |
| |
| // Return the barrier set associated with "this." |
| BarrierSet* bs() { return _bs; } |
| |
| // Set the barrier set. |
| void set_bs(BarrierSet* bs) { _bs = bs; } |
| |
| KlassRemSet* klass_rem_set() { return &_klass_rem_set; } |
| |
| // Do any (sequential) processing necessary to prepare for (possibly |
| // "parallel", if that arg is true) calls to younger_refs_iterate. |
| virtual void prepare_for_younger_refs_iterate(bool parallel) = 0; |
| |
| // Apply the "do_oop" method of "blk" to (exactly) all oop locations |
| // 1) that are in objects allocated in "g" at the time of the last call |
| // to "save_Marks", and |
| // 2) that point to objects in younger generations. |
| virtual void younger_refs_iterate(Generation* g, OopsInGenClosure* blk) = 0; |
| |
| virtual void younger_refs_in_space_iterate(Space* sp, |
| OopsInGenClosure* cl) = 0; |
| |
| // This method is used to notify the remembered set that "new_val" has |
| // been written into "field" by the garbage collector. |
| void write_ref_field_gc(void* field, oop new_val); |
| protected: |
| virtual void write_ref_field_gc_work(void* field, oop new_val) = 0; |
| public: |
| |
| // A version of the above suitable for use by parallel collectors. |
| virtual void write_ref_field_gc_par(void* field, oop new_val) = 0; |
| |
| // Resize one of the regions covered by the remembered set. |
| virtual void resize_covered_region(MemRegion new_region) = 0; |
| |
| // If the rem set imposes any alignment restrictions on boundaries |
| // within the heap, this function tells whether they are met. |
| virtual bool is_aligned(HeapWord* addr) = 0; |
| |
| // If the RS (or BS) imposes an aligment constraint on maximum heap size. |
| // (This must be static, and dispatch on "nm", because it is called |
| // before an RS is created.) |
| static uintx max_alignment_constraint(Name nm); |
| |
| virtual void verify() = 0; |
| |
| // Verify that the remembered set has no entries for |
| // the heap interval denoted by mr. If there are any |
| // alignment constraints on the remembered set, only the |
| // part of the region that is aligned is checked. |
| // |
| // alignment boundaries |
| // +--------+-------+--------+-------+ |
| // [ region mr ) |
| // [ part checked ) |
| virtual void verify_aligned_region_empty(MemRegion mr) = 0; |
| |
| // If appropriate, print some information about the remset on "tty". |
| virtual void print() {} |
| |
| // Informs the RS that the given memregion contains no references to |
| // younger generations. |
| virtual void clear(MemRegion mr) = 0; |
| |
| // Informs the RS that there are no references to generations |
| // younger than gen from generations gen and older. |
| // The parameter clear_perm indicates if the perm_gen's |
| // remembered set should also be processed/cleared. |
| virtual void clear_into_younger(Generation* old_gen) = 0; |
| |
| // Informs the RS that refs in the given "mr" may have changed |
| // arbitrarily, and therefore may contain old-to-young pointers. |
| // If "whole heap" is true, then this invalidation is part of an |
| // invalidation of the whole heap, which an implementation might |
| // handle differently than that of a sub-part of the heap. |
| virtual void invalidate(MemRegion mr, bool whole_heap = false) = 0; |
| |
| // Informs the RS that refs in this generation |
| // may have changed arbitrarily, and therefore may contain |
| // old-to-young pointers in arbitrary locations. |
| virtual void invalidate_or_clear(Generation* old_gen) = 0; |
| }; |
| |
| #endif // SHARE_VM_MEMORY_GENREMSET_HPP |