250 lines
9.3 KiB
C++
250 lines
9.3 KiB
C++
/*
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* Copyright (c) 2003, 2008, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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// All heaps contains a "permanent generation," containing permanent
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// (reflective) objects. This is like a regular generation in some ways,
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// but unlike one in others, and so is split apart.
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class PermanentGenerationSpec;
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// This is the "generation" view of a CompactingPermGen.
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// NOTE: the shared spaces used for CDS are here handled in
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// a somewhat awkward and potentially buggy fashion, see CR 6801625.
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// This infelicity should be fixed, see CR 6897789.
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class CompactingPermGenGen: public OneContigSpaceCardGeneration {
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friend class VMStructs;
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// Abstractly, this is a subtype that gets access to protected fields.
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friend class CompactingPermGen;
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private:
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// Shared spaces
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PermanentGenerationSpec* _spec;
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size_t _shared_space_size;
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VirtualSpace _ro_vs;
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VirtualSpace _rw_vs;
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VirtualSpace _md_vs;
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VirtualSpace _mc_vs;
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BlockOffsetSharedArray* _ro_bts;
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BlockOffsetSharedArray* _rw_bts;
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OffsetTableContigSpace* _ro_space;
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OffsetTableContigSpace* _rw_space;
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// With shared spaces there is a dichotomy in the use of the
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// _virtual_space of the generation. There is a portion of the
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// _virtual_space that is used for the unshared part of the
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// permanent generation and a portion that is reserved for the shared part.
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// The _reserved field in the generation represents both the
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// unshared and shared parts of the generation. The _reserved
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// variable is initialized for only the unshared part but is
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// later extended to include the shared part during initialization
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// if shared spaces are being used.
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// The reserved size for the _virtual_space for CompactingPermGenGen
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// is the size of the space for the permanent generation including the
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// the shared spaces. This can be seen by the use of MaxPermSize
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// in the allocation of PermanentGenerationSpec. The space for the
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// shared spaces is committed separately (???).
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// In general at initialization only a part of the
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// space for the unshared part of the permanent generation is
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// committed and more is committed as the permanent generation is
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// grown. In growing the permanent generation the capacity() and
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// max_capacity() of the generation are used. For the permanent
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// generation (implemented with a CompactingPermGenGen) the capacity()
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// is taken from the capacity of the space (_the_space variable used for the
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// unshared part of the generation) and the max_capacity() is based
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// on the size of the _reserved variable (which includes the size of the
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// shared spaces) minus the size of the shared spaces.
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// These values are redundant, but are called out separately to avoid
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// going through heap/space/gen pointers for performance.
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static HeapWord* unshared_bottom;
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static HeapWord* unshared_end;
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static HeapWord* shared_bottom;
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static HeapWord* readonly_bottom;
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static HeapWord* readonly_end;
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static HeapWord* readwrite_bottom;
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static HeapWord* readwrite_end;
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static HeapWord* miscdata_bottom;
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static HeapWord* miscdata_end;
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static HeapWord* misccode_bottom;
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static HeapWord* misccode_end;
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static HeapWord* shared_end;
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// List of klassOops whose vtbl entries are used to patch others.
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static void** _vtbl_list;
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// Performance Counters
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GenerationCounters* _gen_counters;
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CSpaceCounters* _space_counters;
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void initialize_performance_counters();
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public:
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enum {
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vtbl_list_size = 16, // number of entries in the shared space vtable list.
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num_virtuals = 200 // number of virtual methods in Klass (or
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// subclass) objects, or greater.
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};
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enum {
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ro = 0, // read-only shared space in the heap
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rw = 1, // read-write shared space in the heap
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md = 2, // miscellaneous data for initializing tables, etc.
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mc = 3, // miscellaneous code - vtable replacement.
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n_regions = 4
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};
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CompactingPermGenGen(ReservedSpace rs, ReservedSpace shared_rs,
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size_t initial_byte_size, int level, GenRemSet* remset,
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ContiguousSpace* space,
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PermanentGenerationSpec* perm_spec);
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const char* name() const {
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return "compacting perm gen";
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}
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const char* short_name() const {
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return "Perm";
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}
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// Return the maximum capacity for the object space. This
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// explicitly does not include the shared spaces.
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size_t max_capacity() const;
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void update_counters();
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void compute_new_size() {
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assert(false, "Should not call this -- handled at PermGen level.");
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}
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bool must_be_youngest() const { return false; }
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bool must_be_oldest() const { return false; }
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OffsetTableContigSpace* ro_space() const { return _ro_space; }
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OffsetTableContigSpace* rw_space() const { return _rw_space; }
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VirtualSpace* md_space() { return &_md_vs; }
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VirtualSpace* mc_space() { return &_mc_vs; }
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ContiguousSpace* unshared_space() const { return _the_space; }
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static bool inline is_shared(const oopDesc* p) {
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return (HeapWord*)p >= shared_bottom && (HeapWord*)p < shared_end;
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}
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// RedefineClasses note: this tester is used to check residence of
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// the specified oop in the shared readonly space and not whether
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// the oop is readonly.
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static bool inline is_shared_readonly(const oopDesc* p) {
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return (HeapWord*)p >= readonly_bottom && (HeapWord*)p < readonly_end;
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}
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// RedefineClasses note: this tester is used to check residence of
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// the specified oop in the shared readwrite space and not whether
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// the oop is readwrite.
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static bool inline is_shared_readwrite(const oopDesc* p) {
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return (HeapWord*)p >= readwrite_bottom && (HeapWord*)p < readwrite_end;
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}
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bool is_in_unshared(const void* p) const {
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return OneContigSpaceCardGeneration::is_in(p);
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}
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bool is_in_shared(const void* p) const {
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return p >= shared_bottom && p < shared_end;
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}
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inline bool is_in(const void* p) const {
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return is_in_unshared(p) || is_in_shared(p);
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}
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inline PermanentGenerationSpec* spec() const { return _spec; }
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inline void set_spec(PermanentGenerationSpec* spec) { _spec = spec; }
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void pre_adjust_pointers();
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void adjust_pointers();
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void space_iterate(SpaceClosure* blk, bool usedOnly = false);
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void print_on(outputStream* st) const;
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void younger_refs_iterate(OopsInGenClosure* blk);
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void compact();
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void post_compact();
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size_t contiguous_available() const;
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void clear_remembered_set();
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void invalidate_remembered_set();
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inline bool block_is_obj(const HeapWord* addr) const {
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if (addr < the_space()->top()) return true;
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else if (addr < the_space()->end()) return false;
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else if (addr < ro_space()->top()) return true;
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else if (addr < ro_space()->end()) return false;
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else if (addr < rw_space()->top()) return true;
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else return false;
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}
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inline size_t block_size(const HeapWord* addr) const {
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if (addr < the_space()->top()) {
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return oop(addr)->size();
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}
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else if (addr < the_space()->end()) {
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assert(addr == the_space()->top(), "non-block head arg to block_size");
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return the_space()->end() - the_space()->top();
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}
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else if (addr < ro_space()->top()) {
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return oop(addr)->size();
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}
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else if (addr < ro_space()->end()) {
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assert(addr == ro_space()->top(), "non-block head arg to block_size");
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return ro_space()->end() - ro_space()->top();
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}
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else if (addr < rw_space()->top()) {
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return oop(addr)->size();
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}
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else {
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assert(addr == rw_space()->top(), "non-block head arg to block_size");
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return rw_space()->end() - rw_space()->top();
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}
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}
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static void generate_vtable_methods(void** vtbl_list,
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void** vtable,
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char** md_top, char* md_end,
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char** mc_top, char* mc_end);
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void verify(bool allow_dirty);
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// Serialization
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static void initialize_oops() KERNEL_RETURN;
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static void serialize_oops(SerializeOopClosure* soc);
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void serialize_bts(SerializeOopClosure* soc);
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// Initiate dumping of shared file.
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static jint dump_shared(GrowableArray<oop>* class_promote_order, TRAPS);
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// JVM/TI RedefineClasses() support:
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// Remap the shared readonly space to shared readwrite, private if
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// sharing is enabled. Simply returns true if sharing is not enabled
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// or if the remapping has already been done by a prior call.
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static bool remap_shared_readonly_as_readwrite();
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};
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