jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp

Thu, 22 Sep 2011 10:57:37 -0700

author: johnc
date: Thu, 22 Sep 2011 10:57:37 -0700
changeset 3175: 4dfb2df418f2
parent 2325: c760f78e0a53
child 3900: d2a62e0f25eb
permissions: -rw-r--r--

6484982: G1: process references during evacuation pauses
Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate.
Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp

 /*
  * Copyright (c) 2005, 2010, 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
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 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP
 #include "memory/memRegion.hpp"
 #include "gc_implementation/parallelScavenge/psVirtualspace.hpp"
 #include "utilities/bitMap.inline.hpp"
 class oopDesc;
 class ParMarkBitMapClosure;
 class ParMarkBitMap: public CHeapObj
 {
 public:
   typedef BitMap::idx_t idx_t;
   // Values returned by the iterate() methods.
   enum IterationStatus { incomplete, complete, full, would_overflow };
   inline ParMarkBitMap();
   inline ParMarkBitMap(MemRegion covered_region);
   bool initialize(MemRegion covered_region);
   // Atomically mark an object as live.
   bool mark_obj(HeapWord* addr, size_t size);
   inline bool mark_obj(oop obj, int size);
   inline bool mark_obj(oop obj);
   // Return whether the specified begin or end bit is set.
   inline bool is_obj_beg(idx_t bit) const;
   inline bool is_obj_end(idx_t bit) const;
   // Traditional interface for testing whether an object is marked or not (these
   // test only the begin bits).
   inline bool is_marked(idx_t bit)      const;
   inline bool is_marked(HeapWord* addr) const;
   inline bool is_marked(oop obj)        const;
   inline bool is_unmarked(idx_t bit)      const;
   inline bool is_unmarked(HeapWord* addr) const;
   inline bool is_unmarked(oop obj)        const;
   // Convert sizes from bits to HeapWords and back.  An object that is n bits
   // long will be bits_to_words(n) words long.  An object that is m words long
   // will take up words_to_bits(m) bits in the bitmap.
   inline static size_t bits_to_words(idx_t bits);
   inline static idx_t  words_to_bits(size_t words);
   // Return the size in words of an object given a begin bit and an end bit, or
   // the equivalent beg_addr and end_addr.
   inline size_t obj_size(idx_t beg_bit, idx_t end_bit) const;
   inline size_t obj_size(HeapWord* beg_addr, HeapWord* end_addr) const;
   // Return the size in words of the object (a search is done for the end bit).
   inline size_t obj_size(idx_t beg_bit)  const;
   inline size_t obj_size(HeapWord* addr) const;
   inline size_t obj_size(oop obj)        const;
   // Synonyms for the above.
   size_t obj_size_in_words(oop obj) const { return obj_size((HeapWord*)obj); }
   size_t obj_size_in_words(HeapWord* addr) const { return obj_size(addr); }
   // Apply live_closure to each live object that lies completely within the
   // range [live_range_beg, live_range_end).  This is used to iterate over the
   // compacted region of the heap.  Return values:
   //
   // incomplete         The iteration is not complete.  The last object that
   //                    begins in the range does not end in the range;
   //                    closure->source() is set to the start of that object.
   //
   // complete           The iteration is complete.  All objects in the range
   //                    were processed and the closure is not full;
   //                    closure->source() is set one past the end of the range.
   //
   // full               The closure is full; closure->source() is set to one
   //                    past the end of the last object processed.
   //
   // would_overflow     The next object in the range would overflow the closure;
   //                    closure->source() is set to the start of that object.
   IterationStatus iterate(ParMarkBitMapClosure* live_closure,
                           idx_t range_beg, idx_t range_end) const;
   inline IterationStatus iterate(ParMarkBitMapClosure* live_closure,
                                  HeapWord* range_beg,
                                  HeapWord* range_end) const;
   // Apply live closure as above and additionally apply dead_closure to all dead
   // space in the range [range_beg, dead_range_end).  Note that dead_range_end
   // must be >= range_end.  This is used to iterate over the dense prefix.
   //
   // This method assumes that if the first bit in the range (range_beg) is not
   // marked, then dead space begins at that point and the dead_closure is
   // applied.  Thus callers must ensure that range_beg is not in the middle of a
   // live object.
   IterationStatus iterate(ParMarkBitMapClosure* live_closure,
                           ParMarkBitMapClosure* dead_closure,
                           idx_t range_beg, idx_t range_end,
                           idx_t dead_range_end) const;
   inline IterationStatus iterate(ParMarkBitMapClosure* live_closure,
                                  ParMarkBitMapClosure* dead_closure,
                                  HeapWord* range_beg,
                                  HeapWord* range_end,
                                  HeapWord* dead_range_end) const;
   // Return the number of live words in the range [beg_addr, end_addr) due to
   // objects that start in the range.  If a live object extends onto the range,
   // the caller must detect and account for any live words due to that object.
   // If a live object extends beyond the end of the range, only the words within
   // the range are included in the result.
   size_t live_words_in_range(HeapWord* beg_addr, HeapWord* end_addr) const;
   // Same as the above, except the end of the range must be a live object, which
   // is the case when updating pointers.  This allows a branch to be removed
   // from inside the loop.
   size_t live_words_in_range(HeapWord* beg_addr, oop end_obj) const;
   inline HeapWord* region_start() const;
   inline HeapWord* region_end() const;
   inline size_t    region_size() const;
   inline size_t    size() const;
   // Convert a heap address to/from a bit index.
   inline idx_t     addr_to_bit(HeapWord* addr) const;
   inline HeapWord* bit_to_addr(idx_t bit) const;
   // Return the bit index of the first marked object that begins (or ends,
   // respectively) in the range [beg, end).  If no object is found, return end.
   inline idx_t find_obj_beg(idx_t beg, idx_t end) const;
   inline idx_t find_obj_end(idx_t beg, idx_t end) const;
   inline HeapWord* find_obj_beg(HeapWord* beg, HeapWord* end) const;
   inline HeapWord* find_obj_end(HeapWord* beg, HeapWord* end) const;
   // Clear a range of bits or the entire bitmap (both begin and end bits are
   // cleared).
   inline void clear_range(idx_t beg, idx_t end);
   inline void clear() { clear_range(0, size()); }
   // Return the number of bits required to represent the specified number of
   // HeapWords, or the specified region.
   static inline idx_t bits_required(size_t words);
   static inline idx_t bits_required(MemRegion covered_region);
   static inline idx_t words_required(MemRegion covered_region);
 #ifndef PRODUCT
   // CAS statistics.
   size_t cas_tries() { return _cas_tries; }
   size_t cas_retries() { return _cas_retries; }
   size_t cas_by_another() { return _cas_by_another; }
   void reset_counters();
 #endif  // #ifndef PRODUCT
 #ifdef  ASSERT
   void verify_clear() const;
   inline void verify_bit(idx_t bit) const;
   inline void verify_addr(HeapWord* addr) const;
 #endif  // #ifdef ASSERT
 private:
   // Each bit in the bitmap represents one unit of 'object granularity.' Objects
   // are double-word aligned in 32-bit VMs, but not in 64-bit VMs, so the 32-bit
   // granularity is 2, 64-bit is 1.
   static inline size_t obj_granularity() { return size_t(MinObjAlignment); }
   static inline int obj_granularity_shift() { return LogMinObjAlignment; }
   HeapWord*       _region_start;
   size_t          _region_size;
   BitMap          _beg_bits;
   BitMap          _end_bits;
   PSVirtualSpace* _virtual_space;
 #ifndef PRODUCT
   size_t _cas_tries;
   size_t _cas_retries;
   size_t _cas_by_another;
 #endif  // #ifndef PRODUCT
 };
 inline ParMarkBitMap::ParMarkBitMap():
   _beg_bits(),
   _end_bits()
 {
   _region_start = 0;
   _virtual_space = 0;
 }
 inline ParMarkBitMap::ParMarkBitMap(MemRegion covered_region):
   _beg_bits(),
   _end_bits()
 {
   initialize(covered_region);
 }
 inline void ParMarkBitMap::clear_range(idx_t beg, idx_t end)
 {
   _beg_bits.clear_range(beg, end);
   _end_bits.clear_range(beg, end);
 }
 inline ParMarkBitMap::idx_t
 ParMarkBitMap::bits_required(size_t words)
 {
   // Need two bits (one begin bit, one end bit) for each unit of 'object
   // granularity' in the heap.
   return words_to_bits(words * 2);
 }
 inline ParMarkBitMap::idx_t
 ParMarkBitMap::bits_required(MemRegion covered_region)
 {
   return bits_required(covered_region.word_size());
 }
 inline ParMarkBitMap::idx_t
 ParMarkBitMap::words_required(MemRegion covered_region)
 {
   return bits_required(covered_region) / BitsPerWord;
 }
 inline HeapWord*
 ParMarkBitMap::region_start() const
 {
   return _region_start;
 }
 inline HeapWord*
 ParMarkBitMap::region_end() const
 {
   return region_start() + region_size();
 }
 inline size_t
 ParMarkBitMap::region_size() const
 {
   return _region_size;
 }
 inline size_t
 ParMarkBitMap::size() const
 {
   return _beg_bits.size();
 }
 inline bool ParMarkBitMap::is_obj_beg(idx_t bit) const
 {
   return _beg_bits.at(bit);
 }
 inline bool ParMarkBitMap::is_obj_end(idx_t bit) const
 {
   return _end_bits.at(bit);
 }
 inline bool ParMarkBitMap::is_marked(idx_t bit) const
 {
   return is_obj_beg(bit);
 }
 inline bool ParMarkBitMap::is_marked(HeapWord* addr) const
 {
   return is_marked(addr_to_bit(addr));
 }
 inline bool ParMarkBitMap::is_marked(oop obj) const
 {
   return is_marked((HeapWord*)obj);
 }
 inline bool ParMarkBitMap::is_unmarked(idx_t bit) const
 {
   return !is_marked(bit);
 }
 inline bool ParMarkBitMap::is_unmarked(HeapWord* addr) const
 {
   return !is_marked(addr);
 }
 inline bool ParMarkBitMap::is_unmarked(oop obj) const
 {
   return !is_marked(obj);
 }
 inline size_t
 ParMarkBitMap::bits_to_words(idx_t bits)
 {
   return bits << obj_granularity_shift();
 }
 inline ParMarkBitMap::idx_t
 ParMarkBitMap::words_to_bits(size_t words)
 {
   return words >> obj_granularity_shift();
 }
 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit, idx_t end_bit) const
 {
   DEBUG_ONLY(verify_bit(beg_bit);)
   DEBUG_ONLY(verify_bit(end_bit);)
   return bits_to_words(end_bit - beg_bit + 1);
 }
 inline size_t
 ParMarkBitMap::obj_size(HeapWord* beg_addr, HeapWord* end_addr) const
 {
   DEBUG_ONLY(verify_addr(beg_addr);)
   DEBUG_ONLY(verify_addr(end_addr);)
   return pointer_delta(end_addr, beg_addr) + obj_granularity();
 }
 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit) const
 {
   const idx_t end_bit = _end_bits.get_next_one_offset_inline(beg_bit, size());
   assert(is_marked(beg_bit), "obj not marked");
   assert(end_bit < size(), "end bit missing");
   return obj_size(beg_bit, end_bit);
 }
 inline size_t ParMarkBitMap::obj_size(HeapWord* addr) const
 {
   return obj_size(addr_to_bit(addr));
 }
 inline size_t ParMarkBitMap::obj_size(oop obj) const
 {
   return obj_size((HeapWord*)obj);
 }
 inline ParMarkBitMap::IterationStatus
 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
                        HeapWord* range_beg,
                        HeapWord* range_end) const
 {
   return iterate(live_closure, addr_to_bit(range_beg), addr_to_bit(range_end));
 }
 inline ParMarkBitMap::IterationStatus
 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure,
                        ParMarkBitMapClosure* dead_closure,
                        HeapWord* range_beg,
                        HeapWord* range_end,
                        HeapWord* dead_range_end) const
 {
   return iterate(live_closure, dead_closure,
                  addr_to_bit(range_beg), addr_to_bit(range_end),
                  addr_to_bit(dead_range_end));
 }
 inline bool
 ParMarkBitMap::mark_obj(oop obj, int size)
 {
   return mark_obj((HeapWord*)obj, (size_t)size);
 }
 inline BitMap::idx_t
 ParMarkBitMap::addr_to_bit(HeapWord* addr) const
 {
   DEBUG_ONLY(verify_addr(addr);)
   return words_to_bits(pointer_delta(addr, region_start()));
 }
 inline HeapWord*
 ParMarkBitMap::bit_to_addr(idx_t bit) const
 {
   DEBUG_ONLY(verify_bit(bit);)
   return region_start() + bits_to_words(bit);
 }
 inline ParMarkBitMap::idx_t
 ParMarkBitMap::find_obj_beg(idx_t beg, idx_t end) const
 {
   return _beg_bits.get_next_one_offset_inline_aligned_right(beg, end);
 }
 inline ParMarkBitMap::idx_t
 ParMarkBitMap::find_obj_end(idx_t beg, idx_t end) const
 {
   return _end_bits.get_next_one_offset_inline_aligned_right(beg, end);
 }
 inline HeapWord*
 ParMarkBitMap::find_obj_beg(HeapWord* beg, HeapWord* end) const
 {
   const idx_t beg_bit = addr_to_bit(beg);
   const idx_t end_bit = addr_to_bit(end);
   const idx_t search_end = BitMap::word_align_up(end_bit);
   const idx_t res_bit = MIN2(find_obj_beg(beg_bit, search_end), end_bit);
   return bit_to_addr(res_bit);
 }
 inline HeapWord*
 ParMarkBitMap::find_obj_end(HeapWord* beg, HeapWord* end) const
 {
   const idx_t beg_bit = addr_to_bit(beg);
   const idx_t end_bit = addr_to_bit(end);
   const idx_t search_end = BitMap::word_align_up(end_bit);
   const idx_t res_bit = MIN2(find_obj_end(beg_bit, search_end), end_bit);
   return bit_to_addr(res_bit);
 }
 #ifdef  ASSERT
 inline void ParMarkBitMap::verify_bit(idx_t bit) const {
   // Allow one past the last valid bit; useful for loop bounds.
   assert(bit <= _beg_bits.size(), "bit out of range");
 }
 inline void ParMarkBitMap::verify_addr(HeapWord* addr) const {
   // Allow one past the last valid address; useful for loop bounds.
   assert(addr >= region_start(), "addr too small");
   assert(addr <= region_start() + region_size(), "addr too big");
 }
 #endif  // #ifdef ASSERT
 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PARMARKBITMAP_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp@4dfb2df418f2 (annotated)

src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp