--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parMarkBitMap.hpp Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,427 @@
+/*
+ * Copyright 2005-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+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); }
+
+ 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(NULL, 0),
+ _end_bits(NULL, 0)
+{
+ _region_start = 0;
+ _virtual_space = 0;
+}
+
+inline ParMarkBitMap::ParMarkBitMap(MemRegion covered_region):
+ _beg_bits(NULL, 0),
+ _end_bits(NULL, 0)
+{
+ 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();
+}
+
+inline ParMarkBitMap::idx_t
+ParMarkBitMap::words_to_bits(size_t words)
+{
+ return words / obj_granularity();
+}
+
+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.find_next_one_bit(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.find_next_one_bit(beg, end);
+}
+
+inline ParMarkBitMap::idx_t
+ParMarkBitMap::find_obj_end(idx_t beg, idx_t end) const
+{
+ return _end_bits.find_next_one_bit(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