--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc/parallel/psParallelCompact.hpp Wed May 13 15:16:06 2015 +0200
@@ -0,0 +1,1438 @@
+/*
+ * Copyright (c) 2005, 2015, 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_PARALLEL_PSPARALLELCOMPACT_HPP
+#define SHARE_VM_GC_PARALLEL_PSPARALLELCOMPACT_HPP
+
+#include "gc/parallel/mutableSpace.hpp"
+#include "gc/parallel/objectStartArray.hpp"
+#include "gc/parallel/parMarkBitMap.hpp"
+#include "gc/parallel/parallelScavengeHeap.hpp"
+#include "gc/shared/collectedHeap.hpp"
+#include "gc/shared/collectorCounters.hpp"
+#include "oops/oop.hpp"
+
+class ParallelScavengeHeap;
+class PSAdaptiveSizePolicy;
+class PSYoungGen;
+class PSOldGen;
+class ParCompactionManager;
+class ParallelTaskTerminator;
+class PSParallelCompact;
+class GCTaskManager;
+class GCTaskQueue;
+class PreGCValues;
+class MoveAndUpdateClosure;
+class RefProcTaskExecutor;
+class ParallelOldTracer;
+class STWGCTimer;
+
+// The SplitInfo class holds the information needed to 'split' a source region
+// so that the live data can be copied to two destination *spaces*. Normally,
+// all the live data in a region is copied to a single destination space (e.g.,
+// everything live in a region in eden is copied entirely into the old gen).
+// However, when the heap is nearly full, all the live data in eden may not fit
+// into the old gen. Copying only some of the regions from eden to old gen
+// requires finding a region that does not contain a partial object (i.e., no
+// live object crosses the region boundary) somewhere near the last object that
+// does fit into the old gen. Since it's not always possible to find such a
+// region, splitting is necessary for predictable behavior.
+//
+// A region is always split at the end of the partial object. This avoids
+// additional tests when calculating the new location of a pointer, which is a
+// very hot code path. The partial object and everything to its left will be
+// copied to another space (call it dest_space_1). The live data to the right
+// of the partial object will be copied either within the space itself, or to a
+// different destination space (distinct from dest_space_1).
+//
+// Split points are identified during the summary phase, when region
+// destinations are computed: data about the split, including the
+// partial_object_size, is recorded in a SplitInfo record and the
+// partial_object_size field in the summary data is set to zero. The zeroing is
+// possible (and necessary) since the partial object will move to a different
+// destination space than anything to its right, thus the partial object should
+// not affect the locations of any objects to its right.
+//
+// The recorded data is used during the compaction phase, but only rarely: when
+// the partial object on the split region will be copied across a destination
+// region boundary. This test is made once each time a region is filled, and is
+// a simple address comparison, so the overhead is negligible (see
+// PSParallelCompact::first_src_addr()).
+//
+// Notes:
+//
+// Only regions with partial objects are split; a region without a partial
+// object does not need any extra bookkeeping.
+//
+// At most one region is split per space, so the amount of data required is
+// constant.
+//
+// A region is split only when the destination space would overflow. Once that
+// happens, the destination space is abandoned and no other data (even from
+// other source spaces) is targeted to that destination space. Abandoning the
+// destination space may leave a somewhat large unused area at the end, if a
+// large object caused the overflow.
+//
+// Future work:
+//
+// More bookkeeping would be required to continue to use the destination space.
+// The most general solution would allow data from regions in two different
+// source spaces to be "joined" in a single destination region. At the very
+// least, additional code would be required in next_src_region() to detect the
+// join and skip to an out-of-order source region. If the join region was also
+// the last destination region to which a split region was copied (the most
+// likely case), then additional work would be needed to get fill_region() to
+// stop iteration and switch to a new source region at the right point. Basic
+// idea would be to use a fake value for the top of the source space. It is
+// doable, if a bit tricky.
+//
+// A simpler (but less general) solution would fill the remainder of the
+// destination region with a dummy object and continue filling the next
+// destination region.
+
+class SplitInfo
+{
+public:
+ // Return true if this split info is valid (i.e., if a split has been
+ // recorded). The very first region cannot have a partial object and thus is
+ // never split, so 0 is the 'invalid' value.
+ bool is_valid() const { return _src_region_idx > 0; }
+
+ // Return true if this split holds data for the specified source region.
+ inline bool is_split(size_t source_region) const;
+
+ // The index of the split region, the size of the partial object on that
+ // region and the destination of the partial object.
+ size_t src_region_idx() const { return _src_region_idx; }
+ size_t partial_obj_size() const { return _partial_obj_size; }
+ HeapWord* destination() const { return _destination; }
+
+ // The destination count of the partial object referenced by this split
+ // (either 1 or 2). This must be added to the destination count of the
+ // remainder of the source region.
+ unsigned int destination_count() const { return _destination_count; }
+
+ // If a word within the partial object will be written to the first word of a
+ // destination region, this is the address of the destination region;
+ // otherwise this is NULL.
+ HeapWord* dest_region_addr() const { return _dest_region_addr; }
+
+ // If a word within the partial object will be written to the first word of a
+ // destination region, this is the address of that word within the partial
+ // object; otherwise this is NULL.
+ HeapWord* first_src_addr() const { return _first_src_addr; }
+
+ // Record the data necessary to split the region src_region_idx.
+ void record(size_t src_region_idx, size_t partial_obj_size,
+ HeapWord* destination);
+
+ void clear();
+
+ DEBUG_ONLY(void verify_clear();)
+
+private:
+ size_t _src_region_idx;
+ size_t _partial_obj_size;
+ HeapWord* _destination;
+ unsigned int _destination_count;
+ HeapWord* _dest_region_addr;
+ HeapWord* _first_src_addr;
+};
+
+inline bool SplitInfo::is_split(size_t region_idx) const
+{
+ return _src_region_idx == region_idx && is_valid();
+}
+
+class SpaceInfo
+{
+ public:
+ MutableSpace* space() const { return _space; }
+
+ // Where the free space will start after the collection. Valid only after the
+ // summary phase completes.
+ HeapWord* new_top() const { return _new_top; }
+
+ // Allows new_top to be set.
+ HeapWord** new_top_addr() { return &_new_top; }
+
+ // Where the smallest allowable dense prefix ends (used only for perm gen).
+ HeapWord* min_dense_prefix() const { return _min_dense_prefix; }
+
+ // Where the dense prefix ends, or the compacted region begins.
+ HeapWord* dense_prefix() const { return _dense_prefix; }
+
+ // The start array for the (generation containing the) space, or NULL if there
+ // is no start array.
+ ObjectStartArray* start_array() const { return _start_array; }
+
+ SplitInfo& split_info() { return _split_info; }
+
+ void set_space(MutableSpace* s) { _space = s; }
+ void set_new_top(HeapWord* addr) { _new_top = addr; }
+ void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
+ void set_dense_prefix(HeapWord* addr) { _dense_prefix = addr; }
+ void set_start_array(ObjectStartArray* s) { _start_array = s; }
+
+ void publish_new_top() const { _space->set_top(_new_top); }
+
+ private:
+ MutableSpace* _space;
+ HeapWord* _new_top;
+ HeapWord* _min_dense_prefix;
+ HeapWord* _dense_prefix;
+ ObjectStartArray* _start_array;
+ SplitInfo _split_info;
+};
+
+class ParallelCompactData
+{
+public:
+ // Sizes are in HeapWords, unless indicated otherwise.
+ static const size_t Log2RegionSize;
+ static const size_t RegionSize;
+ static const size_t RegionSizeBytes;
+
+ // Mask for the bits in a size_t to get an offset within a region.
+ static const size_t RegionSizeOffsetMask;
+ // Mask for the bits in a pointer to get an offset within a region.
+ static const size_t RegionAddrOffsetMask;
+ // Mask for the bits in a pointer to get the address of the start of a region.
+ static const size_t RegionAddrMask;
+
+ static const size_t Log2BlockSize;
+ static const size_t BlockSize;
+ static const size_t BlockSizeBytes;
+
+ static const size_t BlockSizeOffsetMask;
+ static const size_t BlockAddrOffsetMask;
+ static const size_t BlockAddrMask;
+
+ static const size_t BlocksPerRegion;
+ static const size_t Log2BlocksPerRegion;
+
+ class RegionData
+ {
+ public:
+ // Destination address of the region.
+ HeapWord* destination() const { return _destination; }
+
+ // The first region containing data destined for this region.
+ size_t source_region() const { return _source_region; }
+
+ // The object (if any) starting in this region and ending in a different
+ // region that could not be updated during the main (parallel) compaction
+ // phase. This is different from _partial_obj_addr, which is an object that
+ // extends onto a source region. However, the two uses do not overlap in
+ // time, so the same field is used to save space.
+ HeapWord* deferred_obj_addr() const { return _partial_obj_addr; }
+
+ // The starting address of the partial object extending onto the region.
+ HeapWord* partial_obj_addr() const { return _partial_obj_addr; }
+
+ // Size of the partial object extending onto the region (words).
+ size_t partial_obj_size() const { return _partial_obj_size; }
+
+ // Size of live data that lies within this region due to objects that start
+ // in this region (words). This does not include the partial object
+ // extending onto the region (if any), or the part of an object that extends
+ // onto the next region (if any).
+ size_t live_obj_size() const { return _dc_and_los & los_mask; }
+
+ // Total live data that lies within the region (words).
+ size_t data_size() const { return partial_obj_size() + live_obj_size(); }
+
+ // The destination_count is the number of other regions to which data from
+ // this region will be copied. At the end of the summary phase, the valid
+ // values of destination_count are
+ //
+ // 0 - data from the region will be compacted completely into itself, or the
+ // region is empty. The region can be claimed and then filled.
+ // 1 - data from the region will be compacted into 1 other region; some
+ // data from the region may also be compacted into the region itself.
+ // 2 - data from the region will be copied to 2 other regions.
+ //
+ // During compaction as regions are emptied, the destination_count is
+ // decremented (atomically) and when it reaches 0, it can be claimed and
+ // then filled.
+ //
+ // A region is claimed for processing by atomically changing the
+ // destination_count to the claimed value (dc_claimed). After a region has
+ // been filled, the destination_count should be set to the completed value
+ // (dc_completed).
+ inline uint destination_count() const;
+ inline uint destination_count_raw() const;
+
+ // Whether the block table for this region has been filled.
+ inline bool blocks_filled() const;
+
+ // Number of times the block table was filled.
+ DEBUG_ONLY(inline size_t blocks_filled_count() const;)
+
+ // The location of the java heap data that corresponds to this region.
+ inline HeapWord* data_location() const;
+
+ // The highest address referenced by objects in this region.
+ inline HeapWord* highest_ref() const;
+
+ // Whether this region is available to be claimed, has been claimed, or has
+ // been completed.
+ //
+ // Minor subtlety: claimed() returns true if the region is marked
+ // completed(), which is desirable since a region must be claimed before it
+ // can be completed.
+ bool available() const { return _dc_and_los < dc_one; }
+ bool claimed() const { return _dc_and_los >= dc_claimed; }
+ bool completed() const { return _dc_and_los >= dc_completed; }
+
+ // These are not atomic.
+ void set_destination(HeapWord* addr) { _destination = addr; }
+ void set_source_region(size_t region) { _source_region = region; }
+ void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
+ void set_partial_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
+ void set_partial_obj_size(size_t words) {
+ _partial_obj_size = (region_sz_t) words;
+ }
+ inline void set_blocks_filled();
+
+ inline void set_destination_count(uint count);
+ inline void set_live_obj_size(size_t words);
+ inline void set_data_location(HeapWord* addr);
+ inline void set_completed();
+ inline bool claim_unsafe();
+
+ // These are atomic.
+ inline void add_live_obj(size_t words);
+ inline void set_highest_ref(HeapWord* addr);
+ inline void decrement_destination_count();
+ inline bool claim();
+
+ private:
+ // The type used to represent object sizes within a region.
+ typedef uint region_sz_t;
+
+ // Constants for manipulating the _dc_and_los field, which holds both the
+ // destination count and live obj size. The live obj size lives at the
+ // least significant end so no masking is necessary when adding.
+ static const region_sz_t dc_shift; // Shift amount.
+ static const region_sz_t dc_mask; // Mask for destination count.
+ static const region_sz_t dc_one; // 1, shifted appropriately.
+ static const region_sz_t dc_claimed; // Region has been claimed.
+ static const region_sz_t dc_completed; // Region has been completed.
+ static const region_sz_t los_mask; // Mask for live obj size.
+
+ HeapWord* _destination;
+ size_t _source_region;
+ HeapWord* _partial_obj_addr;
+ region_sz_t _partial_obj_size;
+ region_sz_t volatile _dc_and_los;
+ bool _blocks_filled;
+
+#ifdef ASSERT
+ size_t _blocks_filled_count; // Number of block table fills.
+
+ // These enable optimizations that are only partially implemented. Use
+ // debug builds to prevent the code fragments from breaking.
+ HeapWord* _data_location;
+ HeapWord* _highest_ref;
+#endif // #ifdef ASSERT
+
+#ifdef ASSERT
+ public:
+ uint _pushed; // 0 until region is pushed onto a stack
+ private:
+#endif
+ };
+
+ // "Blocks" allow shorter sections of the bitmap to be searched. Each Block
+ // holds an offset, which is the amount of live data in the Region to the left
+ // of the first live object that starts in the Block.
+ class BlockData
+ {
+ public:
+ typedef unsigned short int blk_ofs_t;
+
+ blk_ofs_t offset() const { return _offset; }
+ void set_offset(size_t val) { _offset = (blk_ofs_t)val; }
+
+ private:
+ blk_ofs_t _offset;
+ };
+
+public:
+ ParallelCompactData();
+ bool initialize(MemRegion covered_region);
+
+ size_t region_count() const { return _region_count; }
+ size_t reserved_byte_size() const { return _reserved_byte_size; }
+
+ // Convert region indices to/from RegionData pointers.
+ inline RegionData* region(size_t region_idx) const;
+ inline size_t region(const RegionData* const region_ptr) const;
+
+ size_t block_count() const { return _block_count; }
+ inline BlockData* block(size_t block_idx) const;
+ inline size_t block(const BlockData* block_ptr) const;
+
+ void add_obj(HeapWord* addr, size_t len);
+ void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); }
+
+ // Fill in the regions covering [beg, end) so that no data moves; i.e., the
+ // destination of region n is simply the start of region n. The argument beg
+ // must be region-aligned; end need not be.
+ void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
+
+ HeapWord* summarize_split_space(size_t src_region, SplitInfo& split_info,
+ HeapWord* destination, HeapWord* target_end,
+ HeapWord** target_next);
+ bool summarize(SplitInfo& split_info,
+ HeapWord* source_beg, HeapWord* source_end,
+ HeapWord** source_next,
+ HeapWord* target_beg, HeapWord* target_end,
+ HeapWord** target_next);
+
+ void clear();
+ void clear_range(size_t beg_region, size_t end_region);
+ void clear_range(HeapWord* beg, HeapWord* end) {
+ clear_range(addr_to_region_idx(beg), addr_to_region_idx(end));
+ }
+
+ // Return the number of words between addr and the start of the region
+ // containing addr.
+ inline size_t region_offset(const HeapWord* addr) const;
+
+ // Convert addresses to/from a region index or region pointer.
+ inline size_t addr_to_region_idx(const HeapWord* addr) const;
+ inline RegionData* addr_to_region_ptr(const HeapWord* addr) const;
+ inline HeapWord* region_to_addr(size_t region) const;
+ inline HeapWord* region_to_addr(size_t region, size_t offset) const;
+ inline HeapWord* region_to_addr(const RegionData* region) const;
+
+ inline HeapWord* region_align_down(HeapWord* addr) const;
+ inline HeapWord* region_align_up(HeapWord* addr) const;
+ inline bool is_region_aligned(HeapWord* addr) const;
+
+ // Analogous to region_offset() for blocks.
+ size_t block_offset(const HeapWord* addr) const;
+ size_t addr_to_block_idx(const HeapWord* addr) const;
+ size_t addr_to_block_idx(const oop obj) const {
+ return addr_to_block_idx((HeapWord*) obj);
+ }
+ inline BlockData* addr_to_block_ptr(const HeapWord* addr) const;
+ inline HeapWord* block_to_addr(size_t block) const;
+ inline size_t region_to_block_idx(size_t region) const;
+
+ inline HeapWord* block_align_down(HeapWord* addr) const;
+ inline HeapWord* block_align_up(HeapWord* addr) const;
+ inline bool is_block_aligned(HeapWord* addr) const;
+
+ // Return the address one past the end of the partial object.
+ HeapWord* partial_obj_end(size_t region_idx) const;
+
+ // Return the location of the object after compaction.
+ HeapWord* calc_new_pointer(HeapWord* addr);
+
+ HeapWord* calc_new_pointer(oop p) {
+ return calc_new_pointer((HeapWord*) p);
+ }
+
+#ifdef ASSERT
+ void verify_clear(const PSVirtualSpace* vspace);
+ void verify_clear();
+#endif // #ifdef ASSERT
+
+private:
+ bool initialize_block_data();
+ bool initialize_region_data(size_t region_size);
+ PSVirtualSpace* create_vspace(size_t count, size_t element_size);
+
+private:
+ HeapWord* _region_start;
+#ifdef ASSERT
+ HeapWord* _region_end;
+#endif // #ifdef ASSERT
+
+ PSVirtualSpace* _region_vspace;
+ size_t _reserved_byte_size;
+ RegionData* _region_data;
+ size_t _region_count;
+
+ PSVirtualSpace* _block_vspace;
+ BlockData* _block_data;
+ size_t _block_count;
+};
+
+inline uint
+ParallelCompactData::RegionData::destination_count_raw() const
+{
+ return _dc_and_los & dc_mask;
+}
+
+inline uint
+ParallelCompactData::RegionData::destination_count() const
+{
+ return destination_count_raw() >> dc_shift;
+}
+
+inline bool
+ParallelCompactData::RegionData::blocks_filled() const
+{
+ return _blocks_filled;
+}
+
+#ifdef ASSERT
+inline size_t
+ParallelCompactData::RegionData::blocks_filled_count() const
+{
+ return _blocks_filled_count;
+}
+#endif // #ifdef ASSERT
+
+inline void
+ParallelCompactData::RegionData::set_blocks_filled()
+{
+ _blocks_filled = true;
+ // Debug builds count the number of times the table was filled.
+ DEBUG_ONLY(Atomic::inc_ptr(&_blocks_filled_count));
+}
+
+inline void
+ParallelCompactData::RegionData::set_destination_count(uint count)
+{
+ assert(count <= (dc_completed >> dc_shift), "count too large");
+ const region_sz_t live_sz = (region_sz_t) live_obj_size();
+ _dc_and_los = (count << dc_shift) | live_sz;
+}
+
+inline void ParallelCompactData::RegionData::set_live_obj_size(size_t words)
+{
+ assert(words <= los_mask, "would overflow");
+ _dc_and_los = destination_count_raw() | (region_sz_t)words;
+}
+
+inline void ParallelCompactData::RegionData::decrement_destination_count()
+{
+ assert(_dc_and_los < dc_claimed, "already claimed");
+ assert(_dc_and_los >= dc_one, "count would go negative");
+ Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los);
+}
+
+inline HeapWord* ParallelCompactData::RegionData::data_location() const
+{
+ DEBUG_ONLY(return _data_location;)
+ NOT_DEBUG(return NULL;)
+}
+
+inline HeapWord* ParallelCompactData::RegionData::highest_ref() const
+{
+ DEBUG_ONLY(return _highest_ref;)
+ NOT_DEBUG(return NULL;)
+}
+
+inline void ParallelCompactData::RegionData::set_data_location(HeapWord* addr)
+{
+ DEBUG_ONLY(_data_location = addr;)
+}
+
+inline void ParallelCompactData::RegionData::set_completed()
+{
+ assert(claimed(), "must be claimed first");
+ _dc_and_los = dc_completed | (region_sz_t) live_obj_size();
+}
+
+// MT-unsafe claiming of a region. Should only be used during single threaded
+// execution.
+inline bool ParallelCompactData::RegionData::claim_unsafe()
+{
+ if (available()) {
+ _dc_and_los |= dc_claimed;
+ return true;
+ }
+ return false;
+}
+
+inline void ParallelCompactData::RegionData::add_live_obj(size_t words)
+{
+ assert(words <= (size_t)los_mask - live_obj_size(), "overflow");
+ Atomic::add((int) words, (volatile int*) &_dc_and_los);
+}
+
+inline void ParallelCompactData::RegionData::set_highest_ref(HeapWord* addr)
+{
+#ifdef ASSERT
+ HeapWord* tmp = _highest_ref;
+ while (addr > tmp) {
+ tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp);
+ }
+#endif // #ifdef ASSERT
+}
+
+inline bool ParallelCompactData::RegionData::claim()
+{
+ const int los = (int) live_obj_size();
+ const int old = Atomic::cmpxchg(dc_claimed | los,
+ (volatile int*) &_dc_and_los, los);
+ return old == los;
+}
+
+inline ParallelCompactData::RegionData*
+ParallelCompactData::region(size_t region_idx) const
+{
+ assert(region_idx <= region_count(), "bad arg");
+ return _region_data + region_idx;
+}
+
+inline size_t
+ParallelCompactData::region(const RegionData* const region_ptr) const
+{
+ assert(region_ptr >= _region_data, "bad arg");
+ assert(region_ptr <= _region_data + region_count(), "bad arg");
+ return pointer_delta(region_ptr, _region_data, sizeof(RegionData));
+}
+
+inline ParallelCompactData::BlockData*
+ParallelCompactData::block(size_t n) const {
+ assert(n < block_count(), "bad arg");
+ return _block_data + n;
+}
+
+inline size_t
+ParallelCompactData::region_offset(const HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr <= _region_end, "bad addr");
+ return (size_t(addr) & RegionAddrOffsetMask) >> LogHeapWordSize;
+}
+
+inline size_t
+ParallelCompactData::addr_to_region_idx(const HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr <= _region_end, "bad addr");
+ return pointer_delta(addr, _region_start) >> Log2RegionSize;
+}
+
+inline ParallelCompactData::RegionData*
+ParallelCompactData::addr_to_region_ptr(const HeapWord* addr) const
+{
+ return region(addr_to_region_idx(addr));
+}
+
+inline HeapWord*
+ParallelCompactData::region_to_addr(size_t region) const
+{
+ assert(region <= _region_count, "region out of range");
+ return _region_start + (region << Log2RegionSize);
+}
+
+inline HeapWord*
+ParallelCompactData::region_to_addr(const RegionData* region) const
+{
+ return region_to_addr(pointer_delta(region, _region_data,
+ sizeof(RegionData)));
+}
+
+inline HeapWord*
+ParallelCompactData::region_to_addr(size_t region, size_t offset) const
+{
+ assert(region <= _region_count, "region out of range");
+ assert(offset < RegionSize, "offset too big"); // This may be too strict.
+ return region_to_addr(region) + offset;
+}
+
+inline HeapWord*
+ParallelCompactData::region_align_down(HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr < _region_end + RegionSize, "bad addr");
+ return (HeapWord*)(size_t(addr) & RegionAddrMask);
+}
+
+inline HeapWord*
+ParallelCompactData::region_align_up(HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr <= _region_end, "bad addr");
+ return region_align_down(addr + RegionSizeOffsetMask);
+}
+
+inline bool
+ParallelCompactData::is_region_aligned(HeapWord* addr) const
+{
+ return region_offset(addr) == 0;
+}
+
+inline size_t
+ParallelCompactData::block_offset(const HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr <= _region_end, "bad addr");
+ return (size_t(addr) & BlockAddrOffsetMask) >> LogHeapWordSize;
+}
+
+inline size_t
+ParallelCompactData::addr_to_block_idx(const HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr <= _region_end, "bad addr");
+ return pointer_delta(addr, _region_start) >> Log2BlockSize;
+}
+
+inline ParallelCompactData::BlockData*
+ParallelCompactData::addr_to_block_ptr(const HeapWord* addr) const
+{
+ return block(addr_to_block_idx(addr));
+}
+
+inline HeapWord*
+ParallelCompactData::block_to_addr(size_t block) const
+{
+ assert(block < _block_count, "block out of range");
+ return _region_start + (block << Log2BlockSize);
+}
+
+inline size_t
+ParallelCompactData::region_to_block_idx(size_t region) const
+{
+ return region << Log2BlocksPerRegion;
+}
+
+inline HeapWord*
+ParallelCompactData::block_align_down(HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr < _region_end + RegionSize, "bad addr");
+ return (HeapWord*)(size_t(addr) & BlockAddrMask);
+}
+
+inline HeapWord*
+ParallelCompactData::block_align_up(HeapWord* addr) const
+{
+ assert(addr >= _region_start, "bad addr");
+ assert(addr <= _region_end, "bad addr");
+ return block_align_down(addr + BlockSizeOffsetMask);
+}
+
+inline bool
+ParallelCompactData::is_block_aligned(HeapWord* addr) const
+{
+ return block_offset(addr) == 0;
+}
+
+// Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the
+// do_addr() method.
+//
+// The closure is initialized with the number of heap words to process
+// (words_remaining()), and becomes 'full' when it reaches 0. The do_addr()
+// methods in subclasses should update the total as words are processed. Since
+// only one subclass actually uses this mechanism to terminate iteration, the
+// default initial value is > 0. The implementation is here and not in the
+// single subclass that uses it to avoid making is_full() virtual, and thus
+// adding a virtual call per live object.
+
+class ParMarkBitMapClosure: public StackObj {
+ public:
+ typedef ParMarkBitMap::idx_t idx_t;
+ typedef ParMarkBitMap::IterationStatus IterationStatus;
+
+ public:
+ inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm,
+ size_t words = max_uintx);
+
+ inline ParCompactionManager* compaction_manager() const;
+ inline ParMarkBitMap* bitmap() const;
+ inline size_t words_remaining() const;
+ inline bool is_full() const;
+ inline HeapWord* source() const;
+
+ inline void set_source(HeapWord* addr);
+
+ virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0;
+
+ protected:
+ inline void decrement_words_remaining(size_t words);
+
+ private:
+ ParMarkBitMap* const _bitmap;
+ ParCompactionManager* const _compaction_manager;
+ DEBUG_ONLY(const size_t _initial_words_remaining;) // Useful in debugger.
+ size_t _words_remaining; // Words left to copy.
+
+ protected:
+ HeapWord* _source; // Next addr that would be read.
+};
+
+inline
+ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap,
+ ParCompactionManager* cm,
+ size_t words):
+ _bitmap(bitmap), _compaction_manager(cm)
+#ifdef ASSERT
+ , _initial_words_remaining(words)
+#endif
+{
+ _words_remaining = words;
+ _source = NULL;
+}
+
+inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const {
+ return _compaction_manager;
+}
+
+inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const {
+ return _bitmap;
+}
+
+inline size_t ParMarkBitMapClosure::words_remaining() const {
+ return _words_remaining;
+}
+
+inline bool ParMarkBitMapClosure::is_full() const {
+ return words_remaining() == 0;
+}
+
+inline HeapWord* ParMarkBitMapClosure::source() const {
+ return _source;
+}
+
+inline void ParMarkBitMapClosure::set_source(HeapWord* addr) {
+ _source = addr;
+}
+
+inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) {
+ assert(_words_remaining >= words, "processed too many words");
+ _words_remaining -= words;
+}
+
+// The UseParallelOldGC collector is a stop-the-world garbage collector that
+// does parts of the collection using parallel threads. The collection includes
+// the tenured generation and the young generation. The permanent generation is
+// collected at the same time as the other two generations but the permanent
+// generation is collect by a single GC thread. The permanent generation is
+// collected serially because of the requirement that during the processing of a
+// klass AAA, any objects reference by AAA must already have been processed.
+// This requirement is enforced by a left (lower address) to right (higher
+// address) sliding compaction.
+//
+// There are four phases of the collection.
+//
+// - marking phase
+// - summary phase
+// - compacting phase
+// - clean up phase
+//
+// Roughly speaking these phases correspond, respectively, to
+// - mark all the live objects
+// - calculate the destination of each object at the end of the collection
+// - move the objects to their destination
+// - update some references and reinitialize some variables
+//
+// These three phases are invoked in PSParallelCompact::invoke_no_policy(). The
+// marking phase is implemented in PSParallelCompact::marking_phase() and does a
+// complete marking of the heap. The summary phase is implemented in
+// PSParallelCompact::summary_phase(). The move and update phase is implemented
+// in PSParallelCompact::compact().
+//
+// A space that is being collected is divided into regions and with each region
+// is associated an object of type ParallelCompactData. Each region is of a
+// fixed size and typically will contain more than 1 object and may have parts
+// of objects at the front and back of the region.
+//
+// region -----+---------------------+----------
+// objects covered [ AAA )[ BBB )[ CCC )[ DDD )
+//
+// The marking phase does a complete marking of all live objects in the heap.
+// The marking also compiles the size of the data for all live objects covered
+// by the region. This size includes the part of any live object spanning onto
+// the region (part of AAA if it is live) from the front, all live objects
+// contained in the region (BBB and/or CCC if they are live), and the part of
+// any live objects covered by the region that extends off the region (part of
+// DDD if it is live). The marking phase uses multiple GC threads and marking
+// is done in a bit array of type ParMarkBitMap. The marking of the bit map is
+// done atomically as is the accumulation of the size of the live objects
+// covered by a region.
+//
+// The summary phase calculates the total live data to the left of each region
+// XXX. Based on that total and the bottom of the space, it can calculate the
+// starting location of the live data in XXX. The summary phase calculates for
+// each region XXX quantities such as
+//
+// - the amount of live data at the beginning of a region from an object
+// entering the region.
+// - the location of the first live data on the region
+// - a count of the number of regions receiving live data from XXX.
+//
+// See ParallelCompactData for precise details. The summary phase also
+// calculates the dense prefix for the compaction. The dense prefix is a
+// portion at the beginning of the space that is not moved. The objects in the
+// dense prefix do need to have their object references updated. See method
+// summarize_dense_prefix().
+//
+// The summary phase is done using 1 GC thread.
+//
+// The compaction phase moves objects to their new location and updates all
+// references in the object.
+//
+// A current exception is that objects that cross a region boundary are moved
+// but do not have their references updated. References are not updated because
+// it cannot easily be determined if the klass pointer KKK for the object AAA
+// has been updated. KKK likely resides in a region to the left of the region
+// containing AAA. These AAA's have there references updated at the end in a
+// clean up phase. See the method PSParallelCompact::update_deferred_objects().
+// An alternate strategy is being investigated for this deferral of updating.
+//
+// Compaction is done on a region basis. A region that is ready to be filled is
+// put on a ready list and GC threads take region off the list and fill them. A
+// region is ready to be filled if it empty of live objects. Such a region may
+// have been initially empty (only contained dead objects) or may have had all
+// its live objects copied out already. A region that compacts into itself is
+// also ready for filling. The ready list is initially filled with empty
+// regions and regions compacting into themselves. There is always at least 1
+// region that can be put on the ready list. The regions are atomically added
+// and removed from the ready list.
+
+class PSParallelCompact : AllStatic {
+ public:
+ // Convenient access to type names.
+ typedef ParMarkBitMap::idx_t idx_t;
+ typedef ParallelCompactData::RegionData RegionData;
+ typedef ParallelCompactData::BlockData BlockData;
+
+ typedef enum {
+ old_space_id, eden_space_id,
+ from_space_id, to_space_id, last_space_id
+ } SpaceId;
+
+ public:
+ // Inline closure decls
+ //
+ class IsAliveClosure: public BoolObjectClosure {
+ public:
+ virtual bool do_object_b(oop p);
+ };
+
+ class AdjustPointerClosure: public ExtendedOopClosure {
+ public:
+ template <typename T> void do_oop_nv(T* p);
+ virtual void do_oop(oop* p);
+ virtual void do_oop(narrowOop* p);
+
+ // This closure provides its own oop verification code.
+ debug_only(virtual bool should_verify_oops() { return false; })
+ };
+
+ class AdjustKlassClosure : public KlassClosure {
+ public:
+ void do_klass(Klass* klass);
+ };
+
+ friend class AdjustPointerClosure;
+ friend class AdjustKlassClosure;
+ friend class RefProcTaskProxy;
+
+ private:
+ static STWGCTimer _gc_timer;
+ static ParallelOldTracer _gc_tracer;
+ static elapsedTimer _accumulated_time;
+ static unsigned int _total_invocations;
+ static unsigned int _maximum_compaction_gc_num;
+ static jlong _time_of_last_gc; // ms
+ static CollectorCounters* _counters;
+ static ParMarkBitMap _mark_bitmap;
+ static ParallelCompactData _summary_data;
+ static IsAliveClosure _is_alive_closure;
+ static SpaceInfo _space_info[last_space_id];
+ static bool _print_phases;
+ static AdjustPointerClosure _adjust_pointer_closure;
+ static AdjustKlassClosure _adjust_klass_closure;
+
+ // Reference processing (used in ...follow_contents)
+ static ReferenceProcessor* _ref_processor;
+
+ // Values computed at initialization and used by dead_wood_limiter().
+ static double _dwl_mean;
+ static double _dwl_std_dev;
+ static double _dwl_first_term;
+ static double _dwl_adjustment;
+#ifdef ASSERT
+ static bool _dwl_initialized;
+#endif // #ifdef ASSERT
+
+
+ public:
+ static ParallelOldTracer* gc_tracer() { return &_gc_tracer; }
+
+ private:
+
+ static void initialize_space_info();
+
+ // Return true if details about individual phases should be printed.
+ static inline bool print_phases();
+
+ // Clear the marking bitmap and summary data that cover the specified space.
+ static void clear_data_covering_space(SpaceId id);
+
+ static void pre_compact(PreGCValues* pre_gc_values);
+ static void post_compact();
+
+ // Mark live objects
+ static void marking_phase(ParCompactionManager* cm,
+ bool maximum_heap_compaction,
+ ParallelOldTracer *gc_tracer);
+
+ // Compute the dense prefix for the designated space. This is an experimental
+ // implementation currently not used in production.
+ static HeapWord* compute_dense_prefix_via_density(const SpaceId id,
+ bool maximum_compaction);
+
+ // Methods used to compute the dense prefix.
+
+ // Compute the value of the normal distribution at x = density. The mean and
+ // standard deviation are values saved by initialize_dead_wood_limiter().
+ static inline double normal_distribution(double density);
+
+ // Initialize the static vars used by dead_wood_limiter().
+ static void initialize_dead_wood_limiter();
+
+ // Return the percentage of space that can be treated as "dead wood" (i.e.,
+ // not reclaimed).
+ static double dead_wood_limiter(double density, size_t min_percent);
+
+ // Find the first (left-most) region in the range [beg, end) that has at least
+ // dead_words of dead space to the left. The argument beg must be the first
+ // region in the space that is not completely live.
+ static RegionData* dead_wood_limit_region(const RegionData* beg,
+ const RegionData* end,
+ size_t dead_words);
+
+ // Return a pointer to the first region in the range [beg, end) that is not
+ // completely full.
+ static RegionData* first_dead_space_region(const RegionData* beg,
+ const RegionData* end);
+
+ // Return a value indicating the benefit or 'yield' if the compacted region
+ // were to start (or equivalently if the dense prefix were to end) at the
+ // candidate region. Higher values are better.
+ //
+ // The value is based on the amount of space reclaimed vs. the costs of (a)
+ // updating references in the dense prefix plus (b) copying objects and
+ // updating references in the compacted region.
+ static inline double reclaimed_ratio(const RegionData* const candidate,
+ HeapWord* const bottom,
+ HeapWord* const top,
+ HeapWord* const new_top);
+
+ // Compute the dense prefix for the designated space.
+ static HeapWord* compute_dense_prefix(const SpaceId id,
+ bool maximum_compaction);
+
+ // Return true if dead space crosses onto the specified Region; bit must be
+ // the bit index corresponding to the first word of the Region.
+ static inline bool dead_space_crosses_boundary(const RegionData* region,
+ idx_t bit);
+
+ // Summary phase utility routine to fill dead space (if any) at the dense
+ // prefix boundary. Should only be called if the the dense prefix is
+ // non-empty.
+ static void fill_dense_prefix_end(SpaceId id);
+
+ // Clear the summary data source_region field for the specified addresses.
+ static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr);
+
+#ifndef PRODUCT
+ // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot).
+
+ // Fill the region [start, start + words) with live object(s). Only usable
+ // for the old and permanent generations.
+ static void fill_with_live_objects(SpaceId id, HeapWord* const start,
+ size_t words);
+ // Include the new objects in the summary data.
+ static void summarize_new_objects(SpaceId id, HeapWord* start);
+
+ // Add live objects to a survivor space since it's rare that both survivors
+ // are non-empty.
+ static void provoke_split_fill_survivor(SpaceId id);
+
+ // Add live objects and/or choose the dense prefix to provoke splitting.
+ static void provoke_split(bool & maximum_compaction);
+#endif
+
+ static void summarize_spaces_quick();
+ static void summarize_space(SpaceId id, bool maximum_compaction);
+ static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
+
+ // Adjust addresses in roots. Does not adjust addresses in heap.
+ static void adjust_roots();
+
+ DEBUG_ONLY(static void write_block_fill_histogram(outputStream* const out);)
+
+ // Move objects to new locations.
+ static void compact_perm(ParCompactionManager* cm);
+ static void compact();
+
+ // Add available regions to the stack and draining tasks to the task queue.
+ static void enqueue_region_draining_tasks(GCTaskQueue* q,
+ uint parallel_gc_threads);
+
+ // Add dense prefix update tasks to the task queue.
+ static void enqueue_dense_prefix_tasks(GCTaskQueue* q,
+ uint parallel_gc_threads);
+
+ // Add region stealing tasks to the task queue.
+ static void enqueue_region_stealing_tasks(
+ GCTaskQueue* q,
+ ParallelTaskTerminator* terminator_ptr,
+ uint parallel_gc_threads);
+
+ // If objects are left in eden after a collection, try to move the boundary
+ // and absorb them into the old gen. Returns true if eden was emptied.
+ static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
+ PSYoungGen* young_gen,
+ PSOldGen* old_gen);
+
+ // Reset time since last full gc
+ static void reset_millis_since_last_gc();
+
+ public:
+
+ PSParallelCompact();
+
+ static void invoke(bool maximum_heap_compaction);
+ static bool invoke_no_policy(bool maximum_heap_compaction);
+
+ static void post_initialize();
+ // Perform initialization for PSParallelCompact that requires
+ // allocations. This should be called during the VM initialization
+ // at a pointer where it would be appropriate to return a JNI_ENOMEM
+ // in the event of a failure.
+ static bool initialize();
+
+ // Closure accessors
+ static PSParallelCompact::AdjustPointerClosure* adjust_pointer_closure() {
+ return &_adjust_pointer_closure;
+ }
+ static KlassClosure* adjust_klass_closure() { return (KlassClosure*)&_adjust_klass_closure; }
+ static BoolObjectClosure* is_alive_closure() { return (BoolObjectClosure*)&_is_alive_closure; }
+
+ // Public accessors
+ static elapsedTimer* accumulated_time() { return &_accumulated_time; }
+ static unsigned int total_invocations() { return _total_invocations; }
+ static CollectorCounters* counters() { return _counters; }
+
+ // Used to add tasks
+ static GCTaskManager* const gc_task_manager();
+
+ // Marking support
+ static inline bool mark_obj(oop obj);
+ static inline bool is_marked(oop obj);
+
+ template <class T> static inline void adjust_pointer(T* p);
+
+ // Compaction support.
+ // Return true if p is in the range [beg_addr, end_addr).
+ static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr);
+ static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr);
+
+ // Convenience wrappers for per-space data kept in _space_info.
+ static inline MutableSpace* space(SpaceId space_id);
+ static inline HeapWord* new_top(SpaceId space_id);
+ static inline HeapWord* dense_prefix(SpaceId space_id);
+ static inline ObjectStartArray* start_array(SpaceId space_id);
+
+ // Move and update the live objects in the specified space.
+ static void move_and_update(ParCompactionManager* cm, SpaceId space_id);
+
+ // Process the end of the given region range in the dense prefix.
+ // This includes saving any object not updated.
+ static void dense_prefix_regions_epilogue(ParCompactionManager* cm,
+ size_t region_start_index,
+ size_t region_end_index,
+ idx_t exiting_object_offset,
+ idx_t region_offset_start,
+ idx_t region_offset_end);
+
+ // Update a region in the dense prefix. For each live object
+ // in the region, update it's interior references. For each
+ // dead object, fill it with deadwood. Dead space at the end
+ // of a region range will be filled to the start of the next
+ // live object regardless of the region_index_end. None of the
+ // objects in the dense prefix move and dead space is dead
+ // (holds only dead objects that don't need any processing), so
+ // dead space can be filled in any order.
+ static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
+ SpaceId space_id,
+ size_t region_index_start,
+ size_t region_index_end);
+
+ // Return the address of the count + 1st live word in the range [beg, end).
+ static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count);
+
+ // Return the address of the word to be copied to dest_addr, which must be
+ // aligned to a region boundary.
+ static HeapWord* first_src_addr(HeapWord* const dest_addr,
+ SpaceId src_space_id,
+ size_t src_region_idx);
+
+ // Determine the next source region, set closure.source() to the start of the
+ // new region return the region index. Parameter end_addr is the address one
+ // beyond the end of source range just processed. If necessary, switch to a
+ // new source space and set src_space_id (in-out parameter) and src_space_top
+ // (out parameter) accordingly.
+ static size_t next_src_region(MoveAndUpdateClosure& closure,
+ SpaceId& src_space_id,
+ HeapWord*& src_space_top,
+ HeapWord* end_addr);
+
+ // Decrement the destination count for each non-empty source region in the
+ // range [beg_region, region(region_align_up(end_addr))). If the destination
+ // count for a region goes to 0 and it needs to be filled, enqueue it.
+ static void decrement_destination_counts(ParCompactionManager* cm,
+ SpaceId src_space_id,
+ size_t beg_region,
+ HeapWord* end_addr);
+
+ // Fill a region, copying objects from one or more source regions.
+ static void fill_region(ParCompactionManager* cm, size_t region_idx);
+ static void fill_and_update_region(ParCompactionManager* cm, size_t region) {
+ fill_region(cm, region);
+ }
+
+ // Fill in the block table for the specified region.
+ static void fill_blocks(size_t region_idx);
+
+ // Update the deferred objects in the space.
+ static void update_deferred_objects(ParCompactionManager* cm, SpaceId id);
+
+ static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; }
+ static ParallelCompactData& summary_data() { return _summary_data; }
+
+ // Reference Processing
+ static ReferenceProcessor* const ref_processor() { return _ref_processor; }
+
+ static STWGCTimer* gc_timer() { return &_gc_timer; }
+
+ // Return the SpaceId for the given address.
+ static SpaceId space_id(HeapWord* addr);
+
+ // Time since last full gc (in milliseconds).
+ static jlong millis_since_last_gc();
+
+ static void print_on_error(outputStream* st);
+
+#ifndef PRODUCT
+ // Debugging support.
+ static const char* space_names[last_space_id];
+ static void print_region_ranges();
+ static void print_dense_prefix_stats(const char* const algorithm,
+ const SpaceId id,
+ const bool maximum_compaction,
+ HeapWord* const addr);
+ static void summary_phase_msg(SpaceId dst_space_id,
+ HeapWord* dst_beg, HeapWord* dst_end,
+ SpaceId src_space_id,
+ HeapWord* src_beg, HeapWord* src_end);
+#endif // #ifndef PRODUCT
+
+#ifdef ASSERT
+ // Sanity check the new location of a word in the heap.
+ static inline void check_new_location(HeapWord* old_addr, HeapWord* new_addr);
+ // Verify that all the regions have been emptied.
+ static void verify_complete(SpaceId space_id);
+#endif // #ifdef ASSERT
+};
+
+inline bool PSParallelCompact::mark_obj(oop obj) {
+ const int obj_size = obj->size();
+ if (mark_bitmap()->mark_obj(obj, obj_size)) {
+ _summary_data.add_obj(obj, obj_size);
+ return true;
+ } else {
+ return false;
+ }
+}
+
+inline bool PSParallelCompact::is_marked(oop obj) {
+ return mark_bitmap()->is_marked(obj);
+}
+
+inline bool PSParallelCompact::print_phases() {
+ return _print_phases;
+}
+
+inline double PSParallelCompact::normal_distribution(double density) {
+ assert(_dwl_initialized, "uninitialized");
+ const double squared_term = (density - _dwl_mean) / _dwl_std_dev;
+ return _dwl_first_term * exp(-0.5 * squared_term * squared_term);
+}
+
+inline bool
+PSParallelCompact::dead_space_crosses_boundary(const RegionData* region,
+ idx_t bit)
+{
+ assert(bit > 0, "cannot call this for the first bit/region");
+ assert(_summary_data.region_to_addr(region) == _mark_bitmap.bit_to_addr(bit),
+ "sanity check");
+
+ // Dead space crosses the boundary if (1) a partial object does not extend
+ // onto the region, (2) an object does not start at the beginning of the
+ // region, and (3) an object does not end at the end of the prior region.
+ return region->partial_obj_size() == 0 &&
+ !_mark_bitmap.is_obj_beg(bit) &&
+ !_mark_bitmap.is_obj_end(bit - 1);
+}
+
+inline bool
+PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) {
+ return p >= beg_addr && p < end_addr;
+}
+
+inline bool
+PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) {
+ return is_in((HeapWord*)p, beg_addr, end_addr);
+}
+
+inline MutableSpace* PSParallelCompact::space(SpaceId id) {
+ assert(id < last_space_id, "id out of range");
+ return _space_info[id].space();
+}
+
+inline HeapWord* PSParallelCompact::new_top(SpaceId id) {
+ assert(id < last_space_id, "id out of range");
+ return _space_info[id].new_top();
+}
+
+inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) {
+ assert(id < last_space_id, "id out of range");
+ return _space_info[id].dense_prefix();
+}
+
+inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) {
+ assert(id < last_space_id, "id out of range");
+ return _space_info[id].start_array();
+}
+
+#ifdef ASSERT
+inline void
+PSParallelCompact::check_new_location(HeapWord* old_addr, HeapWord* new_addr)
+{
+ assert(old_addr >= new_addr || space_id(old_addr) != space_id(new_addr),
+ "must move left or to a different space");
+ assert(is_object_aligned((intptr_t)old_addr) && is_object_aligned((intptr_t)new_addr),
+ "checking alignment");
+}
+#endif // ASSERT
+
+class MoveAndUpdateClosure: public ParMarkBitMapClosure {
+ public:
+ inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm,
+ ObjectStartArray* start_array,
+ HeapWord* destination, size_t words);
+
+ // Accessors.
+ HeapWord* destination() const { return _destination; }
+
+ // If the object will fit (size <= words_remaining()), copy it to the current
+ // destination, update the interior oops and the start array and return either
+ // full (if the closure is full) or incomplete. If the object will not fit,
+ // return would_overflow.
+ virtual IterationStatus do_addr(HeapWord* addr, size_t size);
+
+ // Copy enough words to fill this closure, starting at source(). Interior
+ // oops and the start array are not updated. Return full.
+ IterationStatus copy_until_full();
+
+ // Copy enough words to fill this closure or to the end of an object,
+ // whichever is smaller, starting at source(). Interior oops and the start
+ // array are not updated.
+ void copy_partial_obj();
+
+ protected:
+ // Update variables to indicate that word_count words were processed.
+ inline void update_state(size_t word_count);
+
+ protected:
+ ObjectStartArray* const _start_array;
+ HeapWord* _destination; // Next addr to be written.
+};
+
+inline
+MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap,
+ ParCompactionManager* cm,
+ ObjectStartArray* start_array,
+ HeapWord* destination,
+ size_t words) :
+ ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array)
+{
+ _destination = destination;
+}
+
+inline void MoveAndUpdateClosure::update_state(size_t words)
+{
+ decrement_words_remaining(words);
+ _source += words;
+ _destination += words;
+}
+
+class UpdateOnlyClosure: public ParMarkBitMapClosure {
+ private:
+ const PSParallelCompact::SpaceId _space_id;
+ ObjectStartArray* const _start_array;
+
+ public:
+ UpdateOnlyClosure(ParMarkBitMap* mbm,
+ ParCompactionManager* cm,
+ PSParallelCompact::SpaceId space_id);
+
+ // Update the object.
+ virtual IterationStatus do_addr(HeapWord* addr, size_t words);
+
+ inline void do_addr(HeapWord* addr);
+};
+
+class FillClosure: public ParMarkBitMapClosure
+{
+public:
+ FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) :
+ ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
+ _start_array(PSParallelCompact::start_array(space_id))
+ {
+ assert(space_id == PSParallelCompact::old_space_id,
+ "cannot use FillClosure in the young gen");
+ }
+
+ virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
+ CollectedHeap::fill_with_objects(addr, size);
+ HeapWord* const end = addr + size;
+ do {
+ _start_array->allocate_block(addr);
+ addr += oop(addr)->size();
+ } while (addr < end);
+ return ParMarkBitMap::incomplete;
+ }
+
+private:
+ ObjectStartArray* const _start_array;
+};
+
+#endif // SHARE_VM_GC_PARALLEL_PSPARALLELCOMPACT_HPP