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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation.
*
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* 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.
*
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#ifndef SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_PROMOTIONINFO_HPP
#define SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_PROMOTIONINFO_HPP
#include "gc_implementation/concurrentMarkSweep/freeChunk.hpp"
#include "memory/allocation.hpp"
// Forward declarations
class CompactibleFreeListSpace;
class PromotedObject VALUE_OBJ_CLASS_SPEC {
private:
enum {
promoted_mask = right_n_bits(2), // i.e. 0x3
displaced_mark = nth_bit(2), // i.e. 0x4
next_mask = ~(right_n_bits(3)) // i.e. ~(0x7)
};
// Below, we want _narrow_next in the "higher" 32 bit slot,
// whose position will depend on endian-ness of the platform.
// This is so that there is no interference with the
// cms_free_bit occupying bit position 7 (lsb == 0)
// when we are using compressed oops; see FreeChunk::is_free().
// We cannot move the cms_free_bit down because currently
// biased locking code assumes that age bits are contiguous
// with the lock bits. Even if that assumption were relaxed,
// the least position we could move this bit to would be
// to bit position 3, which would require 16 byte alignment.
typedef struct {
#ifdef VM_LITTLE_ENDIAN
LP64_ONLY(narrowOop _pad;)
narrowOop _narrow_next;
#else
narrowOop _narrow_next;
LP64_ONLY(narrowOop _pad;)
#endif
} Data;
union {
intptr_t _next;
Data _data;
};
public:
inline PromotedObject* next() const {
assert(!((FreeChunk*)this)->is_free(), "Error");
PromotedObject* res;
if (UseCompressedOops) {
// The next pointer is a compressed oop stored in the top 32 bits
res = (PromotedObject*)oopDesc::decode_heap_oop(_data._narrow_next);
} else {
res = (PromotedObject*)(_next & next_mask);
}
assert(oop(res)->is_oop_or_null(true /* ignore mark word */), "Not an oop?");
return res;
}
inline void setNext(PromotedObject* x) {
assert(((intptr_t)x & ~next_mask) == 0, "Conflict in bit usage, "
"or insufficient alignment of objects");
if (UseCompressedOops) {
assert(_data._narrow_next == 0, "Overwrite?");
_data._narrow_next = oopDesc::encode_heap_oop(oop(x));
} else {
_next |= (intptr_t)x;
}
assert(!((FreeChunk*)this)->is_free(), "Error");
}
inline void setPromotedMark() {
_next |= promoted_mask;
assert(!((FreeChunk*)this)->is_free(), "Error");
}
inline bool hasPromotedMark() const {
assert(!((FreeChunk*)this)->is_free(), "Error");
return (_next & promoted_mask) == promoted_mask;
}
inline void setDisplacedMark() {
_next |= displaced_mark;
assert(!((FreeChunk*)this)->is_free(), "Error");
}
inline bool hasDisplacedMark() const {
assert(!((FreeChunk*)this)->is_free(), "Error");
return (_next & displaced_mark) != 0;
}
inline void clear_next() {
_next = 0;
assert(!((FreeChunk*)this)->is_free(), "Error");
}
debug_only(void *next_addr() { return (void *) &_next; })
};
class SpoolBlock: public FreeChunk {
friend class PromotionInfo;
protected:
SpoolBlock* nextSpoolBlock;
size_t bufferSize; // number of usable words in this block
markOop* displacedHdr; // the displaced headers start here
// Note about bufferSize: it denotes the number of entries available plus 1;
// legal indices range from 1 through BufferSize - 1. See the verification
// code verify() that counts the number of displaced headers spooled.
size_t computeBufferSize() {
return (size() * sizeof(HeapWord) - sizeof(*this)) / sizeof(markOop);
}
public:
void init() {
bufferSize = computeBufferSize();
displacedHdr = (markOop*)&displacedHdr;
nextSpoolBlock = NULL;
}
void print_on(outputStream* st) const;
void print() const { print_on(gclog_or_tty); }
};
class PromotionInfo VALUE_OBJ_CLASS_SPEC {
bool _tracking; // set if tracking
CompactibleFreeListSpace* _space; // the space to which this belongs
PromotedObject* _promoHead; // head of list of promoted objects
PromotedObject* _promoTail; // tail of list of promoted objects
SpoolBlock* _spoolHead; // first spooling block
SpoolBlock* _spoolTail; // last non-full spooling block or null
SpoolBlock* _splice_point; // when _spoolTail is null, holds list tail
SpoolBlock* _spareSpool; // free spool buffer
size_t _firstIndex; // first active index in
// first spooling block (_spoolHead)
size_t _nextIndex; // last active index + 1 in last
// spooling block (_spoolTail)
private:
// ensure that spooling space exists; return true if there is spooling space
bool ensure_spooling_space_work();
public:
PromotionInfo() :
_tracking(0), _space(NULL),
_promoHead(NULL), _promoTail(NULL),
_spoolHead(NULL), _spoolTail(NULL),
_spareSpool(NULL), _firstIndex(1),
_nextIndex(1) {}
bool noPromotions() const {
assert(_promoHead != NULL || _promoTail == NULL, "list inconsistency");
return _promoHead == NULL;
}
void startTrackingPromotions();
void stopTrackingPromotions(uint worker_id = 0);
bool tracking() const { return _tracking; }
void track(PromotedObject* trackOop); // keep track of a promoted oop
// The following variant must be used when trackOop is not fully
// initialized and has a NULL klass:
void track(PromotedObject* trackOop, klassOop klassOfOop); // keep track of a promoted oop
void setSpace(CompactibleFreeListSpace* sp) { _space = sp; }
CompactibleFreeListSpace* space() const { return _space; }
markOop nextDisplacedHeader(); // get next header & forward spool pointer
void saveDisplacedHeader(markOop hdr);
// save header and forward spool
inline size_t refillSize() const;
SpoolBlock* getSpoolBlock(); // return a free spooling block
inline bool has_spooling_space() {
return _spoolTail != NULL && _spoolTail->bufferSize > _nextIndex;
}
// ensure that spooling space exists
bool ensure_spooling_space() {
return has_spooling_space() || ensure_spooling_space_work();
}
#define PROMOTED_OOPS_ITERATE_DECL(OopClosureType, nv_suffix) \
void promoted_oops_iterate##nv_suffix(OopClosureType* cl);
ALL_SINCE_SAVE_MARKS_CLOSURES(PROMOTED_OOPS_ITERATE_DECL)
#undef PROMOTED_OOPS_ITERATE_DECL
void promoted_oops_iterate(OopsInGenClosure* cl) {
promoted_oops_iterate_v(cl);
}
void verify() const;
void reset() {
_promoHead = NULL;
_promoTail = NULL;
_spoolHead = NULL;
_spoolTail = NULL;
_spareSpool = NULL;
_firstIndex = 0;
_nextIndex = 0;
}
void print_on(outputStream* st) const;
void print_statistics(uint worker_id) const;
};
#endif // SHARE_VM_GC_IMPLEMENTATION_CONCURRENTMARKSWEEP_PROMOTIONINFO_HPP