< prev index next > src/hotspot/share/gc/shared/space.cpp
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#include "classfile/vmSymbols.hpp"
#include "gc/shared/blockOffsetTable.inline.hpp"
#include "gc/shared/collectedHeap.inline.hpp"
#include "gc/shared/genCollectedHeap.hpp"
#include "gc/shared/genOopClosures.inline.hpp"
+ #include "gc/shared/slidingForwarding.inline.hpp"
#include "gc/shared/space.hpp"
#include "gc/shared/space.inline.hpp"
#include "gc/shared/spaceDecorator.inline.hpp"
#include "memory/iterator.inline.hpp"
#include "memory/universe.hpp"
Space::clear(mangle_space);
_compaction_top = bottom();
}
HeapWord* CompactibleSpace::forward(oop q, size_t size,
! CompactPoint* cp, HeapWord* compact_top) {
// q is alive
// First check if we should switch compaction space
assert(this == cp->space, "'this' should be current compaction space.");
size_t compaction_max_size = pointer_delta(end(), compact_top);
while (size > compaction_max_size) {
Space::clear(mangle_space);
_compaction_top = bottom();
}
HeapWord* CompactibleSpace::forward(oop q, size_t size,
! CompactPoint* cp, HeapWord* compact_top, SlidingForwarding* const forwarding) {
// q is alive
// First check if we should switch compaction space
assert(this == cp->space, "'this' should be current compaction space.");
size_t compaction_max_size = pointer_delta(end(), compact_top);
while (size > compaction_max_size) {
compaction_max_size = pointer_delta(cp->space->end(), compact_top);
}
// store the forwarding pointer into the mark word
if (cast_from_oop<HeapWord*>(q) != compact_top) {
! q->forward_to(cast_to_oop(compact_top));
assert(q->is_gc_marked(), "encoding the pointer should preserve the mark");
} else {
// if the object isn't moving we can just set the mark to the default
// mark and handle it specially later on.
q->init_mark();
compaction_max_size = pointer_delta(cp->space->end(), compact_top);
}
// store the forwarding pointer into the mark word
if (cast_from_oop<HeapWord*>(q) != compact_top) {
! forwarding->forward_to(q, cast_to_oop(compact_top));
assert(q->is_gc_marked(), "encoding the pointer should preserve the mark");
} else {
// if the object isn't moving we can just set the mark to the default
// mark and handle it specially later on.
q->init_mark();
const intx interval = PrefetchScanIntervalInBytes;
HeapWord* cur_obj = bottom();
HeapWord* scan_limit = top();
while (cur_obj < scan_limit) {
if (cast_to_oop(cur_obj)->is_gc_marked()) {
// prefetch beyond cur_obj
Prefetch::write(cur_obj, interval);
size_t size = cast_to_oop(cur_obj)->size();
! compact_top = cp->space->forward(cast_to_oop(cur_obj), size, cp, compact_top);
cur_obj += size;
end_of_live = cur_obj;
} else {
// run over all the contiguous dead objects
HeapWord* end = cur_obj;
const intx interval = PrefetchScanIntervalInBytes;
HeapWord* cur_obj = bottom();
HeapWord* scan_limit = top();
+ SlidingForwarding* const forwarding = GenCollectedHeap::heap()->forwarding();
while (cur_obj < scan_limit) {
if (cast_to_oop(cur_obj)->is_gc_marked()) {
// prefetch beyond cur_obj
Prefetch::write(cur_obj, interval);
size_t size = cast_to_oop(cur_obj)->size();
! compact_top = cp->space->forward(cast_to_oop(cur_obj), size, cp, compact_top, forwarding);
cur_obj += size;
end_of_live = cur_obj;
} else {
// run over all the contiguous dead objects
HeapWord* end = cur_obj;
// see if we might want to pretend this object is alive so that
// we don't have to compact quite as often.
if (cur_obj == compact_top && dead_spacer.insert_deadspace(cur_obj, end)) {
oop obj = cast_to_oop(cur_obj);
! compact_top = cp->space->forward(obj, obj->size(), cp, compact_top);
end_of_live = end;
} else {
// otherwise, it really is a free region.
// cur_obj is a pointer to a dead object. Use this dead memory to store a pointer to the next live object.
// see if we might want to pretend this object is alive so that
// we don't have to compact quite as often.
if (cur_obj == compact_top && dead_spacer.insert_deadspace(cur_obj, end)) {
oop obj = cast_to_oop(cur_obj);
! compact_top = cp->space->forward(obj, obj->size(), cp, compact_top, forwarding);
end_of_live = end;
} else {
// otherwise, it really is a free region.
// cur_obj is a pointer to a dead object. Use this dead memory to store a pointer to the next live object.
// Used by MarkSweep::mark_sweep_phase3()
HeapWord* cur_obj = bottom();
HeapWord* const end_of_live = _end_of_live; // Established by prepare_for_compaction().
HeapWord* const first_dead = _first_dead; // Established by prepare_for_compaction().
+ const SlidingForwarding* const forwarding = GenCollectedHeap::heap()->forwarding();
assert(first_dead <= end_of_live, "Stands to reason, no?");
const intx interval = PrefetchScanIntervalInBytes;
while (cur_obj < end_of_live) {
Prefetch::write(cur_obj, interval);
if (cur_obj < first_dead || cast_to_oop(cur_obj)->is_gc_marked()) {
// cur_obj is alive
// point all the oops to the new location
! size_t size = MarkSweep::adjust_pointers(cast_to_oop(cur_obj));
debug_only(prev_obj = cur_obj);
cur_obj += size;
} else {
debug_only(prev_obj = cur_obj);
// cur_obj is not a live object, instead it points at the next live object
while (cur_obj < end_of_live) {
Prefetch::write(cur_obj, interval);
if (cur_obj < first_dead || cast_to_oop(cur_obj)->is_gc_marked()) {
// cur_obj is alive
// point all the oops to the new location
! size_t size = MarkSweep::adjust_pointers(forwarding, cast_to_oop(cur_obj));
debug_only(prev_obj = cur_obj);
cur_obj += size;
} else {
debug_only(prev_obj = cur_obj);
// cur_obj is not a live object, instead it points at the next live object
// All object before _first_dead can be skipped. They should not be moved.
// A pointer to the first live object is stored at the memory location for _first_dead.
cur_obj = *(HeapWord**)(_first_dead);
}
+ const SlidingForwarding* const forwarding = GenCollectedHeap::heap()->forwarding();
+
debug_only(HeapWord* prev_obj = NULL);
while (cur_obj < end_of_live) {
if (!cast_to_oop(cur_obj)->is_forwarded()) {
debug_only(prev_obj = cur_obj);
// The first word of the dead object contains a pointer to the next live object or end of space.
// prefetch beyond q
Prefetch::read(cur_obj, scan_interval);
// size and destination
size_t size = cast_to_oop(cur_obj)->size();
! HeapWord* compaction_top = cast_from_oop<HeapWord*>(cast_to_oop(cur_obj)->forwardee());
// prefetch beyond compaction_top
Prefetch::write(compaction_top, copy_interval);
// copy object and reinit its mark
// prefetch beyond q
Prefetch::read(cur_obj, scan_interval);
// size and destination
size_t size = cast_to_oop(cur_obj)->size();
! HeapWord* compaction_top = cast_from_oop<HeapWord*>(forwarding->forwardee(cast_to_oop(cur_obj)));
// prefetch beyond compaction_top
Prefetch::write(compaction_top, copy_interval);
// copy object and reinit its mark
if (size >= align_object_size(array_header_size)) {
size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint));
// allocate uninitialized int array
typeArrayOop t = (typeArrayOop) cast_to_oop(allocate(size));
assert(t != NULL, "allocation should succeed");
! t->set_mark(markWord::prototype());
t->set_klass(Universe::intArrayKlassObj());
t->set_length((int)length);
} else {
assert(size == CollectedHeap::min_fill_size(),
"size for smallest fake object doesn't match");
instanceOop obj = (instanceOop) cast_to_oop(allocate(size));
! obj->set_mark(markWord::prototype());
obj->set_klass_gap(0);
obj->set_klass(vmClasses::Object_klass());
}
}
if (size >= align_object_size(array_header_size)) {
size_t length = (size - array_header_size) * (HeapWordSize / sizeof(jint));
// allocate uninitialized int array
typeArrayOop t = (typeArrayOop) cast_to_oop(allocate(size));
assert(t != NULL, "allocation should succeed");
! t->set_mark(Universe::intArrayKlassObj()->prototype_header());
t->set_klass(Universe::intArrayKlassObj());
t->set_length((int)length);
} else {
assert(size == CollectedHeap::min_fill_size(),
"size for smallest fake object doesn't match");
instanceOop obj = (instanceOop) cast_to_oop(allocate(size));
! obj->set_mark(vmClasses::Object_klass()->prototype_header());
obj->set_klass_gap(0);
obj->set_klass(vmClasses::Object_klass());
}
}
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