HeapWord*
HeapRegion::object_iterate_mem_careful(MemRegion mr,
ObjectClosure* cl) {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// We used to use "block_start_careful" here. But we're actually happy
// to update the BOT while we do this...
HeapWord* cur = block_start(mr.start());
mr = mr.intersection(used_region());
if (mr.is_empty()) return NULL;
// Otherwise, find the obj that extends onto mr.start().
assert(cur <= mr.start()
&& (oop(cur)->klass_or_null() == NULL ||
cur + oop(cur)->size() > mr.start()),
"postcondition of block_start");
oop obj;
while (cur < mr.end()) {
obj = oop(cur);
if (obj->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
} else if (!g1h->is_obj_dead(obj)) {
cl->do_object(obj);
}
if (cl->abort()) return cur;
// The check above must occur before the operation below, since an
// abort might invalidate the "size" operation.
cur += obj->size();
}
return NULL;
}
void ContiguousSpace::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
assert(!mr.is_empty(), "Should be non-empty");
assert(used_region().contains(mr), "Should be within used space");
HeapWord* prev = cl->previous(); // max address from last time
if (prev >= mr.end()) { // nothing to do
return;
}
// See comment above (in more general method above) in case you
// happen to use this method.
assert(prev == NULL || is_in_reserved(prev), "Should be within space");
bool last_was_obj_array = false;
HeapWord *obj_start_addr, *region_start_addr;
if (prev > mr.start()) {
region_start_addr = prev;
obj_start_addr = prev;
assert(obj_start_addr == block_start(region_start_addr), "invariant");
} else {
region_start_addr = mr.start();
obj_start_addr = block_start(region_start_addr);
}
HeapWord* region_end_addr = mr.end();
MemRegion derived_mr(region_start_addr, region_end_addr);
while (obj_start_addr < region_end_addr) {
oop obj = oop(obj_start_addr);
const size_t size = obj->size();
last_was_obj_array = cl->do_object_bm(obj, derived_mr);
obj_start_addr += size;
}
if (!last_was_obj_array) {
assert((bottom() <= obj_start_addr) && (obj_start_addr <= end()),
"Should be within (closed) used space");
assert(obj_start_addr > prev, "Invariant");
cl->set_previous(obj_start_addr); // min address for next time
}
}
HeapWord*
HeapRegion::
oops_on_card_seq_iterate_careful(MemRegion mr,
FilterOutOfRegionClosure* cl,
bool filter_young) {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// If we're within a stop-world GC, then we might look at a card in a
// GC alloc region that extends onto a GC LAB, which may not be
// parseable. Stop such at the "saved_mark" of the region.
if (G1CollectedHeap::heap()->is_gc_active()) {
mr = mr.intersection(used_region_at_save_marks());
} else {
mr = mr.intersection(used_region());
}
if (mr.is_empty()) return NULL;
// Otherwise, find the obj that extends onto mr.start().
// The intersection of the incoming mr (for the card) and the
// allocated part of the region is non-empty. This implies that
// we have actually allocated into this region. The code in
// G1CollectedHeap.cpp that allocates a new region sets the
// is_young tag on the region before allocating. Thus we
// safely know if this region is young.
if (is_young() && filter_young) {
return NULL;
}
assert(!is_young(), "check value of filter_young");
// We used to use "block_start_careful" here. But we're actually happy
// to update the BOT while we do this...
HeapWord* cur = block_start(mr.start());
assert(cur <= mr.start(), "Postcondition");
while (cur <= mr.start()) {
if (oop(cur)->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
}
// Otherwise...
int sz = oop(cur)->size();
if (cur + sz > mr.start()) break;
// Otherwise, go on.
cur = cur + sz;
}
oop obj;
obj = oop(cur);
// If we finish this loop...
assert(cur <= mr.start()
&& obj->klass_or_null() != NULL
&& cur + obj->size() > mr.start(),
"Loop postcondition");
if (!g1h->is_obj_dead(obj)) {
obj->oop_iterate(cl, mr);
}
HeapWord* next;
while (cur < mr.end()) {
obj = oop(cur);
if (obj->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
};
// Otherwise:
next = (cur + obj->size());
if (!g1h->is_obj_dead(obj)) {
if (next < mr.end()) {
obj->oop_iterate(cl);
} else {
// this obj spans the boundary. If it's an array, stop at the
// boundary.
if (obj->is_objArray()) {
obj->oop_iterate(cl, mr);
} else {
obj->oop_iterate(cl);
}
}
}
cur = next;
}
return NULL;
}
// Objects in this generation may have moved, invalidate this
// generation's cards.
void CardGeneration::invalidate_remembered_set() {
_rs->invalidate(used_region());
}
HeapWord*
HeapRegion::
oops_on_card_seq_iterate_careful(MemRegion mr,
FilterOutOfRegionClosure* cl,
bool filter_young,
jbyte* card_ptr) {
// Currently, we should only have to clean the card if filter_young
// is true and vice versa.
if (filter_young) {
assert(card_ptr != NULL, "pre-condition");
} else {
assert(card_ptr == NULL, "pre-condition");
}
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// If we're within a stop-world GC, then we might look at a card in a
// GC alloc region that extends onto a GC LAB, which may not be
// parseable. Stop such at the "saved_mark" of the region.
if (g1h->is_gc_active()) {
mr = mr.intersection(used_region_at_save_marks());
} else {
mr = mr.intersection(used_region());
}
if (mr.is_empty()) return NULL;
// Otherwise, find the obj that extends onto mr.start().
// The intersection of the incoming mr (for the card) and the
// allocated part of the region is non-empty. This implies that
// we have actually allocated into this region. The code in
// G1CollectedHeap.cpp that allocates a new region sets the
// is_young tag on the region before allocating. Thus we
// safely know if this region is young.
if (is_young() && filter_young) {
return NULL;
}
assert(!is_young(), "check value of filter_young");
// We can only clean the card here, after we make the decision that
// the card is not young. And we only clean the card if we have been
// asked to (i.e., card_ptr != NULL).
if (card_ptr != NULL) {
*card_ptr = CardTableModRefBS::clean_card_val();
// We must complete this write before we do any of the reads below.
OrderAccess::storeload();
}
// Cache the boundaries of the memory region in some const locals
HeapWord* const start = mr.start();
HeapWord* const end = mr.end();
// We used to use "block_start_careful" here. But we're actually happy
// to update the BOT while we do this...
HeapWord* cur = block_start(start);
assert(cur <= start, "Postcondition");
oop obj;
HeapWord* next = cur;
while (next <= start) {
cur = next;
obj = oop(cur);
if (obj->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
}
// Otherwise...
next = (cur + obj->size());
}
// If we finish the above loop...We have a parseable object that
// begins on or before the start of the memory region, and ends
// inside or spans the entire region.
assert(obj == oop(cur), "sanity");
assert(cur <= start &&
obj->klass_or_null() != NULL &&
(cur + obj->size()) > start,
"Loop postcondition");
if (!g1h->is_obj_dead(obj)) {
obj->oop_iterate(cl, mr);
}
while (cur < end) {
obj = oop(cur);
if (obj->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
};
// Otherwise:
next = (cur + obj->size());
if (!g1h->is_obj_dead(obj)) {
if (next < end || !obj->is_objArray()) {
// This object either does not span the MemRegion
// boundary, or if it does it's not an array.
// Apply closure to whole object.
obj->oop_iterate(cl);
} else {
// This obj is an array that spans the boundary.
// Stop at the boundary.
obj->oop_iterate(cl, mr);
}
}
cur = next;
}
return NULL;
}
HeapWord*
HeapRegion::
oops_on_card_seq_iterate_careful(MemRegion mr,
FilterOutOfRegionClosure* cl,
bool filter_young,
jbyte* card_ptr) {
// Currently, we should only have to clean the card if filter_young
// is true and vice versa.
if (filter_young) {
assert(card_ptr != NULL, "pre-condition");
} else {
assert(card_ptr == NULL, "pre-condition");
}
G1CollectedHeap* g1h = G1CollectedHeap::heap();
// If we're within a stop-world GC, then we might look at a card in a
// GC alloc region that extends onto a GC LAB, which may not be
// parseable. Stop such at the "scan_top" of the region.
if (g1h->is_gc_active()) {
mr = mr.intersection(MemRegion(bottom(), scan_top()));
} else {
mr = mr.intersection(used_region());
}
if (mr.is_empty()) return NULL;
// Otherwise, find the obj that extends onto mr.start().
// The intersection of the incoming mr (for the card) and the
// allocated part of the region is non-empty. This implies that
// we have actually allocated into this region. The code in
// G1CollectedHeap.cpp that allocates a new region sets the
// is_young tag on the region before allocating. Thus we
// safely know if this region is young.
if (is_young() && filter_young) {
return NULL;
}
assert(!is_young(), "check value of filter_young");
// We can only clean the card here, after we make the decision that
// the card is not young. And we only clean the card if we have been
// asked to (i.e., card_ptr != NULL).
if (card_ptr != NULL) {
*card_ptr = CardTableModRefBS::clean_card_val();
// We must complete this write before we do any of the reads below.
OrderAccess::storeload();
}
// Cache the boundaries of the memory region in some const locals
HeapWord* const start = mr.start();
HeapWord* const end = mr.end();
// We used to use "block_start_careful" here. But we're actually happy
// to update the BOT while we do this...
HeapWord* cur = block_start(start);
assert(cur <= start, "Postcondition");
oop obj;
HeapWord* next = cur;
do {
cur = next;
obj = oop(cur);
if (obj->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
}
// Otherwise...
next = cur + block_size(cur);
} while (next <= start);
// If we finish the above loop...We have a parseable object that
// begins on or before the start of the memory region, and ends
// inside or spans the entire region.
assert(cur <= start, "Loop postcondition");
assert(obj->klass_or_null() != NULL, "Loop postcondition");
do {
obj = oop(cur);
assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
if (obj->klass_or_null() == NULL) {
// Ran into an unparseable point.
return cur;
}
// Advance the current pointer. "obj" still points to the object to iterate.
cur = cur + block_size(cur);
if (!g1h->is_obj_dead(obj)) {
// Non-objArrays are sometimes marked imprecise at the object start. We
// always need to iterate over them in full.
// We only iterate over object arrays in full if they are completely contained
// in the memory region.
if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
obj->oop_iterate(cl);
} else {
obj->oop_iterate(cl, mr);
}
}
} while (cur < end);
return NULL;
}
// Returns true iff the given the space contains the
// given address as part of an allocated object. For
// certain kinds of spaces, this might be a potentially
// expensive operation. To prevent performance problems
// on account of its inadvertent use in product jvm's,
// we restrict its use to assertion checks only.
bool is_in(const void* p) const {
return used_region().contains(p);
}
