Java example source code file (heapRegion.cpp)
The heapRegion.cpp Java example source code/*
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#include "precompiled.hpp"
#include "code/nmethod.hpp"
#include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/g1OopClosures.inline.hpp"
#include "gc_implementation/g1/heapRegion.inline.hpp"
#include "gc_implementation/g1/heapRegionRemSet.hpp"
#include "gc_implementation/g1/heapRegionSeq.inline.hpp"
#include "memory/genOopClosures.inline.hpp"
#include "memory/iterator.hpp"
#include "oops/oop.inline.hpp"
int HeapRegion::LogOfHRGrainBytes = 0;
int HeapRegion::LogOfHRGrainWords = 0;
size_t HeapRegion::GrainBytes = 0;
size_t HeapRegion::GrainWords = 0;
size_t HeapRegion::CardsPerRegion = 0;
HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
HeapRegion* hr, ExtendedOopClosure* cl,
CardTableModRefBS::PrecisionStyle precision,
FilterKind fk) :
ContiguousSpaceDCTOC(hr, cl, precision, NULL),
_hr(hr), _fk(fk), _g1(g1) { }
FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
OopClosure* oc) :
_r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
template<class ClosureType>
HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
HeapRegion* hr,
HeapWord* cur, HeapWord* top) {
oop cur_oop = oop(cur);
int oop_size = cur_oop->size();
HeapWord* next_obj = cur + oop_size;
while (next_obj < top) {
// Keep filtering the remembered set.
if (!g1h->is_obj_dead(cur_oop, hr)) {
// Bottom lies entirely below top, so we can call the
// non-memRegion version of oop_iterate below.
cur_oop->oop_iterate(cl);
}
cur = next_obj;
cur_oop = oop(cur);
oop_size = cur_oop->size();
next_obj = cur + oop_size;
}
return cur;
}
void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
HeapWord* bottom,
HeapWord* top,
ExtendedOopClosure* cl) {
G1CollectedHeap* g1h = _g1;
int oop_size;
ExtendedOopClosure* cl2 = NULL;
FilterIntoCSClosure intoCSFilt(this, g1h, cl);
FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
switch (_fk) {
case NoFilterKind: cl2 = cl; break;
case IntoCSFilterKind: cl2 = &intoCSFilt; break;
case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
default: ShouldNotReachHere();
}
// Start filtering what we add to the remembered set. If the object is
// not considered dead, either because it is marked (in the mark bitmap)
// or it was allocated after marking finished, then we add it. Otherwise
// we can safely ignore the object.
if (!g1h->is_obj_dead(oop(bottom), _hr)) {
oop_size = oop(bottom)->oop_iterate(cl2, mr);
} else {
oop_size = oop(bottom)->size();
}
bottom += oop_size;
if (bottom < top) {
// We replicate the loop below for several kinds of possible filters.
switch (_fk) {
case NoFilterKind:
bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
break;
case IntoCSFilterKind: {
FilterIntoCSClosure filt(this, g1h, cl);
bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
break;
}
case OutOfRegionFilterKind: {
FilterOutOfRegionClosure filt(_hr, cl);
bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
break;
}
default:
ShouldNotReachHere();
}
// Last object. Need to do dead-obj filtering here too.
if (!g1h->is_obj_dead(oop(bottom), _hr)) {
oop(bottom)->oop_iterate(cl2, mr);
}
}
}
// Minimum region size; we won't go lower than that.
// We might want to decrease this in the future, to deal with small
// heaps a bit more efficiently.
#define MIN_REGION_SIZE ( 1024 * 1024 )
// Maximum region size; we don't go higher than that. There's a good
// reason for having an upper bound. We don't want regions to get too
// large, otherwise cleanup's effectiveness would decrease as there
// will be fewer opportunities to find totally empty regions after
// marking.
#define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
// The automatic region size calculation will try to have around this
// many regions in the heap (based on the min heap size).
#define TARGET_REGION_NUMBER 2048
size_t HeapRegion::max_region_size() {
return (size_t)MAX_REGION_SIZE;
}
void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
uintx region_size = G1HeapRegionSize;
if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
region_size = MAX2(average_heap_size / TARGET_REGION_NUMBER,
(uintx) MIN_REGION_SIZE);
}
int region_size_log = log2_long((jlong) region_size);
// Recalculate the region size to make sure it's a power of
// 2. This means that region_size is the largest power of 2 that's
// <= what we've calculated so far.
region_size = ((uintx)1 << region_size_log);
// Now make sure that we don't go over or under our limits.
if (region_size < MIN_REGION_SIZE) {
region_size = MIN_REGION_SIZE;
} else if (region_size > MAX_REGION_SIZE) {
region_size = MAX_REGION_SIZE;
}
// And recalculate the log.
region_size_log = log2_long((jlong) region_size);
// Now, set up the globals.
guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
LogOfHRGrainBytes = region_size_log;
guarantee(LogOfHRGrainWords == 0, "we should only set it once");
LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
guarantee(GrainBytes == 0, "we should only set it once");
// The cast to int is safe, given that we've bounded region_size by
// MIN_REGION_SIZE and MAX_REGION_SIZE.
GrainBytes = (size_t)region_size;
guarantee(GrainWords == 0, "we should only set it once");
GrainWords = GrainBytes >> LogHeapWordSize;
guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
guarantee(CardsPerRegion == 0, "we should only set it once");
CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
}
void HeapRegion::reset_after_compaction() {
G1OffsetTableContigSpace::reset_after_compaction();
// After a compaction the mark bitmap is invalid, so we must
// treat all objects as being inside the unmarked area.
zero_marked_bytes();
init_top_at_mark_start();
}
void HeapRegion::hr_clear(bool par, bool clear_space) {
assert(_humongous_type == NotHumongous,
"we should have already filtered out humongous regions");
assert(_humongous_start_region == NULL,
"we should have already filtered out humongous regions");
assert(_end == _orig_end,
"we should have already filtered out humongous regions");
_in_collection_set = false;
set_young_index_in_cset(-1);
uninstall_surv_rate_group();
set_young_type(NotYoung);
reset_pre_dummy_top();
if (!par) {
// If this is parallel, this will be done later.
HeapRegionRemSet* hrrs = rem_set();
hrrs->clear();
_claimed = InitialClaimValue;
}
zero_marked_bytes();
_offsets.resize(HeapRegion::GrainWords);
init_top_at_mark_start();
if (clear_space) clear(SpaceDecorator::Mangle);
}
void HeapRegion::par_clear() {
assert(used() == 0, "the region should have been already cleared");
assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
HeapRegionRemSet* hrrs = rem_set();
hrrs->clear();
CardTableModRefBS* ct_bs =
(CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
ct_bs->clear(MemRegion(bottom(), end()));
}
void HeapRegion::calc_gc_efficiency() {
// GC efficiency is the ratio of how much space would be
// reclaimed over how long we predict it would take to reclaim it.
G1CollectedHeap* g1h = G1CollectedHeap::heap();
G1CollectorPolicy* g1p = g1h->g1_policy();
// Retrieve a prediction of the elapsed time for this region for
// a mixed gc because the region will only be evacuated during a
// mixed gc.
double region_elapsed_time_ms =
g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
_gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
}
void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
assert(!isHumongous(), "sanity / pre-condition");
assert(end() == _orig_end,
"Should be normal before the humongous object allocation");
assert(top() == bottom(), "should be empty");
assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
_humongous_type = StartsHumongous;
_humongous_start_region = this;
set_end(new_end);
_offsets.set_for_starts_humongous(new_top);
}
void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
assert(!isHumongous(), "sanity / pre-condition");
assert(end() == _orig_end,
"Should be normal before the humongous object allocation");
assert(top() == bottom(), "should be empty");
assert(first_hr->startsHumongous(), "pre-condition");
_humongous_type = ContinuesHumongous;
_humongous_start_region = first_hr;
}
void HeapRegion::set_notHumongous() {
assert(isHumongous(), "pre-condition");
if (startsHumongous()) {
assert(top() <= end(), "pre-condition");
set_end(_orig_end);
if (top() > end()) {
// at least one "continues humongous" region after it
set_top(end());
}
} else {
// continues humongous
assert(end() == _orig_end, "sanity");
}
assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
_humongous_type = NotHumongous;
_humongous_start_region = NULL;
}
bool HeapRegion::claimHeapRegion(jint claimValue) {
jint current = _claimed;
if (current != claimValue) {
jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
if (res == current) {
return true;
}
}
return false;
}
HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
HeapWord* low = addr;
HeapWord* high = end();
while (low < high) {
size_t diff = pointer_delta(high, low);
// Must add one below to bias toward the high amount. Otherwise, if
// "high" were at the desired value, and "low" were one less, we
// would not converge on "high". This is not symmetric, because
// we set "high" to a block start, which might be the right one,
// which we don't do for "low".
HeapWord* middle = low + (diff+1)/2;
if (middle == high) return high;
HeapWord* mid_bs = block_start_careful(middle);
if (mid_bs < addr) {
low = middle;
} else {
high = mid_bs;
}
}
assert(low == high && low >= addr, "Didn't work.");
return low;
}
#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
#endif // _MSC_VER
HeapRegion::HeapRegion(uint hrs_index,
G1BlockOffsetSharedArray* sharedOffsetArray,
MemRegion mr) :
G1OffsetTableContigSpace(sharedOffsetArray, mr),
_hrs_index(hrs_index),
_humongous_type(NotHumongous), _humongous_start_region(NULL),
_in_collection_set(false),
_next_in_special_set(NULL), _orig_end(NULL),
_claimed(InitialClaimValue), _evacuation_failed(false),
_prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
_young_type(NotYoung), _next_young_region(NULL),
_next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
#ifdef ASSERT
_containing_set(NULL),
#endif // ASSERT
_young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
_rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
_predicted_bytes_to_copy(0)
{
_rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
_orig_end = mr.end();
// Note that initialize() will set the start of the unmarked area of the
// region.
hr_clear(false /*par*/, false /*clear_space*/);
set_top(bottom());
set_saved_mark();
assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
}
CompactibleSpace* HeapRegion::next_compaction_space() const {
// We're not using an iterator given that it will wrap around when
// it reaches the last region and this is not what we want here.
G1CollectedHeap* g1h = G1CollectedHeap::heap();
uint index = hrs_index() + 1;
while (index < g1h->n_regions()) {
HeapRegion* hr = g1h->region_at(index);
if (!hr->isHumongous()) {
return hr;
}
index += 1;
}
return NULL;
}
void HeapRegion::save_marks() {
set_saved_mark();
}
void HeapRegion::oops_in_mr_iterate(MemRegion mr, ExtendedOopClosure* cl) {
HeapWord* p = mr.start();
HeapWord* e = mr.end();
oop obj;
while (p < e) {
obj = oop(p);
p += obj->oop_iterate(cl);
}
assert(p == e, "bad memregion: doesn't end on obj boundary");
}
#define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
}
SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
void HeapRegion::oop_before_save_marks_iterate(ExtendedOopClosure* cl) {
oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
}
void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
bool during_conc_mark) {
// We always recreate the prev marking info and we'll explicitly
// mark all objects we find to be self-forwarded on the prev
// bitmap. So all objects need to be below PTAMS.
_prev_top_at_mark_start = top();
_prev_marked_bytes = 0;
if (during_initial_mark) {
// During initial-mark, we'll also explicitly mark all objects
// we find to be self-forwarded on the next bitmap. So all
// objects need to be below NTAMS.
_next_top_at_mark_start = top();
_next_marked_bytes = 0;
} else if (during_conc_mark) {
// During concurrent mark, all objects in the CSet (including
// the ones we find to be self-forwarded) are implicitly live.
// So all objects need to be above NTAMS.
_next_top_at_mark_start = bottom();
_next_marked_bytes = 0;
}
}
void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
bool during_conc_mark,
size_t marked_bytes) {
assert(0 <= marked_bytes && marked_bytes <= used(),
err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
marked_bytes, used()));
_prev_marked_bytes = marked_bytes;
}
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;
}
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;
}
// Code roots support
void HeapRegion::add_strong_code_root(nmethod* nm) {
HeapRegionRemSet* hrrs = rem_set();
hrrs->add_strong_code_root(nm);
}
void HeapRegion::remove_strong_code_root(nmethod* nm) {
HeapRegionRemSet* hrrs = rem_set();
hrrs->remove_strong_code_root(nm);
}
void HeapRegion::migrate_strong_code_roots() {
assert(in_collection_set(), "only collection set regions");
assert(!isHumongous(),
err_msg("humongous region "HR_FORMAT" should not have been added to collection set",
HR_FORMAT_PARAMS(this)));
HeapRegionRemSet* hrrs = rem_set();
hrrs->migrate_strong_code_roots();
}
void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
HeapRegionRemSet* hrrs = rem_set();
hrrs->strong_code_roots_do(blk);
}
class VerifyStrongCodeRootOopClosure: public OopClosure {
const HeapRegion* _hr;
nmethod* _nm;
bool _failures;
bool _has_oops_in_region;
template <class T> void do_oop_work(T* p) {
T heap_oop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(heap_oop)) {
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
// Note: not all the oops embedded in the nmethod are in the
// current region. We only look at those which are.
if (_hr->is_in(obj)) {
// Object is in the region. Check that its less than top
if (_hr->top() <= (HeapWord*)obj) {
// Object is above top
gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
"["PTR_FORMAT", "PTR_FORMAT") is above "
"top "PTR_FORMAT,
(void *)obj, _hr->bottom(), _hr->end(), _hr->top());
_failures = true;
return;
}
// Nmethod has at least one oop in the current region
_has_oops_in_region = true;
}
}
}
public:
VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
_hr(hr), _failures(false), _has_oops_in_region(false) {}
void do_oop(narrowOop* p) { do_oop_work(p); }
void do_oop(oop* p) { do_oop_work(p); }
bool failures() { return _failures; }
bool has_oops_in_region() { return _has_oops_in_region; }
};
class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
const HeapRegion* _hr;
bool _failures;
public:
VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
_hr(hr), _failures(false) {}
void do_code_blob(CodeBlob* cb) {
nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
if (nm != NULL) {
// Verify that the nemthod is live
if (!nm->is_alive()) {
gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
PTR_FORMAT" in its strong code roots",
_hr->bottom(), _hr->end(), nm);
_failures = true;
} else {
VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
nm->oops_do(&oop_cl);
if (!oop_cl.has_oops_in_region()) {
gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
PTR_FORMAT" in its strong code roots "
"with no pointers into region",
_hr->bottom(), _hr->end(), nm);
_failures = true;
} else if (oop_cl.failures()) {
gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
"failures for nmethod "PTR_FORMAT,
_hr->bottom(), _hr->end(), nm);
_failures = true;
}
}
}
}
bool failures() { return _failures; }
};
void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
if (!G1VerifyHeapRegionCodeRoots) {
// We're not verifying code roots.
return;
}
if (vo == VerifyOption_G1UseMarkWord) {
// Marking verification during a full GC is performed after class
// unloading, code cache unloading, etc so the strong code roots
// attached to each heap region are in an inconsistent state. They won't
// be consistent until the strong code roots are rebuilt after the
// actual GC. Skip verifying the strong code roots in this particular
// time.
assert(VerifyDuringGC, "only way to get here");
return;
}
HeapRegionRemSet* hrrs = rem_set();
int strong_code_roots_length = hrrs->strong_code_roots_list_length();
// if this region is empty then there should be no entries
// on its strong code root list
if (is_empty()) {
if (strong_code_roots_length > 0) {
gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
"but has "INT32_FORMAT" code root entries",
bottom(), end(), strong_code_roots_length);
*failures = true;
}
return;
}
if (continuesHumongous()) {
if (strong_code_roots_length > 0) {
gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous "
"region but has "INT32_FORMAT" code root entries",
HR_FORMAT_PARAMS(this), strong_code_roots_length);
*failures = true;
}
return;
}
VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
strong_code_roots_do(&cb_cl);
if (cb_cl.failures()) {
*failures = true;
}
}
void HeapRegion::print() const { print_on(gclog_or_tty); }
void HeapRegion::print_on(outputStream* st) const {
if (isHumongous()) {
if (startsHumongous())
st->print(" HS");
else
st->print(" HC");
} else {
st->print(" ");
}
if (in_collection_set())
st->print(" CS");
else
st->print(" ");
if (is_young())
st->print(is_survivor() ? " SU" : " Y ");
else
st->print(" ");
if (is_empty())
st->print(" F");
else
st->print(" ");
st->print(" TS %5d", _gc_time_stamp);
st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
prev_top_at_mark_start(), next_top_at_mark_start());
G1OffsetTableContigSpace::print_on(st);
}
class VerifyLiveClosure: public OopClosure {
private:
G1CollectedHeap* _g1h;
CardTableModRefBS* _bs;
oop _containing_obj;
bool _failures;
int _n_failures;
VerifyOption _vo;
public:
// _vo == UsePrevMarking -> use "prev" marking information,
// _vo == UseNextMarking -> use "next" marking information,
// _vo == UseMarkWord -> use mark word from object header.
VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
_g1h(g1h), _bs(NULL), _containing_obj(NULL),
_failures(false), _n_failures(0), _vo(vo)
{
BarrierSet* bs = _g1h->barrier_set();
if (bs->is_a(BarrierSet::CardTableModRef))
_bs = (CardTableModRefBS*)bs;
}
void set_containing_obj(oop obj) {
_containing_obj = obj;
}
bool failures() { return _failures; }
int n_failures() { return _n_failures; }
virtual void do_oop(narrowOop* p) { do_oop_work(p); }
virtual void do_oop( oop* p) { do_oop_work(p); }
void print_object(outputStream* out, oop obj) {
#ifdef PRODUCT
Klass* k = obj->klass();
const char* class_name = InstanceKlass::cast(k)->external_name();
out->print_cr("class name %s", class_name);
#else // PRODUCT
obj->print_on(out);
#endif // PRODUCT
}
template <class T>
void do_oop_work(T* p) {
assert(_containing_obj != NULL, "Precondition");
assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
"Precondition");
T heap_oop = oopDesc::load_heap_oop(p);
if (!oopDesc::is_null(heap_oop)) {
oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
bool failed = false;
if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
MutexLockerEx x(ParGCRareEvent_lock,
Mutex::_no_safepoint_check_flag);
if (!_failures) {
gclog_or_tty->print_cr("");
gclog_or_tty->print_cr("----------");
}
if (!_g1h->is_in_closed_subset(obj)) {
HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
gclog_or_tty->print_cr("Field "PTR_FORMAT
" of live obj "PTR_FORMAT" in region "
"["PTR_FORMAT", "PTR_FORMAT")",
p, (void*) _containing_obj,
from->bottom(), from->end());
print_object(gclog_or_tty, _containing_obj);
gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
(void*) obj);
} else {
HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
gclog_or_tty->print_cr("Field "PTR_FORMAT
" of live obj "PTR_FORMAT" in region "
"["PTR_FORMAT", "PTR_FORMAT")",
p, (void*) _containing_obj,
from->bottom(), from->end());
print_object(gclog_or_tty, _containing_obj);
gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
"["PTR_FORMAT", "PTR_FORMAT")",
(void*) obj, to->bottom(), to->end());
print_object(gclog_or_tty, obj);
}
gclog_or_tty->print_cr("----------");
gclog_or_tty->flush();
_failures = true;
failed = true;
_n_failures++;
}
if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
HeapRegion* to = _g1h->heap_region_containing(obj);
if (from != NULL && to != NULL &&
from != to &&
!to->isHumongous()) {
jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
jbyte cv_field = *_bs->byte_for_const(p);
const jbyte dirty = CardTableModRefBS::dirty_card_val();
bool is_bad = !(from->is_young()
|| to->rem_set()->contains_reference(p)
|| !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
(_containing_obj->is_objArray() ?
cv_field == dirty
: cv_obj == dirty || cv_field == dirty));
if (is_bad) {
MutexLockerEx x(ParGCRareEvent_lock,
Mutex::_no_safepoint_check_flag);
if (!_failures) {
gclog_or_tty->print_cr("");
gclog_or_tty->print_cr("----------");
}
gclog_or_tty->print_cr("Missing rem set entry:");
gclog_or_tty->print_cr("Field "PTR_FORMAT" "
"of obj "PTR_FORMAT", "
"in region "HR_FORMAT,
p, (void*) _containing_obj,
HR_FORMAT_PARAMS(from));
_containing_obj->print_on(gclog_or_tty);
gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
"in region "HR_FORMAT,
(void*) obj,
HR_FORMAT_PARAMS(to));
obj->print_on(gclog_or_tty);
gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
cv_obj, cv_field);
gclog_or_tty->print_cr("----------");
gclog_or_tty->flush();
_failures = true;
if (!failed) _n_failures++;
}
}
}
}
}
};
// This really ought to be commoned up into OffsetTableContigSpace somehow.
// We would need a mechanism to make that code skip dead objects.
void HeapRegion::verify(VerifyOption vo,
bool* failures) const {
G1CollectedHeap* g1 = G1CollectedHeap::heap();
*failures = false;
HeapWord* p = bottom();
HeapWord* prev_p = NULL;
VerifyLiveClosure vl_cl(g1, vo);
bool is_humongous = isHumongous();
bool do_bot_verify = !is_young();
size_t object_num = 0;
while (p < top()) {
oop obj = oop(p);
size_t obj_size = obj->size();
object_num += 1;
if (is_humongous != g1->isHumongous(obj_size)) {
gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
SIZE_FORMAT" words) in a %shumongous region",
p, g1->isHumongous(obj_size) ? "" : "non-",
obj_size, is_humongous ? "" : "non-");
*failures = true;
return;
}
// If it returns false, verify_for_object() will output the
// appropriate messasge.
if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) {
*failures = true;
return;
}
if (!g1->is_obj_dead_cond(obj, this, vo)) {
if (obj->is_oop()) {
Klass* klass = obj->klass();
if (!klass->is_metaspace_object()) {
gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
"not metadata", klass, (void *)obj);
*failures = true;
return;
} else if (!klass->is_klass()) {
gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
"not a klass", klass, (void *)obj);
*failures = true;
return;
} else {
vl_cl.set_containing_obj(obj);
obj->oop_iterate_no_header(&vl_cl);
if (vl_cl.failures()) {
*failures = true;
}
if (G1MaxVerifyFailures >= 0 &&
vl_cl.n_failures() >= G1MaxVerifyFailures) {
return;
}
}
} else {
gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
*failures = true;
return;
}
}
prev_p = p;
p += obj_size;
}
if (p != top()) {
gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
"does not match top "PTR_FORMAT, p, top());
*failures = true;
return;
}
HeapWord* the_end = end();
assert(p == top(), "it should still hold");
// Do some extra BOT consistency checking for addresses in the
// range [top, end). BOT look-ups in this range should yield
// top. No point in doing that if top == end (there's nothing there).
if (p < the_end) {
// Look up top
HeapWord* addr_1 = p;
HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
if (b_start_1 != p) {
gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
" yielded "PTR_FORMAT", expecting "PTR_FORMAT,
addr_1, b_start_1, p);
*failures = true;
return;
}
// Look up top + 1
HeapWord* addr_2 = p + 1;
if (addr_2 < the_end) {
HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
if (b_start_2 != p) {
gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
" yielded "PTR_FORMAT", expecting "PTR_FORMAT,
addr_2, b_start_2, p);
*failures = true;
return;
}
}
// Look up an address between top and end
size_t diff = pointer_delta(the_end, p) / 2;
HeapWord* addr_3 = p + diff;
if (addr_3 < the_end) {
HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
if (b_start_3 != p) {
gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
" yielded "PTR_FORMAT", expecting "PTR_FORMAT,
addr_3, b_start_3, p);
*failures = true;
return;
}
}
// Loook up end - 1
HeapWord* addr_4 = the_end - 1;
HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
if (b_start_4 != p) {
gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
" yielded "PTR_FORMAT", expecting "PTR_FORMAT,
addr_4, b_start_4, p);
*failures = true;
return;
}
}
if (is_humongous && object_num > 1) {
gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
"but has "SIZE_FORMAT", objects",
bottom(), end(), object_num);
*failures = true;
return;
}
verify_strong_code_roots(vo, failures);
}
void HeapRegion::verify() const {
bool dummy = false;
verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
}
// G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
// away eventually.
void G1OffsetTableContigSpace::clear(bool mangle_space) {
ContiguousSpace::clear(mangle_space);
_offsets.zero_bottom_entry();
_offsets.initialize_threshold();
}
void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
Space::set_bottom(new_bottom);
_offsets.set_bottom(new_bottom);
}
void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
Space::set_end(new_end);
_offsets.resize(new_end - bottom());
}
void G1OffsetTableContigSpace::print() const {
print_short();
gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
INTPTR_FORMAT ", " INTPTR_FORMAT ")",
bottom(), top(), _offsets.threshold(), end());
}
HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
return _offsets.initialize_threshold();
}
HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
HeapWord* end) {
_offsets.alloc_block(start, end);
return _offsets.threshold();
}
HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
if (_gc_time_stamp < g1h->get_gc_time_stamp())
return top();
else
return ContiguousSpace::saved_mark_word();
}
void G1OffsetTableContigSpace::set_saved_mark() {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
if (_gc_time_stamp < curr_gc_time_stamp) {
// The order of these is important, as another thread might be
// about to start scanning this region. If it does so after
// set_saved_mark and before _gc_time_stamp = ..., then the latter
// will be false, and it will pick up top() as the high water mark
// of region. If it does so after _gc_time_stamp = ..., then it
// will pick up the right saved_mark_word() as the high water mark
// of the region. Either way, the behaviour will be correct.
ContiguousSpace::set_saved_mark();
OrderAccess::storestore();
_gc_time_stamp = curr_gc_time_stamp;
// No need to do another barrier to flush the writes above. If
// this is called in parallel with other threads trying to
// allocate into the region, the caller should call this while
// holding a lock and when the lock is released the writes will be
// flushed.
}
}
G1OffsetTableContigSpace::
G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
MemRegion mr) :
_offsets(sharedOffsetArray, mr),
_par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
_gc_time_stamp(0)
{
_offsets.set_space(this);
// false ==> we'll do the clearing if there's clearing to be done.
ContiguousSpace::initialize(mr, false, SpaceDecorator::Mangle);
_offsets.zero_bottom_entry();
_offsets.initialize_threshold();
}
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