8071913: Filter out entries to free/uncommitted regions during iteration
Reviewed-by: sjohanss, kbarrett
/*
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#ifndef SHARE_VM_GC_G1_G1COLLECTEDHEAP_INLINE_HPP
#define SHARE_VM_GC_G1_G1COLLECTEDHEAP_INLINE_HPP
#include "gc/g1/g1BarrierSet.hpp"
#include "gc/g1/g1CollectedHeap.hpp"
#include "gc/g1/g1CollectorState.hpp"
#include "gc/g1/g1ConcurrentMark.inline.hpp"
#include "gc/g1/heapRegionManager.inline.hpp"
#include "gc/g1/heapRegionSet.inline.hpp"
#include "gc/shared/taskqueue.hpp"
#include "runtime/orderAccess.hpp"
G1EvacStats* G1CollectedHeap::alloc_buffer_stats(InCSetState dest) {
switch (dest.value()) {
case InCSetState::Young:
return &_survivor_evac_stats;
case InCSetState::Old:
return &_old_evac_stats;
default:
ShouldNotReachHere();
return NULL; // Keep some compilers happy
}
}
size_t G1CollectedHeap::desired_plab_sz(InCSetState dest) {
size_t gclab_word_size = alloc_buffer_stats(dest)->desired_plab_sz(workers()->active_workers());
// Prevent humongous PLAB sizes for two reasons:
// * PLABs are allocated using a similar paths as oops, but should
// never be in a humongous region
// * Allowing humongous PLABs needlessly churns the region free lists
return MIN2(_humongous_object_threshold_in_words, gclab_word_size);
}
// Inline functions for G1CollectedHeap
// Return the region with the given index. It assumes the index is valid.
inline HeapRegion* G1CollectedHeap::region_at(uint index) const { return _hrm.at(index); }
// Return the region with the given index, or NULL if unmapped. It assumes the index is valid.
inline HeapRegion* G1CollectedHeap::region_at_or_null(uint index) const { return _hrm.at_or_null(index); }
inline HeapRegion* G1CollectedHeap::next_region_in_humongous(HeapRegion* hr) const {
return _hrm.next_region_in_humongous(hr);
}
inline uint G1CollectedHeap::addr_to_region(HeapWord* addr) const {
assert(is_in_reserved(addr),
"Cannot calculate region index for address " PTR_FORMAT " that is outside of the heap [" PTR_FORMAT ", " PTR_FORMAT ")",
p2i(addr), p2i(reserved_region().start()), p2i(reserved_region().end()));
return (uint)(pointer_delta(addr, reserved_region().start(), sizeof(uint8_t)) >> HeapRegion::LogOfHRGrainBytes);
}
inline HeapWord* G1CollectedHeap::bottom_addr_for_region(uint index) const {
return _hrm.reserved().start() + index * HeapRegion::GrainWords;
}
template <class T>
inline HeapRegion* G1CollectedHeap::heap_region_containing(const T addr) const {
assert(addr != NULL, "invariant");
assert(is_in_g1_reserved((const void*) addr),
"Address " PTR_FORMAT " is outside of the heap ranging from [" PTR_FORMAT " to " PTR_FORMAT ")",
p2i((void*)addr), p2i(g1_reserved().start()), p2i(g1_reserved().end()));
return _hrm.addr_to_region((HeapWord*) addr);
}
template <class T>
inline HeapRegion* G1CollectedHeap::heap_region_containing_or_null(const T addr) const {
assert(addr != NULL, "invariant");
assert(is_in_g1_reserved((const void*) addr),
"Address " PTR_FORMAT " is outside of the heap ranging from [" PTR_FORMAT " to " PTR_FORMAT ")",
p2i((void*)addr), p2i(g1_reserved().start()), p2i(g1_reserved().end()));
uint const region_idx = addr_to_region(addr);
return region_at_or_null(region_idx);
}
inline void G1CollectedHeap::old_set_add(HeapRegion* hr) {
_old_set.add(hr);
}
inline void G1CollectedHeap::old_set_remove(HeapRegion* hr) {
_old_set.remove(hr);
}
inline void G1CollectedHeap::archive_set_add(HeapRegion* hr) {
_archive_set.add(hr);
}
// It dirties the cards that cover the block so that the post
// write barrier never queues anything when updating objects on this
// block. It is assumed (and in fact we assert) that the block
// belongs to a young region.
inline void
G1CollectedHeap::dirty_young_block(HeapWord* start, size_t word_size) {
assert_heap_not_locked();
// Assign the containing region to containing_hr so that we don't
// have to keep calling heap_region_containing() in the
// asserts below.
DEBUG_ONLY(HeapRegion* containing_hr = heap_region_containing(start);)
assert(word_size > 0, "pre-condition");
assert(containing_hr->is_in(start), "it should contain start");
assert(containing_hr->is_young(), "it should be young");
assert(!containing_hr->is_humongous(), "it should not be humongous");
HeapWord* end = start + word_size;
assert(containing_hr->is_in(end - 1), "it should also contain end - 1");
MemRegion mr(start, end);
card_table()->g1_mark_as_young(mr);
}
inline RefToScanQueue* G1CollectedHeap::task_queue(uint i) const {
return _task_queues->queue(i);
}
inline bool G1CollectedHeap::is_marked_next(oop obj) const {
return _cm->next_mark_bitmap()->is_marked((HeapWord*)obj);
}
inline bool G1CollectedHeap::is_in_cset(oop obj) {
return is_in_cset((HeapWord*)obj);
}
inline bool G1CollectedHeap::is_in_cset(HeapWord* addr) {
return _in_cset_fast_test.is_in_cset(addr);
}
bool G1CollectedHeap::is_in_cset(const HeapRegion* hr) {
return _in_cset_fast_test.is_in_cset(hr);
}
bool G1CollectedHeap::is_in_cset_or_humongous(const oop obj) {
return _in_cset_fast_test.is_in_cset_or_humongous((HeapWord*)obj);
}
InCSetState G1CollectedHeap::in_cset_state(const oop obj) {
return _in_cset_fast_test.at((HeapWord*)obj);
}
void G1CollectedHeap::register_humongous_region_with_cset(uint index) {
_in_cset_fast_test.set_humongous(index);
}
#ifndef PRODUCT
// Support for G1EvacuationFailureALot
inline bool
G1CollectedHeap::evacuation_failure_alot_for_gc_type(bool for_young_gc,
bool during_initial_mark,
bool mark_or_rebuild_in_progress) {
bool res = false;
if (mark_or_rebuild_in_progress) {
res |= G1EvacuationFailureALotDuringConcMark;
}
if (during_initial_mark) {
res |= G1EvacuationFailureALotDuringInitialMark;
}
if (for_young_gc) {
res |= G1EvacuationFailureALotDuringYoungGC;
} else {
// GCs are mixed
res |= G1EvacuationFailureALotDuringMixedGC;
}
return res;
}
inline void
G1CollectedHeap::set_evacuation_failure_alot_for_current_gc() {
if (G1EvacuationFailureALot) {
// Note we can't assert that _evacuation_failure_alot_for_current_gc
// is clear here. It may have been set during a previous GC but that GC
// did not copy enough objects (i.e. G1EvacuationFailureALotCount) to
// trigger an evacuation failure and clear the flags and and counts.
// Check if we have gone over the interval.
const size_t gc_num = total_collections();
const size_t elapsed_gcs = gc_num - _evacuation_failure_alot_gc_number;
_evacuation_failure_alot_for_current_gc = (elapsed_gcs >= G1EvacuationFailureALotInterval);
// Now check if G1EvacuationFailureALot is enabled for the current GC type.
const bool in_young_only_phase = collector_state()->in_young_only_phase();
const bool in_initial_mark_gc = collector_state()->in_initial_mark_gc();
const bool mark_or_rebuild_in_progress = collector_state()->mark_or_rebuild_in_progress();
_evacuation_failure_alot_for_current_gc &=
evacuation_failure_alot_for_gc_type(in_young_only_phase,
in_initial_mark_gc,
mark_or_rebuild_in_progress);
}
}
inline bool G1CollectedHeap::evacuation_should_fail() {
if (!G1EvacuationFailureALot || !_evacuation_failure_alot_for_current_gc) {
return false;
}
// G1EvacuationFailureALot is in effect for current GC
// Access to _evacuation_failure_alot_count is not atomic;
// the value does not have to be exact.
if (++_evacuation_failure_alot_count < G1EvacuationFailureALotCount) {
return false;
}
_evacuation_failure_alot_count = 0;
return true;
}
inline void G1CollectedHeap::reset_evacuation_should_fail() {
if (G1EvacuationFailureALot) {
_evacuation_failure_alot_gc_number = total_collections();
_evacuation_failure_alot_count = 0;
_evacuation_failure_alot_for_current_gc = false;
}
}
#endif // #ifndef PRODUCT
inline bool G1CollectedHeap::is_in_young(const oop obj) {
if (obj == NULL) {
return false;
}
return heap_region_containing(obj)->is_young();
}
inline bool G1CollectedHeap::is_obj_dead(const oop obj) const {
if (obj == NULL) {
return false;
}
return is_obj_dead(obj, heap_region_containing(obj));
}
inline bool G1CollectedHeap::is_obj_ill(const oop obj) const {
if (obj == NULL) {
return false;
}
return is_obj_ill(obj, heap_region_containing(obj));
}
inline bool G1CollectedHeap::is_obj_dead_full(const oop obj, const HeapRegion* hr) const {
return !is_marked_next(obj) && !hr->is_archive();
}
inline bool G1CollectedHeap::is_obj_dead_full(const oop obj) const {
return is_obj_dead_full(obj, heap_region_containing(obj));
}
inline void G1CollectedHeap::set_humongous_reclaim_candidate(uint region, bool value) {
assert(_hrm.at(region)->is_starts_humongous(), "Must start a humongous object");
_humongous_reclaim_candidates.set_candidate(region, value);
}
inline bool G1CollectedHeap::is_humongous_reclaim_candidate(uint region) {
assert(_hrm.at(region)->is_starts_humongous(), "Must start a humongous object");
return _humongous_reclaim_candidates.is_candidate(region);
}
inline void G1CollectedHeap::set_humongous_is_live(oop obj) {
uint region = addr_to_region((HeapWord*)obj);
// Clear the flag in the humongous_reclaim_candidates table. Also
// reset the entry in the _in_cset_fast_test table so that subsequent references
// to the same humongous object do not go into the slow path again.
// This is racy, as multiple threads may at the same time enter here, but this
// is benign.
// During collection we only ever clear the "candidate" flag, and only ever clear the
// entry in the in_cset_fast_table.
// We only ever evaluate the contents of these tables (in the VM thread) after
// having synchronized the worker threads with the VM thread, or in the same
// thread (i.e. within the VM thread).
if (is_humongous_reclaim_candidate(region)) {
set_humongous_reclaim_candidate(region, false);
_in_cset_fast_test.clear_humongous(region);
}
}
#endif // SHARE_VM_GC_G1_G1COLLECTEDHEAP_INLINE_HPP