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/*
* Copyright (c) 2017, 2021, Red Hat, Inc. All rights reserved.
+ * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
#include "precompiled.hpp"
#include "gc/shared/tlab_globals.hpp"
#include "gc/shenandoah/shenandoahAsserts.hpp"
#include "gc/shenandoah/shenandoahForwarding.inline.hpp"
#include "gc/shenandoah/shenandoahPhaseTimings.hpp"
+ #include "gc/shenandoah/shenandoahGeneration.hpp"
#include "gc/shenandoah/shenandoahHeap.inline.hpp"
#include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
+ #include "gc/shenandoah/shenandoahOldGeneration.hpp"
#include "gc/shenandoah/shenandoahRootProcessor.hpp"
+ #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp"
#include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
#include "gc/shenandoah/shenandoahUtils.hpp"
#include "gc/shenandoah/shenandoahVerifier.hpp"
+ #include "gc/shenandoah/shenandoahYoungGeneration.hpp"
#include "memory/allocation.hpp"
#include "memory/iterator.inline.hpp"
#include "memory/resourceArea.hpp"
#include "oops/compressedOops.inline.hpp"
#include "runtime/atomic.hpp"
ShenandoahHeap* _heap;
MarkBitMap* _map;
ShenandoahLivenessData* _ld;
void* _interior_loc;
oop _loc;
+ ShenandoahGeneration* _generation;
public:
ShenandoahVerifyOopClosure(ShenandoahVerifierStack* stack, MarkBitMap* map, ShenandoahLivenessData* ld,
const char* phase, ShenandoahVerifier::VerifyOptions options) :
_phase(phase),
_stack(stack),
_heap(ShenandoahHeap::heap()),
_map(map),
_ld(ld),
_interior_loc(nullptr),
- _loc(nullptr) {
+ _loc(nullptr),
+ _generation(nullptr) {
if (options._verify_marked == ShenandoahVerifier::_verify_marked_complete_except_references ||
+ options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty ||
options._verify_marked == ShenandoahVerifier::_verify_marked_disable) {
set_ref_discoverer_internal(new ShenandoahIgnoreReferenceDiscoverer());
}
+
+ if (_heap->mode()->is_generational()) {
+ _generation = _heap->gc_generation();
+ assert(_generation != nullptr, "Expected active generation in this mode");
+ shenandoah_assert_generations_reconciled();
+ }
}
private:
void check(ShenandoahAsserts::SafeLevel level, oop obj, bool test, const char* label) {
if (!test) {
// Single threaded verification can use faster non-atomic stack and bitmap
// methods.
//
// For performance reasons, only fully verify non-marked field values.
// We are here when the host object for *p is already marked.
-
- if (_map->par_mark(obj)) {
+ if (in_generation(obj) && _map->par_mark(obj)) {
verify_oop_at(p, obj);
_stack->push(ShenandoahVerifierTask(obj));
}
}
}
+ bool in_generation(oop obj) {
+ if (_generation == nullptr) {
+ return true;
+ }
+
+ ShenandoahHeapRegion* region = _heap->heap_region_containing(obj);
+ return _generation->contains(region);
+ }
+
void verify_oop(oop obj) {
// Perform consistency checks with gradually decreasing safety level. This guarantees
// that failure report would not try to touch something that was not yet verified to be
// safe to process.
break;
case ShenandoahVerifier::_verify_liveness_complete:
Atomic::add(&_ld[obj_reg->index()], (uint) obj->size(), memory_order_relaxed);
// fallthrough for fast failure for un-live regions:
case ShenandoahVerifier::_verify_liveness_conservative:
- check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live(),
+ check(ShenandoahAsserts::_safe_oop, obj, obj_reg->has_live() ||
+ (obj_reg->is_old() && _heap->gc_generation()->is_young()),
"Object must belong to region with live data");
+ shenandoah_assert_generations_reconciled();
break;
default:
assert(false, "Unhandled liveness verification");
}
}
"Double forwarding");
} else {
fwd_reg = obj_reg;
}
- // ------------ obj and fwd are safe at this point --------------
+ // Do additional checks for special objects: their fields can hold metadata as well.
+ // We want to check class loading/unloading did not corrupt them.
+
+ if (obj_klass == vmClasses::Class_klass()) {
+ Metadata* klass = obj->metadata_field(java_lang_Class::klass_offset());
+ check(ShenandoahAsserts::_safe_oop, obj,
+ klass == nullptr || Metaspace::contains(klass),
+ "Instance class mirror should point to Metaspace");
+
+ Metadata* array_klass = obj->metadata_field(java_lang_Class::array_klass_offset());
+ check(ShenandoahAsserts::_safe_oop, obj,
+ array_klass == nullptr || Metaspace::contains(array_klass),
+ "Array class mirror should point to Metaspace");
+ }
+ // ------------ obj and fwd are safe at this point --------------
switch (_options._verify_marked) {
case ShenandoahVerifier::_verify_marked_disable:
// skip
break;
case ShenandoahVerifier::_verify_marked_incomplete:
case ShenandoahVerifier::_verify_marked_complete:
check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
"Must be marked in complete bitmap");
break;
case ShenandoahVerifier::_verify_marked_complete_except_references:
+ case ShenandoahVerifier::_verify_marked_complete_satb_empty:
check(ShenandoahAsserts::_safe_all, obj, _heap->complete_marking_context()->is_marked(obj),
"Must be marked in complete bitmap, except j.l.r.Reference referents");
break;
default:
assert(false, "Unhandled mark verification");
_loc = obj;
obj->oop_iterate(this);
_loc = nullptr;
}
- virtual void do_oop(oop* p) { do_oop_work(p); }
- virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+ void do_oop(oop* p) override { do_oop_work(p); }
+ void do_oop(narrowOop* p) override { do_oop_work(p); }
};
+ // This closure computes the amounts of used, committed, and garbage memory and the number of regions contained within
+ // a subset (e.g. the young generation or old generation) of the total heap.
class ShenandoahCalculateRegionStatsClosure : public ShenandoahHeapRegionClosure {
private:
- size_t _used, _committed, _garbage;
+ size_t _used, _committed, _garbage, _regions, _humongous_waste, _trashed_regions;
public:
- ShenandoahCalculateRegionStatsClosure() : _used(0), _committed(0), _garbage(0) {};
+ ShenandoahCalculateRegionStatsClosure() :
+ _used(0), _committed(0), _garbage(0), _regions(0), _humongous_waste(0), _trashed_regions(0) {};
- void heap_region_do(ShenandoahHeapRegion* r) {
+ void heap_region_do(ShenandoahHeapRegion* r) override {
_used += r->used();
_garbage += r->garbage();
_committed += r->is_committed() ? ShenandoahHeapRegion::region_size_bytes() : 0;
+ if (r->is_humongous()) {
+ _humongous_waste += r->free();
+ }
+ if (r->is_trash()) {
+ _trashed_regions++;
+ }
+ _regions++;
+ log_debug(gc)("ShenandoahCalculateRegionStatsClosure: adding " SIZE_FORMAT " for %s Region " SIZE_FORMAT ", yielding: " SIZE_FORMAT,
+ r->used(), (r->is_humongous() ? "humongous" : "regular"), r->index(), _used);
+ }
+
+ size_t used() const { return _used; }
+ size_t committed() const { return _committed; }
+ size_t garbage() const { return _garbage; }
+ size_t regions() const { return _regions; }
+ size_t waste() const { return _humongous_waste; }
+
+ // span is the total memory affiliated with these stats (some of which is in use and other is available)
+ size_t span() const { return _regions * ShenandoahHeapRegion::region_size_bytes(); }
+ size_t non_trashed_span() const { return (_regions - _trashed_regions) * ShenandoahHeapRegion::region_size_bytes(); }
+ };
+
+ class ShenandoahGenerationStatsClosure : public ShenandoahHeapRegionClosure {
+ public:
+ ShenandoahCalculateRegionStatsClosure old;
+ ShenandoahCalculateRegionStatsClosure young;
+ ShenandoahCalculateRegionStatsClosure global;
+
+ void heap_region_do(ShenandoahHeapRegion* r) override {
+ switch (r->affiliation()) {
+ case FREE:
+ return;
+ case YOUNG_GENERATION:
+ young.heap_region_do(r);
+ global.heap_region_do(r);
+ break;
+ case OLD_GENERATION:
+ old.heap_region_do(r);
+ global.heap_region_do(r);
+ break;
+ default:
+ ShouldNotReachHere();
+ }
}
- size_t used() { return _used; }
- size_t committed() { return _committed; }
- size_t garbage() { return _garbage; }
+ static void log_usage(ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
+ log_debug(gc)("Safepoint verification: %s verified usage: " SIZE_FORMAT "%s, recorded usage: " SIZE_FORMAT "%s",
+ generation->name(),
+ byte_size_in_proper_unit(generation->used()), proper_unit_for_byte_size(generation->used()),
+ byte_size_in_proper_unit(stats.used()), proper_unit_for_byte_size(stats.used()));
+ }
+
+ static void validate_usage(const bool adjust_for_padding,
+ const char* label, ShenandoahGeneration* generation, ShenandoahCalculateRegionStatsClosure& stats) {
+ ShenandoahHeap* heap = ShenandoahHeap::heap();
+ size_t generation_used = generation->used();
+ size_t generation_used_regions = generation->used_regions();
+ if (adjust_for_padding && (generation->is_young() || generation->is_global())) {
+ size_t pad = heap->old_generation()->get_pad_for_promote_in_place();
+ generation_used += pad;
+ }
+
+ guarantee(stats.used() == generation_used,
+ "%s: generation (%s) used size must be consistent: generation-used: " PROPERFMT ", regions-used: " PROPERFMT,
+ label, generation->name(), PROPERFMTARGS(generation_used), PROPERFMTARGS(stats.used()));
+
+ guarantee(stats.regions() == generation_used_regions,
+ "%s: generation (%s) used regions (" SIZE_FORMAT ") must equal regions that are in use (" SIZE_FORMAT ")",
+ label, generation->name(), generation->used_regions(), stats.regions());
+
+ size_t generation_capacity = generation->max_capacity();
+ guarantee(stats.non_trashed_span() <= generation_capacity,
+ "%s: generation (%s) size spanned by regions (" SIZE_FORMAT ") * region size (" PROPERFMT
+ ") must not exceed current capacity (" PROPERFMT ")",
+ label, generation->name(), stats.regions(), PROPERFMTARGS(ShenandoahHeapRegion::region_size_bytes()),
+ PROPERFMTARGS(generation_capacity));
+
+ size_t humongous_waste = generation->get_humongous_waste();
+ guarantee(stats.waste() == humongous_waste,
+ "%s: generation (%s) humongous waste must be consistent: generation: " PROPERFMT ", regions: " PROPERFMT,
+ label, generation->name(), PROPERFMTARGS(humongous_waste), PROPERFMTARGS(stats.waste()));
+ }
};
class ShenandoahVerifyHeapRegionClosure : public ShenandoahHeapRegionClosure {
private:
ShenandoahHeap* _heap;
if (!test) {
print_failure(r, msg);
}
}
- void heap_region_do(ShenandoahHeapRegion* r) {
+ void heap_region_do(ShenandoahHeapRegion* r) override {
switch (_regions) {
case ShenandoahVerifier::_verify_regions_disable:
break;
case ShenandoahVerifier::_verify_regions_notrash:
verify(r, !r->is_trash(),
"TLAB alloc count should not be larger than capacity");
verify(r, r->get_gclab_allocs() <= r->capacity(),
"GCLAB alloc count should not be larger than capacity");
- verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() == r->used(),
- "Accurate accounting: shared + TLAB + GCLAB = used");
+ verify(r, r->get_plab_allocs() <= r->capacity(),
+ "PLAB alloc count should not be larger than capacity");
+
+ verify(r, r->get_shared_allocs() + r->get_tlab_allocs() + r->get_gclab_allocs() + r->get_plab_allocs() == r->used(),
+ "Accurate accounting: shared + TLAB + GCLAB + PLAB = used");
verify(r, !r->is_empty() || !r->has_live(),
"Empty regions should not have live data");
verify(r, r->is_cset() == _heap->collection_set()->is_in(r),
_heap(ShenandoahHeap::heap()),
_ld(ld),
_bitmap(bitmap),
_processed(0) {};
- size_t processed() {
+ size_t processed() const {
return _processed;
}
- virtual void work(uint worker_id) {
+ void work(uint worker_id) override {
ResourceMark rm;
ShenandoahVerifierStack stack;
// On level 2, we need to only check the roots once.
// On level 3, we want to check the roots, and seed the local stack.
Atomic::add(&_processed, processed, memory_order_relaxed);
}
};
+ class ShenandoahVerifyNoIncompleteSatbBuffers : public ThreadClosure {
+ public:
+ void do_thread(Thread* thread) override {
+ SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread);
+ if (!is_empty(queue)) {
+ fatal("All SATB buffers should have been flushed during mark");
+ }
+ }
+ private:
+ bool is_empty(SATBMarkQueue& queue) {
+ return queue.buffer() == nullptr || queue.index() == queue.capacity();
+ }
+ };
+
class ShenandoahVerifierMarkedRegionTask : public WorkerTask {
private:
const char* _label;
ShenandoahVerifier::VerifyOptions _options;
ShenandoahHeap *_heap;
MarkBitMap* _bitmap;
ShenandoahLivenessData* _ld;
volatile size_t _claimed;
volatile size_t _processed;
+ ShenandoahGeneration* _generation;
public:
ShenandoahVerifierMarkedRegionTask(MarkBitMap* bitmap,
ShenandoahLivenessData* ld,
const char* label,
_options(options),
_heap(ShenandoahHeap::heap()),
_bitmap(bitmap),
_ld(ld),
_claimed(0),
- _processed(0) {};
+ _processed(0),
+ _generation(nullptr) {
+ if (_heap->mode()->is_generational()) {
+ _generation = _heap->gc_generation();
+ assert(_generation != nullptr, "Expected active generation in this mode.");
+ shenandoah_assert_generations_reconciled();
+ }
+ };
size_t processed() {
return Atomic::load(&_processed);
}
- virtual void work(uint worker_id) {
+ void work(uint worker_id) override {
+ if (_options._verify_marked == ShenandoahVerifier::_verify_marked_complete_satb_empty) {
+ ShenandoahVerifyNoIncompleteSatbBuffers verify_satb;
+ Threads::threads_do(&verify_satb);
+ }
+
ShenandoahVerifierStack stack;
ShenandoahVerifyOopClosure cl(&stack, _bitmap, _ld,
ShenandoahMessageBuffer("%s, Marked", _label),
_options);
while (true) {
size_t v = Atomic::fetch_then_add(&_claimed, 1u, memory_order_relaxed);
if (v < _heap->num_regions()) {
ShenandoahHeapRegion* r = _heap->get_region(v);
+ if (!in_generation(r)) {
+ continue;
+ }
+
if (!r->is_humongous() && !r->is_trash()) {
work_regular(r, stack, cl);
} else if (r->is_humongous_start()) {
work_humongous(r, stack, cl);
}
break;
}
}
}
+ bool in_generation(ShenandoahHeapRegion* r) {
+ return _generation == nullptr || _generation->contains(r);
+ }
+
virtual void work_humongous(ShenandoahHeapRegion *r, ShenandoahVerifierStack& stack, ShenandoahVerifyOopClosure& cl) {
size_t processed = 0;
HeapWord* obj = r->bottom();
if (_heap->complete_marking_context()->is_marked(cast_to_oop(obj))) {
verify_and_follow(obj, stack, cl, &processed);
const char* const _label;
char const _expected;
public:
VerifyThreadGCState(const char* label, char expected) : _label(label), _expected(expected) {}
- void do_thread(Thread* t) {
+ void do_thread(Thread* t) override {
char actual = ShenandoahThreadLocalData::gc_state(t);
- if (actual != _expected) {
+ if (!verify_gc_state(actual, _expected)) {
fatal("%s: Thread %s: expected gc-state %d, actual %d", _label, t->name(), _expected, actual);
}
}
+
+ static bool verify_gc_state(char actual, char expected) {
+ // Old generation marking is allowed in all states.
+ if (ShenandoahHeap::heap()->mode()->is_generational()) {
+ return ((actual & ~(ShenandoahHeap::OLD_MARKING | ShenandoahHeap::MARKING)) == expected);
+ } else {
+ assert((actual & ShenandoahHeap::OLD_MARKING) == 0, "Should not mark old in non-generational mode");
+ return (actual == expected);
+ }
+ }
};
- void ShenandoahVerifier::verify_at_safepoint(const char *label,
+ void ShenandoahVerifier::verify_at_safepoint(const char* label,
+ VerifyRememberedSet remembered,
VerifyForwarded forwarded, VerifyMarked marked,
VerifyCollectionSet cset,
VerifyLiveness liveness, VerifyRegions regions,
+ VerifySize sizeness,
VerifyGCState gcstate) {
guarantee(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "only when nothing else happens");
guarantee(ShenandoahVerify, "only when enabled, and bitmap is initialized in ShenandoahHeap::initialize");
ShenandoahHeap::heap()->propagate_gc_state_to_java_threads();
break;
case _verify_gcstate_forwarded:
enabled = true;
expected = ShenandoahHeap::HAS_FORWARDED;
break;
- case _verify_gcstate_evacuation:
- enabled = true;
- expected = ShenandoahHeap::HAS_FORWARDED | ShenandoahHeap::EVACUATION;
- if (!_heap->is_stw_gc_in_progress()) {
- // Only concurrent GC sets this.
- expected |= ShenandoahHeap::WEAK_ROOTS;
- }
- break;
case _verify_gcstate_stable:
enabled = true;
expected = ShenandoahHeap::STABLE;
break;
case _verify_gcstate_stable_weakroots:
assert(false, "Unhandled gc-state verification");
}
if (enabled) {
char actual = _heap->gc_state();
- if (actual != expected) {
+
+ bool is_marking = (actual & ShenandoahHeap::MARKING);
+ bool is_marking_young_or_old = (actual & (ShenandoahHeap::YOUNG_MARKING | ShenandoahHeap::OLD_MARKING));
+ assert(is_marking == is_marking_young_or_old, "MARKING iff (YOUNG_MARKING or OLD_MARKING), gc_state is: %x", actual);
+
+ // Old generation marking is allowed in all states.
+ if (!VerifyThreadGCState::verify_gc_state(actual, expected)) {
fatal("%s: Global gc-state: expected %d, actual %d", label, expected, actual);
}
VerifyThreadGCState vtgcs(label, expected);
Threads::java_threads_do(&vtgcs);
{
ShenandoahHeapLocker lock(_heap->lock());
ShenandoahCalculateRegionStatsClosure cl;
_heap->heap_region_iterate(&cl);
- size_t heap_used = _heap->used();
- guarantee(cl.used() == heap_used,
- "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
- label,
- byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
- byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
-
+ size_t heap_used;
+ if (_heap->mode()->is_generational() && (sizeness == _verify_size_adjusted_for_padding)) {
+ // Prior to evacuation, regular regions that are to be evacuated in place are padded to prevent further allocations
+ heap_used = _heap->used() + _heap->old_generation()->get_pad_for_promote_in_place();
+ } else if (sizeness != _verify_size_disable) {
+ heap_used = _heap->used();
+ }
+ if (sizeness != _verify_size_disable) {
+ guarantee(cl.used() == heap_used,
+ "%s: heap used size must be consistent: heap-used = " SIZE_FORMAT "%s, regions-used = " SIZE_FORMAT "%s",
+ label,
+ byte_size_in_proper_unit(heap_used), proper_unit_for_byte_size(heap_used),
+ byte_size_in_proper_unit(cl.used()), proper_unit_for_byte_size(cl.used()));
+ }
size_t heap_committed = _heap->committed();
guarantee(cl.committed() == heap_committed,
"%s: heap committed size must be consistent: heap-committed = " SIZE_FORMAT "%s, regions-committed = " SIZE_FORMAT "%s",
label,
byte_size_in_proper_unit(heap_committed), proper_unit_for_byte_size(heap_committed),
byte_size_in_proper_unit(cl.committed()), proper_unit_for_byte_size(cl.committed()));
}
+ log_debug(gc)("Safepoint verification finished heap usage verification");
+
+ ShenandoahGeneration* generation;
+ if (_heap->mode()->is_generational()) {
+ generation = _heap->gc_generation();
+ guarantee(generation != nullptr, "Need to know which generation to verify.");
+ shenandoah_assert_generations_reconciled();
+ } else {
+ generation = nullptr;
+ }
+
+ if (generation != nullptr) {
+ ShenandoahHeapLocker lock(_heap->lock());
+
+ switch (remembered) {
+ case _verify_remembered_disable:
+ break;
+ case _verify_remembered_before_marking:
+ log_debug(gc)("Safepoint verification of remembered set at mark");
+ verify_rem_set_before_mark();
+ break;
+ case _verify_remembered_before_updating_references:
+ log_debug(gc)("Safepoint verification of remembered set at update ref");
+ verify_rem_set_before_update_ref();
+ break;
+ case _verify_remembered_after_full_gc:
+ log_debug(gc)("Safepoint verification of remembered set after full gc");
+ verify_rem_set_after_full_gc();
+ break;
+ default:
+ fatal("Unhandled remembered set verification mode");
+ }
+
+ ShenandoahGenerationStatsClosure cl;
+ _heap->heap_region_iterate(&cl);
+
+ if (LogTarget(Debug, gc)::is_enabled()) {
+ ShenandoahGenerationStatsClosure::log_usage(_heap->old_generation(), cl.old);
+ ShenandoahGenerationStatsClosure::log_usage(_heap->young_generation(), cl.young);
+ ShenandoahGenerationStatsClosure::log_usage(_heap->global_generation(), cl.global);
+ }
+ if (sizeness == _verify_size_adjusted_for_padding) {
+ ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
+ ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->young_generation(), cl.young);
+ ShenandoahGenerationStatsClosure::validate_usage(true, label, _heap->global_generation(), cl.global);
+ } else if (sizeness == _verify_size_exact) {
+ ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->old_generation(), cl.old);
+ ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->young_generation(), cl.young);
+ ShenandoahGenerationStatsClosure::validate_usage(false, label, _heap->global_generation(), cl.global);
+ }
+ // else: sizeness must equal _verify_size_disable
+ }
+
+ log_debug(gc)("Safepoint verification finished remembered set verification");
+
// Internal heap region checks
if (ShenandoahVerifyLevel >= 1) {
ShenandoahVerifyHeapRegionClosure cl(label, regions);
- _heap->heap_region_iterate(&cl);
+ if (generation != nullptr) {
+ generation->heap_region_iterate(&cl);
+ } else {
+ _heap->heap_region_iterate(&cl);
+ }
}
+ log_debug(gc)("Safepoint verification finished heap region closure verification");
+
OrderAccess::fence();
if (UseTLAB) {
_heap->labs_make_parsable();
}
ShenandoahVerifierReachableTask task(_verification_bit_map, ld, label, options);
_heap->workers()->run_task(&task);
count_reachable = task.processed();
}
+ log_debug(gc)("Safepoint verification finished getting initial reachable set");
+
// Step 3. Walk marked objects. Marked objects might be unreachable. This verifies what collector,
// not the application, can see during the region scans. There is no reason to process the objects
// that were already verified, e.g. those marked in verification bitmap. There is interaction with TAMS:
// before TAMS, we verify the bitmaps, if available; after TAMS, we walk until the top(). It mimics
// what marked_object_iterate is doing, without calling into that optimized (and possibly incorrect)
// version
size_t count_marked = 0;
- if (ShenandoahVerifyLevel >= 4 && (marked == _verify_marked_complete || marked == _verify_marked_complete_except_references)) {
+ if (ShenandoahVerifyLevel >= 4 &&
+ (marked == _verify_marked_complete ||
+ marked == _verify_marked_complete_except_references ||
+ marked == _verify_marked_complete_satb_empty)) {
guarantee(_heap->marking_context()->is_complete(), "Marking context should be complete");
ShenandoahVerifierMarkedRegionTask task(_verification_bit_map, ld, label, options);
_heap->workers()->run_task(&task);
count_marked = task.processed();
} else {
guarantee(ShenandoahVerifyLevel < 4 || marked == _verify_marked_incomplete || marked == _verify_marked_disable, "Should be");
}
+ log_debug(gc)("Safepoint verification finished walking marked objects");
+
// Step 4. Verify accumulated liveness data, if needed. Only reliable if verification level includes
// marked objects.
if (ShenandoahVerifyLevel >= 4 && marked == _verify_marked_complete && liveness == _verify_liveness_complete) {
for (size_t i = 0; i < _heap->num_regions(); i++) {
ShenandoahHeapRegion* r = _heap->get_region(i);
+ if (generation != nullptr && !generation->contains(r)) {
+ continue;
+ }
juint verf_live = 0;
if (r->is_humongous()) {
// For humongous objects, test if start region is marked live, and if so,
// all humongous regions in that chain have live data equal to their "used".
label, reg_live, verf_live, ss.freeze());
}
}
}
+ log_debug(gc)("Safepoint verification finished accumulation of liveness data");
+
+
log_info(gc)("Verify %s, Level " INTX_FORMAT " (" SIZE_FORMAT " reachable, " SIZE_FORMAT " marked)",
label, ShenandoahVerifyLevel, count_reachable, count_marked);
FREE_C_HEAP_ARRAY(ShenandoahLivenessData, ld);
}
void ShenandoahVerifier::verify_generic(VerifyOption vo) {
verify_at_safepoint(
"Generic Verification",
+ _verify_remembered_disable, // do not verify remembered set
_verify_forwarded_allow, // conservatively allow forwarded
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_disable, // cset may be inconsistent
_verify_liveness_disable, // no reliable liveness data
_verify_regions_disable, // no reliable region data
+ _verify_size_exact, // expect generation and heap sizes to match exactly
_verify_gcstate_disable // no data about gcstate
);
}
void ShenandoahVerifier::verify_before_concmark() {
verify_at_safepoint(
"Before Mark",
+ _verify_remembered_before_marking,
+ // verify read-only remembered set from bottom() to top()
_verify_forwarded_none, // UR should have fixed up
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_none, // UR should have fixed this
_verify_liveness_disable, // no reliable liveness data
_verify_regions_notrash, // no trash regions
+ _verify_size_exact, // expect generation and heap sizes to match exactly
_verify_gcstate_stable // there are no forwarded objects
);
}
void ShenandoahVerifier::verify_after_concmark() {
verify_at_safepoint(
"After Mark",
- _verify_forwarded_none, // no forwarded references
- _verify_marked_complete_except_references, // bitmaps as precise as we can get, except dangling j.l.r.Refs
- _verify_cset_none, // no references to cset anymore
- _verify_liveness_complete, // liveness data must be complete here
- _verify_regions_disable, // trash regions not yet recycled
- _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
+ _verify_remembered_disable, // do not verify remembered set
+ _verify_forwarded_none, // no forwarded references
+ _verify_marked_complete_satb_empty, // bitmaps as precise as we can get, except dangling j.l.r.Refs
+ _verify_cset_none, // no references to cset anymore
+ _verify_liveness_complete, // liveness data must be complete here
+ _verify_regions_disable, // trash regions not yet recycled
+ _verify_size_exact, // expect generation and heap sizes to match exactly
+ _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
+ );
+ }
+
+ void ShenandoahVerifier::verify_after_concmark_with_promotions() {
+ verify_at_safepoint(
+ "After Mark",
+ _verify_remembered_disable, // do not verify remembered set
+ _verify_forwarded_none, // no forwarded references
+ _verify_marked_complete_satb_empty, // bitmaps as precise as we can get, except dangling j.l.r.Refs
+ _verify_cset_none, // no references to cset anymore
+ _verify_liveness_complete, // liveness data must be complete here
+ _verify_regions_disable, // trash regions not yet recycled
+ _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
+ // for promote in place padding
+ _verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
);
}
void ShenandoahVerifier::verify_before_evacuation() {
verify_at_safepoint(
"Before Evacuation",
+ _verify_remembered_disable, // do not verify remembered set
_verify_forwarded_none, // no forwarded references
_verify_marked_complete_except_references, // walk over marked objects too
_verify_cset_disable, // non-forwarded references to cset expected
_verify_liveness_complete, // liveness data must be complete here
_verify_regions_disable, // trash regions not yet recycled
+ _verify_size_adjusted_for_padding, // expect generation and heap sizes to match after adjustments
+ // for promote in place padding
_verify_gcstate_stable_weakroots // heap is still stable, weakroots are in progress
);
}
- void ShenandoahVerifier::verify_during_evacuation() {
- verify_at_safepoint(
- "During Evacuation",
- _verify_forwarded_allow, // some forwarded references are allowed
- _verify_marked_disable, // walk only roots
- _verify_cset_disable, // some cset references are not forwarded yet
- _verify_liveness_disable, // liveness data might be already stale after pre-evacs
- _verify_regions_disable, // trash regions not yet recycled
- _verify_gcstate_evacuation // evacuation is in progress
- );
- }
-
- void ShenandoahVerifier::verify_after_evacuation() {
- verify_at_safepoint(
- "After Evacuation",
- _verify_forwarded_allow, // objects are still forwarded
- _verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
- _verify_cset_forwarded, // all cset refs are fully forwarded
- _verify_liveness_disable, // no reliable liveness data anymore
- _verify_regions_notrash, // trash regions have been recycled already
- _verify_gcstate_forwarded // evacuation produced some forwarded objects
- );
- }
-
void ShenandoahVerifier::verify_before_updaterefs() {
verify_at_safepoint(
"Before Updating References",
+ _verify_remembered_before_updating_references, // verify read-write remembered set
_verify_forwarded_allow, // forwarded references allowed
_verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
_verify_cset_forwarded, // all cset refs are fully forwarded
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash, // trash regions have been recycled already
+ _verify_size_exact, // expect generation and heap sizes to match exactly
_verify_gcstate_forwarded // evacuation should have produced some forwarded objects
);
}
+ // We have not yet cleanup (reclaimed) the collection set
void ShenandoahVerifier::verify_after_updaterefs() {
verify_at_safepoint(
"After Updating References",
+ _verify_remembered_disable, // do not verify remembered set
_verify_forwarded_none, // no forwarded references
_verify_marked_complete, // bitmaps might be stale, but alloc-after-mark should be well
_verify_cset_none, // no cset references, all updated
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_nocset, // no cset regions, trash regions have appeared
+ _verify_size_exact, // expect generation and heap sizes to match exactly
_verify_gcstate_stable // update refs had cleaned up forwarded objects
);
}
void ShenandoahVerifier::verify_after_degenerated() {
verify_at_safepoint(
"After Degenerated GC",
+ _verify_remembered_disable, // do not verify remembered set
_verify_forwarded_none, // all objects are non-forwarded
_verify_marked_complete, // all objects are marked in complete bitmap
_verify_cset_none, // no cset references
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash_nocset, // no trash, no cset
+ _verify_size_exact, // expect generation and heap sizes to match exactly
_verify_gcstate_stable // degenerated refs had cleaned up forwarded objects
);
}
void ShenandoahVerifier::verify_before_fullgc() {
verify_at_safepoint(
"Before Full GC",
+ _verify_remembered_disable, // do not verify remembered set
_verify_forwarded_allow, // can have forwarded objects
_verify_marked_disable, // do not verify marked: lots ot time wasted checking dead allocations
_verify_cset_disable, // cset might be foobared
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_disable, // no reliable region data here
+ _verify_size_disable, // if we degenerate during evacuation, usage not valid: padding and deferred accounting
_verify_gcstate_disable // no reliable gcstate data
);
}
void ShenandoahVerifier::verify_after_fullgc() {
verify_at_safepoint(
"After Full GC",
+ _verify_remembered_after_full_gc, // verify read-write remembered set
_verify_forwarded_none, // all objects are non-forwarded
_verify_marked_complete, // all objects are marked in complete bitmap
_verify_cset_none, // no cset references
_verify_liveness_disable, // no reliable liveness data anymore
_verify_regions_notrash_nocset, // no trash, no cset
+ _verify_size_exact, // expect generation and heap sizes to match exactly
_verify_gcstate_stable // full gc cleaned up everything
);
}
- class ShenandoahVerifyNoForwared : public OopClosure {
+ class ShenandoahVerifyNoForwarded : public BasicOopIterateClosure {
private:
template <class T>
void do_oop_work(T* p) {
T o = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(o)) {
public:
void do_oop(narrowOop* p) { do_oop_work(p); }
void do_oop(oop* p) { do_oop_work(p); }
};
- class ShenandoahVerifyInToSpaceClosure : public OopClosure {
+ class ShenandoahVerifyInToSpaceClosure : public BasicOopIterateClosure {
private:
template <class T>
void do_oop_work(T* p) {
T o = RawAccess<>::oop_load(p);
if (!CompressedOops::is_null(o)) {
oop obj = CompressedOops::decode_not_null(o);
ShenandoahHeap* heap = ShenandoahHeap::heap();
- if (!heap->marking_context()->is_marked(obj)) {
+ if (!heap->marking_context()->is_marked_or_old(obj)) {
ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
"Verify Roots In To-Space", "Should be marked", __FILE__, __LINE__);
}
if (heap->in_collection_set(obj)) {
}
}
}
public:
- void do_oop(narrowOop* p) { do_oop_work(p); }
- void do_oop(oop* p) { do_oop_work(p); }
+ void do_oop(narrowOop* p) override { do_oop_work(p); }
+ void do_oop(oop* p) override { do_oop_work(p); }
};
void ShenandoahVerifier::verify_roots_in_to_space() {
ShenandoahVerifyInToSpaceClosure cl;
ShenandoahRootVerifier::roots_do(&cl);
}
void ShenandoahVerifier::verify_roots_no_forwarded() {
- ShenandoahVerifyNoForwared cl;
+ ShenandoahVerifyNoForwarded cl;
ShenandoahRootVerifier::roots_do(&cl);
}
+
+ template<typename Scanner>
+ class ShenandoahVerifyRemSetClosure : public BasicOopIterateClosure {
+ protected:
+ ShenandoahGenerationalHeap* const _heap;
+ Scanner* const _scanner;
+ const char* _message;
+
+ public:
+ // Argument distinguishes between initial mark or start of update refs verification.
+ explicit ShenandoahVerifyRemSetClosure(Scanner* scanner, const char* message) :
+ _heap(ShenandoahGenerationalHeap::heap()),
+ _scanner(scanner),
+ _message(message) {}
+
+ template<class T>
+ inline void work(T* p) {
+ T o = RawAccess<>::oop_load(p);
+ if (!CompressedOops::is_null(o)) {
+ oop obj = CompressedOops::decode_not_null(o);
+ if (_heap->is_in_young(obj) && !_scanner->is_card_dirty((HeapWord*) p)) {
+ ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, p, nullptr,
+ _message, "clean card should be dirty", __FILE__, __LINE__);
+ }
+ }
+ }
+
+ void do_oop(narrowOop* p) override { work(p); }
+ void do_oop(oop* p) override { work(p); }
+ };
+
+ ShenandoahMarkingContext* ShenandoahVerifier::get_marking_context_for_old() {
+ shenandoah_assert_generations_reconciled();
+ if (_heap->old_generation()->is_mark_complete() || _heap->gc_generation()->is_global()) {
+ return _heap->complete_marking_context();
+ }
+ return nullptr;
+ }
+
+ template<typename Scanner>
+ void ShenandoahVerifier::help_verify_region_rem_set(Scanner* scanner, ShenandoahHeapRegion* r, ShenandoahMarkingContext* ctx,
+ HeapWord* registration_watermark, const char* message) {
+ ShenandoahVerifyRemSetClosure<Scanner> check_interesting_pointers(scanner, message);
+ HeapWord* from = r->bottom();
+ HeapWord* obj_addr = from;
+ if (r->is_humongous_start()) {
+ oop obj = cast_to_oop(obj_addr);
+ if ((ctx == nullptr) || ctx->is_marked(obj)) {
+ // For humongous objects, the typical object is an array, so the following checks may be overkill
+ // For regular objects (not object arrays), if the card holding the start of the object is dirty,
+ // we do not need to verify that cards spanning interesting pointers within this object are dirty.
+ if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
+ obj->oop_iterate(&check_interesting_pointers);
+ }
+ // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
+ }
+ // else, this humongous object is not live so no need to verify its internal pointers
+
+ if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
+ ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
+ "object not properly registered", __FILE__, __LINE__);
+ }
+ } else if (!r->is_humongous()) {
+ HeapWord* top = r->top();
+ while (obj_addr < top) {
+ oop obj = cast_to_oop(obj_addr);
+ // ctx->is_marked() returns true if mark bit set or if obj above TAMS.
+ if ((ctx == nullptr) || ctx->is_marked(obj)) {
+ // For regular objects (not object arrays), if the card holding the start of the object is dirty,
+ // we do not need to verify that cards spanning interesting pointers within this object are dirty.
+ if (!scanner->is_card_dirty(obj_addr) || obj->is_objArray()) {
+ obj->oop_iterate(&check_interesting_pointers);
+ }
+ // else, object's start is marked dirty and obj is not an objArray, so any interesting pointers are covered
+
+ if ((obj_addr < registration_watermark) && !scanner->verify_registration(obj_addr, ctx)) {
+ ShenandoahAsserts::print_failure(ShenandoahAsserts::_safe_all, obj, obj_addr, nullptr, message,
+ "object not properly registered", __FILE__, __LINE__);
+ }
+ obj_addr += obj->size();
+ } else {
+ // This object is not live so we don't verify dirty cards contained therein
+ HeapWord* tams = ctx->top_at_mark_start(r);
+ obj_addr = ctx->get_next_marked_addr(obj_addr, tams);
+ }
+ }
+ }
+ }
+
+ class ShenandoahWriteTableScanner {
+ private:
+ ShenandoahScanRemembered* _scanner;
+ public:
+ explicit ShenandoahWriteTableScanner(ShenandoahScanRemembered* scanner) : _scanner(scanner) {}
+
+ bool is_card_dirty(HeapWord* obj_addr) {
+ return _scanner->is_write_card_dirty(obj_addr);
+ }
+
+ bool verify_registration(HeapWord* obj_addr, ShenandoahMarkingContext* ctx) {
+ return _scanner->verify_registration(obj_addr, ctx);
+ }
+ };
+
+ // Assure that the remember set has a dirty card everywhere there is an interesting pointer.
+ // This examines the read_card_table between bottom() and top() since all PLABS are retired
+ // before the safepoint for init_mark. Actually, we retire them before update-references and don't
+ // restore them until the start of evacuation.
+ void ShenandoahVerifier::verify_rem_set_before_mark() {
+ shenandoah_assert_safepoint();
+ shenandoah_assert_generational();
+
+ ShenandoahMarkingContext* ctx = get_marking_context_for_old();
+ ShenandoahOldGeneration* old_generation = _heap->old_generation();
+
+ log_debug(gc)("Verifying remembered set at %s mark", old_generation->is_doing_mixed_evacuations() ? "mixed" : "young");
+
+ ShenandoahScanRemembered* scanner = old_generation->card_scan();
+ for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
+ ShenandoahHeapRegion* r = _heap->get_region(i);
+ if (r->is_old() && r->is_active()) {
+ help_verify_region_rem_set(scanner, r, ctx, r->end(), "Verify init-mark remembered set violation");
+ }
+ }
+ }
+
+ void ShenandoahVerifier::verify_rem_set_after_full_gc() {
+ shenandoah_assert_safepoint();
+ shenandoah_assert_generational();
+
+ ShenandoahWriteTableScanner scanner(ShenandoahGenerationalHeap::heap()->old_generation()->card_scan());
+ for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
+ ShenandoahHeapRegion* r = _heap->get_region(i);
+ if (r->is_old() && !r->is_cset()) {
+ help_verify_region_rem_set(&scanner, r, nullptr, r->top(), "Remembered set violation at end of Full GC");
+ }
+ }
+ }
+
+ // Assure that the remember set has a dirty card everywhere there is an interesting pointer. Even though
+ // the update-references scan of remembered set only examines cards up to update_watermark, the remembered
+ // set should be valid through top. This examines the write_card_table between bottom() and top() because
+ // all PLABS are retired immediately before the start of update refs.
+ void ShenandoahVerifier::verify_rem_set_before_update_ref() {
+ shenandoah_assert_safepoint();
+ shenandoah_assert_generational();
+
+ ShenandoahMarkingContext* ctx = get_marking_context_for_old();
+ ShenandoahWriteTableScanner scanner(_heap->old_generation()->card_scan());
+ for (size_t i = 0, n = _heap->num_regions(); i < n; ++i) {
+ ShenandoahHeapRegion* r = _heap->get_region(i);
+ if (r->is_old() && !r->is_cset()) {
+ help_verify_region_rem_set(&scanner, r, ctx, r->get_update_watermark(), "Remembered set violation at init-update-references");
+ }
+ }
+ }
+
+ void ShenandoahVerifier::verify_before_rebuilding_free_set() {
+ ShenandoahGenerationStatsClosure cl;
+ _heap->heap_region_iterate(&cl);
+
+ ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->old_generation(), cl.old);
+ ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->young_generation(), cl.young);
+ ShenandoahGenerationStatsClosure::validate_usage(false, "Before free set rebuild", _heap->global_generation(), cl.global);
+ }
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