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8195103: Refactor out card table from CardTableModRefBS to flatten the BarrierSet hierarchy

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Reviewed-by: kbarrett, tschatzl
This commit is contained in:
Erik Österlund 2018-01-10 22:48:27 +01:00
parent ceb48aba9b
commit 0fb7dffb83
32 changed files with 282 additions and 372 deletions
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6
src/hotspot/share/gc/cms/cmsHeap.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2017, 2018, Oracle and/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
@ -75,10 +75,6 @@ public:
// supports. Caller does not hold the Heap_lock on entry.
void collect(GCCause::Cause cause);
bool card_mark_must_follow_store() const {
return true;
}
void stop();
void safepoint_synchronize_begin();
void safepoint_synchronize_end();

1
src/hotspot/share/gc/g1/g1CollectedHeap.cpp
View file

@ -1573,7 +1573,6 @@ jint G1CollectedHeap::initialize_young_gen_sampling_thread() {
}
jint G1CollectedHeap::initialize() {
CollectedHeap::pre_initialize();
os::enable_vtime();
// Necessary to satisfy locking discipline assertions.

28
src/hotspot/share/gc/g1/g1CollectedHeap.hpp
View file

@ -1272,36 +1272,8 @@ public:
size_t max_tlab_size() const;
size_t unsafe_max_tlab_alloc(Thread* ignored) const;
// Can a compiler initialize a new object without store barriers?
// This permission only extends from the creation of a new object
// via a TLAB up to the first subsequent safepoint. If such permission
// is granted for this heap type, the compiler promises to call
// defer_store_barrier() below on any slow path allocation of
// a new object for which such initializing store barriers will
// have been elided. G1, like CMS, allows this, but should be
// ready to provide a compensating write barrier as necessary
// if that storage came out of a non-young region. The efficiency
// of this implementation depends crucially on being able to
// answer very efficiently in constant time whether a piece of
// storage in the heap comes from a young region or not.
// See ReduceInitialCardMarks.
virtual bool can_elide_tlab_store_barriers() const {
return true;
}
virtual bool card_mark_must_follow_store() const {
return true;
}
inline bool is_in_young(const oop obj);
// We don't need barriers for initializing stores to objects
// in the young gen: for the SATB pre-barrier, there is no
// pre-value that needs to be remembered; for the remembered-set
// update logging post-barrier, we don't maintain remembered set
// information for young gen objects.
virtual inline bool can_elide_initializing_store_barrier(oop new_obj);
// Returns "true" iff the given word_size is "very large".
static bool is_humongous(size_t word_size) {
// Note this has to be strictly greater-than as the TLABs

11
src/hotspot/share/gc/g1/g1CollectedHeap.inline.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -241,15 +241,6 @@ inline bool G1CollectedHeap::is_in_young(const oop obj) {
return heap_region_containing(obj)->is_young();
}
// We don't need barriers for initializing stores to objects
// in the young gen: for the SATB pre-barrier, there is no
// pre-value that needs to be remembered; for the remembered-set
// update logging post-barrier, we don't maintain remembered set
// information for young gen objects.
inline bool G1CollectedHeap::can_elide_initializing_store_barrier(oop new_obj) {
return is_in_young(new_obj);
}
inline bool G1CollectedHeap::is_obj_dead(const oop obj) const {
if (obj == NULL) {
return false;

14
src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -131,6 +131,7 @@ G1SATBCardTableLoggingModRefBS(MemRegion whole_heap) :
}
void G1SATBCardTableLoggingModRefBS::initialize(G1RegionToSpaceMapper* mapper) {
initialize_deferred_card_mark_barriers();
mapper->set_mapping_changed_listener(&_listener);
_byte_map_size = mapper->reserved().byte_size();
@ -213,3 +214,14 @@ G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr) {
}
}
}
bool G1SATBCardTableModRefBS::is_in_young(oop obj) const {
volatile jbyte* p = byte_for((void*)obj);
return *p == g1_young_card_val();
}
void G1SATBCardTableLoggingModRefBS::flush_deferred_barriers(JavaThread* thread) {
CardTableModRefBS::flush_deferred_barriers(thread);
thread->satb_mark_queue().flush();
thread->dirty_card_queue().flush();
}

12
src/hotspot/share/gc/g1/g1SATBCardTableModRefBS.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -92,6 +92,8 @@ public:
jbyte val = _byte_map[card_index];
return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val();
}
virtual bool is_in_young(oop obj) const;
};
template<>
@ -145,13 +147,19 @@ class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
// above no longer applies.
void invalidate(MemRegion mr);
void write_region_work(MemRegion mr) { invalidate(mr); }
void write_region(MemRegion mr) { invalidate(mr); }
void write_ref_array_work(MemRegion mr) { invalidate(mr); }
template <DecoratorSet decorators, typename T>
void write_ref_field_post(T* field, oop new_val);
void write_ref_field_post_slow(volatile jbyte* byte);
virtual void flush_deferred_barriers(JavaThread* thread);
virtual bool card_mark_must_follow_store() const {
return true;
}
// Callbacks for runtime accesses.
template <DecoratorSet decorators, typename BarrierSetT = G1SATBCardTableLoggingModRefBS>
class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> {

8
src/hotspot/share/gc/parallel/cardTableExtension.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -26,7 +26,7 @@
#include "gc/parallel/cardTableExtension.hpp"
#include "gc/parallel/gcTaskManager.hpp"
#include "gc/parallel/objectStartArray.inline.hpp"
#include "gc/parallel/parallelScavengeHeap.hpp"
#include "gc/parallel/parallelScavengeHeap.inline.hpp"
#include "gc/parallel/psPromotionManager.inline.hpp"
#include "gc/parallel/psScavenge.hpp"
#include "gc/parallel/psTasks.hpp"
@ -677,3 +677,7 @@ HeapWord* CardTableExtension::lowest_prev_committed_start(int ind) const {
}
return min_start;
}
bool CardTableExtension::is_in_young(oop obj) const {
return ParallelScavengeHeap::heap()->is_in_young(obj);
}

9
src/hotspot/share/gc/parallel/cardTableExtension.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -108,6 +108,13 @@ class CardTableExtension : public CardTableModRefBS {
}
#endif // ASSERT
// ReduceInitialCardMarks support
virtual bool is_in_young(oop obj) const;
virtual bool card_mark_must_follow_store() const {
return false;
}
};
template<>

12
src/hotspot/share/gc/parallel/parallelScavengeHeap.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -57,8 +57,6 @@ PSGCAdaptivePolicyCounters* ParallelScavengeHeap::_gc_policy_counters = NULL;
GCTaskManager* ParallelScavengeHeap::_gc_task_manager = NULL;
jint ParallelScavengeHeap::initialize() {
CollectedHeap::pre_initialize();
const size_t heap_size = _collector_policy->max_heap_byte_size();
ReservedSpace heap_rs = Universe::reserve_heap(heap_size, _collector_policy->heap_alignment());
@ -490,13 +488,6 @@ void ParallelScavengeHeap::resize_all_tlabs() {
CollectedHeap::resize_all_tlabs();
}
bool ParallelScavengeHeap::can_elide_initializing_store_barrier(oop new_obj) {
// We don't need barriers for stores to objects in the
// young gen and, a fortiori, for initializing stores to
// objects therein.
return is_in_young(new_obj);
}
// This method is used by System.gc() and JVMTI.
void ParallelScavengeHeap::collect(GCCause::Cause cause) {
assert(!Heap_lock->owned_by_self(),
@ -719,4 +710,3 @@ GrowableArray<MemoryPool*> ParallelScavengeHeap::memory_pools() {
memory_pools.append(_old_pool);
return memory_pools;
}

17
src/hotspot/share/gc/parallel/parallelScavengeHeap.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -205,21 +205,6 @@ class ParallelScavengeHeap : public CollectedHeap {
size_t tlab_used(Thread* thr) const;
size_t unsafe_max_tlab_alloc(Thread* thr) const;
// Can a compiler initialize a new object without store barriers?
// This permission only extends from the creation of a new object
// via a TLAB up to the first subsequent safepoint.
virtual bool can_elide_tlab_store_barriers() const {
return true;
}
virtual bool card_mark_must_follow_store() const {
return false;
}
// Return true if we don't we need a store barrier for
// initializing stores to an object at this address.
virtual bool can_elide_initializing_store_barrier(oop new_obj);
void object_iterate(ObjectClosure* cl);
void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }

6
src/hotspot/share/gc/serial/serialHeap.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2017, 2018, Oracle and/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
@ -61,10 +61,6 @@ public:
virtual bool is_in_closed_subset(const void* p) const {
return is_in(p);
}
virtual bool card_mark_must_follow_store() const {
return false;
}
};
#endif // SHARE_VM_GC_CMS_CMSHEAP_HPP

20
src/hotspot/share/gc/shared/barrierSet.hpp
View file

@ -32,6 +32,8 @@
#include "oops/oopsHierarchy.hpp"
#include "utilities/fakeRttiSupport.hpp"
class JavaThread;
// This class provides the interface between a barrier implementation and
// the rest of the system.
@ -107,18 +109,18 @@ public:
static void static_write_ref_array_pre(HeapWord* start, size_t count);
static void static_write_ref_array_post(HeapWord* start, size_t count);
// Support for optimizing compilers to call the barrier set on slow path allocations
// that did not enter a TLAB. Used for e.g. ReduceInitialCardMarks.
// The allocation is safe to use iff it returns true. If not, the slow-path allocation
// is redone until it succeeds. This can e.g. prevent allocations from the slow path
// to be in old.
virtual void on_slowpath_allocation_exit(JavaThread* thread, oop new_obj) {}
virtual void flush_deferred_barriers(JavaThread* thread) {}
virtual void make_parsable(JavaThread* thread) {}
protected:
virtual void write_ref_array_work(MemRegion mr) = 0;
public:
// (For efficiency reasons, this operation is specialized for certain
// barrier types. Semantically, it should be thought of as a call to the
// virtual "_work" function below, which must implement the barrier.)
void write_region(MemRegion mr);
protected:
virtual void write_region_work(MemRegion mr) = 0;
public:
// Inform the BarrierSet that the the covered heap region that starts
// with "base" has been changed to have the given size (possibly from 0,

6
src/hotspot/share/gc/shared/barrierSet.inline.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -52,8 +52,4 @@ void BarrierSet::write_ref_array(HeapWord* start, size_t count) {
write_ref_array_work(MemRegion(aligned_start, aligned_end));
}
inline void BarrierSet::write_region(MemRegion mr) {
write_region_work(mr);
}
#endif // SHARE_VM_GC_SHARED_BARRIERSET_INLINE_HPP

116
src/hotspot/share/gc/shared/cardTableModRefBS.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/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
@ -30,6 +30,7 @@
#include "logging/log.hpp"
#include "memory/virtualspace.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/thread.hpp"
#include "services/memTracker.hpp"
#include "utilities/align.hpp"
#include "utilities/macros.hpp"
@ -61,7 +62,8 @@ CardTableModRefBS::CardTableModRefBS(
_committed(NULL),
_cur_covered_regions(0),
_byte_map(NULL),
byte_map_base(NULL)
byte_map_base(NULL),
_defer_initial_card_mark(false)
{
assert((uintptr_t(_whole_heap.start()) & (card_size - 1)) == 0, "heap must start at card boundary");
assert((uintptr_t(_whole_heap.end()) & (card_size - 1)) == 0, "heap must end at card boundary");
@ -75,6 +77,7 @@ CardTableModRefBS::CardTableModRefBS(
}
void CardTableModRefBS::initialize() {
initialize_deferred_card_mark_barriers();
_guard_index = cards_required(_whole_heap.word_size()) - 1;
_last_valid_index = _guard_index - 1;
@ -521,3 +524,112 @@ void CardTableModRefBS::print_on(outputStream* st) const {
st->print_cr("Card table byte_map: [" INTPTR_FORMAT "," INTPTR_FORMAT "] byte_map_base: " INTPTR_FORMAT,
p2i(_byte_map), p2i(_byte_map + _byte_map_size), p2i(byte_map_base));
}
// Helper for ReduceInitialCardMarks. For performance,
// compiled code may elide card-marks for initializing stores
// to a newly allocated object along the fast-path. We
// compensate for such elided card-marks as follows:
// (a) Generational, non-concurrent collectors, such as
// GenCollectedHeap(ParNew,DefNew,Tenured) and
// ParallelScavengeHeap(ParallelGC, ParallelOldGC)
// need the card-mark if and only if the region is
// in the old gen, and do not care if the card-mark
// succeeds or precedes the initializing stores themselves,
// so long as the card-mark is completed before the next
// scavenge. For all these cases, we can do a card mark
// at the point at which we do a slow path allocation
// in the old gen, i.e. in this call.
// (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
// in addition that the card-mark for an old gen allocated
// object strictly follow any associated initializing stores.
// In these cases, the memRegion remembered below is
// used to card-mark the entire region either just before the next
// slow-path allocation by this thread or just before the next scavenge or
// CMS-associated safepoint, whichever of these events happens first.
// (The implicit assumption is that the object has been fully
// initialized by this point, a fact that we assert when doing the
// card-mark.)
// (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
// G1 concurrent marking is in progress an SATB (pre-write-)barrier
// is used to remember the pre-value of any store. Initializing
// stores will not need this barrier, so we need not worry about
// compensating for the missing pre-barrier here. Turning now
// to the post-barrier, we note that G1 needs a RS update barrier
// which simply enqueues a (sequence of) dirty cards which may
// optionally be refined by the concurrent update threads. Note
// that this barrier need only be applied to a non-young write,
// but, like in CMS, because of the presence of concurrent refinement
// (much like CMS' precleaning), must strictly follow the oop-store.
// Thus, using the same protocol for maintaining the intended
// invariants turns out, serendepitously, to be the same for both
// G1 and CMS.
//
// For any future collector, this code should be reexamined with
// that specific collector in mind, and the documentation above suitably
// extended and updated.
void CardTableModRefBS::on_slowpath_allocation_exit(JavaThread* thread, oop new_obj) {
if (!ReduceInitialCardMarks) {
return;
}
// If a previous card-mark was deferred, flush it now.
flush_deferred_card_mark_barrier(thread);
if (new_obj->is_typeArray() || is_in_young(new_obj)) {
// Arrays of non-references don't need a post-barrier.
// The deferred_card_mark region should be empty
// following the flush above.
assert(thread->deferred_card_mark().is_empty(), "Error");
} else {
MemRegion mr((HeapWord*)new_obj, new_obj->size());
assert(!mr.is_empty(), "Error");
if (_defer_initial_card_mark) {
// Defer the card mark
thread->set_deferred_card_mark(mr);
} else {
// Do the card mark
write_region(mr);
}
}
}
void CardTableModRefBS::initialize_deferred_card_mark_barriers() {
// Used for ReduceInitialCardMarks (when COMPILER2 or JVMCI is used);
// otherwise remains unused.
#if defined(COMPILER2) || INCLUDE_JVMCI
_defer_initial_card_mark = is_server_compilation_mode_vm() && ReduceInitialCardMarks && can_elide_tlab_store_barriers()
&& (DeferInitialCardMark || card_mark_must_follow_store());
#else
assert(_defer_initial_card_mark == false, "Who would set it?");
#endif
}
void CardTableModRefBS::flush_deferred_card_mark_barrier(JavaThread* thread) {
#if defined(COMPILER2) || INCLUDE_JVMCI
MemRegion deferred = thread->deferred_card_mark();
if (!deferred.is_empty()) {
assert(_defer_initial_card_mark, "Otherwise should be empty");
{
// Verify that the storage points to a parsable object in heap
DEBUG_ONLY(oop old_obj = oop(deferred.start());)
assert(!is_in_young(old_obj),
"Else should have been filtered in on_slowpath_allocation_exit()");
assert(oopDesc::is_oop(old_obj, true), "Not an oop");
assert(deferred.word_size() == (size_t)(old_obj->size()),
"Mismatch: multiple objects?");
}
write_region(deferred);
// "Clear" the deferred_card_mark field
thread->set_deferred_card_mark(MemRegion());
}
assert(thread->deferred_card_mark().is_empty(), "invariant");
#else
assert(!_defer_initial_card_mark, "Should be false");
assert(thread->deferred_card_mark().is_empty(), "Should be empty");
#endif
}
void CardTableModRefBS::flush_deferred_barriers(JavaThread* thread) {
// The deferred store barriers must all have been flushed to the
// card-table (or other remembered set structure) before GC starts
// processing the card-table (or other remembered set).
flush_deferred_card_mark_barrier(thread);
}

53
src/hotspot/share/gc/shared/cardTableModRefBS.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/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
@ -58,6 +58,10 @@ class CardTableModRefBS: public ModRefBarrierSet {
CT_MR_BS_last_reserved = 16
};
// Used in support of ReduceInitialCardMarks; only consulted if COMPILER2
// or INCLUDE_JVMCI is being used
bool _defer_initial_card_mark;
// a word's worth (row) of clean card values
static const intptr_t clean_card_row = (intptr_t)(-1);
@ -180,8 +184,8 @@ class CardTableModRefBS: public ModRefBarrierSet {
CardTableModRefBS(MemRegion whole_heap, const BarrierSet::FakeRtti& fake_rtti);
~CardTableModRefBS();
protected:
void write_region_work(MemRegion mr) {
public:
void write_region(MemRegion mr) {
dirty_MemRegion(mr);
}
@ -314,6 +318,49 @@ class CardTableModRefBS: public ModRefBarrierSet {
void verify_not_dirty_region(MemRegion mr) PRODUCT_RETURN;
void verify_dirty_region(MemRegion mr) PRODUCT_RETURN;
// ReduceInitialCardMarks
void initialize_deferred_card_mark_barriers();
// If the CollectedHeap was asked to defer a store barrier above,
// this informs it to flush such a deferred store barrier to the
// remembered set.
void flush_deferred_card_mark_barrier(JavaThread* thread);
// Can a compiler initialize a new object without store barriers?
// This permission only extends from the creation of a new object
// via a TLAB up to the first subsequent safepoint. If such permission
// is granted for this heap type, the compiler promises to call
// defer_store_barrier() below on any slow path allocation of
// a new object for which such initializing store barriers will
// have been elided. G1, like CMS, allows this, but should be
// ready to provide a compensating write barrier as necessary
// if that storage came out of a non-young region. The efficiency
// of this implementation depends crucially on being able to
// answer very efficiently in constant time whether a piece of
// storage in the heap comes from a young region or not.
// See ReduceInitialCardMarks.
virtual bool can_elide_tlab_store_barriers() const {
return true;
}
// If a compiler is eliding store barriers for TLAB-allocated objects,
// we will be informed of a slow-path allocation by a call
// to on_slowpath_allocation_exit() below. Such a call precedes the
// initialization of the object itself, and no post-store-barriers will
// be issued. Some heap types require that the barrier strictly follows
// the initializing stores. (This is currently implemented by deferring the
// barrier until the next slow-path allocation or gc-related safepoint.)
// This interface answers whether a particular barrier type needs the card
// mark to be thus strictly sequenced after the stores.
virtual bool card_mark_must_follow_store() const = 0;
virtual bool is_in_young(oop obj) const = 0;
virtual void on_slowpath_allocation_exit(JavaThread* thread, oop new_obj);
virtual void flush_deferred_barriers(JavaThread* thread);
virtual void make_parsable(JavaThread* thread) { flush_deferred_card_mark_barrier(thread); }
template <DecoratorSet decorators, typename BarrierSetT = CardTableModRefBS>
class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> {};
};

5
src/hotspot/share/gc/shared/cardTableModRefBSForCTRS.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2018, Oracle and/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
@ -121,3 +121,6 @@ void CardTableModRefBSForCTRS::non_clean_card_iterate_possibly_parallel(
}
}
bool CardTableModRefBSForCTRS::is_in_young(oop obj) const {
return GenCollectedHeap::heap()->is_in_young(obj);
}

8
src/hotspot/share/gc/shared/cardTableModRefBSForCTRS.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2015, 2018, Oracle and/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
@ -43,6 +43,12 @@ public:
void set_CTRS(CardTableRS* rs) { _rs = rs; }
virtual bool card_mark_must_follow_store() const {
return UseConcMarkSweepGC;
}
virtual bool is_in_young(oop obj) const;
private:
CardTableRS* _rs;

116
src/hotspot/share/gc/shared/collectedHeap.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -177,8 +177,7 @@ CollectedHeap::CollectedHeap() :
_total_collections(0),
_total_full_collections(0),
_gc_cause(GCCause::_no_gc),
_gc_lastcause(GCCause::_no_gc),
_defer_initial_card_mark(false) // strengthened by subclass in pre_initialize() below.
_gc_lastcause(GCCause::_no_gc)
{
const size_t max_len = size_t(arrayOopDesc::max_array_length(T_INT));
const size_t elements_per_word = HeapWordSize / sizeof(jint);
@ -239,17 +238,6 @@ void CollectedHeap::set_barrier_set(BarrierSet* barrier_set) {
BarrierSet::set_bs(barrier_set);
}
void CollectedHeap::pre_initialize() {
// Used for ReduceInitialCardMarks (when COMPILER2 is used);
// otherwise remains unused.
#if COMPILER2_OR_JVMCI
_defer_initial_card_mark = is_server_compilation_mode_vm() && ReduceInitialCardMarks && can_elide_tlab_store_barriers()
&& (DeferInitialCardMark || card_mark_must_follow_store());
#else
assert(_defer_initial_card_mark == false, "Who would set it?");
#endif
}
#ifndef PRODUCT
void CollectedHeap::check_for_bad_heap_word_value(HeapWord* addr, size_t size) {
if (CheckMemoryInitialization && ZapUnusedHeapArea) {
@ -333,28 +321,6 @@ HeapWord* CollectedHeap::allocate_from_tlab_slow(Klass* klass, Thread* thread, s
return obj;
}
void CollectedHeap::flush_deferred_store_barrier(JavaThread* thread) {
MemRegion deferred = thread->deferred_card_mark();
if (!deferred.is_empty()) {
assert(_defer_initial_card_mark, "Otherwise should be empty");
{
// Verify that the storage points to a parsable object in heap
DEBUG_ONLY(oop old_obj = oop(deferred.start());)
assert(is_in(old_obj), "Not in allocated heap");
assert(!can_elide_initializing_store_barrier(old_obj),
"Else should have been filtered in new_store_pre_barrier()");
assert(oopDesc::is_oop(old_obj, true), "Not an oop");
assert(deferred.word_size() == (size_t)(old_obj->size()),
"Mismatch: multiple objects?");
}
BarrierSet* bs = barrier_set();
bs->write_region(deferred);
// "Clear" the deferred_card_mark field
thread->set_deferred_card_mark(MemRegion());
}
assert(thread->deferred_card_mark().is_empty(), "invariant");
}
size_t CollectedHeap::max_tlab_size() const {
// TLABs can't be bigger than we can fill with a int[Integer.MAX_VALUE].
// This restriction could be removed by enabling filling with multiple arrays.
@ -370,72 +336,6 @@ size_t CollectedHeap::max_tlab_size() const {
return align_down(max_int_size, MinObjAlignment);
}
// Helper for ReduceInitialCardMarks. For performance,
// compiled code may elide card-marks for initializing stores
// to a newly allocated object along the fast-path. We
// compensate for such elided card-marks as follows:
// (a) Generational, non-concurrent collectors, such as
// GenCollectedHeap(ParNew,DefNew,Tenured) and
// ParallelScavengeHeap(ParallelGC, ParallelOldGC)
// need the card-mark if and only if the region is
// in the old gen, and do not care if the card-mark
// succeeds or precedes the initializing stores themselves,
// so long as the card-mark is completed before the next
// scavenge. For all these cases, we can do a card mark
// at the point at which we do a slow path allocation
// in the old gen, i.e. in this call.
// (b) GenCollectedHeap(ConcurrentMarkSweepGeneration) requires
// in addition that the card-mark for an old gen allocated
// object strictly follow any associated initializing stores.
// In these cases, the memRegion remembered below is
// used to card-mark the entire region either just before the next
// slow-path allocation by this thread or just before the next scavenge or
// CMS-associated safepoint, whichever of these events happens first.
// (The implicit assumption is that the object has been fully
// initialized by this point, a fact that we assert when doing the
// card-mark.)
// (c) G1CollectedHeap(G1) uses two kinds of write barriers. When a
// G1 concurrent marking is in progress an SATB (pre-write-)barrier
// is used to remember the pre-value of any store. Initializing
// stores will not need this barrier, so we need not worry about
// compensating for the missing pre-barrier here. Turning now
// to the post-barrier, we note that G1 needs a RS update barrier
// which simply enqueues a (sequence of) dirty cards which may
// optionally be refined by the concurrent update threads. Note
// that this barrier need only be applied to a non-young write,
// but, like in CMS, because of the presence of concurrent refinement
// (much like CMS' precleaning), must strictly follow the oop-store.
// Thus, using the same protocol for maintaining the intended
// invariants turns out, serendepitously, to be the same for both
// G1 and CMS.
//
// For any future collector, this code should be reexamined with
// that specific collector in mind, and the documentation above suitably
// extended and updated.
oop CollectedHeap::new_store_pre_barrier(JavaThread* thread, oop new_obj) {
// If a previous card-mark was deferred, flush it now.
flush_deferred_store_barrier(thread);
if (can_elide_initializing_store_barrier(new_obj) ||
new_obj->is_typeArray()) {
// Arrays of non-references don't need a pre-barrier.
// The deferred_card_mark region should be empty
// following the flush above.
assert(thread->deferred_card_mark().is_empty(), "Error");
} else {
MemRegion mr((HeapWord*)new_obj, new_obj->size());
assert(!mr.is_empty(), "Error");
if (_defer_initial_card_mark) {
// Defer the card mark
thread->set_deferred_card_mark(mr);
} else {
// Do the card mark
BarrierSet* bs = barrier_set();
bs->write_region(mr);
}
}
return new_obj;
}
size_t CollectedHeap::filler_array_hdr_size() {
return align_object_offset(arrayOopDesc::header_size(T_INT)); // align to Long
}
@ -538,24 +438,16 @@ void CollectedHeap::ensure_parsability(bool retire_tlabs) {
" otherwise concurrent mutator activity may make heap "
" unparsable again");
const bool use_tlab = UseTLAB;
const bool deferred = _defer_initial_card_mark;
// The main thread starts allocating via a TLAB even before it
// has added itself to the threads list at vm boot-up.
JavaThreadIteratorWithHandle jtiwh;
assert(!use_tlab || jtiwh.length() > 0,
"Attempt to fill tlabs before main thread has been added"
" to threads list is doomed to failure!");
BarrierSet *bs = barrier_set();
for (; JavaThread *thread = jtiwh.next(); ) {
if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
#if COMPILER2_OR_JVMCI
// The deferred store barriers must all have been flushed to the
// card-table (or other remembered set structure) before GC starts
// processing the card-table (or other remembered set).
if (deferred) flush_deferred_store_barrier(thread);
#else
assert(!deferred, "Should be false");
assert(thread->deferred_card_mark().is_empty(), "Should be empty");
#endif
bs->make_parsable(thread);
}
}

52
src/hotspot/share/gc/shared/collectedHeap.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -101,10 +101,6 @@ class CollectedHeap : public CHeapObj<mtInternal> {
GCHeapLog* _gc_heap_log;
// Used in support of ReduceInitialCardMarks; only consulted if COMPILER2
// or INCLUDE_JVMCI is being used
bool _defer_initial_card_mark;
MemRegion _reserved;
protected:
@ -129,13 +125,6 @@ class CollectedHeap : public CHeapObj<mtInternal> {
// Constructor
CollectedHeap();
// Do common initializations that must follow instance construction,
// for example, those needing virtual calls.
// This code could perhaps be moved into initialize() but would
// be slightly more awkward because we want the latter to be a
// pure virtual.
void pre_initialize();
// Create a new tlab. All TLAB allocations must go through this.
virtual HeapWord* allocate_new_tlab(size_t size);
@ -408,45 +397,6 @@ class CollectedHeap : public CHeapObj<mtInternal> {
return 0;
}
// Can a compiler initialize a new object without store barriers?
// This permission only extends from the creation of a new object
// via a TLAB up to the first subsequent safepoint. If such permission
// is granted for this heap type, the compiler promises to call
// defer_store_barrier() below on any slow path allocation of
// a new object for which such initializing store barriers will
// have been elided.
virtual bool can_elide_tlab_store_barriers() const = 0;
// If a compiler is eliding store barriers for TLAB-allocated objects,
// there is probably a corresponding slow path which can produce
// an object allocated anywhere. The compiler's runtime support
// promises to call this function on such a slow-path-allocated
// object before performing initializations that have elided
// store barriers. Returns new_obj, or maybe a safer copy thereof.
virtual oop new_store_pre_barrier(JavaThread* thread, oop new_obj);
// Answers whether an initializing store to a new object currently
// allocated at the given address doesn't need a store
// barrier. Returns "true" if it doesn't need an initializing
// store barrier; answers "false" if it does.
virtual bool can_elide_initializing_store_barrier(oop new_obj) = 0;
// If a compiler is eliding store barriers for TLAB-allocated objects,
// we will be informed of a slow-path allocation by a call
// to new_store_pre_barrier() above. Such a call precedes the
// initialization of the object itself, and no post-store-barriers will
// be issued. Some heap types require that the barrier strictly follows
// the initializing stores. (This is currently implemented by deferring the
// barrier until the next slow-path allocation or gc-related safepoint.)
// This interface answers whether a particular heap type needs the card
// mark to be thus strictly sequenced after the stores.
virtual bool card_mark_must_follow_store() const = 0;
// If the CollectedHeap was asked to defer a store barrier above,
// this informs it to flush such a deferred store barrier to the
// remembered set.
virtual void flush_deferred_store_barrier(JavaThread* thread);
// Perform a collection of the heap; intended for use in implementing
// "System.gc". This probably implies as full a collection as the
// "CollectedHeap" supports.

4
src/hotspot/share/gc/shared/genCollectedHeap.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/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
@ -71,8 +71,6 @@ GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
}
jint GenCollectedHeap::initialize() {
CollectedHeap::pre_initialize();
// While there are no constraints in the GC code that HeapWordSize
// be any particular value, there are multiple other areas in the
// system which believe this to be true (e.g. oop->object_size in some

18
src/hotspot/share/gc/shared/genCollectedHeap.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/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
@ -270,22 +270,6 @@ public:
virtual size_t unsafe_max_tlab_alloc(Thread* thr) const;
virtual HeapWord* allocate_new_tlab(size_t size);
// Can a compiler initialize a new object without store barriers?
// This permission only extends from the creation of a new object
// via a TLAB up to the first subsequent safepoint.
virtual bool can_elide_tlab_store_barriers() const {
return true;
}
// We don't need barriers for stores to objects in the
// young gen and, a fortiori, for initializing stores to
// objects therein. This applies to DefNew+Tenured and ParNew+CMS
// only and may need to be re-examined in case other
// kinds of collectors are implemented in the future.
virtual bool can_elide_initializing_store_barrier(oop new_obj) {
return is_in_young(new_obj);
}
// The "requestor" generation is performing some garbage collection
// action for which it would be useful to have scratch space. The
// requestor promises to allocate no more than "max_alloc_words" in any

3
src/hotspot/share/gc/shared/modRefBarrierSet.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/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
@ -45,6 +45,7 @@ public:
// Causes all refs in "mr" to be assumed to be modified.
virtual void invalidate(MemRegion mr) = 0;
virtual void write_region(MemRegion mr) = 0;
// The caller guarantees that "mr" contains no references. (Perhaps it's
// objects have been moved elsewhere.)

27
src/hotspot/share/jvmci/jvmciRuntime.cpp
View file

@ -116,10 +116,7 @@ JRT_BLOCK_ENTRY(void, JVMCIRuntime::new_instance(JavaThread* thread, Klass* klas
oop obj = ik->allocate_instance(CHECK);
thread->set_vm_result(obj);
JRT_BLOCK_END;
if (ReduceInitialCardMarks) {
new_store_pre_barrier(thread);
}
SharedRuntime::on_slowpath_allocation_exit(thread);
JRT_END
JRT_BLOCK_ENTRY(void, JVMCIRuntime::new_array(JavaThread* thread, Klass* array_klass, jint length))
@ -151,29 +148,9 @@ JRT_BLOCK_ENTRY(void, JVMCIRuntime::new_array(JavaThread* thread, Klass* array_k
}
}
JRT_BLOCK_END;
if (ReduceInitialCardMarks) {
new_store_pre_barrier(thread);
}
SharedRuntime::on_slowpath_allocation_exit(thread);
JRT_END
void JVMCIRuntime::new_store_pre_barrier(JavaThread* thread) {
// After any safepoint, just before going back to compiled code,
// we inform the GC that we will be doing initializing writes to
// this object in the future without emitting card-marks, so
// GC may take any compensating steps.
// NOTE: Keep this code consistent with GraphKit::store_barrier.
oop new_obj = thread->vm_result();
if (new_obj == NULL) return;
assert(Universe::heap()->can_elide_tlab_store_barriers(),
"compiler must check this first");
// GC may decide to give back a safer copy of new_obj.
new_obj = Universe::heap()->new_store_pre_barrier(thread, new_obj);
thread->set_vm_result(new_obj);
}
JRT_ENTRY(void, JVMCIRuntime::new_multi_array(JavaThread* thread, Klass* klass, int rank, jint* dims))
assert(klass->is_klass(), "not a class");
assert(rank >= 1, "rank must be nonzero");

3
src/hotspot/share/jvmci/jvmciRuntime.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2012, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2012, 2018, Oracle and/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
@ -154,7 +154,6 @@ class JVMCIRuntime: public AllStatic {
static void write_barrier_pre(JavaThread* thread, oopDesc* obj);
static void write_barrier_post(JavaThread* thread, void* card);
static jboolean validate_object(JavaThread* thread, oopDesc* parent, oopDesc* child);
static void new_store_pre_barrier(JavaThread* thread);
// used to throw exceptions from compiled JVMCI code
static void throw_and_post_jvmti_exception(JavaThread* thread, const char* exception, const char* message);

6
src/hotspot/share/opto/graphKit.cpp
View file

@ -3861,7 +3861,7 @@ void GraphKit::write_barrier_post(Node* oop_store,
if (use_ReduceInitialCardMarks()
&& obj == just_allocated_object(control())) {
// We can skip marks on a freshly-allocated object in Eden.
// Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
// Keep this code in sync with new_deferred_store_barrier() in runtime.cpp.
// That routine informs GC to take appropriate compensating steps,
// upon a slow-path allocation, so as to make this card-mark
// elision safe.
@ -4159,7 +4159,7 @@ void GraphKit::g1_write_barrier_pre(bool do_load,
* as part of the allocation in the case the allocated object is not located
* in the nursery, this would happen for humongous objects. This is similar to
* how CMS is required to handle this case, see the comments for the method
* CollectedHeap::new_store_pre_barrier and OptoRuntime::new_store_pre_barrier.
* CardTableModRefBS::on_allocation_slowpath_exit and OptoRuntime::new_deferred_store_barrier.
* A deferred card mark is required for these objects and handled in the above
* mentioned methods.
*
@ -4249,7 +4249,7 @@ void GraphKit::g1_write_barrier_post(Node* oop_store,
if (use_ReduceInitialCardMarks() && obj == just_allocated_object(control())) {
// We can skip marks on a freshly-allocated object in Eden.
// Keep this code in sync with new_store_pre_barrier() in runtime.cpp.
// Keep this code in sync with new_deferred_store_barrier() in runtime.cpp.
// That routine informs GC to take appropriate compensating steps,
// upon a slow-path allocation, so as to make this card-mark
// elision safe.

8
src/hotspot/share/opto/graphKit.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2018, Oracle and/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
@ -755,8 +755,10 @@ class GraphKit : public Phase {
Node* just_allocated_object(Node* current_control);
static bool use_ReduceInitialCardMarks() {
return (ReduceInitialCardMarks
&& Universe::heap()->can_elide_tlab_store_barriers());
BarrierSet *bs = Universe::heap()->barrier_set();
return bs->is_a(BarrierSet::CardTableModRef)
&& barrier_set_cast<CardTableModRefBS>(bs)->can_elide_tlab_store_barriers()
&& ReduceInitialCardMarks;
}
// Sync Ideal and Graph kits.

38
src/hotspot/share/opto/runtime.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2018, Oracle and/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
@ -194,23 +194,6 @@ const char* OptoRuntime::stub_name(address entry) {
// We failed the fast-path allocation. Now we need to do a scavenge or GC
// and try allocation again.
void OptoRuntime::new_store_pre_barrier(JavaThread* thread) {
// After any safepoint, just before going back to compiled code,
// we inform the GC that we will be doing initializing writes to
// this object in the future without emitting card-marks, so
// GC may take any compensating steps.
// NOTE: Keep this code consistent with GraphKit::store_barrier.
oop new_obj = thread->vm_result();
if (new_obj == NULL) return;
assert(Universe::heap()->can_elide_tlab_store_barriers(),
"compiler must check this first");
// GC may decide to give back a safer copy of new_obj.
new_obj = Universe::heap()->new_store_pre_barrier(thread, new_obj);
thread->set_vm_result(new_obj);
}
// object allocation
JRT_BLOCK_ENTRY(void, OptoRuntime::new_instance_C(Klass* klass, JavaThread* thread))
JRT_BLOCK;
@ -244,10 +227,8 @@ JRT_BLOCK_ENTRY(void, OptoRuntime::new_instance_C(Klass* klass, JavaThread* thre
deoptimize_caller_frame(thread, HAS_PENDING_EXCEPTION);
JRT_BLOCK_END;
if (GraphKit::use_ReduceInitialCardMarks()) {
// inform GC that we won't do card marks for initializing writes.
new_store_pre_barrier(thread);
}
// inform GC that we won't do card marks for initializing writes.
SharedRuntime::on_slowpath_allocation_exit(thread);
JRT_END
@ -284,10 +265,8 @@ JRT_BLOCK_ENTRY(void, OptoRuntime::new_array_C(Klass* array_type, int len, JavaT
thread->set_vm_result(result);
JRT_BLOCK_END;
if (GraphKit::use_ReduceInitialCardMarks()) {
// inform GC that we won't do card marks for initializing writes.
new_store_pre_barrier(thread);
}
// inform GC that we won't do card marks for initializing writes.
SharedRuntime::on_slowpath_allocation_exit(thread);
JRT_END
// array allocation without zeroing
@ -314,10 +293,9 @@ JRT_BLOCK_ENTRY(void, OptoRuntime::new_array_nozero_C(Klass* array_type, int len
thread->set_vm_result(result);
JRT_BLOCK_END;
if (GraphKit::use_ReduceInitialCardMarks()) {
// inform GC that we won't do card marks for initializing writes.
new_store_pre_barrier(thread);
}
// inform GC that we won't do card marks for initializing writes.
SharedRuntime::on_slowpath_allocation_exit(thread);
oop result = thread->vm_result();
if ((len > 0) && (result != NULL) &&

6
src/hotspot/share/opto/runtime.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2015, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2018, Oracle and/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
@ -163,10 +163,6 @@ class OptoRuntime : public AllStatic {
static void new_array_C(Klass* array_klass, int len, JavaThread *thread);
static void new_array_nozero_C(Klass* array_klass, int len, JavaThread *thread);
// Post-slow-path-allocation, pre-initializing-stores step for
// implementing ReduceInitialCardMarks
static void new_store_pre_barrier(JavaThread* thread);
// Allocate storage for a multi-dimensional arrays
// Note: needs to be fixed for arbitrary number of dimensions
static void multianewarray2_C(Klass* klass, int len1, int len2, JavaThread *thread);

15
src/hotspot/share/runtime/sharedRuntime.cpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2018, Oracle and/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
@ -3169,3 +3169,16 @@ frame SharedRuntime::look_for_reserved_stack_annotated_method(JavaThread* thread
}
return activation;
}
void SharedRuntime::on_slowpath_allocation_exit(JavaThread* thread) {
// After any safepoint, just before going back to compiled code,
// we inform the GC that we will be doing initializing writes to
// this object in the future without emitting card-marks, so
// GC may take any compensating steps.
oop new_obj = thread->vm_result();
if (new_obj == NULL) return;
BarrierSet *bs = Universe::heap()->barrier_set();
bs->on_slowpath_allocation_exit(thread, new_obj);
}

6
src/hotspot/share/runtime/sharedRuntime.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1997, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1997, 2018, Oracle and/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
@ -211,6 +211,10 @@ class SharedRuntime: AllStatic {
static address deoptimize_for_implicit_exception(JavaThread* thread, address pc, CompiledMethod* nm, int deopt_reason);
#endif
// Post-slow-path-allocation, pre-initializing-stores step for
// implementing e.g. ReduceInitialCardMarks
static void on_slowpath_allocation_exit(JavaThread* thread);
static void enable_stack_reserved_zone(JavaThread* thread);
static frame look_for_reserved_stack_annotated_method(JavaThread* thread, frame fr);

18
src/hotspot/share/runtime/thread.cpp
View file

@ -1994,20 +1994,10 @@ void JavaThread::exit(bool destroy_vm, ExitType exit_type) {
JvmtiExport::cleanup_thread(this);
}
// We must flush any deferred card marks before removing a thread from
// the list of active threads.
Universe::heap()->flush_deferred_store_barrier(this);
assert(deferred_card_mark().is_empty(), "Should have been flushed");
#if INCLUDE_ALL_GCS
// We must flush the G1-related buffers before removing a thread
// from the list of active threads. We must do this after any deferred
// card marks have been flushed (above) so that any entries that are
// added to the thread's dirty card queue as a result are not lost.
if (UseG1GC) {
flush_barrier_queues();
}
#endif // INCLUDE_ALL_GCS
// We must flush any deferred card marks and other various GC barrier
// related buffers (e.g. G1 SATB buffer and G1 dirty card queue buffer)
// before removing a thread from the list of active threads.
BarrierSet::barrier_set()->flush_deferred_barriers(this);
log_info(os, thread)("JavaThread %s (tid: " UINTX_FORMAT ").",
exit_type == JavaThread::normal_exit ? "exiting" : "detaching",

2
src/hotspot/share/runtime/vmStructs.cpp
View file

@ -466,6 +466,7 @@ typedef PaddedEnd<ObjectMonitor> PaddedObjectMonitor;
nonstatic_field(CardGeneration, _capacity_at_prologue, size_t) \
nonstatic_field(CardGeneration, _used_at_prologue, size_t) \
\
nonstatic_field(CardTableModRefBS, _defer_initial_card_mark, bool) \
nonstatic_field(CardTableModRefBS, _whole_heap, const MemRegion) \
nonstatic_field(CardTableModRefBS, _guard_index, const size_t) \
nonstatic_field(CardTableModRefBS, _last_valid_index, const size_t) \
@ -482,7 +483,6 @@ typedef PaddedEnd<ObjectMonitor> PaddedObjectMonitor;
\
nonstatic_field(CollectedHeap, _reserved, MemRegion) \
nonstatic_field(CollectedHeap, _barrier_set, BarrierSet*) \
nonstatic_field(CollectedHeap, _defer_initial_card_mark, bool) \
nonstatic_field(CollectedHeap, _is_gc_active, bool) \
nonstatic_field(CollectedHeap, _total_collections, unsigned int) \
\