--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -1441,6 +1441,7 @@
}
jint G1CollectedHeap::initialize() {
+ CollectedHeap::pre_initialize();
os::enable_vtime();
// Necessary to satisfy locking discipline assertions.
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -1007,6 +1007,10 @@
return true;
}
+ virtual bool card_mark_must_follow_store() const {
+ return true;
+ }
+
bool is_in_young(oop obj) {
HeapRegion* hr = heap_region_containing(obj);
return hr != NULL && hr->is_young();
--- a/hotspot/src/share/vm/gc_implementation/g1/ptrQueue.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/ptrQueue.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -73,7 +73,12 @@
void PtrQueue::locking_enqueue_completed_buffer(void** buf) {
assert(_lock->owned_by_self(), "Required.");
+
+ // We have to unlock _lock (which may be Shared_DirtyCardQ_lock) before
+ // we acquire DirtyCardQ_CBL_mon inside enqeue_complete_buffer as they
+ // have the same rank and we may get the "possible deadlock" message
_lock->unlock();
+
qset()->enqueue_complete_buffer(buf);
// We must relock only because the caller will unlock, for the normal
// case.
@@ -140,7 +145,36 @@
// holding the lock if there is one).
if (_buf != NULL) {
if (_lock) {
- locking_enqueue_completed_buffer(_buf);
+ assert(_lock->owned_by_self(), "Required.");
+
+ // The current PtrQ may be the shared dirty card queue and
+ // may be being manipulated by more than one worker thread
+ // during a pause. Since the enqueuing of the completed
+ // buffer unlocks the Shared_DirtyCardQ_lock more than one
+ // worker thread can 'race' on reading the shared queue attributes
+ // (_buf and _index) and multiple threads can call into this
+ // routine for the same buffer. This will cause the completed
+ // buffer to be added to the CBL multiple times.
+
+ // We "claim" the current buffer by caching value of _buf in
+ // a local and clearing the field while holding _lock. When
+ // _lock is released (while enqueueing the completed buffer)
+ // the thread that acquires _lock will skip this code,
+ // preventing the subsequent the multiple enqueue, and
+ // install a newly allocated buffer below.
+
+ void** buf = _buf; // local pointer to completed buffer
+ _buf = NULL; // clear shared _buf field
+
+ locking_enqueue_completed_buffer(buf); // enqueue completed buffer
+
+ // While the current thread was enqueuing the buffer another thread
+ // may have a allocated a new buffer and inserted it into this pointer
+ // queue. If that happens then we just return so that the current
+ // thread doesn't overwrite the buffer allocated by the other thread
+ // and potentially losing some dirtied cards.
+
+ if (_buf != NULL) return;
} else {
if (qset()->process_or_enqueue_complete_buffer(_buf)) {
// Recycle the buffer. No allocation.
--- a/hotspot/src/share/vm/gc_implementation/g1/ptrQueue.inline.hpp Wed Jul 05 17:05:40 2017 +0200
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,41 +0,0 @@
-/*
- * Copyright 2001-2007 Sun Microsystems, Inc. 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.
- *
- * This code is distributed in the hope that it will be useful, but WITHOUT
- * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
- * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
- * version 2 for more details (a copy is included in the LICENSE file that
- * accompanied this code).
- *
- * You should have received a copy of the GNU General Public License version
- * 2 along with this work; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
- *
- */
-
-void PtrQueue::handle_zero_index() {
- assert(0 == _index, "Precondition.");
- // This thread records the full buffer and allocates a new one (while
- // holding the lock if there is one).
- void** buf = _buf;
- _buf = qset()->allocate_buffer();
- _sz = qset()->buffer_size();
- _index = _sz;
- assert(0 <= _index && _index <= _sz, "Invariant.");
- if (buf != NULL) {
- if (_lock) {
- locking_enqueue_completed_buffer(buf);
- } else {
- qset()->enqueue_complete_buffer(buf);
- }
- }
-}
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -51,6 +51,8 @@
}
jint ParallelScavengeHeap::initialize() {
+ CollectedHeap::pre_initialize();
+
// Cannot be initialized until after the flags are parsed
GenerationSizer flag_parser;
@@ -717,10 +719,6 @@
return young_gen()->allocate(size, true);
}
-void ParallelScavengeHeap::fill_all_tlabs(bool retire) {
- CollectedHeap::fill_all_tlabs(retire);
-}
-
void ParallelScavengeHeap::accumulate_statistics_all_tlabs() {
CollectedHeap::accumulate_statistics_all_tlabs();
}
--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -54,7 +54,6 @@
protected:
static inline size_t total_invocations();
HeapWord* allocate_new_tlab(size_t size);
- void fill_all_tlabs(bool retire);
public:
ParallelScavengeHeap() : CollectedHeap() {
@@ -191,6 +190,10 @@
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);
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -59,8 +59,18 @@
PerfDataManager::create_string_variable(SUN_GC, "lastCause",
80, GCCause::to_string(_gc_lastcause), CHECK);
}
+ _defer_initial_card_mark = false; // strengthened by subclass in pre_initialize() below.
}
+void CollectedHeap::pre_initialize() {
+ // Used for ReduceInitialCardMarks (when COMPILER2 is used);
+ // otherwise remains unused.
+#ifdef COMPLER2
+ _defer_initial_card_mark = ReduceInitialCardMarks && (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) {
@@ -140,12 +150,13 @@
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 defer_store_barrier()");
+ "Else should have been filtered in new_store_pre_barrier()");
assert(!is_in_permanent(old_obj), "Sanity: not expected");
assert(old_obj->is_oop(true), "Not an oop");
assert(old_obj->is_parsable(), "Will not be concurrently parsable");
@@ -174,9 +185,7 @@
// 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. For uniformity, however, we end
-// up using the same scheme (see below) for all three
-// cases (deferring the card-mark appropriately).
+// 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.
@@ -199,12 +208,13 @@
// 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 all
-// three collectors/heap types above.
+// invariants turns out, serendepitously, to be the same for both
+// G1 and CMS.
//
-// For each future collector, this should be reexamined with
-// that specific collector in mind.
-oop CollectedHeap::defer_store_barrier(JavaThread* thread, oop new_obj) {
+// 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)) {
@@ -212,10 +222,17 @@
// following the flush above.
assert(thread->deferred_card_mark().is_empty(), "Error");
} else {
- // Remember info for the newly deferred store barrier
- MemRegion deferred = MemRegion((HeapWord*)new_obj, new_obj->size());
- assert(!deferred.is_empty(), "Error");
- thread->set_deferred_card_mark(deferred);
+ 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();
+ assert(bs->has_write_region_opt(), "No write_region() on BarrierSet");
+ bs->write_region(mr);
+ }
}
return new_obj;
}
@@ -241,9 +258,9 @@
assert(Universe::heap()->is_in_reserved(start + words - 1), "not in heap");
}
-void CollectedHeap::zap_filler_array(HeapWord* start, size_t words)
+void CollectedHeap::zap_filler_array(HeapWord* start, size_t words, bool zap)
{
- if (ZapFillerObjects) {
+ if (ZapFillerObjects && zap) {
Copy::fill_to_words(start + filler_array_hdr_size(),
words - filler_array_hdr_size(), 0XDEAFBABE);
}
@@ -251,7 +268,7 @@
#endif // ASSERT
void
-CollectedHeap::fill_with_array(HeapWord* start, size_t words)
+CollectedHeap::fill_with_array(HeapWord* start, size_t words, bool zap)
{
assert(words >= filler_array_min_size(), "too small for an array");
assert(words <= filler_array_max_size(), "too big for a single object");
@@ -262,16 +279,16 @@
// Set the length first for concurrent GC.
((arrayOop)start)->set_length((int)len);
post_allocation_setup_common(Universe::intArrayKlassObj(), start, words);
- DEBUG_ONLY(zap_filler_array(start, words);)
+ DEBUG_ONLY(zap_filler_array(start, words, zap);)
}
void
-CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words)
+CollectedHeap::fill_with_object_impl(HeapWord* start, size_t words, bool zap)
{
assert(words <= filler_array_max_size(), "too big for a single object");
if (words >= filler_array_min_size()) {
- fill_with_array(start, words);
+ fill_with_array(start, words, zap);
} else if (words > 0) {
assert(words == min_fill_size(), "unaligned size");
post_allocation_setup_common(SystemDictionary::Object_klass(), start,
@@ -279,14 +296,14 @@
}
}
-void CollectedHeap::fill_with_object(HeapWord* start, size_t words)
+void CollectedHeap::fill_with_object(HeapWord* start, size_t words, bool zap)
{
DEBUG_ONLY(fill_args_check(start, words);)
HandleMark hm; // Free handles before leaving.
- fill_with_object_impl(start, words);
+ fill_with_object_impl(start, words, zap);
}
-void CollectedHeap::fill_with_objects(HeapWord* start, size_t words)
+void CollectedHeap::fill_with_objects(HeapWord* start, size_t words, bool zap)
{
DEBUG_ONLY(fill_args_check(start, words);)
HandleMark hm; // Free handles before leaving.
@@ -299,13 +316,13 @@
const size_t max = filler_array_max_size();
while (words > max) {
const size_t cur = words - max >= min ? max : max - min;
- fill_with_array(start, cur);
+ fill_with_array(start, cur, zap);
start += cur;
words -= cur;
}
#endif
- fill_with_object_impl(start, words);
+ fill_with_object_impl(start, words, zap);
}
HeapWord* CollectedHeap::allocate_new_tlab(size_t size) {
@@ -313,22 +330,6 @@
return NULL;
}
-void CollectedHeap::fill_all_tlabs(bool retire) {
- assert(UseTLAB, "should not reach here");
- // See note in ensure_parsability() below.
- assert(SafepointSynchronize::is_at_safepoint() ||
- !is_init_completed(),
- "should only fill tlabs at safepoint");
- // The main thread starts allocating via a TLAB even before it
- // has added itself to the threads list at vm boot-up.
- assert(Threads::first() != NULL,
- "Attempt to fill tlabs before main thread has been added"
- " to threads list is doomed to failure!");
- for(JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
- thread->tlab().make_parsable(retire);
- }
-}
-
void CollectedHeap::ensure_parsability(bool retire_tlabs) {
// The second disjunct in the assertion below makes a concession
// for the start-up verification done while the VM is being
@@ -343,8 +344,24 @@
"Should only be called at a safepoint or at start-up"
" otherwise concurrent mutator activity may make heap "
" unparsable again");
- if (UseTLAB) {
- fill_all_tlabs(retire_tlabs);
+ 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.
+ assert(!use_tlab || Threads::first() != NULL,
+ "Attempt to fill tlabs before main thread has been added"
+ " to threads list is doomed to failure!");
+ for (JavaThread *thread = Threads::first(); thread; thread = thread->next()) {
+ if (use_tlab) thread->tlab().make_parsable(retire_tlabs);
+#ifdef COMPILER2
+ // 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
}
}
--- a/hotspot/src/share/vm/gc_interface/collectedHeap.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/gc_interface/collectedHeap.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -51,6 +51,9 @@
// Used for filler objects (static, but initialized in ctor).
static size_t _filler_array_max_size;
+ // Used in support of ReduceInitialCardMarks; only consulted if COMPILER2 is being used
+ bool _defer_initial_card_mark;
+
protected:
MemRegion _reserved;
BarrierSet* _barrier_set;
@@ -70,13 +73,16 @@
// 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
virtual HeapWord* allocate_new_tlab(size_t size);
- // Fix up tlabs to make the heap well-formed again,
- // optionally retiring the tlabs.
- virtual void fill_all_tlabs(bool retire);
-
// Accumulate statistics on all tlabs.
virtual void accumulate_statistics_all_tlabs();
@@ -127,14 +133,14 @@
static inline size_t filler_array_max_size();
DEBUG_ONLY(static void fill_args_check(HeapWord* start, size_t words);)
- DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words);)
+ DEBUG_ONLY(static void zap_filler_array(HeapWord* start, size_t words, bool zap = true);)
// Fill with a single array; caller must ensure filler_array_min_size() <=
// words <= filler_array_max_size().
- static inline void fill_with_array(HeapWord* start, size_t words);
+ static inline void fill_with_array(HeapWord* start, size_t words, bool zap = true);
// Fill with a single object (either an int array or a java.lang.Object).
- static inline void fill_with_object_impl(HeapWord* start, size_t words);
+ static inline void fill_with_object_impl(HeapWord* start, size_t words, bool zap = true);
// Verification functions
virtual void check_for_bad_heap_word_value(HeapWord* addr, size_t size)
@@ -338,14 +344,14 @@
return size_t(align_object_size(oopDesc::header_size()));
}
- static void fill_with_objects(HeapWord* start, size_t words);
+ static void fill_with_objects(HeapWord* start, size_t words, bool zap = true);
- static void fill_with_object(HeapWord* start, size_t words);
- static void fill_with_object(MemRegion region) {
- fill_with_object(region.start(), region.word_size());
+ static void fill_with_object(HeapWord* start, size_t words, bool zap = true);
+ static void fill_with_object(MemRegion region, bool zap = true) {
+ fill_with_object(region.start(), region.word_size(), zap);
}
- static void fill_with_object(HeapWord* start, HeapWord* end) {
- fill_with_object(start, pointer_delta(end, start));
+ static void fill_with_object(HeapWord* start, HeapWord* end, bool zap = true) {
+ fill_with_object(start, pointer_delta(end, start), zap);
}
// Some heaps may offer a contiguous region for shared non-blocking
@@ -431,14 +437,25 @@
// 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 defer_store_barrier(JavaThread* thread, oop new_obj);
+ 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 (deferred) store
+ // 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.
--- a/hotspot/src/share/vm/memory/genCollectedHeap.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -51,6 +51,8 @@
}
jint GenCollectedHeap::initialize() {
+ CollectedHeap::pre_initialize();
+
int i;
_n_gens = gen_policy()->number_of_generations();
@@ -129,6 +131,7 @@
_rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
set_barrier_set(rem_set()->bs());
+
_gch = this;
for (i = 0; i < _n_gens; i++) {
--- a/hotspot/src/share/vm/memory/genCollectedHeap.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -260,6 +260,10 @@
return true;
}
+ virtual bool card_mark_must_follow_store() const {
+ return UseConcMarkSweepGC;
+ }
+
// 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,ParNew}+{Tenured,CMS}
--- a/hotspot/src/share/vm/memory/threadLocalAllocBuffer.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/memory/threadLocalAllocBuffer.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -100,7 +100,7 @@
void ThreadLocalAllocBuffer::make_parsable(bool retire) {
if (end() != NULL) {
invariants();
- CollectedHeap::fill_with_object(top(), hard_end());
+ CollectedHeap::fill_with_object(top(), hard_end(), retire);
if (retire || ZeroTLAB) { // "Reset" the TLAB
set_start(NULL);
--- a/hotspot/src/share/vm/memory/threadLocalAllocBuffer.inline.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/memory/threadLocalAllocBuffer.inline.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright 1999-2007 Sun Microsystems, Inc. All Rights Reserved.
+ * Copyright 1999-2009 Sun Microsystems, Inc. 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
@@ -27,8 +27,13 @@
HeapWord* obj = top();
if (pointer_delta(end(), obj) >= size) {
// successful thread-local allocation
-
- DEBUG_ONLY(Copy::fill_to_words(obj, size, badHeapWordVal));
+#ifdef ASSERT
+ // Skip mangling the space corresponding to the object header to
+ // ensure that the returned space is not considered parsable by
+ // any concurrent GC thread.
+ size_t hdr_size = CollectedHeap::min_fill_size();
+ Copy::fill_to_words(obj + hdr_size, size - hdr_size, badHeapWordVal);
+#endif // ASSERT
// This addition is safe because we know that top is
// at least size below end, so the add can't wrap.
set_top(obj + size);
--- a/hotspot/src/share/vm/opto/graphKit.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/opto/graphKit.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -3259,9 +3259,10 @@
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 maybe_defer_card_mark() in runtime.cpp.
- // That routine informs GC to take appropriate compensating steps
- // so as to make this card-mark elision safe.
+ // Keep this code in sync with new_store_pre_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.
return;
}
--- a/hotspot/src/share/vm/opto/runtime.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/opto/runtime.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -143,7 +143,7 @@
// We failed the fast-path allocation. Now we need to do a scavenge or GC
// and try allocation again.
-void OptoRuntime::maybe_defer_card_mark(JavaThread* thread) {
+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
@@ -156,7 +156,7 @@
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()->defer_store_barrier(thread, new_obj);
+ new_obj = Universe::heap()->new_store_pre_barrier(thread, new_obj);
thread->set_vm_result(new_obj);
}
@@ -200,7 +200,7 @@
if (GraphKit::use_ReduceInitialCardMarks()) {
// inform GC that we won't do card marks for initializing writes.
- maybe_defer_card_mark(thread);
+ new_store_pre_barrier(thread);
}
JRT_END
@@ -239,7 +239,7 @@
if (GraphKit::use_ReduceInitialCardMarks()) {
// inform GC that we won't do card marks for initializing writes.
- maybe_defer_card_mark(thread);
+ new_store_pre_barrier(thread);
}
JRT_END
--- a/hotspot/src/share/vm/opto/runtime.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/opto/runtime.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -133,8 +133,9 @@
// Allocate storage for a objArray or typeArray
static void new_array_C(klassOopDesc* array_klass, int len, JavaThread *thread);
- // Post-slow-path-allocation step for implementing ReduceInitialCardMarks:
- static void maybe_defer_card_mark(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
--- a/hotspot/src/share/vm/runtime/globals.hpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/runtime/globals.hpp Tue Jan 19 14:23:18 2010 -0800
@@ -2012,6 +2012,10 @@
diagnostic(bool, GCParallelVerificationEnabled, true, \
"Enable parallel memory system verification") \
\
+ diagnostic(bool, DeferInitialCardMark, false, \
+ "When +ReduceInitialCardMarks, explicitly defer any that " \
+ "may arise from new_pre_store_barrier") \
+ \
diagnostic(bool, VerifyRememberedSets, false, \
"Verify GC remembered sets") \
\
--- a/hotspot/src/share/vm/runtime/thread.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/runtime/thread.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -2357,9 +2357,8 @@
};
void JavaThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
- // Flush deferred store-barriers, if any, associated with
- // initializing stores done by this JavaThread in the current epoch.
- Universe::heap()->flush_deferred_store_barrier(this);
+ // Verify that the deferred card marks have been flushed.
+ assert(deferred_card_mark().is_empty(), "Should be empty during GC");
// The ThreadProfiler oops_do is done from FlatProfiler::oops_do
// since there may be more than one thread using each ThreadProfiler.
--- a/hotspot/src/share/vm/runtime/vmStructs.cpp Wed Jul 05 17:05:40 2017 +0200
+++ b/hotspot/src/share/vm/runtime/vmStructs.cpp Tue Jan 19 14:23:18 2010 -0800
@@ -309,6 +309,7 @@
nonstatic_field(CollectedHeap, _reserved, MemRegion) \
nonstatic_field(SharedHeap, _perm_gen, PermGen*) \
nonstatic_field(CollectedHeap, _barrier_set, BarrierSet*) \
+ nonstatic_field(CollectedHeap, _defer_initial_card_mark, bool) \
nonstatic_field(CollectedHeap, _is_gc_active, bool) \
nonstatic_field(CompactibleSpace, _compaction_top, HeapWord*) \
nonstatic_field(CompactibleSpace, _first_dead, HeapWord*) \