--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.cpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -31,6 +31,7 @@
#include "gc_implementation/g1/g1ErgoVerbose.hpp"
#include "gc_implementation/g1/g1OopClosures.inline.hpp"
#include "gc_implementation/g1/g1RemSet.hpp"
+#include "gc_implementation/g1/heapRegion.inline.hpp"
#include "gc_implementation/g1/heapRegionRemSet.hpp"
#include "gc_implementation/g1/heapRegionSeq.inline.hpp"
#include "gc_implementation/shared/vmGCOperations.hpp"
@@ -183,12 +184,11 @@
void CMMarkStack::allocate(size_t size) {
_base = NEW_C_HEAP_ARRAY(oop, size);
if (_base == NULL) {
- vm_exit_during_initialization("Failed to allocate "
- "CM region mark stack");
+ vm_exit_during_initialization("Failed to allocate CM region mark stack");
}
_index = 0;
_capacity = (jint) size;
- _oops_do_bound = -1;
+ _saved_index = -1;
NOT_PRODUCT(_max_depth = 0);
}
@@ -283,7 +283,6 @@
}
}
-
CMRegionStack::CMRegionStack() : _base(NULL) {}
void CMRegionStack::allocate(size_t size) {
@@ -302,6 +301,8 @@
}
void CMRegionStack::push_lock_free(MemRegion mr) {
+ guarantee(false, "push_lock_free(): don't call this any more");
+
assert(mr.word_size() > 0, "Precondition");
while (true) {
jint index = _index;
@@ -325,6 +326,8 @@
// marking / remark phases. Should only be called in tandem with
// other lock-free pops.
MemRegion CMRegionStack::pop_lock_free() {
+ guarantee(false, "pop_lock_free(): don't call this any more");
+
while (true) {
jint index = _index;
@@ -390,6 +393,8 @@
#endif
bool CMRegionStack::invalidate_entries_into_cset() {
+ guarantee(false, "invalidate_entries_into_cset(): don't call this any more");
+
bool result = false;
G1CollectedHeap* g1h = G1CollectedHeap::heap();
for (int i = 0; i < _oops_do_bound; ++i) {
@@ -438,14 +443,29 @@
return res;
}
+void CMMarkStack::note_start_of_gc() {
+ assert(_saved_index == -1,
+ "note_start_of_gc()/end_of_gc() bracketed incorrectly");
+ _saved_index = _index;
+}
+
+void CMMarkStack::note_end_of_gc() {
+ // This is intentionally a guarantee, instead of an assert. If we
+ // accidentally add something to the mark stack during GC, it
+ // will be a correctness issue so it's better if we crash. we'll
+ // only check this once per GC anyway, so it won't be a performance
+ // issue in any way.
+ guarantee(_saved_index == _index,
+ err_msg("saved index: %d index: %d", _saved_index, _index));
+ _saved_index = -1;
+}
+
void CMMarkStack::oops_do(OopClosure* f) {
- if (_index == 0) return;
- assert(_oops_do_bound != -1 && _oops_do_bound <= _index,
- "Bound must be set.");
- for (int i = 0; i < _oops_do_bound; i++) {
+ assert(_saved_index == _index,
+ err_msg("saved index: %d index: %d", _saved_index, _index));
+ for (int i = 0; i < _index; i += 1) {
f->do_oop(&_base[i]);
}
- _oops_do_bound = -1;
}
bool ConcurrentMark::not_yet_marked(oop obj) const {
@@ -783,7 +803,7 @@
public:
bool doHeapRegion(HeapRegion* r) {
if (!r->continuesHumongous()) {
- r->note_start_of_marking(true);
+ r->note_start_of_marking();
}
return false;
}
@@ -804,6 +824,10 @@
// Initialise marking structures. This has to be done in a STW phase.
reset();
+
+ // For each region note start of marking.
+ NoteStartOfMarkHRClosure startcl;
+ g1h->heap_region_iterate(&startcl);
}
@@ -818,10 +842,6 @@
// every remark and we'll eventually not need to cause one.
force_overflow_stw()->init();
- // For each region note start of marking.
- NoteStartOfMarkHRClosure startcl;
- g1h->heap_region_iterate(&startcl);
-
// Start Concurrent Marking weak-reference discovery.
ReferenceProcessor* rp = g1h->ref_processor_cm();
// enable ("weak") refs discovery
@@ -946,22 +966,9 @@
}
#endif // !PRODUCT
-void ConcurrentMark::grayRoot(oop p) {
- HeapWord* addr = (HeapWord*) p;
- // We can't really check against _heap_start and _heap_end, since it
- // is possible during an evacuation pause with piggy-backed
- // initial-mark that the committed space is expanded during the
- // pause without CM observing this change. So the assertions below
- // is a bit conservative; but better than nothing.
- assert(_g1h->g1_committed().contains(addr),
- "address should be within the heap bounds");
-
- if (!_nextMarkBitMap->isMarked(addr)) {
- _nextMarkBitMap->parMark(addr);
- }
-}
-
void ConcurrentMark::grayRegionIfNecessary(MemRegion mr) {
+ guarantee(false, "grayRegionIfNecessary(): don't call this any more");
+
// The objects on the region have already been marked "in bulk" by
// the caller. We only need to decide whether to push the region on
// the region stack or not.
@@ -1007,6 +1014,8 @@
}
void ConcurrentMark::markAndGrayObjectIfNecessary(oop p) {
+ guarantee(false, "markAndGrayObjectIfNecessary(): don't call this any more");
+
// The object is not marked by the caller. We need to at least mark
// it and maybe push in on the stack.
@@ -1224,7 +1233,6 @@
true /* expected_active */);
if (VerifyDuringGC) {
-
HandleMark hm; // handle scope
gclog_or_tty->print(" VerifyDuringGC:(after)");
Universe::heap()->prepare_for_verify();
@@ -1879,10 +1887,6 @@
double end = os::elapsedTime();
_cleanup_times.add((end - start) * 1000.0);
- // G1CollectedHeap::heap()->print();
- // gclog_or_tty->print_cr("HEAP GC TIME STAMP : %d",
- // G1CollectedHeap::heap()->get_gc_time_stamp());
-
if (PrintGC || PrintGCDetails) {
g1h->print_size_transition(gclog_or_tty,
start_used_bytes,
@@ -2669,6 +2673,8 @@
}
void ConcurrentMark::drainAllSATBBuffers() {
+ guarantee(false, "drainAllSATBBuffers(): don't call this any more");
+
CMGlobalObjectClosure oc(this);
SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
satb_mq_set.set_closure(&oc);
@@ -2687,12 +2693,6 @@
assert(satb_mq_set.completed_buffers_num() == 0, "invariant");
}
-void ConcurrentMark::markPrev(oop p) {
- // Note we are overriding the read-only view of the prev map here, via
- // the cast.
- ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*)p);
-}
-
void ConcurrentMark::clear(oop p) {
assert(p != NULL && p->is_oop(), "expected an oop");
HeapWord* addr = (HeapWord*)p;
@@ -2702,13 +2702,21 @@
_nextMarkBitMap->clear(addr);
}
-void ConcurrentMark::clearRangeBothMaps(MemRegion mr) {
+void ConcurrentMark::clearRangePrevBitmap(MemRegion mr) {
// Note we are overriding the read-only view of the prev map here, via
// the cast.
((CMBitMap*)_prevMarkBitMap)->clearRange(mr);
+}
+
+void ConcurrentMark::clearRangeNextBitmap(MemRegion mr) {
_nextMarkBitMap->clearRange(mr);
}
+void ConcurrentMark::clearRangeBothBitmaps(MemRegion mr) {
+ clearRangePrevBitmap(mr);
+ clearRangeNextBitmap(mr);
+}
+
HeapRegion*
ConcurrentMark::claim_region(int task_num) {
// "checkpoint" the finger
@@ -2803,6 +2811,9 @@
}
bool ConcurrentMark::invalidate_aborted_regions_in_cset() {
+ guarantee(false, "invalidate_aborted_regions_in_cset(): "
+ "don't call this any more");
+
bool result = false;
for (int i = 0; i < (int)_max_task_num; ++i) {
CMTask* the_task = _tasks[i];
@@ -2854,24 +2865,135 @@
// ...then over the contents of the all the task queues.
queue->oops_do(cl);
}
-
- // Invalidate any entries, that are in the region stack, that
- // point into the collection set
- if (_regionStack.invalidate_entries_into_cset()) {
- // otherwise, any gray objects copied during the evacuation pause
- // might not be visited.
- assert(_should_gray_objects, "invariant");
+}
+
+#ifndef PRODUCT
+enum VerifyNoCSetOopsPhase {
+ VerifyNoCSetOopsStack,
+ VerifyNoCSetOopsQueues,
+ VerifyNoCSetOopsSATBCompleted,
+ VerifyNoCSetOopsSATBThread
+};
+
+class VerifyNoCSetOopsClosure : public OopClosure, public ObjectClosure {
+private:
+ G1CollectedHeap* _g1h;
+ VerifyNoCSetOopsPhase _phase;
+ int _info;
+
+ const char* phase_str() {
+ switch (_phase) {
+ case VerifyNoCSetOopsStack: return "Stack";
+ case VerifyNoCSetOopsQueues: return "Queue";
+ case VerifyNoCSetOopsSATBCompleted: return "Completed SATB Buffers";
+ case VerifyNoCSetOopsSATBThread: return "Thread SATB Buffers";
+ default: ShouldNotReachHere();
+ }
+ return NULL;
+ }
+
+ void do_object_work(oop obj) {
+ guarantee(!_g1h->obj_in_cs(obj),
+ err_msg("obj: "PTR_FORMAT" in CSet, phase: %s, info: %d",
+ (void*) obj, phase_str(), _info));
+ }
+
+public:
+ VerifyNoCSetOopsClosure() : _g1h(G1CollectedHeap::heap()) { }
+
+ void set_phase(VerifyNoCSetOopsPhase phase, int info = -1) {
+ _phase = phase;
+ _info = info;
+ }
+
+ virtual void do_oop(oop* p) {
+ oop obj = oopDesc::load_decode_heap_oop(p);
+ do_object_work(obj);
+ }
+
+ virtual void do_oop(narrowOop* p) {
+ // We should not come across narrow oops while scanning marking
+ // stacks and SATB buffers.
+ ShouldNotReachHere();
+ }
+
+ virtual void do_object(oop obj) {
+ do_object_work(obj);
+ }
+};
+
+void ConcurrentMark::verify_no_cset_oops(bool verify_stacks,
+ bool verify_enqueued_buffers,
+ bool verify_thread_buffers,
+ bool verify_fingers) {
+ assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
+ if (!G1CollectedHeap::heap()->mark_in_progress()) {
+ return;
}
- // Invalidate any aborted regions, recorded in the individual CM
- // tasks, that point into the collection set.
- if (invalidate_aborted_regions_in_cset()) {
- // otherwise, any gray objects copied during the evacuation pause
- // might not be visited.
- assert(_should_gray_objects, "invariant");
+ VerifyNoCSetOopsClosure cl;
+
+ if (verify_stacks) {
+ // Verify entries on the global mark stack
+ cl.set_phase(VerifyNoCSetOopsStack);
+ _markStack.oops_do(&cl);
+
+ // Verify entries on the task queues
+ for (int i = 0; i < (int) _max_task_num; i += 1) {
+ cl.set_phase(VerifyNoCSetOopsQueues, i);
+ OopTaskQueue* queue = _task_queues->queue(i);
+ queue->oops_do(&cl);
+ }
+ }
+
+ SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set();
+
+ // Verify entries on the enqueued SATB buffers
+ if (verify_enqueued_buffers) {
+ cl.set_phase(VerifyNoCSetOopsSATBCompleted);
+ satb_qs.iterate_completed_buffers_read_only(&cl);
+ }
+
+ // Verify entries on the per-thread SATB buffers
+ if (verify_thread_buffers) {
+ cl.set_phase(VerifyNoCSetOopsSATBThread);
+ satb_qs.iterate_thread_buffers_read_only(&cl);
}
+ if (verify_fingers) {
+ // Verify the global finger
+ HeapWord* global_finger = finger();
+ if (global_finger != NULL && global_finger < _heap_end) {
+ // The global finger always points to a heap region boundary. We
+ // use heap_region_containing_raw() to get the containing region
+ // given that the global finger could be pointing to a free region
+ // which subsequently becomes continues humongous. If that
+ // happens, heap_region_containing() will return the bottom of the
+ // corresponding starts humongous region and the check below will
+ // not hold any more.
+ HeapRegion* global_hr = _g1h->heap_region_containing_raw(global_finger);
+ guarantee(global_finger == global_hr->bottom(),
+ err_msg("global finger: "PTR_FORMAT" region: "HR_FORMAT,
+ global_finger, HR_FORMAT_PARAMS(global_hr)));
+ }
+
+ // Verify the task fingers
+ assert(parallel_marking_threads() <= _max_task_num, "sanity");
+ for (int i = 0; i < (int) parallel_marking_threads(); i += 1) {
+ CMTask* task = _tasks[i];
+ HeapWord* task_finger = task->finger();
+ if (task_finger != NULL && task_finger < _heap_end) {
+ // See above note on the global finger verification.
+ HeapRegion* task_hr = _g1h->heap_region_containing_raw(task_finger);
+ guarantee(task_finger == task_hr->bottom() ||
+ !task_hr->in_collection_set(),
+ err_msg("task finger: "PTR_FORMAT" region: "HR_FORMAT,
+ task_finger, HR_FORMAT_PARAMS(task_hr)));
+ }
+ }
+ }
}
+#endif // PRODUCT
void ConcurrentMark::clear_marking_state(bool clear_overflow) {
_markStack.setEmpty();
@@ -3080,19 +3202,6 @@
}
};
-class SetClaimValuesInCSetHRClosure: public HeapRegionClosure {
- jint _claim_value;
-
-public:
- SetClaimValuesInCSetHRClosure(jint claim_value) :
- _claim_value(claim_value) { }
-
- bool doHeapRegion(HeapRegion* hr) {
- hr->set_claim_value(_claim_value);
- return false;
- }
-};
-
class G1ParCompleteMarkInCSetTask: public AbstractGangTask {
protected:
G1CollectedHeap* _g1h;
@@ -3112,6 +3221,9 @@
};
void ConcurrentMark::complete_marking_in_collection_set() {
+ guarantee(false, "complete_marking_in_collection_set(): "
+ "don't call this any more");
+
G1CollectedHeap* g1h = G1CollectedHeap::heap();
if (!g1h->mark_in_progress()) {
@@ -3135,9 +3247,8 @@
assert(g1h->check_cset_heap_region_claim_values(HeapRegion::CompleteMarkCSetClaimValue), "sanity");
- // Now reset the claim values in the regions in the collection set.
- SetClaimValuesInCSetHRClosure set_cv_cl(HeapRegion::InitialClaimValue);
- g1h->collection_set_iterate(&set_cv_cl);
+ // Reset the claim values in the regions in the collection set.
+ g1h->reset_cset_heap_region_claim_values();
assert(g1h->check_cset_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity");
@@ -3160,6 +3271,8 @@
// newCSet().
void ConcurrentMark::newCSet() {
+ guarantee(false, "newCSet(): don't call this any more");
+
if (!concurrent_marking_in_progress()) {
// nothing to do if marking is not in progress
return;
@@ -3198,6 +3311,8 @@
}
void ConcurrentMark::registerCSetRegion(HeapRegion* hr) {
+ guarantee(false, "registerCSetRegion(): don't call this any more");
+
if (!concurrent_marking_in_progress()) return;
HeapWord* region_end = hr->end();
@@ -3209,6 +3324,9 @@
// Resets the region fields of active CMTasks whose values point
// into the collection set.
void ConcurrentMark::reset_active_task_region_fields_in_cset() {
+ guarantee(false, "reset_active_task_region_fields_in_cset(): "
+ "don't call this any more");
+
assert(SafepointSynchronize::is_at_safepoint(), "should be in STW");
assert(parallel_marking_threads() <= _max_task_num, "sanity");
@@ -3919,6 +4037,10 @@
}
void CMTask::drain_region_stack(BitMapClosure* bc) {
+ assert(_cm->region_stack_empty(), "region stack should be empty");
+ assert(_aborted_region.is_empty(), "aborted region should be empty");
+ return;
+
if (has_aborted()) return;
assert(_region_finger == NULL,
--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -166,10 +166,10 @@
// Ideally this should be GrowableArray<> just like MSC's marking stack(s).
class CMMarkStack VALUE_OBJ_CLASS_SPEC {
ConcurrentMark* _cm;
- oop* _base; // bottom of stack
- jint _index; // one more than last occupied index
- jint _capacity; // max #elements
- jint _oops_do_bound; // Number of elements to include in next iteration.
+ oop* _base; // bottom of stack
+ jint _index; // one more than last occupied index
+ jint _capacity; // max #elements
+ jint _saved_index; // value of _index saved at start of GC
NOT_PRODUCT(jint _max_depth;) // max depth plumbed during run
bool _overflow;
@@ -247,16 +247,12 @@
void setEmpty() { _index = 0; clear_overflow(); }
- // Record the current size; a subsequent "oops_do" will iterate only over
- // indices valid at the time of this call.
- void set_oops_do_bound(jint bound = -1) {
- if (bound == -1) {
- _oops_do_bound = _index;
- } else {
- _oops_do_bound = bound;
- }
- }
- jint oops_do_bound() { return _oops_do_bound; }
+ // Record the current index.
+ void note_start_of_gc();
+
+ // Make sure that we have not added any entries to the stack during GC.
+ void note_end_of_gc();
+
// iterate over the oops in the mark stack, up to the bound recorded via
// the call above.
void oops_do(OopClosure* f);
@@ -724,10 +720,9 @@
// G1CollectedHeap
// This notifies CM that a root during initial-mark needs to be
- // grayed and it's MT-safe. Currently, we just mark it. But, in the
- // future, we can experiment with pushing it on the stack and we can
- // do this without changing G1CollectedHeap.
- void grayRoot(oop p);
+ // grayed. It is MT-safe.
+ inline void grayRoot(oop obj, size_t word_size);
+
// It's used during evacuation pauses to gray a region, if
// necessary, and it's MT-safe. It assumes that the caller has
// marked any objects on that region. If _should_gray_objects is
@@ -735,6 +730,7 @@
// pushed on the region stack, if it is located below the global
// finger, otherwise we do nothing.
void grayRegionIfNecessary(MemRegion mr);
+
// It's used during evacuation pauses to mark and, if necessary,
// gray a single object and it's MT-safe. It assumes the caller did
// not mark the object. If _should_gray_objects is true and we're
@@ -791,24 +787,40 @@
// Mark in the previous bitmap. NB: this is usually read-only, so use
// this carefully!
- void markPrev(oop p);
+ inline void markPrev(oop p);
+ inline void markNext(oop p);
void clear(oop p);
- // Clears marks for all objects in the given range, for both prev and
- // next bitmaps. NB: the previous bitmap is usually read-only, so use
- // this carefully!
- void clearRangeBothMaps(MemRegion mr);
+ // Clears marks for all objects in the given range, for the prev,
+ // next, or both bitmaps. NB: the previous bitmap is usually
+ // read-only, so use this carefully!
+ void clearRangePrevBitmap(MemRegion mr);
+ void clearRangeNextBitmap(MemRegion mr);
+ void clearRangeBothBitmaps(MemRegion mr);
- // Record the current top of the mark and region stacks; a
- // subsequent oops_do() on the mark stack and
- // invalidate_entries_into_cset() on the region stack will iterate
- // only over indices valid at the time of this call.
- void set_oops_do_bound() {
- _markStack.set_oops_do_bound();
- _regionStack.set_oops_do_bound();
+ // Notify data structures that a GC has started.
+ void note_start_of_gc() {
+ _markStack.note_start_of_gc();
}
+
+ // Notify data structures that a GC is finished.
+ void note_end_of_gc() {
+ _markStack.note_end_of_gc();
+ }
+
// Iterate over the oops in the mark stack and all local queues. It
// also calls invalidate_entries_into_cset() on the region stack.
void oops_do(OopClosure* f);
+
+ // Verify that there are no CSet oops on the stacks (taskqueues /
+ // global mark stack), enqueued SATB buffers, per-thread SATB
+ // buffers, and fingers (global / per-task). The boolean parameters
+ // decide which of the above data structures to verify. If marking
+ // is not in progress, it's a no-op.
+ void verify_no_cset_oops(bool verify_stacks,
+ bool verify_enqueued_buffers,
+ bool verify_thread_buffers,
+ bool verify_fingers) PRODUCT_RETURN;
+
// It is called at the end of an evacuation pause during marking so
// that CM is notified of where the new end of the heap is. It
// doesn't do anything if concurrent_marking_in_progress() is false,
@@ -1166,6 +1178,7 @@
// It keeps picking SATB buffers and processing them until no SATB
// buffers are available.
void drain_satb_buffers();
+
// It keeps popping regions from the region stack and processing
// them until the region stack is empty.
void drain_region_stack(BitMapClosure* closure);
--- a/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -153,4 +153,46 @@
}
}
+inline void ConcurrentMark::markPrev(oop p) {
+ assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity");
+ // Note we are overriding the read-only view of the prev map here, via
+ // the cast.
+ ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p);
+}
+
+inline void ConcurrentMark::markNext(oop p) {
+ assert(!_nextMarkBitMap->isMarked((HeapWord*) p), "sanity");
+ _nextMarkBitMap->mark((HeapWord*) p);
+}
+
+inline void ConcurrentMark::grayRoot(oop obj, size_t word_size) {
+ HeapWord* addr = (HeapWord*) obj;
+
+ // Currently we don't do anything with word_size but we will use it
+ // in the very near future in the liveness calculation piggy-backing
+ // changes.
+
+#ifdef ASSERT
+ HeapRegion* hr = _g1h->heap_region_containing(addr);
+ assert(hr != NULL, "sanity");
+ assert(!hr->is_survivor(), "should not allocate survivors during IM");
+ assert(addr < hr->next_top_at_mark_start(),
+ err_msg("addr: "PTR_FORMAT" hr: "HR_FORMAT" NTAMS: "PTR_FORMAT,
+ addr, HR_FORMAT_PARAMS(hr), hr->next_top_at_mark_start()));
+ // We cannot assert that word_size == obj->size() given that obj
+ // might not be in a consistent state (another thread might be in
+ // the process of copying it). So the best thing we can do is to
+ // assert that word_size is under an upper bound which is its
+ // containing region's capacity.
+ assert(word_size * HeapWordSize <= hr->capacity(),
+ err_msg("size: "SIZE_FORMAT" capacity: "SIZE_FORMAT" "HR_FORMAT,
+ word_size * HeapWordSize, hr->capacity(),
+ HR_FORMAT_PARAMS(hr)));
+#endif // ASSERT
+
+ if (!_nextMarkBitMap->isMarked(addr)) {
+ _nextMarkBitMap->parMark(addr);
+ }
+}
+
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -32,9 +32,11 @@
#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
#include "gc_implementation/g1/g1CollectorPolicy.hpp"
#include "gc_implementation/g1/g1ErgoVerbose.hpp"
+#include "gc_implementation/g1/g1EvacFailure.hpp"
#include "gc_implementation/g1/g1MarkSweep.hpp"
#include "gc_implementation/g1/g1OopClosures.inline.hpp"
#include "gc_implementation/g1/g1RemSet.inline.hpp"
+#include "gc_implementation/g1/heapRegion.inline.hpp"
#include "gc_implementation/g1/heapRegionRemSet.hpp"
#include "gc_implementation/g1/heapRegionSeq.inline.hpp"
#include "gc_implementation/g1/vm_operations_g1.hpp"
@@ -591,17 +593,29 @@
}
res = new_region_try_secondary_free_list();
}
- if (res == NULL && do_expand) {
+ if (res == NULL && do_expand && _expand_heap_after_alloc_failure) {
+ // Currently, only attempts to allocate GC alloc regions set
+ // do_expand to true. So, we should only reach here during a
+ // safepoint. If this assumption changes we might have to
+ // reconsider the use of _expand_heap_after_alloc_failure.
+ assert(SafepointSynchronize::is_at_safepoint(), "invariant");
+
ergo_verbose1(ErgoHeapSizing,
"attempt heap expansion",
ergo_format_reason("region allocation request failed")
ergo_format_byte("allocation request"),
word_size * HeapWordSize);
if (expand(word_size * HeapWordSize)) {
- // Even though the heap was expanded, it might not have reached
- // the desired size. So, we cannot assume that the allocation
- // will succeed.
+ // Given that expand() succeeded in expanding the heap, and we
+ // always expand the heap by an amount aligned to the heap
+ // region size, the free list should in theory not be empty. So
+ // it would probably be OK to use remove_head(). But the extra
+ // check for NULL is unlikely to be a performance issue here (we
+ // just expanded the heap!) so let's just be conservative and
+ // use remove_head_or_null().
res = _free_list.remove_head_or_null();
+ } else {
+ _expand_heap_after_alloc_failure = false;
}
}
return res;
@@ -1838,6 +1852,7 @@
_young_list(new YoungList(this)),
_gc_time_stamp(0),
_retained_old_gc_alloc_region(NULL),
+ _expand_heap_after_alloc_failure(true),
_surviving_young_words(NULL),
_full_collections_completed(0),
_in_cset_fast_test(NULL),
@@ -2605,12 +2620,16 @@
}
};
-void
-G1CollectedHeap::reset_heap_region_claim_values() {
+void G1CollectedHeap::reset_heap_region_claim_values() {
ResetClaimValuesClosure blk;
heap_region_iterate(&blk);
}
+void G1CollectedHeap::reset_cset_heap_region_claim_values() {
+ ResetClaimValuesClosure blk;
+ collection_set_iterate(&blk);
+}
+
#ifdef ASSERT
// This checks whether all regions in the heap have the correct claim
// value. I also piggy-backed on this a check to ensure that the
@@ -3000,14 +3019,20 @@
} else {
VerifyObjsInRegionClosure not_dead_yet_cl(r, _vo);
r->object_iterate(¬_dead_yet_cl);
- if (r->max_live_bytes() < not_dead_yet_cl.live_bytes()) {
- gclog_or_tty->print_cr("["PTR_FORMAT","PTR_FORMAT"] "
- "max_live_bytes "SIZE_FORMAT" "
- "< calculated "SIZE_FORMAT,
- r->bottom(), r->end(),
- r->max_live_bytes(),
+ if (_vo != VerifyOption_G1UseNextMarking) {
+ if (r->max_live_bytes() < not_dead_yet_cl.live_bytes()) {
+ gclog_or_tty->print_cr("["PTR_FORMAT","PTR_FORMAT"] "
+ "max_live_bytes "SIZE_FORMAT" "
+ "< calculated "SIZE_FORMAT,
+ r->bottom(), r->end(),
+ r->max_live_bytes(),
not_dead_yet_cl.live_bytes());
- _failures = true;
+ _failures = true;
+ }
+ } else {
+ // When vo == UseNextMarking we cannot currently do a sanity
+ // check on the live bytes as the calculation has not been
+ // finalized yet.
}
}
}
@@ -3641,25 +3666,6 @@
}
perm_gen()->save_marks();
- // We must do this before any possible evacuation that should propagate
- // marks.
- if (mark_in_progress()) {
- double start_time_sec = os::elapsedTime();
-
- _cm->drainAllSATBBuffers();
- double finish_mark_ms = (os::elapsedTime() - start_time_sec) * 1000.0;
- g1_policy()->record_satb_drain_time(finish_mark_ms);
- }
- // Record the number of elements currently on the mark stack, so we
- // only iterate over these. (Since evacuation may add to the mark
- // stack, doing more exposes race conditions.) If no mark is in
- // progress, this will be zero.
- _cm->set_oops_do_bound();
-
- if (mark_in_progress()) {
- concurrent_mark()->newCSet();
- }
-
#if YOUNG_LIST_VERBOSE
gclog_or_tty->print_cr("\nBefore choosing collection set.\nYoung_list:");
_young_list->print();
@@ -3668,6 +3674,16 @@
g1_policy()->choose_collection_set(target_pause_time_ms);
+ _cm->note_start_of_gc();
+ // We should not verify the per-thread SATB buffers given that
+ // we have not filtered them yet (we'll do so during the
+ // GC). We also call this after choose_collection_set() to
+ // ensure that the CSet has been finalized.
+ _cm->verify_no_cset_oops(true /* verify_stacks */,
+ true /* verify_enqueued_buffers */,
+ false /* verify_thread_buffers */,
+ true /* verify_fingers */);
+
if (_hr_printer.is_active()) {
HeapRegion* hr = g1_policy()->collection_set();
while (hr != NULL) {
@@ -3684,16 +3700,6 @@
}
}
- // We have chosen the complete collection set. If marking is
- // active then, we clear the region fields of any of the
- // concurrent marking tasks whose region fields point into
- // the collection set as these values will become stale. This
- // will cause the owning marking threads to claim a new region
- // when marking restarts.
- if (mark_in_progress()) {
- concurrent_mark()->reset_active_task_region_fields_in_cset();
- }
-
#ifdef ASSERT
VerifyCSetClosure cl;
collection_set_iterate(&cl);
@@ -3707,6 +3713,16 @@
// Actually do the work...
evacuate_collection_set();
+ // We do this to mainly verify the per-thread SATB buffers
+ // (which have been filtered by now) since we didn't verify
+ // them earlier. No point in re-checking the stacks / enqueued
+ // buffers given that the CSet has not changed since last time
+ // we checked.
+ _cm->verify_no_cset_oops(false /* verify_stacks */,
+ false /* verify_enqueued_buffers */,
+ true /* verify_thread_buffers */,
+ true /* verify_fingers */);
+
free_collection_set(g1_policy()->collection_set());
g1_policy()->clear_collection_set();
@@ -3775,6 +3791,8 @@
size_t expand_bytes = g1_policy()->expansion_amount();
if (expand_bytes > 0) {
size_t bytes_before = capacity();
+ // No need for an ergo verbose message here,
+ // expansion_amount() does this when it returns a value > 0.
if (!expand(expand_bytes)) {
// We failed to expand the heap so let's verify that
// committed/uncommitted amount match the backing store
@@ -3784,6 +3802,14 @@
}
}
+ // We redo the verificaiton but now wrt to the new CSet which
+ // has just got initialized after the previous CSet was freed.
+ _cm->verify_no_cset_oops(true /* verify_stacks */,
+ true /* verify_enqueued_buffers */,
+ true /* verify_thread_buffers */,
+ true /* verify_fingers */);
+ _cm->note_end_of_gc();
+
double end_time_sec = os::elapsedTime();
double pause_time_ms = (end_time_sec - start_time_sec) * MILLIUNITS;
g1_policy()->record_pause_time_ms(pause_time_ms);
@@ -3831,21 +3857,6 @@
// CM reference discovery will be re-enabled if necessary.
}
- {
- size_t expand_bytes = g1_policy()->expansion_amount();
- if (expand_bytes > 0) {
- size_t bytes_before = capacity();
- // No need for an ergo verbose message here,
- // expansion_amount() does this when it returns a value > 0.
- if (!expand(expand_bytes)) {
- // We failed to expand the heap so let's verify that
- // committed/uncommitted amount match the backing store
- assert(capacity() == _g1_storage.committed_size(), "committed size mismatch");
- assert(max_capacity() == _g1_storage.reserved_size(), "reserved size mismatch");
- }
- }
- }
-
// We should do this after we potentially expand the heap so
// that all the COMMIT events are generated before the end GC
// event, and after we retire the GC alloc regions so that all
@@ -3949,6 +3960,8 @@
// we allocate to in the region sets. We'll re-add it later, when
// it's retired again.
_old_set.remove(retained_region);
+ bool during_im = g1_policy()->during_initial_mark_pause();
+ retained_region->note_start_of_copying(during_im);
_old_gc_alloc_region.set(retained_region);
_hr_printer.reuse(retained_region);
}
@@ -3985,157 +3998,26 @@
_evac_failure_scan_stack = NULL;
}
-class UpdateRSetDeferred : public OopsInHeapRegionClosure {
-private:
- G1CollectedHeap* _g1;
- DirtyCardQueue *_dcq;
- CardTableModRefBS* _ct_bs;
-
-public:
- UpdateRSetDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) :
- _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) {}
-
- virtual void do_oop(narrowOop* p) { do_oop_work(p); }
- virtual void do_oop( oop* p) { do_oop_work(p); }
- template <class T> void do_oop_work(T* p) {
- assert(_from->is_in_reserved(p), "paranoia");
- if (!_from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) &&
- !_from->is_survivor()) {
- size_t card_index = _ct_bs->index_for(p);
- if (_ct_bs->mark_card_deferred(card_index)) {
- _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index));
- }
- }
- }
-};
-
-class RemoveSelfPointerClosure: public ObjectClosure {
-private:
- G1CollectedHeap* _g1;
- ConcurrentMark* _cm;
- HeapRegion* _hr;
- size_t _prev_marked_bytes;
- size_t _next_marked_bytes;
- OopsInHeapRegionClosure *_cl;
-public:
- RemoveSelfPointerClosure(G1CollectedHeap* g1, HeapRegion* hr,
- OopsInHeapRegionClosure* cl) :
- _g1(g1), _hr(hr), _cm(_g1->concurrent_mark()), _prev_marked_bytes(0),
- _next_marked_bytes(0), _cl(cl) {}
-
- size_t prev_marked_bytes() { return _prev_marked_bytes; }
- size_t next_marked_bytes() { return _next_marked_bytes; }
-
- // <original comment>
- // The original idea here was to coalesce evacuated and dead objects.
- // However that caused complications with the block offset table (BOT).
- // In particular if there were two TLABs, one of them partially refined.
- // |----- TLAB_1--------|----TLAB_2-~~~(partially refined part)~~~|
- // The BOT entries of the unrefined part of TLAB_2 point to the start
- // of TLAB_2. If the last object of the TLAB_1 and the first object
- // of TLAB_2 are coalesced, then the cards of the unrefined part
- // would point into middle of the filler object.
- // The current approach is to not coalesce and leave the BOT contents intact.
- // </original comment>
- //
- // We now reset the BOT when we start the object iteration over the
- // region and refine its entries for every object we come across. So
- // the above comment is not really relevant and we should be able
- // to coalesce dead objects if we want to.
- void do_object(oop obj) {
- HeapWord* obj_addr = (HeapWord*) obj;
- assert(_hr->is_in(obj_addr), "sanity");
- size_t obj_size = obj->size();
- _hr->update_bot_for_object(obj_addr, obj_size);
- if (obj->is_forwarded() && obj->forwardee() == obj) {
- // The object failed to move.
- assert(!_g1->is_obj_dead(obj), "We should not be preserving dead objs.");
- _cm->markPrev(obj);
- assert(_cm->isPrevMarked(obj), "Should be marked!");
- _prev_marked_bytes += (obj_size * HeapWordSize);
- if (_g1->mark_in_progress() && !_g1->is_obj_ill(obj)) {
- _cm->markAndGrayObjectIfNecessary(obj);
- }
- obj->set_mark(markOopDesc::prototype());
- // While we were processing RSet buffers during the
- // collection, we actually didn't scan any cards on the
- // collection set, since we didn't want to update remebered
- // sets with entries that point into the collection set, given
- // that live objects fromthe collection set are about to move
- // and such entries will be stale very soon. This change also
- // dealt with a reliability issue which involved scanning a
- // card in the collection set and coming across an array that
- // was being chunked and looking malformed. The problem is
- // that, if evacuation fails, we might have remembered set
- // entries missing given that we skipped cards on the
- // collection set. So, we'll recreate such entries now.
- obj->oop_iterate(_cl);
- assert(_cm->isPrevMarked(obj), "Should be marked!");
- } else {
- // The object has been either evacuated or is dead. Fill it with a
- // dummy object.
- MemRegion mr((HeapWord*)obj, obj_size);
- CollectedHeap::fill_with_object(mr);
- _cm->clearRangeBothMaps(mr);
- }
- }
-};
-
void G1CollectedHeap::remove_self_forwarding_pointers() {
- UpdateRSetImmediate immediate_update(_g1h->g1_rem_set());
- DirtyCardQueue dcq(&_g1h->dirty_card_queue_set());
- UpdateRSetDeferred deferred_update(_g1h, &dcq);
- OopsInHeapRegionClosure *cl;
- if (G1DeferredRSUpdate) {
- cl = &deferred_update;
+ assert(check_cset_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity");
+ assert(g1_policy()->assertMarkedBytesDataOK(), "Should be!");
+
+ G1ParRemoveSelfForwardPtrsTask rsfp_task(this);
+
+ if (G1CollectedHeap::use_parallel_gc_threads()) {
+ set_par_threads();
+ workers()->run_task(&rsfp_task);
+ set_par_threads(0);
} else {
- cl = &immediate_update;
- }
- HeapRegion* cur = g1_policy()->collection_set();
- while (cur != NULL) {
- assert(g1_policy()->assertMarkedBytesDataOK(), "Should be!");
- assert(!cur->isHumongous(), "sanity");
-
- if (cur->evacuation_failed()) {
- assert(cur->in_collection_set(), "bad CS");
- RemoveSelfPointerClosure rspc(_g1h, cur, cl);
-
- // In the common case we make sure that this is done when the
- // region is freed so that it is "ready-to-go" when it's
- // re-allocated. However, when evacuation failure happens, a
- // region will remain in the heap and might ultimately be added
- // to a CSet in the future. So we have to be careful here and
- // make sure the region's RSet is ready for parallel iteration
- // whenever this might be required in the future.
- cur->rem_set()->reset_for_par_iteration();
- cur->reset_bot();
- cl->set_region(cur);
- cur->object_iterate(&rspc);
-
- // A number of manipulations to make the TAMS be the current top,
- // and the marked bytes be the ones observed in the iteration.
- if (_g1h->concurrent_mark()->at_least_one_mark_complete()) {
- // The comments below are the postconditions achieved by the
- // calls. Note especially the last such condition, which says that
- // the count of marked bytes has been properly restored.
- cur->note_start_of_marking(false);
- // _next_top_at_mark_start == top, _next_marked_bytes == 0
- cur->add_to_marked_bytes(rspc.prev_marked_bytes());
- // _next_marked_bytes == prev_marked_bytes.
- cur->note_end_of_marking();
- // _prev_top_at_mark_start == top(),
- // _prev_marked_bytes == prev_marked_bytes
- }
- // If there is no mark in progress, we modified the _next variables
- // above needlessly, but harmlessly.
- if (_g1h->mark_in_progress()) {
- cur->note_start_of_marking(false);
- // _next_top_at_mark_start == top, _next_marked_bytes == 0
- // _next_marked_bytes == next_marked_bytes.
- }
- }
- cur = cur->next_in_collection_set();
- }
+ rsfp_task.work(0);
+ }
+
+ assert(check_cset_heap_region_claim_values(HeapRegion::ParEvacFailureClaimValue), "sanity");
+
+ // Reset the claim values in the regions in the collection set.
+ reset_cset_heap_region_claim_values();
+
+ assert(check_cset_heap_region_claim_values(HeapRegion::InitialClaimValue), "sanity");
assert(g1_policy()->assertMarkedBytesDataOK(), "Should be!");
// Now restore saved marks, if any.
@@ -4148,6 +4030,7 @@
markOop m = _preserved_marks_of_objs->at(i);
obj->set_mark(m);
}
+
// Delete the preserved marks growable arrays (allocated on the C heap).
delete _objs_with_preserved_marks;
delete _preserved_marks_of_objs;
@@ -4172,8 +4055,7 @@
oop
G1CollectedHeap::handle_evacuation_failure_par(OopsInHeapRegionClosure* cl,
- oop old,
- bool should_mark_root) {
+ oop old) {
assert(obj_in_cs(old),
err_msg("obj: "PTR_FORMAT" should still be in the CSet",
(HeapWord*) old));
@@ -4182,15 +4064,6 @@
if (forward_ptr == NULL) {
// Forward-to-self succeeded.
- // should_mark_root will be true when this routine is called
- // from a root scanning closure during an initial mark pause.
- // In this case the thread that succeeds in self-forwarding the
- // object is also responsible for marking the object.
- if (should_mark_root) {
- assert(!oopDesc::is_null(old), "shouldn't be");
- _cm->grayRoot(old);
- }
-
if (_evac_failure_closure != cl) {
MutexLockerEx x(EvacFailureStack_lock, Mutex::_no_safepoint_check_flag);
assert(!_drain_in_progress,
@@ -4286,30 +4159,8 @@
return NULL;
}
-#ifndef PRODUCT
-bool GCLabBitMapClosure::do_bit(size_t offset) {
- HeapWord* addr = _bitmap->offsetToHeapWord(offset);
- guarantee(_cm->isMarked(oop(addr)), "it should be!");
- return true;
-}
-#endif // PRODUCT
-
G1ParGCAllocBuffer::G1ParGCAllocBuffer(size_t gclab_word_size) :
- ParGCAllocBuffer(gclab_word_size),
- _should_mark_objects(false),
- _bitmap(G1CollectedHeap::heap()->reserved_region().start(), gclab_word_size),
- _retired(false)
-{
- //_should_mark_objects is set to true when G1ParCopyHelper needs to
- // mark the forwarded location of an evacuated object.
- // We set _should_mark_objects to true if marking is active, i.e. when we
- // need to propagate a mark, or during an initial mark pause, i.e. when we
- // need to mark objects immediately reachable by the roots.
- if (G1CollectedHeap::heap()->mark_in_progress() ||
- G1CollectedHeap::heap()->g1_policy()->during_initial_mark_pause()) {
- _should_mark_objects = true;
- }
-}
+ ParGCAllocBuffer(gclab_word_size), _retired(false) { }
G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, int queue_num)
: _g1h(g1h),
@@ -4323,8 +4174,7 @@
_tenured_alloc_buffer(g1h->desired_plab_sz(GCAllocForTenured)),
_age_table(false),
_strong_roots_time(0), _term_time(0),
- _alloc_buffer_waste(0), _undo_waste(0)
-{
+ _alloc_buffer_waste(0), _undo_waste(0) {
// we allocate G1YoungSurvRateNumRegions plus one entries, since
// we "sacrifice" entry 0 to keep track of surviving bytes for
// non-young regions (where the age is -1)
@@ -4429,35 +4279,53 @@
} while (!refs()->is_empty());
}
-G1ParClosureSuper::G1ParClosureSuper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state) :
+G1ParClosureSuper::G1ParClosureSuper(G1CollectedHeap* g1,
+ G1ParScanThreadState* par_scan_state) :
_g1(g1), _g1_rem(_g1->g1_rem_set()), _cm(_g1->concurrent_mark()),
_par_scan_state(par_scan_state),
_during_initial_mark(_g1->g1_policy()->during_initial_mark_pause()),
_mark_in_progress(_g1->mark_in_progress()) { }
-template <class T> void G1ParCopyHelper::mark_object(T* p) {
- // This is called from do_oop_work for objects that are not
- // in the collection set. Objects in the collection set
- // are marked after they have been evacuated.
-
- T heap_oop = oopDesc::load_heap_oop(p);
- if (!oopDesc::is_null(heap_oop)) {
- oop obj = oopDesc::decode_heap_oop(heap_oop);
- HeapWord* addr = (HeapWord*)obj;
- if (_g1->is_in_g1_reserved(addr)) {
- _cm->grayRoot(oop(addr));
- }
- }
-}
-
-oop G1ParCopyHelper::copy_to_survivor_space(oop old, bool should_mark_root,
- bool should_mark_copy) {
+void G1ParCopyHelper::mark_object(oop obj) {
+#ifdef ASSERT
+ HeapRegion* hr = _g1->heap_region_containing(obj);
+ assert(hr != NULL, "sanity");
+ assert(!hr->in_collection_set(), "should not mark objects in the CSet");
+#endif // ASSERT
+
+ // We know that the object is not moving so it's safe to read its size.
+ _cm->grayRoot(obj, (size_t) obj->size());
+}
+
+void G1ParCopyHelper::mark_forwarded_object(oop from_obj, oop to_obj) {
+#ifdef ASSERT
+ assert(from_obj->is_forwarded(), "from obj should be forwarded");
+ assert(from_obj->forwardee() == to_obj, "to obj should be the forwardee");
+ assert(from_obj != to_obj, "should not be self-forwarded");
+
+ HeapRegion* from_hr = _g1->heap_region_containing(from_obj);
+ assert(from_hr != NULL, "sanity");
+ assert(from_hr->in_collection_set(), "from obj should be in the CSet");
+
+ HeapRegion* to_hr = _g1->heap_region_containing(to_obj);
+ assert(to_hr != NULL, "sanity");
+ assert(!to_hr->in_collection_set(), "should not mark objects in the CSet");
+#endif // ASSERT
+
+ // The object might be in the process of being copied by another
+ // worker so we cannot trust that its to-space image is
+ // well-formed. So we have to read its size from its from-space
+ // image which we know should not be changing.
+ _cm->grayRoot(to_obj, (size_t) from_obj->size());
+}
+
+oop G1ParCopyHelper::copy_to_survivor_space(oop old) {
size_t word_sz = old->size();
HeapRegion* from_region = _g1->heap_region_containing_raw(old);
// +1 to make the -1 indexes valid...
int young_index = from_region->young_index_in_cset()+1;
- assert( (from_region->is_young() && young_index > 0) ||
- (!from_region->is_young() && young_index == 0), "invariant" );
+ assert( (from_region->is_young() && young_index > 0) ||
+ (!from_region->is_young() && young_index == 0), "invariant" );
G1CollectorPolicy* g1p = _g1->g1_policy();
markOop m = old->mark();
int age = m->has_displaced_mark_helper() ? m->displaced_mark_helper()->age()
@@ -4471,7 +4339,7 @@
// This will either forward-to-self, or detect that someone else has
// installed a forwarding pointer.
OopsInHeapRegionClosure* cl = _par_scan_state->evac_failure_closure();
- return _g1->handle_evacuation_failure_par(cl, old, should_mark_root);
+ return _g1->handle_evacuation_failure_par(cl, old);
}
// We're going to allocate linearly, so might as well prefetch ahead.
@@ -4507,28 +4375,14 @@
obj->set_mark(m);
}
- // Mark the evacuated object or propagate "next" mark bit
- if (should_mark_copy) {
- if (!use_local_bitmaps ||
- !_par_scan_state->alloc_buffer(alloc_purpose)->mark(obj_ptr)) {
- // if we couldn't mark it on the local bitmap (this happens when
- // the object was not allocated in the GCLab), we have to bite
- // the bullet and do the standard parallel mark
- _cm->markAndGrayObjectIfNecessary(obj);
- }
-
- if (_g1->isMarkedNext(old)) {
- // Unmark the object's old location so that marking
- // doesn't think the old object is alive.
- _cm->nextMarkBitMap()->parClear((HeapWord*)old);
- }
- }
-
size_t* surv_young_words = _par_scan_state->surviving_young_words();
surv_young_words[young_index] += word_sz;
if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) {
- arrayOop(old)->set_length(0);
+ // We keep track of the next start index in the length field of
+ // the to-space object. The actual length can be found in the
+ // length field of the from-space object.
+ arrayOop(obj)->set_length(0);
oop* old_p = set_partial_array_mask(old);
_par_scan_state->push_on_queue(old_p);
} else {
@@ -4550,61 +4404,24 @@
::do_oop_work(T* p) {
oop obj = oopDesc::load_decode_heap_oop(p);
assert(barrier != G1BarrierRS || obj != NULL,
- "Precondition: G1BarrierRS implies obj is nonNull");
-
- // Marking:
- // If the object is in the collection set, then the thread
- // that copies the object should mark, or propagate the
- // mark to, the evacuated object.
- // If the object is not in the collection set then we
- // should call the mark_object() method depending on the
- // value of the template parameter do_mark_object (which will
- // be true for root scanning closures during an initial mark
- // pause).
- // The mark_object() method first checks whether the object
- // is marked and, if not, attempts to mark the object.
+ "Precondition: G1BarrierRS implies obj is non-NULL");
// here the null check is implicit in the cset_fast_test() test
if (_g1->in_cset_fast_test(obj)) {
+ oop forwardee;
if (obj->is_forwarded()) {
- oopDesc::encode_store_heap_oop(p, obj->forwardee());
- // If we are a root scanning closure during an initial
- // mark pause (i.e. do_mark_object will be true) then
- // we also need to handle marking of roots in the
- // event of an evacuation failure. In the event of an
- // evacuation failure, the object is forwarded to itself
- // and not copied. For root-scanning closures, the
- // object would be marked after a successful self-forward
- // but an object could be pointed to by both a root and non
- // root location and be self-forwarded by a non-root-scanning
- // closure. Therefore we also have to attempt to mark the
- // self-forwarded root object here.
- if (do_mark_object && obj->forwardee() == obj) {
- mark_object(p);
- }
+ forwardee = obj->forwardee();
} else {
- // During an initial mark pause, objects that are pointed to
- // by the roots need to be marked - even in the event of an
- // evacuation failure. We pass the template parameter
- // do_mark_object (which is true for root scanning closures
- // during an initial mark pause) to copy_to_survivor_space
- // which will pass it on to the evacuation failure handling
- // code. The thread that successfully self-forwards a root
- // object to itself is responsible for marking the object.
- bool should_mark_root = do_mark_object;
-
- // We need to mark the copied object if we're a root scanning
- // closure during an initial mark pause (i.e. do_mark_object
- // will be true), or the object is already marked and we need
- // to propagate the mark to the evacuated copy.
- bool should_mark_copy = do_mark_object ||
- _during_initial_mark ||
- (_mark_in_progress && !_g1->is_obj_ill(obj));
-
- oop copy_oop = copy_to_survivor_space(obj, should_mark_root,
- should_mark_copy);
- oopDesc::encode_store_heap_oop(p, copy_oop);
+ forwardee = copy_to_survivor_space(obj);
}
+ assert(forwardee != NULL, "forwardee should not be NULL");
+ oopDesc::encode_store_heap_oop(p, forwardee);
+ if (do_mark_object && forwardee != obj) {
+ // If the object is self-forwarded we don't need to explicitly
+ // mark it, the evacuation failure protocol will do so.
+ mark_forwarded_object(obj, forwardee);
+ }
+
// When scanning the RS, we only care about objs in CS.
if (barrier == G1BarrierRS) {
_par_scan_state->update_rs(_from, p, _par_scan_state->queue_num());
@@ -4613,8 +4430,8 @@
// The object is not in collection set. If we're a root scanning
// closure during an initial mark pause (i.e. do_mark_object will
// be true) then attempt to mark the object.
- if (do_mark_object) {
- mark_object(p);
+ if (do_mark_object && _g1->is_in_g1_reserved(obj)) {
+ mark_object(obj);
}
}
@@ -4632,35 +4449,51 @@
template <class T> void G1ParScanPartialArrayClosure::do_oop_nv(T* p) {
assert(has_partial_array_mask(p), "invariant");
- oop old = clear_partial_array_mask(p);
- assert(old->is_objArray(), "must be obj array");
- assert(old->is_forwarded(), "must be forwarded");
- assert(Universe::heap()->is_in_reserved(old), "must be in heap.");
-
- objArrayOop obj = objArrayOop(old->forwardee());
- assert((void*)old != (void*)old->forwardee(), "self forwarding here?");
- // Process ParGCArrayScanChunk elements now
- // and push the remainder back onto queue
- int start = arrayOop(old)->length();
- int end = obj->length();
- int remainder = end - start;
- assert(start <= end, "just checking");
+ oop from_obj = clear_partial_array_mask(p);
+
+ assert(Universe::heap()->is_in_reserved(from_obj), "must be in heap.");
+ assert(from_obj->is_objArray(), "must be obj array");
+ objArrayOop from_obj_array = objArrayOop(from_obj);
+ // The from-space object contains the real length.
+ int length = from_obj_array->length();
+
+ assert(from_obj->is_forwarded(), "must be forwarded");
+ oop to_obj = from_obj->forwardee();
+ assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
+ objArrayOop to_obj_array = objArrayOop(to_obj);
+ // We keep track of the next start index in the length field of the
+ // to-space object.
+ int next_index = to_obj_array->length();
+ assert(0 <= next_index && next_index < length,
+ err_msg("invariant, next index: %d, length: %d", next_index, length));
+
+ int start = next_index;
+ int end = length;
+ int remainder = end - start;
+ // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
if (remainder > 2 * ParGCArrayScanChunk) {
- // Test above combines last partial chunk with a full chunk
end = start + ParGCArrayScanChunk;
- arrayOop(old)->set_length(end);
- // Push remainder.
- oop* old_p = set_partial_array_mask(old);
- assert(arrayOop(old)->length() < obj->length(), "Empty push?");
- _par_scan_state->push_on_queue(old_p);
+ to_obj_array->set_length(end);
+ // Push the remainder before we process the range in case another
+ // worker has run out of things to do and can steal it.
+ oop* from_obj_p = set_partial_array_mask(from_obj);
+ _par_scan_state->push_on_queue(from_obj_p);
} else {
- // Restore length so that the heap remains parsable in
- // case of evacuation failure.
- arrayOop(old)->set_length(end);
- }
- _scanner.set_region(_g1->heap_region_containing_raw(obj));
- // process our set of indices (include header in first chunk)
- obj->oop_iterate_range(&_scanner, start, end);
+ assert(length == end, "sanity");
+ // We'll process the final range for this object. Restore the length
+ // so that the heap remains parsable in case of evacuation failure.
+ to_obj_array->set_length(end);
+ }
+ _scanner.set_region(_g1->heap_region_containing_raw(to_obj));
+ // Process indexes [start,end). It will also process the header
+ // along with the first chunk (i.e., the chunk with start == 0).
+ // Note that at this point the length field of to_obj_array is not
+ // correct given that we are using it to keep track of the next
+ // start index. oop_iterate_range() (thankfully!) ignores the length
+ // field and only relies on the start / end parameters. It does
+ // however return the size of the object which will be incorrect. So
+ // we have to ignore it even if we wanted to use it.
+ to_obj_array->oop_iterate_range(&_scanner, start, end);
}
class G1ParEvacuateFollowersClosure : public VoidClosure {
@@ -4893,12 +4726,16 @@
g1_policy()->record_ext_root_scan_time(worker_i, ext_root_time_ms);
- // Scan strong roots in mark stack.
- if (!_process_strong_tasks->is_task_claimed(G1H_PS_mark_stack_oops_do)) {
- concurrent_mark()->oops_do(scan_non_heap_roots);
- }
- double mark_stack_scan_ms = (os::elapsedTime() - ext_roots_end) * 1000.0;
- g1_policy()->record_mark_stack_scan_time(worker_i, mark_stack_scan_ms);
+ // During conc marking we have to filter the per-thread SATB buffers
+ // to make sure we remove any oops into the CSet (which will show up
+ // as implicitly live).
+ if (!_process_strong_tasks->is_task_claimed(G1H_PS_filter_satb_buffers)) {
+ if (mark_in_progress()) {
+ JavaThread::satb_mark_queue_set().filter_thread_buffers();
+ }
+ }
+ double satb_filtering_ms = (os::elapsedTime() - ext_roots_end) * 1000.0;
+ g1_policy()->record_satb_filtering_time(worker_i, satb_filtering_ms);
// Now scan the complement of the collection set.
if (scan_rs != NULL) {
@@ -5439,6 +5276,7 @@
}
void G1CollectedHeap::evacuate_collection_set() {
+ _expand_heap_after_alloc_failure = true;
set_evacuation_failed(false);
g1_rem_set()->prepare_for_oops_into_collection_set_do();
@@ -5516,13 +5354,6 @@
finalize_for_evac_failure();
- // Must do this before clearing the per-region evac-failure flags
- // (which is currently done when we free the collection set).
- // We also only do this if marking is actually in progress and so
- // have to do this before we set the mark_in_progress flag at the
- // end of an initial mark pause.
- concurrent_mark()->complete_marking_in_collection_set();
-
if (evacuation_failed()) {
remove_self_forwarding_pointers();
if (PrintGCDetails) {
@@ -6179,6 +6010,8 @@
} else {
_hr_printer.alloc(new_alloc_region, G1HRPrinter::Old);
}
+ bool during_im = g1_policy()->during_initial_mark_pause();
+ new_alloc_region->note_start_of_copying(during_im);
return new_alloc_region;
} else {
g1_policy()->note_alloc_region_limit_reached(ap);
@@ -6190,7 +6023,8 @@
void G1CollectedHeap::retire_gc_alloc_region(HeapRegion* alloc_region,
size_t allocated_bytes,
GCAllocPurpose ap) {
- alloc_region->note_end_of_copying();
+ bool during_im = g1_policy()->during_initial_mark_pause();
+ alloc_region->note_end_of_copying(during_im);
g1_policy()->record_bytes_copied_during_gc(allocated_bytes);
if (ap == GCAllocForSurvived) {
young_list()->add_survivor_region(alloc_region);
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -285,6 +285,14 @@
// Typically, it is not full so we should re-use it during the next GC.
HeapRegion* _retained_old_gc_alloc_region;
+ // It specifies whether we should attempt to expand the heap after a
+ // region allocation failure. If heap expansion fails we set this to
+ // false so that we don't re-attempt the heap expansion (it's likely
+ // that subsequent expansion attempts will also fail if one fails).
+ // Currently, it is only consulted during GC and it's reset at the
+ // start of each GC.
+ bool _expand_heap_after_alloc_failure;
+
// It resets the mutator alloc region before new allocations can take place.
void init_mutator_alloc_region();
@@ -861,8 +869,7 @@
void finalize_for_evac_failure();
// An attempt to evacuate "obj" has failed; take necessary steps.
- oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj,
- bool should_mark_root);
+ oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj);
void handle_evacuation_failure_common(oop obj, markOop m);
// ("Weak") Reference processing support.
@@ -954,7 +961,7 @@
unsigned int* _worker_cset_start_region_time_stamp;
enum G1H_process_strong_roots_tasks {
- G1H_PS_mark_stack_oops_do,
+ G1H_PS_filter_satb_buffers,
G1H_PS_refProcessor_oops_do,
// Leave this one last.
G1H_PS_NumElements
@@ -1305,6 +1312,10 @@
// It resets all the region claim values to the default.
void reset_heap_region_claim_values();
+ // Resets the claim values of regions in the current
+ // collection set to the default.
+ void reset_cset_heap_region_claim_values();
+
#ifdef ASSERT
bool check_heap_region_claim_values(jint claim_value);
@@ -1740,10 +1751,8 @@
_gclab_word_size(gclab_word_size),
_real_start_word(NULL),
_real_end_word(NULL),
- _start_word(NULL)
- {
- guarantee( size_in_words() >= bitmap_size_in_words(),
- "just making sure");
+ _start_word(NULL) {
+ guarantee(false, "GCLabBitMap::GCLabBitmap(): don't call this any more");
}
inline unsigned heapWordToOffset(HeapWord* addr) {
@@ -1797,6 +1806,8 @@
}
void set_buffer(HeapWord* start) {
+ guarantee(false, "set_buffer(): don't call this any more");
+
guarantee(use_local_bitmaps, "invariant");
clear();
@@ -1820,6 +1831,8 @@
#endif // PRODUCT
void retire() {
+ guarantee(false, "retire(): don't call this any more");
+
guarantee(use_local_bitmaps, "invariant");
assert(fields_well_formed(), "invariant");
@@ -1853,32 +1866,18 @@
class G1ParGCAllocBuffer: public ParGCAllocBuffer {
private:
bool _retired;
- bool _should_mark_objects;
- GCLabBitMap _bitmap;
public:
G1ParGCAllocBuffer(size_t gclab_word_size);
- inline bool mark(HeapWord* addr) {
- guarantee(use_local_bitmaps, "invariant");
- assert(_should_mark_objects, "invariant");
- return _bitmap.mark(addr);
- }
-
- inline void set_buf(HeapWord* buf) {
- if (use_local_bitmaps && _should_mark_objects) {
- _bitmap.set_buffer(buf);
- }
+ void set_buf(HeapWord* buf) {
ParGCAllocBuffer::set_buf(buf);
_retired = false;
}
- inline void retire(bool end_of_gc, bool retain) {
+ void retire(bool end_of_gc, bool retain) {
if (_retired)
return;
- if (use_local_bitmaps && _should_mark_objects) {
- _bitmap.retire();
- }
ParGCAllocBuffer::retire(end_of_gc, retain);
_retired = true;
}
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -281,7 +281,7 @@
_par_last_gc_worker_start_times_ms = new double[_parallel_gc_threads];
_par_last_ext_root_scan_times_ms = new double[_parallel_gc_threads];
- _par_last_mark_stack_scan_times_ms = new double[_parallel_gc_threads];
+ _par_last_satb_filtering_times_ms = new double[_parallel_gc_threads];
_par_last_update_rs_times_ms = new double[_parallel_gc_threads];
_par_last_update_rs_processed_buffers = new double[_parallel_gc_threads];
@@ -905,10 +905,19 @@
gclog_or_tty->print(" (%s)", gcs_are_young() ? "young" : "mixed");
}
- // We only need to do this here as the policy will only be applied
- // to the GC we're about to start. so, no point is calculating this
- // every time we calculate / recalculate the target young length.
- update_survivors_policy();
+ if (!during_initial_mark_pause()) {
+ // We only need to do this here as the policy will only be applied
+ // to the GC we're about to start. so, no point is calculating this
+ // every time we calculate / recalculate the target young length.
+ update_survivors_policy();
+ } else {
+ // The marking phase has a "we only copy implicitly live
+ // objects during marking" invariant. The easiest way to ensure it
+ // holds is not to allocate any survivor regions and tenure all
+ // objects. In the future we might change this and handle survivor
+ // regions specially during marking.
+ tenure_all_objects();
+ }
assert(_g1->used() == _g1->recalculate_used(),
err_msg("sanity, used: "SIZE_FORMAT" recalculate_used: "SIZE_FORMAT,
@@ -939,7 +948,7 @@
for (int i = 0; i < _parallel_gc_threads; ++i) {
_par_last_gc_worker_start_times_ms[i] = -1234.0;
_par_last_ext_root_scan_times_ms[i] = -1234.0;
- _par_last_mark_stack_scan_times_ms[i] = -1234.0;
+ _par_last_satb_filtering_times_ms[i] = -1234.0;
_par_last_update_rs_times_ms[i] = -1234.0;
_par_last_update_rs_processed_buffers[i] = -1234.0;
_par_last_scan_rs_times_ms[i] = -1234.0;
@@ -1227,7 +1236,7 @@
// of the PrintGCDetails output, in the non-parallel case.
double ext_root_scan_time = avg_value(_par_last_ext_root_scan_times_ms);
- double mark_stack_scan_time = avg_value(_par_last_mark_stack_scan_times_ms);
+ double satb_filtering_time = avg_value(_par_last_satb_filtering_times_ms);
double update_rs_time = avg_value(_par_last_update_rs_times_ms);
double update_rs_processed_buffers =
sum_of_values(_par_last_update_rs_processed_buffers);
@@ -1236,7 +1245,7 @@
double termination_time = avg_value(_par_last_termination_times_ms);
double known_time = ext_root_scan_time +
- mark_stack_scan_time +
+ satb_filtering_time +
update_rs_time +
scan_rs_time +
obj_copy_time;
@@ -1282,7 +1291,7 @@
body_summary->record_satb_drain_time_ms(_cur_satb_drain_time_ms);
body_summary->record_ext_root_scan_time_ms(ext_root_scan_time);
- body_summary->record_mark_stack_scan_time_ms(mark_stack_scan_time);
+ body_summary->record_satb_filtering_time_ms(satb_filtering_time);
body_summary->record_update_rs_time_ms(update_rs_time);
body_summary->record_scan_rs_time_ms(scan_rs_time);
body_summary->record_obj_copy_time_ms(obj_copy_time);
@@ -1376,16 +1385,12 @@
(last_pause_included_initial_mark) ? " (initial-mark)" : "",
elapsed_ms / 1000.0);
- if (print_marking_info) {
- print_stats(1, "SATB Drain Time", _cur_satb_drain_time_ms);
- }
-
if (parallel) {
print_stats(1, "Parallel Time", _cur_collection_par_time_ms);
print_par_stats(2, "GC Worker Start", _par_last_gc_worker_start_times_ms);
print_par_stats(2, "Ext Root Scanning", _par_last_ext_root_scan_times_ms);
if (print_marking_info) {
- print_par_stats(2, "Mark Stack Scanning", _par_last_mark_stack_scan_times_ms);
+ print_par_stats(2, "SATB Filtering", _par_last_satb_filtering_times_ms);
}
print_par_stats(2, "Update RS", _par_last_update_rs_times_ms);
print_par_sizes(3, "Processed Buffers", _par_last_update_rs_processed_buffers);
@@ -1399,7 +1404,7 @@
_par_last_gc_worker_times_ms[i] = _par_last_gc_worker_end_times_ms[i] - _par_last_gc_worker_start_times_ms[i];
double worker_known_time = _par_last_ext_root_scan_times_ms[i] +
- _par_last_mark_stack_scan_times_ms[i] +
+ _par_last_satb_filtering_times_ms[i] +
_par_last_update_rs_times_ms[i] +
_par_last_scan_rs_times_ms[i] +
_par_last_obj_copy_times_ms[i] +
@@ -1412,7 +1417,7 @@
} else {
print_stats(1, "Ext Root Scanning", ext_root_scan_time);
if (print_marking_info) {
- print_stats(1, "Mark Stack Scanning", mark_stack_scan_time);
+ print_stats(1, "SATB Filtering", satb_filtering_time);
}
print_stats(1, "Update RS", update_rs_time);
print_stats(2, "Processed Buffers", (int)update_rs_processed_buffers);
@@ -1983,11 +1988,10 @@
if (summary->get_total_seq()->num() > 0) {
print_summary_sd(0, "Evacuation Pauses", summary->get_total_seq());
if (body_summary != NULL) {
- print_summary(1, "SATB Drain", body_summary->get_satb_drain_seq());
if (parallel) {
print_summary(1, "Parallel Time", body_summary->get_parallel_seq());
print_summary(2, "Ext Root Scanning", body_summary->get_ext_root_scan_seq());
- print_summary(2, "Mark Stack Scanning", body_summary->get_mark_stack_scan_seq());
+ print_summary(2, "SATB Filtering", body_summary->get_satb_filtering_seq());
print_summary(2, "Update RS", body_summary->get_update_rs_seq());
print_summary(2, "Scan RS", body_summary->get_scan_rs_seq());
print_summary(2, "Object Copy", body_summary->get_obj_copy_seq());
@@ -1996,7 +2000,7 @@
{
NumberSeq* other_parts[] = {
body_summary->get_ext_root_scan_seq(),
- body_summary->get_mark_stack_scan_seq(),
+ body_summary->get_satb_filtering_seq(),
body_summary->get_update_rs_seq(),
body_summary->get_scan_rs_seq(),
body_summary->get_obj_copy_seq(),
@@ -2009,7 +2013,7 @@
}
} else {
print_summary(1, "Ext Root Scanning", body_summary->get_ext_root_scan_seq());
- print_summary(1, "Mark Stack Scanning", body_summary->get_mark_stack_scan_seq());
+ print_summary(1, "SATB Filtering", body_summary->get_satb_filtering_seq());
print_summary(1, "Update RS", body_summary->get_update_rs_seq());
print_summary(1, "Scan RS", body_summary->get_scan_rs_seq());
print_summary(1, "Object Copy", body_summary->get_obj_copy_seq());
@@ -2036,7 +2040,7 @@
body_summary->get_satb_drain_seq(),
body_summary->get_update_rs_seq(),
body_summary->get_ext_root_scan_seq(),
- body_summary->get_mark_stack_scan_seq(),
+ body_summary->get_satb_filtering_seq(),
body_summary->get_scan_rs_seq(),
body_summary->get_obj_copy_seq()
};
@@ -2433,9 +2437,6 @@
assert(_inc_cset_build_state == Active, "Precondition");
assert(!hr->is_young(), "non-incremental add of young region");
- if (_g1->mark_in_progress())
- _g1->concurrent_mark()->registerCSetRegion(hr);
-
assert(!hr->in_collection_set(), "should not already be in the CSet");
hr->set_in_collection_set(true);
hr->set_next_in_collection_set(_collection_set);
@@ -2705,9 +2706,6 @@
// Clear the fields that point to the survivor list - they are all young now.
young_list->clear_survivors();
- if (_g1->mark_in_progress())
- _g1->concurrent_mark()->register_collection_set_finger(_inc_cset_max_finger);
-
_collection_set = _inc_cset_head;
_collection_set_bytes_used_before = _inc_cset_bytes_used_before;
time_remaining_ms -= _inc_cset_predicted_elapsed_time_ms;
--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -67,7 +67,7 @@
define_num_seq(satb_drain) // optional
define_num_seq(parallel) // parallel only
define_num_seq(ext_root_scan)
- define_num_seq(mark_stack_scan)
+ define_num_seq(satb_filtering)
define_num_seq(update_rs)
define_num_seq(scan_rs)
define_num_seq(obj_copy)
@@ -215,7 +215,7 @@
double* _par_last_gc_worker_start_times_ms;
double* _par_last_ext_root_scan_times_ms;
- double* _par_last_mark_stack_scan_times_ms;
+ double* _par_last_satb_filtering_times_ms;
double* _par_last_update_rs_times_ms;
double* _par_last_update_rs_processed_buffers;
double* _par_last_scan_rs_times_ms;
@@ -841,8 +841,8 @@
_par_last_ext_root_scan_times_ms[worker_i] = ms;
}
- void record_mark_stack_scan_time(int worker_i, double ms) {
- _par_last_mark_stack_scan_times_ms[worker_i] = ms;
+ void record_satb_filtering_time(int worker_i, double ms) {
+ _par_last_satb_filtering_times_ms[worker_i] = ms;
}
void record_satb_drain_time(double ms) {
@@ -1146,6 +1146,11 @@
_survivor_surv_rate_group->stop_adding_regions();
}
+ void tenure_all_objects() {
+ _max_survivor_regions = 0;
+ _tenuring_threshold = 0;
+ }
+
void record_survivor_regions(size_t regions,
HeapRegion* head,
HeapRegion* tail) {
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -0,0 +1,236 @@
+/*
+ * Copyright (c) 2012, 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
+ * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
+#define SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
+
+#include "gc_implementation/g1/concurrentMark.inline.hpp"
+#include "gc_implementation/g1/dirtyCardQueue.hpp"
+#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
+#include "gc_implementation/g1/g1_globals.hpp"
+#include "gc_implementation/g1/g1OopClosures.inline.hpp"
+#include "gc_implementation/g1/heapRegion.hpp"
+#include "gc_implementation/g1/heapRegionRemSet.hpp"
+#include "utilities/workgroup.hpp"
+
+// Closures and tasks associated with any self-forwarding pointers
+// installed as a result of an evacuation failure.
+
+class UpdateRSetDeferred : public OopsInHeapRegionClosure {
+private:
+ G1CollectedHeap* _g1;
+ DirtyCardQueue *_dcq;
+ CardTableModRefBS* _ct_bs;
+
+public:
+ UpdateRSetDeferred(G1CollectedHeap* g1, DirtyCardQueue* dcq) :
+ _g1(g1), _ct_bs((CardTableModRefBS*)_g1->barrier_set()), _dcq(dcq) {}
+
+ virtual void do_oop(narrowOop* p) { do_oop_work(p); }
+ virtual void do_oop( oop* p) { do_oop_work(p); }
+ template <class T> void do_oop_work(T* p) {
+ assert(_from->is_in_reserved(p), "paranoia");
+ if (!_from->is_in_reserved(oopDesc::load_decode_heap_oop(p)) &&
+ !_from->is_survivor()) {
+ size_t card_index = _ct_bs->index_for(p);
+ if (_ct_bs->mark_card_deferred(card_index)) {
+ _dcq->enqueue((jbyte*)_ct_bs->byte_for_index(card_index));
+ }
+ }
+ }
+};
+
+class RemoveSelfForwardPtrObjClosure: public ObjectClosure {
+private:
+ G1CollectedHeap* _g1;
+ ConcurrentMark* _cm;
+ HeapRegion* _hr;
+ size_t _marked_bytes;
+ OopsInHeapRegionClosure *_update_rset_cl;
+ bool _during_initial_mark;
+ bool _during_conc_mark;
+public:
+ RemoveSelfForwardPtrObjClosure(G1CollectedHeap* g1, ConcurrentMark* cm,
+ HeapRegion* hr,
+ OopsInHeapRegionClosure* update_rset_cl,
+ bool during_initial_mark,
+ bool during_conc_mark) :
+ _g1(g1), _cm(cm), _hr(hr), _marked_bytes(0),
+ _update_rset_cl(update_rset_cl),
+ _during_initial_mark(during_initial_mark),
+ _during_conc_mark(during_conc_mark) { }
+
+ size_t marked_bytes() { return _marked_bytes; }
+
+ // <original comment>
+ // The original idea here was to coalesce evacuated and dead objects.
+ // However that caused complications with the block offset table (BOT).
+ // In particular if there were two TLABs, one of them partially refined.
+ // |----- TLAB_1--------|----TLAB_2-~~~(partially refined part)~~~|
+ // The BOT entries of the unrefined part of TLAB_2 point to the start
+ // of TLAB_2. If the last object of the TLAB_1 and the first object
+ // of TLAB_2 are coalesced, then the cards of the unrefined part
+ // would point into middle of the filler object.
+ // The current approach is to not coalesce and leave the BOT contents intact.
+ // </original comment>
+ //
+ // We now reset the BOT when we start the object iteration over the
+ // region and refine its entries for every object we come across. So
+ // the above comment is not really relevant and we should be able
+ // to coalesce dead objects if we want to.
+ void do_object(oop obj) {
+ HeapWord* obj_addr = (HeapWord*) obj;
+ assert(_hr->is_in(obj_addr), "sanity");
+ size_t obj_size = obj->size();
+ _hr->update_bot_for_object(obj_addr, obj_size);
+
+ if (obj->is_forwarded() && obj->forwardee() == obj) {
+ // The object failed to move.
+
+ // We consider all objects that we find self-forwarded to be
+ // live. What we'll do is that we'll update the prev marking
+ // info so that they are all under PTAMS and explicitly marked.
+ _cm->markPrev(obj);
+ if (_during_initial_mark) {
+ // For the next marking info we'll only mark the
+ // self-forwarded objects explicitly if we are during
+ // initial-mark (since, normally, we only mark objects pointed
+ // to by roots if we succeed in copying them). By marking all
+ // self-forwarded objects we ensure that we mark any that are
+ // still pointed to be roots. During concurrent marking, and
+ // after initial-mark, we don't need to mark any objects
+ // explicitly and all objects in the CSet are considered
+ // (implicitly) live. So, we won't mark them explicitly and
+ // we'll leave them over NTAMS.
+ _cm->markNext(obj);
+ }
+ _marked_bytes += (obj_size * HeapWordSize);
+ obj->set_mark(markOopDesc::prototype());
+
+ // While we were processing RSet buffers during the collection,
+ // we actually didn't scan any cards on the collection set,
+ // since we didn't want to update remembered sets with entries
+ // that point into the collection set, given that live objects
+ // from the collection set are about to move and such entries
+ // will be stale very soon.
+ // This change also dealt with a reliability issue which
+ // involved scanning a card in the collection set and coming
+ // across an array that was being chunked and looking malformed.
+ // The problem is that, if evacuation fails, we might have
+ // remembered set entries missing given that we skipped cards on
+ // the collection set. So, we'll recreate such entries now.
+ obj->oop_iterate(_update_rset_cl);
+ assert(_cm->isPrevMarked(obj), "Should be marked!");
+ } else {
+ // The object has been either evacuated or is dead. Fill it with a
+ // dummy object.
+ MemRegion mr((HeapWord*) obj, obj_size);
+ CollectedHeap::fill_with_object(mr);
+ }
+ }
+};
+
+class RemoveSelfForwardPtrHRClosure: public HeapRegionClosure {
+ G1CollectedHeap* _g1h;
+ ConcurrentMark* _cm;
+ OopsInHeapRegionClosure *_update_rset_cl;
+
+public:
+ RemoveSelfForwardPtrHRClosure(G1CollectedHeap* g1h,
+ OopsInHeapRegionClosure* update_rset_cl) :
+ _g1h(g1h), _update_rset_cl(update_rset_cl),
+ _cm(_g1h->concurrent_mark()) { }
+
+ bool doHeapRegion(HeapRegion *hr) {
+ bool during_initial_mark = _g1h->g1_policy()->during_initial_mark_pause();
+ bool during_conc_mark = _g1h->mark_in_progress();
+
+ assert(!hr->isHumongous(), "sanity");
+ assert(hr->in_collection_set(), "bad CS");
+
+ if (hr->claimHeapRegion(HeapRegion::ParEvacFailureClaimValue)) {
+ if (hr->evacuation_failed()) {
+ RemoveSelfForwardPtrObjClosure rspc(_g1h, _cm, hr, _update_rset_cl,
+ during_initial_mark,
+ during_conc_mark);
+
+ MemRegion mr(hr->bottom(), hr->end());
+ // We'll recreate the prev marking info so we'll first clear
+ // the prev bitmap range for this region. We never mark any
+ // CSet objects explicitly so the next bitmap range should be
+ // cleared anyway.
+ _cm->clearRangePrevBitmap(mr);
+
+ hr->note_self_forwarding_removal_start(during_initial_mark,
+ during_conc_mark);
+
+ // In the common case (i.e. when there is no evacuation
+ // failure) we make sure that the following is done when
+ // the region is freed so that it is "ready-to-go" when it's
+ // re-allocated. However, when evacuation failure happens, a
+ // region will remain in the heap and might ultimately be added
+ // to a CSet in the future. So we have to be careful here and
+ // make sure the region's RSet is ready for parallel iteration
+ // whenever this might be required in the future.
+ hr->rem_set()->reset_for_par_iteration();
+ hr->reset_bot();
+ _update_rset_cl->set_region(hr);
+ hr->object_iterate(&rspc);
+
+ hr->note_self_forwarding_removal_end(during_initial_mark,
+ during_conc_mark,
+ rspc.marked_bytes());
+ }
+ }
+ return false;
+ }
+};
+
+class G1ParRemoveSelfForwardPtrsTask: public AbstractGangTask {
+protected:
+ G1CollectedHeap* _g1h;
+
+public:
+ G1ParRemoveSelfForwardPtrsTask(G1CollectedHeap* g1h) :
+ AbstractGangTask("G1 Remove Self-forwarding Pointers"),
+ _g1h(g1h) { }
+
+ void work(uint worker_id) {
+ UpdateRSetImmediate immediate_update(_g1h->g1_rem_set());
+ DirtyCardQueue dcq(&_g1h->dirty_card_queue_set());
+ UpdateRSetDeferred deferred_update(_g1h, &dcq);
+
+ OopsInHeapRegionClosure *update_rset_cl = &deferred_update;
+ if (!G1DeferredRSUpdate) {
+ update_rset_cl = &immediate_update;
+ }
+
+ RemoveSelfForwardPtrHRClosure rsfp_cl(_g1h, update_rset_cl);
+
+ HeapRegion* hr = _g1h->start_cset_region_for_worker(worker_id);
+ _g1h->collection_set_iterate_from(hr, &rsfp_cl);
+ }
+};
+
+#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1EVACFAILURE_HPP
--- a/hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1OopClosures.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -121,17 +121,25 @@
class G1ParCopyHelper : public G1ParClosureSuper {
G1ParScanClosure *_scanner;
protected:
- template <class T> void mark_object(T* p);
- oop copy_to_survivor_space(oop obj, bool should_mark_root,
- bool should_mark_copy);
+ // Mark the object if it's not already marked. This is used to mark
+ // objects pointed to by roots that are guaranteed not to move
+ // during the GC (i.e., non-CSet objects). It is MT-safe.
+ void mark_object(oop obj);
+
+ // Mark the object if it's not already marked. This is used to mark
+ // objects pointed to by roots that have been forwarded during a
+ // GC. It is MT-safe.
+ void mark_forwarded_object(oop from_obj, oop to_obj);
+
+ oop copy_to_survivor_space(oop obj);
+
public:
G1ParCopyHelper(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state,
G1ParScanClosure *scanner) :
G1ParClosureSuper(g1, par_scan_state), _scanner(scanner) { }
};
-template<bool do_gen_barrier, G1Barrier barrier,
- bool do_mark_object>
+template <bool do_gen_barrier, G1Barrier barrier, bool do_mark_object>
class G1ParCopyClosure : public G1ParCopyHelper {
G1ParScanClosure _scanner;
@@ -140,9 +148,8 @@
public:
G1ParCopyClosure(G1CollectedHeap* g1, G1ParScanThreadState* par_scan_state,
ReferenceProcessor* rp) :
- _scanner(g1, par_scan_state, rp),
- G1ParCopyHelper(g1, par_scan_state, &_scanner)
- {
+ _scanner(g1, par_scan_state, rp),
+ G1ParCopyHelper(g1, par_scan_state, &_scanner) {
assert(_ref_processor == NULL, "sanity");
}
--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -295,7 +295,7 @@
"Percentage (0-100) of the heap size to use as minimum " \
"young gen size.") \
\
- develop(uintx, G1DefaultMaxNewGenPercent, 50, \
+ develop(uintx, G1DefaultMaxNewGenPercent, 80, \
"Percentage (0-100) of the heap size to use as maximum " \
"young gen size.")
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.cpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -575,6 +575,40 @@
oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
}
+void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
+ bool during_conc_mark) {
+ // We always recreate the prev marking info and we'll explicitly
+ // mark all objects we find to be self-forwarded on the prev
+ // bitmap. So all objects need to be below PTAMS.
+ _prev_top_at_mark_start = top();
+ _prev_marked_bytes = 0;
+
+ if (during_initial_mark) {
+ // During initial-mark, we'll also explicitly mark all objects
+ // we find to be self-forwarded on the next bitmap. So all
+ // objects need to be below NTAMS.
+ _next_top_at_mark_start = top();
+ set_top_at_conc_mark_count(bottom());
+ _next_marked_bytes = 0;
+ } else if (during_conc_mark) {
+ // During concurrent mark, all objects in the CSet (including
+ // the ones we find to be self-forwarded) are implicitly live.
+ // So all objects need to be above NTAMS.
+ _next_top_at_mark_start = bottom();
+ set_top_at_conc_mark_count(bottom());
+ _next_marked_bytes = 0;
+ }
+}
+
+void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
+ bool during_conc_mark,
+ size_t marked_bytes) {
+ assert(0 <= marked_bytes && marked_bytes <= used(),
+ err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
+ marked_bytes, used()));
+ _prev_marked_bytes = marked_bytes;
+}
+
HeapWord*
HeapRegion::object_iterate_mem_careful(MemRegion mr,
ObjectClosure* cl) {
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -373,7 +373,8 @@
ScrubRemSetClaimValue = 3,
ParVerifyClaimValue = 4,
RebuildRSClaimValue = 5,
- CompleteMarkCSetClaimValue = 6
+ CompleteMarkCSetClaimValue = 6,
+ ParEvacFailureClaimValue = 7
};
inline HeapWord* par_allocate_no_bot_updates(size_t word_size) {
@@ -582,37 +583,33 @@
// that the collector is about to start or has finished (concurrently)
// marking the heap.
- // Note the start of a marking phase. Record the
- // start of the unmarked area of the region here.
- void note_start_of_marking(bool during_initial_mark) {
- init_top_at_conc_mark_count();
- _next_marked_bytes = 0;
- if (during_initial_mark && is_young() && !is_survivor())
- _next_top_at_mark_start = bottom();
- else
- _next_top_at_mark_start = top();
- }
+ // Notify the region that concurrent marking is starting. Initialize
+ // all fields related to the next marking info.
+ inline void note_start_of_marking();
+
+ // Notify the region that concurrent marking has finished. Copy the
+ // (now finalized) next marking info fields into the prev marking
+ // info fields.
+ inline void note_end_of_marking();
+
+ // Notify the region that it will be used as to-space during a GC
+ // and we are about to start copying objects into it.
+ inline void note_start_of_copying(bool during_initial_mark);
- // Note the end of a marking phase. Install the start of
- // the unmarked area that was captured at start of marking.
- void note_end_of_marking() {
- _prev_top_at_mark_start = _next_top_at_mark_start;
- _prev_marked_bytes = _next_marked_bytes;
- _next_marked_bytes = 0;
+ // Notify the region that it ceases being to-space during a GC and
+ // we will not copy objects into it any more.
+ inline void note_end_of_copying(bool during_initial_mark);
- guarantee(_prev_marked_bytes <=
- (size_t) (prev_top_at_mark_start() - bottom()) * HeapWordSize,
- "invariant");
- }
+ // Notify the region that we are about to start processing
+ // self-forwarded objects during evac failure handling.
+ void note_self_forwarding_removal_start(bool during_initial_mark,
+ bool during_conc_mark);
- // After an evacuation, we need to update _next_top_at_mark_start
- // to be the current top. Note this is only valid if we have only
- // ever evacuated into this region. If we evacuate, allocate, and
- // then evacuate we are in deep doodoo.
- void note_end_of_copying() {
- assert(top() >= _next_top_at_mark_start, "Increase only");
- _next_top_at_mark_start = top();
- }
+ // Notify the region that we have finished processing self-forwarded
+ // objects during evac failure handling.
+ void note_self_forwarding_removal_end(bool during_initial_mark,
+ bool during_conc_mark,
+ size_t marked_bytes);
// Returns "false" iff no object in the region was allocated when the
// last mark phase ended.
--- a/hotspot/src/share/vm/gc_implementation/g1/heapRegion.inline.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/heapRegion.inline.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -55,4 +55,71 @@
return _offsets.block_start_const(p);
}
+inline void HeapRegion::note_start_of_marking() {
+ init_top_at_conc_mark_count();
+ _next_marked_bytes = 0;
+ _next_top_at_mark_start = top();
+}
+
+inline void HeapRegion::note_end_of_marking() {
+ _prev_top_at_mark_start = _next_top_at_mark_start;
+ _prev_marked_bytes = _next_marked_bytes;
+ _next_marked_bytes = 0;
+
+ assert(_prev_marked_bytes <=
+ (size_t) pointer_delta(prev_top_at_mark_start(), bottom()) *
+ HeapWordSize, "invariant");
+}
+
+inline void HeapRegion::note_start_of_copying(bool during_initial_mark) {
+ if (during_initial_mark) {
+ if (is_survivor()) {
+ assert(false, "should not allocate survivors during IM");
+ } else {
+ // During initial-mark we'll explicitly mark any objects on old
+ // regions that are pointed to by roots. Given that explicit
+ // marks only make sense under NTAMS it'd be nice if we could
+ // check that condition if we wanted to. Given that we don't
+ // know where the top of this region will end up, we simply set
+ // NTAMS to the end of the region so all marks will be below
+ // NTAMS. We'll set it to the actual top when we retire this region.
+ _next_top_at_mark_start = end();
+ }
+ } else {
+ if (is_survivor()) {
+ // This is how we always allocate survivors.
+ assert(_next_top_at_mark_start == bottom(), "invariant");
+ } else {
+ // We could have re-used this old region as to-space over a
+ // couple of GCs since the start of the concurrent marking
+ // cycle. This means that [bottom,NTAMS) will contain objects
+ // copied up to and including initial-mark and [NTAMS, top)
+ // will contain objects copied during the concurrent marking cycle.
+ assert(top() >= _next_top_at_mark_start, "invariant");
+ }
+ }
+}
+
+inline void HeapRegion::note_end_of_copying(bool during_initial_mark) {
+ if (during_initial_mark) {
+ if (is_survivor()) {
+ assert(false, "should not allocate survivors during IM");
+ } else {
+ // See the comment for note_start_of_copying() for the details
+ // on this.
+ assert(_next_top_at_mark_start == end(), "pre-condition");
+ _next_top_at_mark_start = top();
+ }
+ } else {
+ if (is_survivor()) {
+ // This is how we always allocate survivors.
+ assert(_next_top_at_mark_start == bottom(), "invariant");
+ } else {
+ // See the comment for note_start_of_copying() for the details
+ // on this.
+ assert(top() >= _next_top_at_mark_start, "invariant");
+ }
+ }
+}
+
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGION_INLINE_HPP
--- a/hotspot/src/share/vm/gc_implementation/g1/ptrQueue.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/ptrQueue.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -70,7 +70,7 @@
// given PtrQueueSet.
PtrQueue(PtrQueueSet* qset, bool perm = false, bool active = false);
// Release any contained resources.
- void flush();
+ virtual void flush();
// Calls flush() when destroyed.
~PtrQueue() { flush(); }
--- a/hotspot/src/share/vm/gc_implementation/g1/satbQueue.cpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/satbQueue.cpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -31,6 +31,14 @@
#include "runtime/thread.hpp"
#include "runtime/vmThread.hpp"
+void ObjPtrQueue::flush() {
+ // The buffer might contain refs into the CSet. We have to filter it
+ // first before we flush it, otherwise we might end up with an
+ // enqueued buffer with refs into the CSet which breaks our invariants.
+ filter();
+ PtrQueue::flush();
+}
+
// This method removes entries from an SATB buffer that will not be
// useful to the concurrent marking threads. An entry is removed if it
// satisfies one of the following conditions:
@@ -44,38 +52,27 @@
// process it again).
//
// The rest of the entries will be retained and are compacted towards
-// the top of the buffer. If with this filtering we clear a large
-// enough chunk of the buffer we can re-use it (instead of enqueueing
-// it) and we can just allow the mutator to carry on executing.
-
-bool ObjPtrQueue::should_enqueue_buffer() {
- assert(_lock == NULL || _lock->owned_by_self(),
- "we should have taken the lock before calling this");
+// the top of the buffer. Note that, because we do not allow old
+// regions in the CSet during marking, all objects on the CSet regions
+// are young (eden or survivors) and therefore implicitly live. So any
+// references into the CSet will be removed during filtering.
- // A value of 0 means "don't filter SATB buffers".
- if (G1SATBBufferEnqueueingThresholdPercent == 0) {
- return true;
- }
-
+void ObjPtrQueue::filter() {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
-
- // This method should only be called if there is a non-NULL buffer
- // that is full.
- assert(_index == 0, "pre-condition");
- assert(_buf != NULL, "pre-condition");
-
void** buf = _buf;
size_t sz = _sz;
+ if (buf == NULL) {
+ // nothing to do
+ return;
+ }
+
// Used for sanity checking at the end of the loop.
debug_only(size_t entries = 0; size_t retained = 0;)
size_t i = sz;
size_t new_index = sz;
- // Given that we are expecting _index == 0, we could have changed
- // the loop condition to (i > 0). But we are using _index for
- // generality.
while (i > _index) {
assert(i > 0, "we should have at least one more entry to process");
i -= oopSize;
@@ -103,22 +100,58 @@
debug_only(retained += 1;)
}
}
+
+#ifdef ASSERT
size_t entries_calc = (sz - _index) / oopSize;
assert(entries == entries_calc, "the number of entries we counted "
"should match the number of entries we calculated");
size_t retained_calc = (sz - new_index) / oopSize;
assert(retained == retained_calc, "the number of retained entries we counted "
"should match the number of retained entries we calculated");
- size_t perc = retained_calc * 100 / entries_calc;
+#endif // ASSERT
+
+ _index = new_index;
+}
+
+// This method will first apply the above filtering to the buffer. If
+// post-filtering a large enough chunk of the buffer has been cleared
+// we can re-use the buffer (instead of enqueueing it) and we can just
+// allow the mutator to carry on executing using the same buffer
+// instead of replacing it.
+
+bool ObjPtrQueue::should_enqueue_buffer() {
+ assert(_lock == NULL || _lock->owned_by_self(),
+ "we should have taken the lock before calling this");
+
+ // Even if G1SATBBufferEnqueueingThresholdPercent == 0 we have to
+ // filter the buffer given that this will remove any references into
+ // the CSet as we currently assume that no such refs will appear in
+ // enqueued buffers.
+
+ // This method should only be called if there is a non-NULL buffer
+ // that is full.
+ assert(_index == 0, "pre-condition");
+ assert(_buf != NULL, "pre-condition");
+
+ filter();
+
+ size_t sz = _sz;
+ size_t all_entries = sz / oopSize;
+ size_t retained_entries = (sz - _index) / oopSize;
+ size_t perc = retained_entries * 100 / all_entries;
bool should_enqueue = perc > (size_t) G1SATBBufferEnqueueingThresholdPercent;
- _index = new_index;
-
return should_enqueue;
}
void ObjPtrQueue::apply_closure(ObjectClosure* cl) {
if (_buf != NULL) {
apply_closure_to_buffer(cl, _buf, _index, _sz);
+ }
+}
+
+void ObjPtrQueue::apply_closure_and_empty(ObjectClosure* cl) {
+ if (_buf != NULL) {
+ apply_closure_to_buffer(cl, _buf, _index, _sz);
_index = _sz;
}
}
@@ -135,6 +168,21 @@
}
}
+#ifndef PRODUCT
+// Helpful for debugging
+
+void ObjPtrQueue::print(const char* name) {
+ print(name, _buf, _index, _sz);
+}
+
+void ObjPtrQueue::print(const char* name,
+ void** buf, size_t index, size_t sz) {
+ gclog_or_tty->print_cr(" SATB BUFFER [%s] buf: "PTR_FORMAT" "
+ "index: "SIZE_FORMAT" sz: "SIZE_FORMAT,
+ name, buf, index, sz);
+}
+#endif // PRODUCT
+
#ifdef ASSERT
void ObjPtrQueue::verify_oops_in_buffer() {
if (_buf == NULL) return;
@@ -150,12 +198,9 @@
#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
#endif // _MSC_VER
-
SATBMarkQueueSet::SATBMarkQueueSet() :
- PtrQueueSet(),
- _closure(NULL), _par_closures(NULL),
- _shared_satb_queue(this, true /*perm*/)
-{}
+ PtrQueueSet(), _closure(NULL), _par_closures(NULL),
+ _shared_satb_queue(this, true /*perm*/) { }
void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
int process_completed_threshold,
@@ -167,7 +212,6 @@
}
}
-
void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) {
DEBUG_ONLY(t->satb_mark_queue().verify_oops_in_buffer();)
t->satb_mark_queue().handle_zero_index();
@@ -228,6 +272,13 @@
}
}
+void SATBMarkQueueSet::filter_thread_buffers() {
+ for(JavaThread* t = Threads::first(); t; t = t->next()) {
+ t->satb_mark_queue().filter();
+ }
+ shared_satb_queue()->filter();
+}
+
void SATBMarkQueueSet::set_closure(ObjectClosure* closure) {
_closure = closure;
}
@@ -239,9 +290,9 @@
void SATBMarkQueueSet::iterate_closure_all_threads() {
for(JavaThread* t = Threads::first(); t; t = t->next()) {
- t->satb_mark_queue().apply_closure(_closure);
+ t->satb_mark_queue().apply_closure_and_empty(_closure);
}
- shared_satb_queue()->apply_closure(_closure);
+ shared_satb_queue()->apply_closure_and_empty(_closure);
}
void SATBMarkQueueSet::par_iterate_closure_all_threads(int worker) {
@@ -250,7 +301,7 @@
for(JavaThread* t = Threads::first(); t; t = t->next()) {
if (t->claim_oops_do(true, parity)) {
- t->satb_mark_queue().apply_closure(_par_closures[worker]);
+ t->satb_mark_queue().apply_closure_and_empty(_par_closures[worker]);
}
}
@@ -264,7 +315,7 @@
VMThread* vmt = VMThread::vm_thread();
if (vmt->claim_oops_do(true, parity)) {
- shared_satb_queue()->apply_closure(_par_closures[worker]);
+ shared_satb_queue()->apply_closure_and_empty(_par_closures[worker]);
}
}
@@ -292,6 +343,61 @@
}
}
+void SATBMarkQueueSet::iterate_completed_buffers_read_only(ObjectClosure* cl) {
+ assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
+ assert(cl != NULL, "pre-condition");
+
+ BufferNode* nd = _completed_buffers_head;
+ while (nd != NULL) {
+ void** buf = BufferNode::make_buffer_from_node(nd);
+ ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz);
+ nd = nd->next();
+ }
+}
+
+void SATBMarkQueueSet::iterate_thread_buffers_read_only(ObjectClosure* cl) {
+ assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
+ assert(cl != NULL, "pre-condition");
+
+ for (JavaThread* t = Threads::first(); t; t = t->next()) {
+ t->satb_mark_queue().apply_closure(cl);
+ }
+ shared_satb_queue()->apply_closure(cl);
+}
+
+#ifndef PRODUCT
+// Helpful for debugging
+
+#define SATB_PRINTER_BUFFER_SIZE 256
+
+void SATBMarkQueueSet::print_all(const char* msg) {
+ char buffer[SATB_PRINTER_BUFFER_SIZE];
+ assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
+
+ gclog_or_tty->cr();
+ gclog_or_tty->print_cr("SATB BUFFERS [%s]", msg);
+
+ BufferNode* nd = _completed_buffers_head;
+ int i = 0;
+ while (nd != NULL) {
+ void** buf = BufferNode::make_buffer_from_node(nd);
+ jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Enqueued: %d", i);
+ ObjPtrQueue::print(buffer, buf, 0, _sz);
+ nd = nd->next();
+ i += 1;
+ }
+
+ for (JavaThread* t = Threads::first(); t; t = t->next()) {
+ jio_snprintf(buffer, SATB_PRINTER_BUFFER_SIZE, "Thread: %s", t->name());
+ t->satb_mark_queue().print(buffer);
+ }
+
+ shared_satb_queue()->print("Shared");
+
+ gclog_or_tty->cr();
+}
+#endif // PRODUCT
+
void SATBMarkQueueSet::abandon_partial_marking() {
BufferNode* buffers_to_delete = NULL;
{
@@ -316,5 +422,5 @@
for (JavaThread* t = Threads::first(); t; t = t->next()) {
t->satb_mark_queue().reset();
}
- shared_satb_queue()->reset();
+ shared_satb_queue()->reset();
}
--- a/hotspot/src/share/vm/gc_implementation/g1/satbQueue.hpp Thu Jan 12 09:59:55 2012 -0500
+++ b/hotspot/src/share/vm/gc_implementation/g1/satbQueue.hpp Fri Jan 13 01:55:22 2012 -0800
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, 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
@@ -29,9 +29,26 @@
class ObjectClosure;
class JavaThread;
+class SATBMarkQueueSet;
// A ptrQueue whose elements are "oops", pointers to object heads.
class ObjPtrQueue: public PtrQueue {
+ friend class SATBMarkQueueSet;
+
+private:
+ // Filter out unwanted entries from the buffer.
+ void filter();
+
+ // Apply the closure to all elements.
+ void apply_closure(ObjectClosure* cl);
+
+ // Apply the closure to all elements and empty the buffer;
+ void apply_closure_and_empty(ObjectClosure* cl);
+
+ // Apply the closure to all elements of "buf", down to "index" (inclusive.)
+ static void apply_closure_to_buffer(ObjectClosure* cl,
+ void** buf, size_t index, size_t sz);
+
public:
ObjPtrQueue(PtrQueueSet* qset, bool perm = false) :
// SATB queues are only active during marking cycles. We create
@@ -41,23 +58,23 @@
// field to true. This is done in JavaThread::initialize_queues().
PtrQueue(qset, perm, false /* active */) { }
+ // Overrides PtrQueue::flush() so that it can filter the buffer
+ // before it is flushed.
+ virtual void flush();
+
// Overrides PtrQueue::should_enqueue_buffer(). See the method's
// definition for more information.
virtual bool should_enqueue_buffer();
- // Apply the closure to all elements, and reset the index to make the
- // buffer empty.
- void apply_closure(ObjectClosure* cl);
-
- // Apply the closure to all elements of "buf", down to "index" (inclusive.)
- static void apply_closure_to_buffer(ObjectClosure* cl,
- void** buf, size_t index, size_t sz);
+#ifndef PRODUCT
+ // Helpful for debugging
+ void print(const char* name);
+ static void print(const char* name, void** buf, size_t index, size_t sz);
+#endif // PRODUCT
void verify_oops_in_buffer() NOT_DEBUG_RETURN;
};
-
-
class SATBMarkQueueSet: public PtrQueueSet {
ObjectClosure* _closure;
ObjectClosure** _par_closures; // One per ParGCThread.
@@ -88,6 +105,9 @@
// set itself, has an active value same as expected_active.
void set_active_all_threads(bool b, bool expected_active);
+ // Filter all the currently-active SATB buffers.
+ void filter_thread_buffers();
+
// Register "blk" as "the closure" for all queues. Only one such closure
// is allowed. The "apply_closure_to_completed_buffer" method will apply
// this closure to a completed buffer, and "iterate_closure_all_threads"
@@ -98,10 +118,9 @@
// closures, one for each parallel GC thread.
void set_par_closure(int i, ObjectClosure* closure);
- // If there is a registered closure for buffers, apply it to all entries
- // in all currently-active buffers. This should only be applied at a
- // safepoint. (Currently must not be called in parallel; this should
- // change in the future.)
+ // Apply the registered closure to all entries on each
+ // currently-active buffer and then empty the buffer. It should only
+ // be called serially and at a safepoint.
void iterate_closure_all_threads();
// Parallel version of the above.
void par_iterate_closure_all_threads(int worker);
@@ -117,11 +136,21 @@
return apply_closure_to_completed_buffer_work(true, worker);
}
+ // Apply the given closure on enqueued and currently-active buffers
+ // respectively. Both methods are read-only, i.e., they do not
+ // modify any of the buffers.
+ void iterate_completed_buffers_read_only(ObjectClosure* cl);
+ void iterate_thread_buffers_read_only(ObjectClosure* cl);
+
+#ifndef PRODUCT
+ // Helpful for debugging
+ void print_all(const char* msg);
+#endif // PRODUCT
+
ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
// If a marking is being abandoned, reset any unprocessed log buffers.
void abandon_partial_marking();
-
};
#endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP