Mercurial > hg > truffle
changeset 4787:2ace1c4ee8da
6888336: G1: avoid explicitly marking and pushing objects in survivor spaces
Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso
line wrap: on
line diff
--- a/src/share/vm/gc_implementation/g1/concurrentMark.cpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/concurrentMark.cpp Tue Jan 10 18:58:13 2012 -0500 @@ -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(); @@ -3099,6 +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()) { @@ -3146,6 +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; @@ -3184,6 +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(); @@ -3195,6 +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"); @@ -3905,6 +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/src/share/vm/gc_implementation/g1/concurrentMark.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/concurrentMark.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/concurrentMark.inline.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp Tue Jan 10 18:58:13 2012 -0500 @@ -36,6 +36,7 @@ #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" @@ -3018,14 +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. } } } @@ -3659,25 +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(); @@ -3686,6 +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) { @@ -3702,16 +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); @@ -3725,6 +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(); @@ -3804,6 +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); @@ -3954,6 +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); } @@ -4047,8 +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)); @@ -4057,15 +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, @@ -4161,30 +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), @@ -4198,8 +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) @@ -4304,35 +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() @@ -4346,7 +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. @@ -4382,23 +4375,6 @@ 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; @@ -4428,61 +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()); @@ -4491,8 +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); } } @@ -4787,12 +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) { @@ -5411,13 +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) { @@ -6074,6 +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); @@ -6085,7 +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/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -869,8 +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. @@ -962,7 +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 @@ -1752,10 +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) { @@ -1809,6 +1806,8 @@ } void set_buffer(HeapWord* start) { + guarantee(false, "set_buffer(): don't call this any more"); + guarantee(use_local_bitmaps, "invariant"); clear(); @@ -1832,6 +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"); @@ -1865,32 +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/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.cpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/g1CollectorPolicy.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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) {
--- a/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/g1EvacFailure.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -66,19 +66,22 @@ G1CollectedHeap* _g1; ConcurrentMark* _cm; HeapRegion* _hr; - size_t _prev_marked_bytes; - size_t _next_marked_bytes; + 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) : - _g1(g1), _cm(cm), _hr(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), - _prev_marked_bytes(0), _next_marked_bytes(0) {} + _during_initial_mark(during_initial_mark), + _during_conc_mark(during_conc_mark) { } - size_t prev_marked_bytes() { return _prev_marked_bytes; } - size_t next_marked_bytes() { return _next_marked_bytes; } + size_t marked_bytes() { return _marked_bytes; } // <original comment> // The original idea here was to coalesce evacuated and dead objects. @@ -100,18 +103,29 @@ 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."); + + // 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); - 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); + 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, @@ -126,15 +140,13 @@ // 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); + MemRegion mr((HeapWord*) obj, obj_size); CollectedHeap::fill_with_object(mr); - _cm->clearRangeBothMaps(mr); } } }; @@ -151,12 +163,27 @@ _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); + 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 @@ -171,28 +198,9 @@ _update_rset_cl->set_region(hr); hr->object_iterate(&rspc); - // A number of manipulations to make the TAMS for this region - // be the current top, and the marked bytes be the ones observed - // in the iteration. - if (_cm->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. - hr->note_start_of_marking(false); - // _next_top_at_mark_start == top, _next_marked_bytes == 0 - hr->add_to_marked_bytes(rspc.prev_marked_bytes()); - // _next_marked_bytes == prev_marked_bytes. - hr->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()) { - hr->note_start_of_marking(false); - // _next_top_at_mark_start == top, _next_marked_bytes == 0 - // _next_marked_bytes == next_marked_bytes. - } + hr->note_self_forwarding_removal_end(during_initial_mark, + during_conc_mark, + rspc.marked_bytes()); } } return false;
--- a/src/share/vm/gc_implementation/g1/g1OopClosures.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/g1OopClosures.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/heapRegion.cpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/heapRegion.cpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/heapRegion.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/heapRegion.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -583,37 +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/src/share/vm/gc_implementation/g1/heapRegion.inline.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/heapRegion.inline.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/ptrQueue.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/ptrQueue.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/satbQueue.cpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/satbQueue.cpp Tue Jan 10 18:58:13 2012 -0500 @@ -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/src/share/vm/gc_implementation/g1/satbQueue.hpp Tue Jan 10 20:02:41 2012 +0100 +++ b/src/share/vm/gc_implementation/g1/satbQueue.hpp Tue Jan 10 18:58:13 2012 -0500 @@ -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