diff -r 05df7e64ecfc -r e726308008c0 hotspot/src/share/vm/gc/g1/g1ConcurrentMark.inline.hpp --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/hotspot/src/share/vm/gc/g1/g1ConcurrentMark.inline.hpp Fri Feb 05 16:03:56 2016 +0100 @@ -0,0 +1,394 @@ +/* + * Copyright (c) 2001, 2016, 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_G1_G1CONCURRENTMARK_INLINE_HPP +#define SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP + +#include "gc/g1/g1CollectedHeap.inline.hpp" +#include "gc/g1/g1ConcurrentMark.hpp" +#include "gc/shared/taskqueue.inline.hpp" + +// Utility routine to set an exclusive range of cards on the given +// card liveness bitmap +inline void G1ConcurrentMark::set_card_bitmap_range(BitMap* card_bm, + BitMap::idx_t start_idx, + BitMap::idx_t end_idx, + bool is_par) { + + // Set the exclusive bit range [start_idx, end_idx). + assert((end_idx - start_idx) > 0, "at least one card"); + assert(end_idx <= card_bm->size(), "sanity"); + + // Silently clip the end index + end_idx = MIN2(end_idx, card_bm->size()); + + // For small ranges use a simple loop; otherwise use set_range or + // use par_at_put_range (if parallel). The range is made up of the + // cards that are spanned by an object/mem region so 8 cards will + // allow up to object sizes up to 4K to be handled using the loop. + if ((end_idx - start_idx) <= 8) { + for (BitMap::idx_t i = start_idx; i < end_idx; i += 1) { + if (is_par) { + card_bm->par_set_bit(i); + } else { + card_bm->set_bit(i); + } + } + } else { + // Note BitMap::par_at_put_range() and BitMap::set_range() are exclusive. + if (is_par) { + card_bm->par_at_put_range(start_idx, end_idx, true); + } else { + card_bm->set_range(start_idx, end_idx); + } + } +} + +// Returns the index in the liveness accounting card bitmap +// for the given address +inline BitMap::idx_t G1ConcurrentMark::card_bitmap_index_for(HeapWord* addr) { + // Below, the term "card num" means the result of shifting an address + // by the card shift -- address 0 corresponds to card number 0. One + // must subtract the card num of the bottom of the heap to obtain a + // card table index. + intptr_t card_num = intptr_t(uintptr_t(addr) >> CardTableModRefBS::card_shift); + return card_num - heap_bottom_card_num(); +} + +// Counts the given memory region in the given task/worker +// counting data structures. +inline void G1ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr, + size_t* marked_bytes_array, + BitMap* task_card_bm) { + G1CollectedHeap* g1h = _g1h; + CardTableModRefBS* ct_bs = g1h->g1_barrier_set(); + + HeapWord* start = mr.start(); + HeapWord* end = mr.end(); + size_t region_size_bytes = mr.byte_size(); + uint index = hr->hrm_index(); + + assert(hr == g1h->heap_region_containing(start), "sanity"); + assert(marked_bytes_array != NULL, "pre-condition"); + assert(task_card_bm != NULL, "pre-condition"); + + // Add to the task local marked bytes for this region. + marked_bytes_array[index] += region_size_bytes; + + BitMap::idx_t start_idx = card_bitmap_index_for(start); + BitMap::idx_t end_idx = card_bitmap_index_for(end); + + // Note: if we're looking at the last region in heap - end + // could be actually just beyond the end of the heap; end_idx + // will then correspond to a (non-existent) card that is also + // just beyond the heap. + if (g1h->is_in_g1_reserved(end) && !ct_bs->is_card_aligned(end)) { + // end of region is not card aligned - increment to cover + // all the cards spanned by the region. + end_idx += 1; + } + // The card bitmap is task/worker specific => no need to use + // the 'par' BitMap routines. + // Set bits in the exclusive bit range [start_idx, end_idx). + set_card_bitmap_range(task_card_bm, start_idx, end_idx, false /* is_par */); +} + +// Counts the given object in the given task/worker counting data structures. +inline void G1ConcurrentMark::count_object(oop obj, + HeapRegion* hr, + size_t* marked_bytes_array, + BitMap* task_card_bm, + size_t word_size) { + assert(!hr->is_continues_humongous(), "Cannot enter count_object with continues humongous"); + if (!hr->is_starts_humongous()) { + MemRegion mr((HeapWord*)obj, word_size); + count_region(mr, hr, marked_bytes_array, task_card_bm); + } else { + do { + MemRegion mr(hr->bottom(), hr->top()); + count_region(mr, hr, marked_bytes_array, task_card_bm); + hr = _g1h->next_region_in_humongous(hr); + } while (hr != NULL); + } +} + +// Attempts to mark the given object and, if successful, counts +// the object in the given task/worker counting structures. +inline bool G1ConcurrentMark::par_mark_and_count(oop obj, + HeapRegion* hr, + size_t* marked_bytes_array, + BitMap* task_card_bm) { + if (_nextMarkBitMap->parMark((HeapWord*)obj)) { + // Update the task specific count data for the object. + count_object(obj, hr, marked_bytes_array, task_card_bm, obj->size()); + return true; + } + return false; +} + +// Attempts to mark the given object and, if successful, counts +// the object in the task/worker counting structures for the +// given worker id. +inline bool G1ConcurrentMark::par_mark_and_count(oop obj, + size_t word_size, + HeapRegion* hr, + uint worker_id) { + if (_nextMarkBitMap->parMark((HeapWord*)obj)) { + size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id); + BitMap* task_card_bm = count_card_bitmap_for(worker_id); + count_object(obj, hr, marked_bytes_array, task_card_bm, word_size); + return true; + } + return false; +} + +inline bool G1CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { + HeapWord* start_addr = MAX2(startWord(), mr.start()); + HeapWord* end_addr = MIN2(endWord(), mr.end()); + + if (end_addr > start_addr) { + // Right-open interval [start-offset, end-offset). + BitMap::idx_t start_offset = heapWordToOffset(start_addr); + BitMap::idx_t end_offset = heapWordToOffset(end_addr); + + start_offset = _bm.get_next_one_offset(start_offset, end_offset); + while (start_offset < end_offset) { + if (!cl->do_bit(start_offset)) { + return false; + } + HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr); + BitMap::idx_t next_offset = heapWordToOffset(next_addr); + start_offset = _bm.get_next_one_offset(next_offset, end_offset); + } + } + return true; +} + +// The argument addr should be the start address of a valid object +HeapWord* G1CMBitMapRO::nextObject(HeapWord* addr) { + oop obj = (oop) addr; + HeapWord* res = addr + obj->size(); + assert(offsetToHeapWord(heapWordToOffset(res)) == res, "sanity"); + return res; +} + +#define check_mark(addr) \ + assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize), \ + "outside underlying space?"); \ + assert(G1CollectedHeap::heap()->is_in_exact(addr), \ + "Trying to access not available bitmap " PTR_FORMAT \ + " corresponding to " PTR_FORMAT " (%u)", \ + p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr)); + +inline void G1CMBitMap::mark(HeapWord* addr) { + check_mark(addr); + _bm.set_bit(heapWordToOffset(addr)); +} + +inline void G1CMBitMap::clear(HeapWord* addr) { + check_mark(addr); + _bm.clear_bit(heapWordToOffset(addr)); +} + +inline bool G1CMBitMap::parMark(HeapWord* addr) { + check_mark(addr); + return _bm.par_set_bit(heapWordToOffset(addr)); +} + +#undef check_mark + +template +inline void G1CMMarkStack::iterate(Fn fn) { + assert(_saved_index == _index, "saved index: %d index: %d", _saved_index, _index); + for (int i = 0; i < _index; ++i) { + fn(_base[i]); + } +} + +// It scans an object and visits its children. +inline void G1CMTask::scan_object(oop obj) { process_grey_object(obj); } + +inline void G1CMTask::push(oop obj) { + HeapWord* objAddr = (HeapWord*) obj; + assert(_g1h->is_in_g1_reserved(objAddr), "invariant"); + assert(!_g1h->is_on_master_free_list( + _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant"); + assert(!_g1h->is_obj_ill(obj), "invariant"); + assert(_nextMarkBitMap->isMarked(objAddr), "invariant"); + + if (!_task_queue->push(obj)) { + // The local task queue looks full. We need to push some entries + // to the global stack. + move_entries_to_global_stack(); + + // this should succeed since, even if we overflow the global + // stack, we should have definitely removed some entries from the + // local queue. So, there must be space on it. + bool success = _task_queue->push(obj); + assert(success, "invariant"); + } +} + +inline bool G1CMTask::is_below_finger(oop obj, HeapWord* global_finger) const { + // If obj is above the global finger, then the mark bitmap scan + // will find it later, and no push is needed. Similarly, if we have + // a current region and obj is between the local finger and the + // end of the current region, then no push is needed. The tradeoff + // of checking both vs only checking the global finger is that the + // local check will be more accurate and so result in fewer pushes, + // but may also be a little slower. + HeapWord* objAddr = (HeapWord*)obj; + if (_finger != NULL) { + // We have a current region. + + // Finger and region values are all NULL or all non-NULL. We + // use _finger to check since we immediately use its value. + assert(_curr_region != NULL, "invariant"); + assert(_region_limit != NULL, "invariant"); + assert(_region_limit <= global_finger, "invariant"); + + // True if obj is less than the local finger, or is between + // the region limit and the global finger. + if (objAddr < _finger) { + return true; + } else if (objAddr < _region_limit) { + return false; + } // Else check global finger. + } + // Check global finger. + return objAddr < global_finger; +} + +template +inline void G1CMTask::process_grey_object(oop obj) { + assert(scan || obj->is_typeArray(), "Skipping scan of grey non-typeArray"); + assert(_nextMarkBitMap->isMarked((HeapWord*) obj), "invariant"); + + size_t obj_size = obj->size(); + _words_scanned += obj_size; + + if (scan) { + obj->oop_iterate(_cm_oop_closure); + } + check_limits(); +} + + + +inline void G1CMTask::make_reference_grey(oop obj, HeapRegion* hr) { + if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) { + // No OrderAccess:store_load() is needed. It is implicit in the + // CAS done in G1CMBitMap::parMark() call in the routine above. + HeapWord* global_finger = _cm->finger(); + + // We only need to push a newly grey object on the mark + // stack if it is in a section of memory the mark bitmap + // scan has already examined. Mark bitmap scanning + // maintains progress "fingers" for determining that. + // + // Notice that the global finger might be moving forward + // concurrently. This is not a problem. In the worst case, we + // mark the object while it is above the global finger and, by + // the time we read the global finger, it has moved forward + // past this object. In this case, the object will probably + // be visited when a task is scanning the region and will also + // be pushed on the stack. So, some duplicate work, but no + // correctness problems. + if (is_below_finger(obj, global_finger)) { + if (obj->is_typeArray()) { + // Immediately process arrays of primitive types, rather + // than pushing on the mark stack. This keeps us from + // adding humongous objects to the mark stack that might + // be reclaimed before the entry is processed - see + // selection of candidates for eager reclaim of humongous + // objects. The cost of the additional type test is + // mitigated by avoiding a trip through the mark stack, + // by only doing a bookkeeping update and avoiding the + // actual scan of the object - a typeArray contains no + // references, and the metadata is built-in. + process_grey_object(obj); + } else { + push(obj); + } + } + } +} + +inline void G1CMTask::deal_with_reference(oop obj) { + increment_refs_reached(); + + HeapWord* objAddr = (HeapWord*) obj; + assert(obj->is_oop_or_null(true /* ignore mark word */), "Expected an oop or NULL at " PTR_FORMAT, p2i(obj)); + if (_g1h->is_in_g1_reserved(objAddr)) { + assert(obj != NULL, "null check is implicit"); + if (!_nextMarkBitMap->isMarked(objAddr)) { + // Only get the containing region if the object is not marked on the + // bitmap (otherwise, it's a waste of time since we won't do + // anything with it). + HeapRegion* hr = _g1h->heap_region_containing(obj); + if (!hr->obj_allocated_since_next_marking(obj)) { + make_reference_grey(obj, hr); + } + } + } +} + +inline void G1ConcurrentMark::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. + ((G1CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p); +} + +bool G1ConcurrentMark::isPrevMarked(oop p) const { + assert(p != NULL && p->is_oop(), "expected an oop"); + HeapWord* addr = (HeapWord*)p; + assert(addr >= _prevMarkBitMap->startWord() || + addr < _prevMarkBitMap->endWord(), "in a region"); + + return _prevMarkBitMap->isMarked(addr); +} + +inline void G1ConcurrentMark::grayRoot(oop obj, size_t word_size, + uint worker_id, HeapRegion* hr) { + assert(obj != NULL, "pre-condition"); + HeapWord* addr = (HeapWord*) obj; + if (hr == NULL) { + hr = _g1h->heap_region_containing(addr); + } else { + assert(hr->is_in(addr), "pre-condition"); + } + assert(hr != NULL, "sanity"); + // Given that we're looking for a region that contains an object + // header it's impossible to get back a HC region. + assert(!hr->is_continues_humongous(), "sanity"); + + if (addr < hr->next_top_at_mark_start()) { + if (!_nextMarkBitMap->isMarked(addr)) { + par_mark_and_count(obj, word_size, hr, worker_id); + } + } +} + +#endif // SHARE_VM_GC_G1_G1CONCURRENTMARK_INLINE_HPP