/* * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP #include "gc_implementation/g1/concurrentMark.hpp" #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" // Utility routine to set an exclusive range of cards on the given // card liveness bitmap inline void ConcurrentMark::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 ConcurrentMark::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 ConcurrentMark::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->continuesHumongous(), "should not be HC region"); assert(hr == g1h->heap_region_containing(start), "sanity"); assert(hr == g1h->heap_region_containing(mr.last()), "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 - incremement 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 memory region in the task/worker counting // data structures for the given worker id. inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr, uint worker_id) { size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id); BitMap* task_card_bm = count_card_bitmap_for(worker_id); count_region(mr, hr, marked_bytes_array, task_card_bm); } // Counts the given object in the given task/worker counting data structures. inline void ConcurrentMark::count_object(oop obj, HeapRegion* hr, size_t* marked_bytes_array, BitMap* task_card_bm) { MemRegion mr((HeapWord*)obj, obj->size()); count_region(mr, hr, marked_bytes_array, task_card_bm); } // Attempts to mark the given object and, if successful, counts // the object in the given task/worker counting structures. inline bool ConcurrentMark::par_mark_and_count(oop obj, HeapRegion* hr, size_t* marked_bytes_array, BitMap* task_card_bm) { HeapWord* addr = (HeapWord*)obj; if (_nextMarkBitMap->parMark(addr)) { // Update the task specific count data for the object. count_object(obj, hr, marked_bytes_array, task_card_bm); 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 ConcurrentMark::par_mark_and_count(oop obj, size_t word_size, HeapRegion* hr, uint worker_id) { HeapWord* addr = (HeapWord*)obj; if (_nextMarkBitMap->parMark(addr)) { MemRegion mr(addr, word_size); count_region(mr, hr, worker_id); return true; } return false; } inline bool CMBitMapRO::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; } inline bool CMBitMapRO::iterate(BitMapClosure* cl) { MemRegion mr(startWord(), sizeInWords()); return iterate(cl, mr); } #define check_mark(addr) \ assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize), \ "outside underlying space?"); \ assert(G1CollectedHeap::heap()->is_in_exact(addr), \ err_msg("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 CMBitMap::mark(HeapWord* addr) { check_mark(addr); _bm.set_bit(heapWordToOffset(addr)); } inline void CMBitMap::clear(HeapWord* addr) { check_mark(addr); _bm.clear_bit(heapWordToOffset(addr)); } inline bool CMBitMap::parMark(HeapWord* addr) { check_mark(addr); return _bm.par_set_bit(heapWordToOffset(addr)); } inline bool CMBitMap::parClear(HeapWord* addr) { check_mark(addr); return _bm.par_clear_bit(heapWordToOffset(addr)); } #undef check_mark inline void CMTask::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 (_cm->verbose_high()) { gclog_or_tty->print_cr("[%u] pushing " PTR_FORMAT, _worker_id, p2i((void*) obj)); } if (!_task_queue->push(obj)) { // The local task queue looks full. We need to push some entries // to the global stack. if (_cm->verbose_medium()) { gclog_or_tty->print_cr("[%u] task queue overflow, " "moving entries to the global stack", _worker_id); } 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"); } statsOnly( int tmp_size = _task_queue->size(); if (tmp_size > _local_max_size) { _local_max_size = tmp_size; } ++_local_pushes ); } inline bool CMTask::is_below_finger(HeapWord* objAddr, HeapWord* global_finger) const { // If objAddr 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 objAddr 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. 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 objAddr 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; } inline void CMTask::deal_with_reference(oop obj) { if (_cm->verbose_high()) { gclog_or_tty->print_cr("[%u] we're dealing with reference = "PTR_FORMAT, _worker_id, p2i((void*) obj)); } ++_refs_reached; HeapWord* objAddr = (HeapWord*) obj; assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); 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_raw(obj); if (!hr->obj_allocated_since_next_marking(obj)) { if (_cm->verbose_high()) { gclog_or_tty->print_cr("[%u] "PTR_FORMAT" is not considered marked", _worker_id, p2i((void*) obj)); } // we need to mark it first 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 CMBitMap::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(objAddr, global_finger)) { if (_cm->verbose_high()) { gclog_or_tty->print_cr("[%u] below a finger (local: " PTR_FORMAT ", global: " PTR_FORMAT ") pushing " PTR_FORMAT " on mark stack", _worker_id, p2i(_finger), p2i(global_finger), p2i(objAddr)); } push(obj); } } } } } } 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::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_raw(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->continuesHumongous(), "sanity"); // 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))); 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_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP