--- /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<typename Fn>
+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<true>(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<bool scan>
+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<false>(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