707 lines
27 KiB
C++
707 lines
27 KiB
C++
/*
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* Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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#include "gc/parallel/gcTaskManager.hpp"
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#include "gc/parallel/objectStartArray.inline.hpp"
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#include "gc/parallel/parallelScavengeHeap.inline.hpp"
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#include "gc/parallel/psCardTable.hpp"
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#include "gc/parallel/psPromotionManager.inline.hpp"
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#include "gc/parallel/psScavenge.inline.hpp"
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#include "gc/parallel/psYoungGen.hpp"
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#include "memory/iterator.inline.hpp"
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#include "oops/access.inline.hpp"
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#include "oops/oop.inline.hpp"
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#include "runtime/prefetch.inline.hpp"
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#include "utilities/align.hpp"
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// Checks an individual oop for missing precise marks. Mark
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// may be either dirty or newgen.
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class CheckForUnmarkedOops : public BasicOopIterateClosure {
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private:
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PSYoungGen* _young_gen;
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PSCardTable* _card_table;
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HeapWord* _unmarked_addr;
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protected:
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template <class T> void do_oop_work(T* p) {
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oop obj = RawAccess<>::oop_load(p);
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if (_young_gen->is_in_reserved(obj) &&
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!_card_table->addr_is_marked_imprecise(p)) {
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// Don't overwrite the first missing card mark
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if (_unmarked_addr == NULL) {
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_unmarked_addr = (HeapWord*)p;
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}
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}
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}
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public:
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CheckForUnmarkedOops(PSYoungGen* young_gen, PSCardTable* card_table) :
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_young_gen(young_gen), _card_table(card_table), _unmarked_addr(NULL) { }
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virtual void do_oop(oop* p) { CheckForUnmarkedOops::do_oop_work(p); }
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virtual void do_oop(narrowOop* p) { CheckForUnmarkedOops::do_oop_work(p); }
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bool has_unmarked_oop() {
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return _unmarked_addr != NULL;
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}
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};
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// Checks all objects for the existence of some type of mark,
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// precise or imprecise, dirty or newgen.
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class CheckForUnmarkedObjects : public ObjectClosure {
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private:
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PSYoungGen* _young_gen;
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PSCardTable* _card_table;
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public:
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CheckForUnmarkedObjects() {
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ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
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_young_gen = heap->young_gen();
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_card_table = heap->card_table();
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}
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// Card marks are not precise. The current system can leave us with
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// a mismatch of precise marks and beginning of object marks. This means
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// we test for missing precise marks first. If any are found, we don't
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// fail unless the object head is also unmarked.
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virtual void do_object(oop obj) {
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CheckForUnmarkedOops object_check(_young_gen, _card_table);
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obj->oop_iterate(&object_check);
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if (object_check.has_unmarked_oop()) {
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guarantee(_card_table->addr_is_marked_imprecise(obj), "Found unmarked young_gen object");
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}
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}
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};
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// Checks for precise marking of oops as newgen.
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class CheckForPreciseMarks : public BasicOopIterateClosure {
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private:
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PSYoungGen* _young_gen;
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PSCardTable* _card_table;
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protected:
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template <class T> void do_oop_work(T* p) {
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oop obj = RawAccess<IS_NOT_NULL>::oop_load(p);
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if (_young_gen->is_in_reserved(obj)) {
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assert(_card_table->addr_is_marked_precise(p), "Found unmarked precise oop");
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_card_table->set_card_newgen(p);
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}
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}
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public:
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CheckForPreciseMarks(PSYoungGen* young_gen, PSCardTable* card_table) :
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_young_gen(young_gen), _card_table(card_table) { }
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virtual void do_oop(oop* p) { CheckForPreciseMarks::do_oop_work(p); }
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virtual void do_oop(narrowOop* p) { CheckForPreciseMarks::do_oop_work(p); }
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};
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// We get passed the space_top value to prevent us from traversing into
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// the old_gen promotion labs, which cannot be safely parsed.
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// Do not call this method if the space is empty.
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// It is a waste to start tasks and get here only to
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// do no work. If this method needs to be called
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// when the space is empty, fix the calculation of
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// end_card to allow sp_top == sp->bottom().
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// The generation (old gen) is divided into slices, which are further
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// subdivided into stripes, with one stripe per GC thread. The size of
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// a stripe is a constant, ssize.
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//
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// +===============+ slice 0
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// | stripe 0 |
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// +---------------+
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// | stripe 1 |
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// +---------------+
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// | stripe 2 |
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// +---------------+
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// | stripe 3 |
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// +===============+ slice 1
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// | stripe 0 |
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// +---------------+
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// | stripe 1 |
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// +---------------+
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// | stripe 2 |
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// +---------------+
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// | stripe 3 |
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// +===============+ slice 2
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// ...
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//
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// In this case there are 4 threads, so 4 stripes. A GC thread first works on
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// its stripe within slice 0 and then moves to its stripe in the next slice
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// until it has exceeded the top of the generation. The distance to stripe in
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// the next slice is calculated based on the number of stripes. The next
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// stripe is at ssize * number_of_stripes (= slice_stride).. So after
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// finishing stripe 0 in slice 0, the thread finds the stripe 0 in slice1 by
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// adding slice_stride to the start of stripe 0 in slice 0 to get to the start
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// of stride 0 in slice 1.
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void PSCardTable::scavenge_contents_parallel(ObjectStartArray* start_array,
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MutableSpace* sp,
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HeapWord* space_top,
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PSPromotionManager* pm,
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uint stripe_number,
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uint stripe_total) {
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int ssize = 128; // Naked constant! Work unit = 64k.
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int dirty_card_count = 0;
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// It is a waste to get here if empty.
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assert(sp->bottom() < sp->top(), "Should not be called if empty");
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oop* sp_top = (oop*)space_top;
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CardValue* start_card = byte_for(sp->bottom());
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CardValue* end_card = byte_for(sp_top - 1) + 1;
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oop* last_scanned = NULL; // Prevent scanning objects more than once
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// The width of the stripe ssize*stripe_total must be
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// consistent with the number of stripes so that the complete slice
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// is covered.
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size_t slice_width = ssize * stripe_total;
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for (CardValue* slice = start_card; slice < end_card; slice += slice_width) {
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CardValue* worker_start_card = slice + stripe_number * ssize;
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if (worker_start_card >= end_card)
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return; // We're done.
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CardValue* worker_end_card = worker_start_card + ssize;
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if (worker_end_card > end_card)
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worker_end_card = end_card;
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// We do not want to scan objects more than once. In order to accomplish
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// this, we assert that any object with an object head inside our 'slice'
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// belongs to us. We may need to extend the range of scanned cards if the
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// last object continues into the next 'slice'.
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//
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// Note! ending cards are exclusive!
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HeapWord* slice_start = addr_for(worker_start_card);
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HeapWord* slice_end = MIN2((HeapWord*) sp_top, addr_for(worker_end_card));
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#ifdef ASSERT
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if (GCWorkerDelayMillis > 0) {
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// Delay 1 worker so that it proceeds after all the work
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// has been completed.
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if (stripe_number < 2) {
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os::sleep(Thread::current(), GCWorkerDelayMillis, false);
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}
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}
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#endif
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// If there are not objects starting within the chunk, skip it.
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if (!start_array->object_starts_in_range(slice_start, slice_end)) {
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continue;
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}
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// Update our beginning addr
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HeapWord* first_object = start_array->object_start(slice_start);
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debug_only(oop* first_object_within_slice = (oop*) first_object;)
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if (first_object < slice_start) {
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last_scanned = (oop*)(first_object + oop(first_object)->size());
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debug_only(first_object_within_slice = last_scanned;)
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worker_start_card = byte_for(last_scanned);
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}
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// Update the ending addr
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if (slice_end < (HeapWord*)sp_top) {
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// The subtraction is important! An object may start precisely at slice_end.
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HeapWord* last_object = start_array->object_start(slice_end - 1);
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slice_end = last_object + oop(last_object)->size();
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// worker_end_card is exclusive, so bump it one past the end of last_object's
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// covered span.
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worker_end_card = byte_for(slice_end) + 1;
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if (worker_end_card > end_card)
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worker_end_card = end_card;
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}
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assert(slice_end <= (HeapWord*)sp_top, "Last object in slice crosses space boundary");
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assert(is_valid_card_address(worker_start_card), "Invalid worker start card");
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assert(is_valid_card_address(worker_end_card), "Invalid worker end card");
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// Note that worker_start_card >= worker_end_card is legal, and happens when
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// an object spans an entire slice.
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assert(worker_start_card <= end_card, "worker start card beyond end card");
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assert(worker_end_card <= end_card, "worker end card beyond end card");
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CardValue* current_card = worker_start_card;
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while (current_card < worker_end_card) {
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// Find an unclean card.
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while (current_card < worker_end_card && card_is_clean(*current_card)) {
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current_card++;
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}
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CardValue* first_unclean_card = current_card;
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// Find the end of a run of contiguous unclean cards
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while (current_card < worker_end_card && !card_is_clean(*current_card)) {
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while (current_card < worker_end_card && !card_is_clean(*current_card)) {
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current_card++;
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}
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if (current_card < worker_end_card) {
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// Some objects may be large enough to span several cards. If such
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// an object has more than one dirty card, separated by a clean card,
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// we will attempt to scan it twice. The test against "last_scanned"
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// prevents the redundant object scan, but it does not prevent newly
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// marked cards from being cleaned.
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HeapWord* last_object_in_dirty_region = start_array->object_start(addr_for(current_card)-1);
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size_t size_of_last_object = oop(last_object_in_dirty_region)->size();
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HeapWord* end_of_last_object = last_object_in_dirty_region + size_of_last_object;
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CardValue* ending_card_of_last_object = byte_for(end_of_last_object);
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assert(ending_card_of_last_object <= worker_end_card, "ending_card_of_last_object is greater than worker_end_card");
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if (ending_card_of_last_object > current_card) {
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// This means the object spans the next complete card.
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// We need to bump the current_card to ending_card_of_last_object
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current_card = ending_card_of_last_object;
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}
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}
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}
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CardValue* following_clean_card = current_card;
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if (first_unclean_card < worker_end_card) {
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oop* p = (oop*) start_array->object_start(addr_for(first_unclean_card));
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assert((HeapWord*)p <= addr_for(first_unclean_card), "checking");
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// "p" should always be >= "last_scanned" because newly GC dirtied
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// cards are no longer scanned again (see comment at end
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// of loop on the increment of "current_card"). Test that
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// hypothesis before removing this code.
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// If this code is removed, deal with the first time through
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// the loop when the last_scanned is the object starting in
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// the previous slice.
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assert((p >= last_scanned) ||
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(last_scanned == first_object_within_slice),
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"Should no longer be possible");
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if (p < last_scanned) {
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// Avoid scanning more than once; this can happen because
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// newgen cards set by GC may a different set than the
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// originally dirty set
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p = last_scanned;
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}
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oop* to = (oop*)addr_for(following_clean_card);
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// Test slice_end first!
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if ((HeapWord*)to > slice_end) {
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to = (oop*)slice_end;
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} else if (to > sp_top) {
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to = sp_top;
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}
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// we know which cards to scan, now clear them
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if (first_unclean_card <= worker_start_card+1)
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first_unclean_card = worker_start_card+1;
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if (following_clean_card >= worker_end_card-1)
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following_clean_card = worker_end_card-1;
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while (first_unclean_card < following_clean_card) {
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*first_unclean_card++ = clean_card;
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}
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const int interval = PrefetchScanIntervalInBytes;
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// scan all objects in the range
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if (interval != 0) {
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while (p < to) {
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Prefetch::write(p, interval);
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oop m = oop(p);
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assert(oopDesc::is_oop_or_null(m), "Expected an oop or NULL for header field at " PTR_FORMAT, p2i(m));
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pm->push_contents(m);
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p += m->size();
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}
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pm->drain_stacks_cond_depth();
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} else {
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while (p < to) {
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oop m = oop(p);
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assert(oopDesc::is_oop_or_null(m), "Expected an oop or NULL for header field at " PTR_FORMAT, p2i(m));
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pm->push_contents(m);
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p += m->size();
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}
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pm->drain_stacks_cond_depth();
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}
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last_scanned = p;
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}
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// "current_card" is still the "following_clean_card" or
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// the current_card is >= the worker_end_card so the
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// loop will not execute again.
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assert((current_card == following_clean_card) ||
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(current_card >= worker_end_card),
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"current_card should only be incremented if it still equals "
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"following_clean_card");
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// Increment current_card so that it is not processed again.
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// It may now be dirty because a old-to-young pointer was
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// found on it an updated. If it is now dirty, it cannot be
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// be safely cleaned in the next iteration.
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current_card++;
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}
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}
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}
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// This should be called before a scavenge.
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void PSCardTable::verify_all_young_refs_imprecise() {
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CheckForUnmarkedObjects check;
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ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
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PSOldGen* old_gen = heap->old_gen();
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old_gen->object_iterate(&check);
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}
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// This should be called immediately after a scavenge, before mutators resume.
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void PSCardTable::verify_all_young_refs_precise() {
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ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
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PSOldGen* old_gen = heap->old_gen();
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CheckForPreciseMarks check(heap->young_gen(), this);
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old_gen->oop_iterate(&check);
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verify_all_young_refs_precise_helper(old_gen->object_space()->used_region());
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}
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void PSCardTable::verify_all_young_refs_precise_helper(MemRegion mr) {
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CardValue* bot = byte_for(mr.start());
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CardValue* top = byte_for(mr.end());
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while (bot <= top) {
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assert(*bot == clean_card || *bot == verify_card, "Found unwanted or unknown card mark");
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if (*bot == verify_card)
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*bot = youngergen_card;
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bot++;
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}
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}
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bool PSCardTable::addr_is_marked_imprecise(void *addr) {
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CardValue* p = byte_for(addr);
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CardValue val = *p;
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if (card_is_dirty(val))
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return true;
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if (card_is_newgen(val))
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return true;
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if (card_is_clean(val))
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return false;
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assert(false, "Found unhandled card mark type");
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return false;
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}
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// Also includes verify_card
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bool PSCardTable::addr_is_marked_precise(void *addr) {
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CardValue* p = byte_for(addr);
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CardValue val = *p;
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if (card_is_newgen(val))
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return true;
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if (card_is_verify(val))
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return true;
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if (card_is_clean(val))
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return false;
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if (card_is_dirty(val))
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return false;
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assert(false, "Found unhandled card mark type");
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return false;
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}
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// Assumes that only the base or the end changes. This allows indentification
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// of the region that is being resized. The
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// CardTable::resize_covered_region() is used for the normal case
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// where the covered regions are growing or shrinking at the high end.
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// The method resize_covered_region_by_end() is analogous to
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// CardTable::resize_covered_region() but
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// for regions that grow or shrink at the low end.
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void PSCardTable::resize_covered_region(MemRegion new_region) {
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for (int i = 0; i < _cur_covered_regions; i++) {
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if (_covered[i].start() == new_region.start()) {
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// Found a covered region with the same start as the
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// new region. The region is growing or shrinking
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// from the start of the region.
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resize_covered_region_by_start(new_region);
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return;
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}
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if (_covered[i].start() > new_region.start()) {
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break;
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}
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}
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int changed_region = -1;
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for (int j = 0; j < _cur_covered_regions; j++) {
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if (_covered[j].end() == new_region.end()) {
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changed_region = j;
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// This is a case where the covered region is growing or shrinking
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// at the start of the region.
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assert(changed_region != -1, "Don't expect to add a covered region");
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assert(_covered[changed_region].byte_size() != new_region.byte_size(),
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"The sizes should be different here");
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resize_covered_region_by_end(changed_region, new_region);
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return;
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}
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}
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// This should only be a new covered region (where no existing
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// covered region matches at the start or the end).
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assert(_cur_covered_regions < _max_covered_regions,
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|
"An existing region should have been found");
|
|
resize_covered_region_by_start(new_region);
|
|
}
|
|
|
|
void PSCardTable::resize_covered_region_by_start(MemRegion new_region) {
|
|
CardTable::resize_covered_region(new_region);
|
|
debug_only(verify_guard();)
|
|
}
|
|
|
|
void PSCardTable::resize_covered_region_by_end(int changed_region,
|
|
MemRegion new_region) {
|
|
assert(SafepointSynchronize::is_at_safepoint(),
|
|
"Only expect an expansion at the low end at a GC");
|
|
debug_only(verify_guard();)
|
|
#ifdef ASSERT
|
|
for (int k = 0; k < _cur_covered_regions; k++) {
|
|
if (_covered[k].end() == new_region.end()) {
|
|
assert(changed_region == k, "Changed region is incorrect");
|
|
break;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
// Commit new or uncommit old pages, if necessary.
|
|
if (resize_commit_uncommit(changed_region, new_region)) {
|
|
// Set the new start of the committed region
|
|
resize_update_committed_table(changed_region, new_region);
|
|
}
|
|
|
|
// Update card table entries
|
|
resize_update_card_table_entries(changed_region, new_region);
|
|
|
|
// Update the covered region
|
|
resize_update_covered_table(changed_region, new_region);
|
|
|
|
int ind = changed_region;
|
|
log_trace(gc, barrier)("CardTable::resize_covered_region: ");
|
|
log_trace(gc, barrier)(" _covered[%d].start(): " INTPTR_FORMAT " _covered[%d].last(): " INTPTR_FORMAT,
|
|
ind, p2i(_covered[ind].start()), ind, p2i(_covered[ind].last()));
|
|
log_trace(gc, barrier)(" _committed[%d].start(): " INTPTR_FORMAT " _committed[%d].last(): " INTPTR_FORMAT,
|
|
ind, p2i(_committed[ind].start()), ind, p2i(_committed[ind].last()));
|
|
log_trace(gc, barrier)(" byte_for(start): " INTPTR_FORMAT " byte_for(last): " INTPTR_FORMAT,
|
|
p2i(byte_for(_covered[ind].start())), p2i(byte_for(_covered[ind].last())));
|
|
log_trace(gc, barrier)(" addr_for(start): " INTPTR_FORMAT " addr_for(last): " INTPTR_FORMAT,
|
|
p2i(addr_for((CardValue*) _committed[ind].start())), p2i(addr_for((CardValue*) _committed[ind].last())));
|
|
|
|
debug_only(verify_guard();)
|
|
}
|
|
|
|
bool PSCardTable::resize_commit_uncommit(int changed_region,
|
|
MemRegion new_region) {
|
|
bool result = false;
|
|
// Commit new or uncommit old pages, if necessary.
|
|
MemRegion cur_committed = _committed[changed_region];
|
|
assert(_covered[changed_region].end() == new_region.end(),
|
|
"The ends of the regions are expected to match");
|
|
// Extend the start of this _committed region to
|
|
// to cover the start of any previous _committed region.
|
|
// This forms overlapping regions, but never interior regions.
|
|
HeapWord* min_prev_start = lowest_prev_committed_start(changed_region);
|
|
if (min_prev_start < cur_committed.start()) {
|
|
// Only really need to set start of "cur_committed" to
|
|
// the new start (min_prev_start) but assertion checking code
|
|
// below use cur_committed.end() so make it correct.
|
|
MemRegion new_committed =
|
|
MemRegion(min_prev_start, cur_committed.end());
|
|
cur_committed = new_committed;
|
|
}
|
|
#ifdef ASSERT
|
|
ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
|
|
assert(cur_committed.start() == align_up(cur_committed.start(), os::vm_page_size()),
|
|
"Starts should have proper alignment");
|
|
#endif
|
|
|
|
CardValue* new_start = byte_for(new_region.start());
|
|
// Round down because this is for the start address
|
|
HeapWord* new_start_aligned = align_down((HeapWord*)new_start, os::vm_page_size());
|
|
// The guard page is always committed and should not be committed over.
|
|
// This method is used in cases where the generation is growing toward
|
|
// lower addresses but the guard region is still at the end of the
|
|
// card table. That still makes sense when looking for writes
|
|
// off the end of the card table.
|
|
if (new_start_aligned < cur_committed.start()) {
|
|
// Expand the committed region
|
|
//
|
|
// Case A
|
|
// |+ guard +|
|
|
// |+ cur committed +++++++++|
|
|
// |+ new committed +++++++++++++++++|
|
|
//
|
|
// Case B
|
|
// |+ guard +|
|
|
// |+ cur committed +|
|
|
// |+ new committed +++++++|
|
|
//
|
|
// These are not expected because the calculation of the
|
|
// cur committed region and the new committed region
|
|
// share the same end for the covered region.
|
|
// Case C
|
|
// |+ guard +|
|
|
// |+ cur committed +|
|
|
// |+ new committed +++++++++++++++++|
|
|
// Case D
|
|
// |+ guard +|
|
|
// |+ cur committed +++++++++++|
|
|
// |+ new committed +++++++|
|
|
|
|
HeapWord* new_end_for_commit =
|
|
MIN2(cur_committed.end(), _guard_region.start());
|
|
if(new_start_aligned < new_end_for_commit) {
|
|
MemRegion new_committed =
|
|
MemRegion(new_start_aligned, new_end_for_commit);
|
|
os::commit_memory_or_exit((char*)new_committed.start(),
|
|
new_committed.byte_size(), !ExecMem,
|
|
"card table expansion");
|
|
}
|
|
result = true;
|
|
} else if (new_start_aligned > cur_committed.start()) {
|
|
// Shrink the committed region
|
|
#if 0 // uncommitting space is currently unsafe because of the interactions
|
|
// of growing and shrinking regions. One region A can uncommit space
|
|
// that it owns but which is being used by another region B (maybe).
|
|
// Region B has not committed the space because it was already
|
|
// committed by region A.
|
|
MemRegion uncommit_region = committed_unique_to_self(changed_region,
|
|
MemRegion(cur_committed.start(), new_start_aligned));
|
|
if (!uncommit_region.is_empty()) {
|
|
if (!os::uncommit_memory((char*)uncommit_region.start(),
|
|
uncommit_region.byte_size())) {
|
|
// If the uncommit fails, ignore it. Let the
|
|
// committed table resizing go even though the committed
|
|
// table will over state the committed space.
|
|
}
|
|
}
|
|
#else
|
|
assert(!result, "Should be false with current workaround");
|
|
#endif
|
|
}
|
|
assert(_committed[changed_region].end() == cur_committed.end(),
|
|
"end should not change");
|
|
return result;
|
|
}
|
|
|
|
void PSCardTable::resize_update_committed_table(int changed_region,
|
|
MemRegion new_region) {
|
|
|
|
CardValue* new_start = byte_for(new_region.start());
|
|
// Set the new start of the committed region
|
|
HeapWord* new_start_aligned = align_down((HeapWord*)new_start, os::vm_page_size());
|
|
MemRegion new_committed = MemRegion(new_start_aligned,
|
|
_committed[changed_region].end());
|
|
_committed[changed_region] = new_committed;
|
|
_committed[changed_region].set_start(new_start_aligned);
|
|
}
|
|
|
|
void PSCardTable::resize_update_card_table_entries(int changed_region,
|
|
MemRegion new_region) {
|
|
debug_only(verify_guard();)
|
|
MemRegion original_covered = _covered[changed_region];
|
|
// Initialize the card entries. Only consider the
|
|
// region covered by the card table (_whole_heap)
|
|
CardValue* entry;
|
|
if (new_region.start() < _whole_heap.start()) {
|
|
entry = byte_for(_whole_heap.start());
|
|
} else {
|
|
entry = byte_for(new_region.start());
|
|
}
|
|
CardValue* end = byte_for(original_covered.start());
|
|
// If _whole_heap starts at the original covered regions start,
|
|
// this loop will not execute.
|
|
while (entry < end) { *entry++ = clean_card; }
|
|
}
|
|
|
|
void PSCardTable::resize_update_covered_table(int changed_region,
|
|
MemRegion new_region) {
|
|
// Update the covered region
|
|
_covered[changed_region].set_start(new_region.start());
|
|
_covered[changed_region].set_word_size(new_region.word_size());
|
|
|
|
// reorder regions. There should only be at most 1 out
|
|
// of order.
|
|
for (int i = _cur_covered_regions-1 ; i > 0; i--) {
|
|
if (_covered[i].start() < _covered[i-1].start()) {
|
|
MemRegion covered_mr = _covered[i-1];
|
|
_covered[i-1] = _covered[i];
|
|
_covered[i] = covered_mr;
|
|
MemRegion committed_mr = _committed[i-1];
|
|
_committed[i-1] = _committed[i];
|
|
_committed[i] = committed_mr;
|
|
break;
|
|
}
|
|
}
|
|
#ifdef ASSERT
|
|
for (int m = 0; m < _cur_covered_regions-1; m++) {
|
|
assert(_covered[m].start() <= _covered[m+1].start(),
|
|
"Covered regions out of order");
|
|
assert(_committed[m].start() <= _committed[m+1].start(),
|
|
"Committed regions out of order");
|
|
}
|
|
#endif
|
|
}
|
|
|
|
// Returns the start of any committed region that is lower than
|
|
// the target committed region (index ind) and that intersects the
|
|
// target region. If none, return start of target region.
|
|
//
|
|
// -------------
|
|
// | |
|
|
// -------------
|
|
// ------------
|
|
// | target |
|
|
// ------------
|
|
// -------------
|
|
// | |
|
|
// -------------
|
|
// ^ returns this
|
|
//
|
|
// -------------
|
|
// | |
|
|
// -------------
|
|
// ------------
|
|
// | target |
|
|
// ------------
|
|
// -------------
|
|
// | |
|
|
// -------------
|
|
// ^ returns this
|
|
|
|
HeapWord* PSCardTable::lowest_prev_committed_start(int ind) const {
|
|
assert(_cur_covered_regions >= 0, "Expecting at least on region");
|
|
HeapWord* min_start = _committed[ind].start();
|
|
for (int j = 0; j < ind; j++) {
|
|
HeapWord* this_start = _committed[j].start();
|
|
if ((this_start < min_start) &&
|
|
!(_committed[j].intersection(_committed[ind])).is_empty()) {
|
|
min_start = this_start;
|
|
}
|
|
}
|
|
return min_start;
|
|
}
|
|
|
|
bool PSCardTable::is_in_young(oop obj) const {
|
|
return ParallelScavengeHeap::heap()->is_in_young(obj);
|
|
}
|