1/*
2 * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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24
25#ifndef SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
26#define SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
27
28#include "gc/g1/g1ParScanThreadState.hpp"
29#include "gc/g1/g1RemSet.inline.hpp"
30#include "oops/oop.inline.hpp"
31
32template <class T> void G1ParScanThreadState::do_oop_evac(T* p, HeapRegion* from) {
33  assert(!oopDesc::is_null(oopDesc::load_decode_heap_oop(p)),
34         "Reference should not be NULL here as such are never pushed to the task queue.");
35  oop obj = oopDesc::load_decode_heap_oop_not_null(p);
36
37  // Although we never intentionally push references outside of the collection
38  // set, due to (benign) races in the claim mechanism during RSet scanning more
39  // than one thread might claim the same card. So the same card may be
40  // processed multiple times. So redo this check.
41  const InCSetState in_cset_state = _g1h->in_cset_state(obj);
42  if (in_cset_state.is_in_cset()) {
43    markOop m = obj->mark();
44    if (m->is_marked()) {
45      obj = (oop) m->decode_pointer();
46    } else {
47      obj = copy_to_survivor_space(in_cset_state, obj, m);
48    }
49    oopDesc::encode_store_heap_oop(p, obj);
50  } else if (in_cset_state.is_humongous()) {
51    _g1h->set_humongous_is_live(obj);
52  } else {
53    assert(in_cset_state.is_default() || in_cset_state.is_ext(),
54           "In_cset_state must be NotInCSet or Ext here, but is " CSETSTATE_FORMAT, in_cset_state.value());
55  }
56
57  assert(obj != NULL, "Must be");
58  update_rs(from, p, obj);
59}
60
61template <class T> inline void G1ParScanThreadState::push_on_queue(T* ref) {
62  assert(verify_ref(ref), "sanity");
63  _refs->push(ref);
64}
65
66inline void G1ParScanThreadState::do_oop_partial_array(oop* p) {
67  assert(has_partial_array_mask(p), "invariant");
68  oop from_obj = clear_partial_array_mask(p);
69
70  assert(_g1h->is_in_reserved(from_obj), "must be in heap.");
71  assert(from_obj->is_objArray(), "must be obj array");
72  objArrayOop from_obj_array = objArrayOop(from_obj);
73  // The from-space object contains the real length.
74  int length                 = from_obj_array->length();
75
76  assert(from_obj->is_forwarded(), "must be forwarded");
77  oop to_obj                 = from_obj->forwardee();
78  assert(from_obj != to_obj, "should not be chunking self-forwarded objects");
79  objArrayOop to_obj_array   = objArrayOop(to_obj);
80  // We keep track of the next start index in the length field of the
81  // to-space object.
82  int next_index             = to_obj_array->length();
83  assert(0 <= next_index && next_index < length,
84         "invariant, next index: %d, length: %d", next_index, length);
85
86  int start                  = next_index;
87  int end                    = length;
88  int remainder              = end - start;
89  // We'll try not to push a range that's smaller than ParGCArrayScanChunk.
90  if (remainder > 2 * ParGCArrayScanChunk) {
91    end = start + ParGCArrayScanChunk;
92    to_obj_array->set_length(end);
93    // Push the remainder before we process the range in case another
94    // worker has run out of things to do and can steal it.
95    oop* from_obj_p = set_partial_array_mask(from_obj);
96    push_on_queue(from_obj_p);
97  } else {
98    assert(length == end, "sanity");
99    // We'll process the final range for this object. Restore the length
100    // so that the heap remains parsable in case of evacuation failure.
101    to_obj_array->set_length(end);
102  }
103  _scanner.set_region(_g1h->heap_region_containing(to_obj));
104  // Process indexes [start,end). It will also process the header
105  // along with the first chunk (i.e., the chunk with start == 0).
106  // Note that at this point the length field of to_obj_array is not
107  // correct given that we are using it to keep track of the next
108  // start index. oop_iterate_range() (thankfully!) ignores the length
109  // field and only relies on the start / end parameters.  It does
110  // however return the size of the object which will be incorrect. So
111  // we have to ignore it even if we wanted to use it.
112  to_obj_array->oop_iterate_range(&_scanner, start, end);
113}
114
115template <class T> inline void G1ParScanThreadState::deal_with_reference(T* ref_to_scan) {
116  if (!has_partial_array_mask(ref_to_scan)) {
117    HeapRegion* r = _g1h->heap_region_containing(ref_to_scan);
118    do_oop_evac(ref_to_scan, r);
119  } else {
120    do_oop_partial_array((oop*)ref_to_scan);
121  }
122}
123
124inline void G1ParScanThreadState::dispatch_reference(StarTask ref) {
125  assert(verify_task(ref), "sanity");
126  if (ref.is_narrow()) {
127    deal_with_reference((narrowOop*)ref);
128  } else {
129    deal_with_reference((oop*)ref);
130  }
131}
132
133void G1ParScanThreadState::steal_and_trim_queue(RefToScanQueueSet *task_queues) {
134  StarTask stolen_task;
135  while (task_queues->steal(_worker_id, &_hash_seed, stolen_task)) {
136    assert(verify_task(stolen_task), "sanity");
137    dispatch_reference(stolen_task);
138
139    // We've just processed a reference and we might have made
140    // available new entries on the queues. So we have to make sure
141    // we drain the queues as necessary.
142    trim_queue();
143  }
144}
145
146#endif // SHARE_VM_GC_G1_G1PARSCANTHREADSTATE_INLINE_HPP
147
148