Mon, 12 Mar 2012 14:59:00 -0700
7147724: G1: hang in SurrogateLockerThread::manipulatePLL
Summary: Attempting to initiate a marking cycle when allocating a humongous object can, if a marking cycle is successfully initiated by another thread, result in the allocating thread spinning until the marking cycle is complete. Eliminate a deadlock between the main ConcurrentMarkThread, the SurrogateLocker thread, the VM thread, and a mutator thread waiting on the SecondaryFreeList_lock (while free regions are going to become available) by not manipulating the pending list lock during the prologue and epilogue of the cleanup pause.
Reviewed-by: brutisso, jcoomes, tonyp
ysr@777 | 1 | /* |
tonyp@3114 | 2 | * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
ysr@777 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
ysr@777 | 4 | * |
ysr@777 | 5 | * This code is free software; you can redistribute it and/or modify it |
ysr@777 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ysr@777 | 7 | * published by the Free Software Foundation. |
ysr@777 | 8 | * |
ysr@777 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
ysr@777 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
ysr@777 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
ysr@777 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
ysr@777 | 13 | * accompanied this code). |
ysr@777 | 14 | * |
ysr@777 | 15 | * You should have received a copy of the GNU General Public License version |
ysr@777 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
ysr@777 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
ysr@777 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
ysr@777 | 22 | * |
ysr@777 | 23 | */ |
ysr@777 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
stefank@2314 | 26 | #include "gc_implementation/g1/g1MMUTracker.hpp" |
stefank@2314 | 27 | #include "runtime/mutexLocker.hpp" |
stefank@2314 | 28 | #include "utilities/ostream.hpp" |
ysr@777 | 29 | |
ysr@777 | 30 | #define _DISABLE_MMU 0 |
ysr@777 | 31 | |
ysr@777 | 32 | // can't rely on comparing doubles with tolerating a small margin for error |
ysr@777 | 33 | #define SMALL_MARGIN 0.0000001 |
ysr@777 | 34 | #define is_double_leq_0(_value) ( (_value) < SMALL_MARGIN ) |
ysr@777 | 35 | #define is_double_leq(_val1, _val2) is_double_leq_0((_val1) - (_val2)) |
ysr@777 | 36 | #define is_double_geq(_val1, _val2) is_double_leq_0((_val2) - (_val1)) |
ysr@777 | 37 | |
ysr@777 | 38 | /***** ALL TIMES ARE IN SECS!!!!!!! *****/ |
ysr@777 | 39 | |
ysr@777 | 40 | G1MMUTracker::G1MMUTracker(double time_slice, double max_gc_time) : |
ysr@777 | 41 | _time_slice(time_slice), |
tonyp@1371 | 42 | _max_gc_time(max_gc_time) { } |
ysr@777 | 43 | |
ysr@777 | 44 | G1MMUTrackerQueue::G1MMUTrackerQueue(double time_slice, double max_gc_time) : |
ysr@777 | 45 | G1MMUTracker(time_slice, max_gc_time), |
ysr@777 | 46 | _head_index(0), |
ysr@777 | 47 | _tail_index(trim_index(_head_index+1)), |
ysr@777 | 48 | _no_entries(0) { } |
ysr@777 | 49 | |
ysr@777 | 50 | void G1MMUTrackerQueue::remove_expired_entries(double current_time) { |
ysr@777 | 51 | double limit = current_time - _time_slice; |
ysr@777 | 52 | while (_no_entries > 0) { |
ysr@777 | 53 | if (is_double_geq(limit, _array[_tail_index].end_time())) { |
ysr@777 | 54 | _tail_index = trim_index(_tail_index + 1); |
ysr@777 | 55 | --_no_entries; |
ysr@777 | 56 | } else |
ysr@777 | 57 | return; |
ysr@777 | 58 | } |
ysr@777 | 59 | guarantee(_no_entries == 0, "should have no entries in the array"); |
ysr@777 | 60 | } |
ysr@777 | 61 | |
ysr@777 | 62 | double G1MMUTrackerQueue::calculate_gc_time(double current_time) { |
ysr@777 | 63 | double gc_time = 0.0; |
ysr@777 | 64 | double limit = current_time - _time_slice; |
ysr@777 | 65 | for (int i = 0; i < _no_entries; ++i) { |
ysr@777 | 66 | int index = trim_index(_tail_index + i); |
ysr@777 | 67 | G1MMUTrackerQueueElem *elem = &_array[index]; |
ysr@777 | 68 | if (elem->end_time() > limit) { |
ysr@777 | 69 | if (elem->start_time() > limit) |
ysr@777 | 70 | gc_time += elem->duration(); |
ysr@777 | 71 | else |
ysr@777 | 72 | gc_time += elem->end_time() - limit; |
ysr@777 | 73 | } |
ysr@777 | 74 | } |
ysr@777 | 75 | return gc_time; |
ysr@777 | 76 | } |
ysr@777 | 77 | |
ysr@777 | 78 | void G1MMUTrackerQueue::add_pause(double start, double end, bool gc_thread) { |
ysr@777 | 79 | double longest_allowed = longest_pause_internal(start); |
ysr@777 | 80 | if (longest_allowed < 0.0) |
ysr@777 | 81 | longest_allowed = 0.0; |
ysr@777 | 82 | double duration = end - start; |
ysr@777 | 83 | |
ysr@777 | 84 | remove_expired_entries(end); |
ysr@777 | 85 | if (_no_entries == QueueLength) { |
johnc@1946 | 86 | // OK, we've filled up the queue. There are a few ways |
johnc@1946 | 87 | // of dealing with this "gracefully" |
ysr@777 | 88 | // increase the array size (:-) |
ysr@777 | 89 | // remove the oldest entry (this might allow more GC time for |
johnc@1946 | 90 | // the time slice than what's allowed) - this is what we |
johnc@1946 | 91 | // currently do |
ysr@1523 | 92 | // consolidate the two entries with the minimum gap between them |
ysr@1523 | 93 | // (this might allow less GC time than what's allowed) |
johnc@1946 | 94 | |
ysr@1523 | 95 | // In the case where ScavengeALot is true, such overflow is not |
ysr@1523 | 96 | // uncommon; in such cases, we can, without much loss of precision |
ysr@1523 | 97 | // or performance (we are GC'ing most of the time anyway!), |
johnc@1946 | 98 | // simply overwrite the oldest entry in the tracker. |
johnc@1946 | 99 | |
ysr@1523 | 100 | _head_index = trim_index(_head_index + 1); |
ysr@1523 | 101 | assert(_head_index == _tail_index, "Because we have a full circular buffer"); |
ysr@1523 | 102 | _tail_index = trim_index(_tail_index + 1); |
ysr@1523 | 103 | } else { |
ysr@1523 | 104 | _head_index = trim_index(_head_index + 1); |
ysr@1523 | 105 | ++_no_entries; |
ysr@777 | 106 | } |
ysr@777 | 107 | _array[_head_index] = G1MMUTrackerQueueElem(start, end); |
ysr@777 | 108 | } |
ysr@777 | 109 | |
ysr@777 | 110 | // basically the _internal call does not remove expired entries |
ysr@777 | 111 | // this is for trying things out in the future and a couple |
ysr@777 | 112 | // of other places (debugging) |
ysr@777 | 113 | |
ysr@777 | 114 | double G1MMUTrackerQueue::longest_pause(double current_time) { |
ysr@777 | 115 | if (_DISABLE_MMU) |
ysr@777 | 116 | return _max_gc_time; |
ysr@777 | 117 | |
ysr@777 | 118 | MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag); |
ysr@777 | 119 | remove_expired_entries(current_time); |
ysr@777 | 120 | |
ysr@777 | 121 | return longest_pause_internal(current_time); |
ysr@777 | 122 | } |
ysr@777 | 123 | |
ysr@777 | 124 | double G1MMUTrackerQueue::longest_pause_internal(double current_time) { |
ysr@777 | 125 | double target_time = _max_gc_time; |
ysr@777 | 126 | |
ysr@777 | 127 | while( 1 ) { |
ysr@777 | 128 | double gc_time = |
tonyp@1371 | 129 | calculate_gc_time(current_time + target_time); |
ysr@777 | 130 | double diff = target_time + gc_time - _max_gc_time; |
ysr@777 | 131 | if (!is_double_leq_0(diff)) { |
ysr@777 | 132 | target_time -= diff; |
ysr@777 | 133 | if (is_double_leq_0(target_time)) { |
ysr@777 | 134 | target_time = -1.0; |
ysr@777 | 135 | break; |
ysr@777 | 136 | } |
ysr@777 | 137 | } else { |
ysr@777 | 138 | break; |
ysr@777 | 139 | } |
ysr@777 | 140 | } |
ysr@777 | 141 | |
ysr@777 | 142 | return target_time; |
ysr@777 | 143 | } |
ysr@777 | 144 | |
ysr@777 | 145 | // basically the _internal call does not remove expired entries |
ysr@777 | 146 | // this is for trying things out in the future and a couple |
ysr@777 | 147 | // of other places (debugging) |
ysr@777 | 148 | |
ysr@777 | 149 | double G1MMUTrackerQueue::when_sec(double current_time, double pause_time) { |
ysr@777 | 150 | if (_DISABLE_MMU) |
ysr@777 | 151 | return 0.0; |
ysr@777 | 152 | |
ysr@777 | 153 | MutexLockerEx x(MMUTracker_lock, Mutex::_no_safepoint_check_flag); |
ysr@777 | 154 | remove_expired_entries(current_time); |
ysr@777 | 155 | |
ysr@777 | 156 | return when_internal(current_time, pause_time); |
ysr@777 | 157 | } |
ysr@777 | 158 | |
ysr@777 | 159 | double G1MMUTrackerQueue::when_internal(double current_time, |
ysr@777 | 160 | double pause_time) { |
ysr@777 | 161 | // if the pause is over the maximum, just assume that it's the maximum |
ysr@777 | 162 | double adjusted_pause_time = |
ysr@777 | 163 | (pause_time > max_gc_time()) ? max_gc_time() : pause_time; |
ysr@777 | 164 | double earliest_end = current_time + adjusted_pause_time; |
ysr@777 | 165 | double limit = earliest_end - _time_slice; |
ysr@777 | 166 | double gc_time = calculate_gc_time(earliest_end); |
ysr@777 | 167 | double diff = gc_time + adjusted_pause_time - max_gc_time(); |
ysr@777 | 168 | if (is_double_leq_0(diff)) |
ysr@777 | 169 | return 0.0; |
ysr@777 | 170 | |
ysr@777 | 171 | int index = _tail_index; |
ysr@777 | 172 | while ( 1 ) { |
ysr@777 | 173 | G1MMUTrackerQueueElem *elem = &_array[index]; |
ysr@777 | 174 | if (elem->end_time() > limit) { |
ysr@777 | 175 | if (elem->start_time() > limit) |
ysr@777 | 176 | diff -= elem->duration(); |
ysr@777 | 177 | else |
ysr@777 | 178 | diff -= elem->end_time() - limit; |
ysr@777 | 179 | if (is_double_leq_0(diff)) |
ysr@777 | 180 | return elem->end_time() + diff + _time_slice - adjusted_pause_time - current_time; |
ysr@777 | 181 | } |
ysr@777 | 182 | index = trim_index(index+1); |
ysr@777 | 183 | guarantee(index != trim_index(_head_index + 1), "should not go past head"); |
ysr@777 | 184 | } |
ysr@777 | 185 | } |