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| 1 | + |
| 2 | +/* |
| 3 | +* Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved. |
| 4 | +* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 5 | +* |
| 6 | +* This code is free software; you can redistribute it and/or modify it |
| 7 | +* under the terms of the GNU General Public License version 2 only, as |
| 8 | +* published by the Free Software Foundation. |
| 9 | +* |
| 10 | +* This code is distributed in the hope that it will be useful, but WITHOUT |
| 11 | +* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 12 | +* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 13 | +* version 2 for more details (a copy is included in the LICENSE file that |
| 14 | +* accompanied this code). |
| 15 | +* |
| 16 | +* You should have received a copy of the GNU General Public License version |
| 17 | +* 2 along with this work; if not, write to the Free Software Foundation, |
| 18 | +* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 19 | +* |
| 20 | +* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| 21 | +* or visit www.oracle.com if you need additional information or have any |
| 22 | +* questions. |
| 23 | +* |
| 24 | +*/ |
| 25 | + |
| 26 | +#include "precompiled.hpp" |
| 27 | +#include "runtime/interfaceSupport.inline.hpp" |
| 28 | +#include "runtime/thread.hpp" |
| 29 | +#include "runtime/threadSMR.hpp" |
| 30 | +#include "runtime/timerTrace.hpp" |
| 31 | +#include "services/threadIdTable.hpp" |
| 32 | +#include "utilities/concurrentHashTable.inline.hpp" |
| 33 | +#include "utilities/concurrentHashTableTasks.inline.hpp" |
| 34 | + |
| 35 | + |
| 36 | +typedef ConcurrentHashTable<ThreadIdTableConfig, mtInternal> ThreadIdTableHash; |
| 37 | + |
| 38 | +// 2^24 is max size |
| 39 | +static const size_t END_SIZE = 24; |
| 40 | +// Default initial size 256 |
| 41 | +static const size_t DEFAULT_TABLE_SIZE_LOG = 8; |
| 42 | +// Prefer short chains of avg 2 |
| 43 | +static const double PREF_AVG_LIST_LEN = 2.0; |
| 44 | +static ThreadIdTableHash* volatile _local_table = NULL; |
| 45 | +static volatile size_t _current_size = 0; |
| 46 | +static volatile size_t _items_count = 0; |
| 47 | + |
| 48 | +volatile bool ThreadIdTable::_is_initialized = false; |
| 49 | + |
| 50 | +class ThreadIdTableEntry : public CHeapObj<mtInternal> { |
| 51 | +private: |
| 52 | + jlong _tid; |
| 53 | + JavaThread* _java_thread; |
| 54 | +public: |
| 55 | + ThreadIdTableEntry(jlong tid, JavaThread* java_thread) : |
| 56 | + _tid(tid), _java_thread(java_thread) {} |
| 57 | + |
| 58 | + jlong tid() const { return _tid; } |
| 59 | + JavaThread* thread() const { return _java_thread; } |
| 60 | +}; |
| 61 | + |
| 62 | +class ThreadIdTableConfig : public AllStatic { |
| 63 | + public: |
| 64 | + typedef ThreadIdTableEntry* Value; |
| 65 | + |
| 66 | + static uintx get_hash(Value const& value, bool* is_dead) { |
| 67 | + jlong tid = value->tid(); |
| 68 | + return primitive_hash(tid); |
| 69 | + } |
| 70 | + static void* allocate_node(size_t size, Value const& value) { |
| 71 | + ThreadIdTable::item_added(); |
| 72 | + return AllocateHeap(size, mtInternal); |
| 73 | + } |
| 74 | + static void free_node(void* memory, Value const& value) { |
| 75 | + delete value; |
| 76 | + FreeHeap(memory); |
| 77 | + ThreadIdTable::item_removed(); |
| 78 | + } |
| 79 | +}; |
| 80 | + |
| 81 | +static size_t ceil_log2(size_t val) { |
| 82 | + size_t ret; |
| 83 | + for (ret = 1; ((size_t)1 << ret) < val; ++ret); |
| 84 | + return ret; |
| 85 | +} |
| 86 | + |
| 87 | +// Lazily creates the table and populates it with the given |
| 88 | +// thread list |
| 89 | +void ThreadIdTable::lazy_initialize(const ThreadsList *threads) { |
| 90 | + if (!_is_initialized) { |
| 91 | + { |
| 92 | + // There is no obvious benefits in allowing the thread table |
| 93 | + // to be concurently populated during the initalization. |
| 94 | + MutexLocker ml(ThreadIdTableCreate_lock); |
| 95 | + if (_is_initialized) { |
| 96 | + return; |
| 97 | + } |
| 98 | + create_table(threads->length()); |
| 99 | + _is_initialized = true; |
| 100 | + } |
| 101 | + for (uint i = 0; i < threads->length(); i++) { |
| 102 | + JavaThread* thread = threads->thread_at(i); |
| 103 | + oop tobj = thread->threadObj(); |
| 104 | + if (tobj != NULL) { |
| 105 | + jlong java_tid = java_lang_Thread::thread_id(tobj); |
| 106 | + MutexLocker ml(Threads_lock); |
| 107 | + if (!thread->is_exiting()) { |
| 108 | + // Must be inside the lock to ensure that we don't add a thread to the table |
| 109 | + // that has just passed the removal point in ThreadsSMRSupport::remove_thread() |
| 110 | + add_thread(java_tid, thread); |
| 111 | + } |
| 112 | + } |
| 113 | + } |
| 114 | + } |
| 115 | +} |
| 116 | + |
| 117 | +void ThreadIdTable::create_table(size_t size) { |
| 118 | + assert(_local_table == NULL, "Thread table is already created"); |
| 119 | + size_t size_log = ceil_log2(size); |
| 120 | + size_t start_size_log = |
| 121 | + size_log > DEFAULT_TABLE_SIZE_LOG ? size_log : DEFAULT_TABLE_SIZE_LOG; |
| 122 | + _current_size = (size_t)1 << start_size_log; |
| 123 | + _local_table = new ThreadIdTableHash(start_size_log, END_SIZE); |
| 124 | +} |
| 125 | + |
| 126 | +void ThreadIdTable::item_added() { |
| 127 | + Atomic::inc(&_items_count); |
| 128 | + log_trace(thread, table) ("Thread entry added"); |
| 129 | +} |
| 130 | + |
| 131 | +void ThreadIdTable::item_removed() { |
| 132 | + Atomic::dec(&_items_count); |
| 133 | + log_trace(thread, table) ("Thread entry removed"); |
| 134 | +} |
| 135 | + |
| 136 | +double ThreadIdTable::get_load_factor() { |
| 137 | + return ((double)_items_count) / _current_size; |
| 138 | +} |
| 139 | + |
| 140 | +size_t ThreadIdTable::table_size() { |
| 141 | + return (size_t)1 << _local_table->get_size_log2(Thread::current()); |
| 142 | +} |
| 143 | + |
| 144 | +void ThreadIdTable::grow(JavaThread* jt) { |
| 145 | + ThreadIdTableHash::GrowTask gt(_local_table); |
| 146 | + if (!gt.prepare(jt)) { |
| 147 | + return; |
| 148 | + } |
| 149 | + log_trace(thread, table)("Started to grow"); |
| 150 | + TraceTime timer("Grow", TRACETIME_LOG(Debug, membername, table, perf)); |
| 151 | + while (gt.do_task(jt)) { |
| 152 | + gt.pause(jt); |
| 153 | + { |
| 154 | + ThreadBlockInVM tbivm(jt); |
| 155 | + } |
| 156 | + gt.cont(jt); |
| 157 | + } |
| 158 | + gt.done(jt); |
| 159 | + _current_size = table_size(); |
| 160 | + log_info(thread, table)("Grown to size:" SIZE_FORMAT, _current_size); |
| 161 | +} |
| 162 | + |
| 163 | +class ThreadIdTableLookup : public StackObj { |
| 164 | +private: |
| 165 | + jlong _tid; |
| 166 | + uintx _hash; |
| 167 | +public: |
| 168 | + ThreadIdTableLookup(jlong tid) |
| 169 | + : _tid(tid), _hash(primitive_hash(tid)) {} |
| 170 | + uintx get_hash() const { |
| 171 | + return _hash; |
| 172 | + } |
| 173 | + bool equals(ThreadIdTableEntry** value, bool* is_dead) { |
| 174 | + bool equals = primitive_equals(_tid, (*value)->tid()); |
| 175 | + if (!equals) { |
| 176 | + return false; |
| 177 | + } |
| 178 | + return true; |
| 179 | + } |
| 180 | +}; |
| 181 | + |
| 182 | +class ThreadGet : public StackObj { |
| 183 | +private: |
| 184 | + JavaThread* _return; |
| 185 | +public: |
| 186 | + ThreadGet(): _return(NULL) {} |
| 187 | + void operator()(ThreadIdTableEntry** val) { |
| 188 | + _return = (*val)->thread(); |
| 189 | + } |
| 190 | + JavaThread* get_res_thread() { |
| 191 | + return _return; |
| 192 | + } |
| 193 | +}; |
| 194 | + |
| 195 | +void ThreadIdTable::grow_if_required() { |
| 196 | + assert(Thread::current()->is_Java_thread(),"Must be Java thread"); |
| 197 | + assert(_is_initialized, "Thread table is not initialized"); |
| 198 | + double load_factor = get_load_factor(); |
| 199 | + log_debug(thread, table)("Concurrent work, load factor: %g", load_factor); |
| 200 | + if (load_factor > PREF_AVG_LIST_LEN && !_local_table->is_max_size_reached()) { |
| 201 | + grow(JavaThread::current()); |
| 202 | + } |
| 203 | +} |
| 204 | + |
| 205 | +JavaThread* ThreadIdTable::add_thread(jlong tid, JavaThread* java_thread) { |
| 206 | + assert(_is_initialized, "Thread table is not initialized"); |
| 207 | + Thread* thread = Thread::current(); |
| 208 | + ThreadIdTableLookup lookup(tid); |
| 209 | + ThreadGet tg; |
| 210 | + while (true) { |
| 211 | + if (_local_table->get(thread, lookup, tg)) { |
| 212 | + return tg.get_res_thread(); |
| 213 | + } |
| 214 | + ThreadIdTableEntry* entry = new ThreadIdTableEntry(tid, java_thread); |
| 215 | + // The hash table takes ownership of the ThreadTableEntry, |
| 216 | + // even if it's not inserted. |
| 217 | + if (_local_table->insert(thread, lookup, entry)) { |
| 218 | + grow_if_required(); |
| 219 | + return java_thread; |
| 220 | + } |
| 221 | + } |
| 222 | +} |
| 223 | + |
| 224 | +JavaThread* ThreadIdTable::find_thread_by_tid(jlong tid) { |
| 225 | + assert(_is_initialized, "Thread table is not initialized"); |
| 226 | + Thread* thread = Thread::current(); |
| 227 | + ThreadIdTableLookup lookup(tid); |
| 228 | + ThreadGet tg; |
| 229 | + _local_table->get(thread, lookup, tg); |
| 230 | + return tg.get_res_thread(); |
| 231 | +} |
| 232 | + |
| 233 | +bool ThreadIdTable::remove_thread(jlong tid) { |
| 234 | + assert(_is_initialized, "Thread table is not initialized"); |
| 235 | + Thread* thread = Thread::current(); |
| 236 | + ThreadIdTableLookup lookup(tid); |
| 237 | + return _local_table->remove(thread, lookup); |
| 238 | +} |
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