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| <pre><span class="source-line-no">001</span><span id="line-1">/*</span> |
| <span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span> |
| <span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span> |
| <span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span> |
| <span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span> |
| <span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span> |
| <span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span> |
| <span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span> |
| <span class="source-line-no">009</span><span id="line-9"> *</span> |
| <span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span> |
| <span class="source-line-no">011</span><span id="line-11"> *</span> |
| <span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span> |
| <span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span> |
| <span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span> |
| <span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span> |
| <span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span> |
| <span class="source-line-no">017</span><span id="line-17"> */</span> |
| <span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.procedure2;</span> |
| <span class="source-line-no">019</span><span id="line-19"></span> |
| <span class="source-line-no">020</span><span id="line-20">import java.util.function.Function;</span> |
| <span class="source-line-no">021</span><span id="line-21">import java.util.function.Predicate;</span> |
| <span class="source-line-no">022</span><span id="line-22">import java.util.stream.Stream;</span> |
| <span class="source-line-no">023</span><span id="line-23">import org.apache.commons.lang3.builder.ToStringBuilder;</span> |
| <span class="source-line-no">024</span><span id="line-24">import org.apache.commons.lang3.builder.ToStringStyle;</span> |
| <span class="source-line-no">025</span><span id="line-25">import org.apache.yetus.audience.InterfaceAudience;</span> |
| <span class="source-line-no">026</span><span id="line-26"></span> |
| <span class="source-line-no">027</span><span id="line-27">/**</span> |
| <span class="source-line-no">028</span><span id="line-28"> * Locking for mutual exclusion between procedures. Used only by procedure framework internally.</span> |
| <span class="source-line-no">029</span><span id="line-29"> * {@link LockAndQueue} has two purposes:</span> |
| <span class="source-line-no">030</span><span id="line-30"> * <ol></span> |
| <span class="source-line-no">031</span><span id="line-31"> * <li>Acquire/release exclusive/shared locks.</li></span> |
| <span class="source-line-no">032</span><span id="line-32"> * <li>Maintains a list of procedures waiting on this lock. {@link LockAndQueue} extends</span> |
| <span class="source-line-no">033</span><span id="line-33"> * {@link ProcedureDeque} class. Blocked Procedures are added to our super Deque. Using inheritance</span> |
| <span class="source-line-no">034</span><span id="line-34"> * over composition to keep the Deque of waiting Procedures is unusual, but we do it this way</span> |
| <span class="source-line-no">035</span><span id="line-35"> * because in certain cases, there will be millions of regions. This layout uses less memory.</span> |
| <span class="source-line-no">036</span><span id="line-36"> * </ol></span> |
| <span class="source-line-no">037</span><span id="line-37"> * <p/></span> |
| <span class="source-line-no">038</span><span id="line-38"> * NOT thread-safe. Needs external concurrency control: e.g. uses in MasterProcedureScheduler are</span> |
| <span class="source-line-no">039</span><span id="line-39"> * guarded by schedLock(). <br/></span> |
| <span class="source-line-no">040</span><span id="line-40"> * There is no need of 'volatile' keyword for member variables because of memory synchronization</span> |
| <span class="source-line-no">041</span><span id="line-41"> * guarantees of locks (see</span> |
| <span class="source-line-no">042</span><span id="line-42"> * <a href="http://docs.oracle.com/javase/8/docs/api/java/util/concurrent/locks/Lock.html">Memory</span> |
| <span class="source-line-no">043</span><span id="line-43"> * Synchronization</a>) <br/></span> |
| <span class="source-line-no">044</span><span id="line-44"> * We do not implement Lock interface because we need exclusive and shared locking, and also because</span> |
| <span class="source-line-no">045</span><span id="line-45"> * try-lock functions require procedure id. <br/></span> |
| <span class="source-line-no">046</span><span id="line-46"> * We do not use ReentrantReadWriteLock directly because of its high memory overhead.</span> |
| <span class="source-line-no">047</span><span id="line-47"> */</span> |
| <span class="source-line-no">048</span><span id="line-48">@InterfaceAudience.Private</span> |
| <span class="source-line-no">049</span><span id="line-49">public class LockAndQueue implements LockStatus {</span> |
| <span class="source-line-no">050</span><span id="line-50"></span> |
| <span class="source-line-no">051</span><span id="line-51"> private final Function<Long, Procedure<?>> procedureRetriever;</span> |
| <span class="source-line-no">052</span><span id="line-52"> private final ProcedureDeque queue = new ProcedureDeque();</span> |
| <span class="source-line-no">053</span><span id="line-53"> private Procedure<?> exclusiveLockOwnerProcedure = null;</span> |
| <span class="source-line-no">054</span><span id="line-54"> private int sharedLock = 0;</span> |
| <span class="source-line-no">055</span><span id="line-55"></span> |
| <span class="source-line-no">056</span><span id="line-56"> // ======================================================================</span> |
| <span class="source-line-no">057</span><span id="line-57"> // Lock Status</span> |
| <span class="source-line-no">058</span><span id="line-58"> // ======================================================================</span> |
| <span class="source-line-no">059</span><span id="line-59"></span> |
| <span class="source-line-no">060</span><span id="line-60"> public LockAndQueue(Function<Long, Procedure<?>> procedureRetriever) {</span> |
| <span class="source-line-no">061</span><span id="line-61"> this.procedureRetriever = procedureRetriever;</span> |
| <span class="source-line-no">062</span><span id="line-62"> }</span> |
| <span class="source-line-no">063</span><span id="line-63"></span> |
| <span class="source-line-no">064</span><span id="line-64"> @Override</span> |
| <span class="source-line-no">065</span><span id="line-65"> public boolean hasExclusiveLock() {</span> |
| <span class="source-line-no">066</span><span id="line-66"> return this.exclusiveLockOwnerProcedure != null;</span> |
| <span class="source-line-no">067</span><span id="line-67"> }</span> |
| <span class="source-line-no">068</span><span id="line-68"></span> |
| <span class="source-line-no">069</span><span id="line-69"> @Override</span> |
| <span class="source-line-no">070</span><span id="line-70"> public boolean hasLockAccess(Procedure<?> proc) {</span> |
| <span class="source-line-no">071</span><span id="line-71"> if (exclusiveLockOwnerProcedure == null) {</span> |
| <span class="source-line-no">072</span><span id="line-72"> return false;</span> |
| <span class="source-line-no">073</span><span id="line-73"> }</span> |
| <span class="source-line-no">074</span><span id="line-74"> long lockOwnerId = exclusiveLockOwnerProcedure.getProcId();</span> |
| <span class="source-line-no">075</span><span id="line-75"> if (proc.getProcId() == lockOwnerId) {</span> |
| <span class="source-line-no">076</span><span id="line-76"> return true;</span> |
| <span class="source-line-no">077</span><span id="line-77"> }</span> |
| <span class="source-line-no">078</span><span id="line-78"> if (!proc.hasParent()) {</span> |
| <span class="source-line-no">079</span><span id="line-79"> return false;</span> |
| <span class="source-line-no">080</span><span id="line-80"> }</span> |
| <span class="source-line-no">081</span><span id="line-81"> // fast path to check root procedure</span> |
| <span class="source-line-no">082</span><span id="line-82"> if (proc.getRootProcId() == lockOwnerId) {</span> |
| <span class="source-line-no">083</span><span id="line-83"> return true;</span> |
| <span class="source-line-no">084</span><span id="line-84"> }</span> |
| <span class="source-line-no">085</span><span id="line-85"> // check ancestors</span> |
| <span class="source-line-no">086</span><span id="line-86"> for (Procedure<?> p = proc;;) {</span> |
| <span class="source-line-no">087</span><span id="line-87"> if (p.getParentProcId() == lockOwnerId) {</span> |
| <span class="source-line-no">088</span><span id="line-88"> return true;</span> |
| <span class="source-line-no">089</span><span id="line-89"> }</span> |
| <span class="source-line-no">090</span><span id="line-90"> p = procedureRetriever.apply(p.getParentProcId());</span> |
| <span class="source-line-no">091</span><span id="line-91"> if (p == null || !p.hasParent()) {</span> |
| <span class="source-line-no">092</span><span id="line-92"> return false;</span> |
| <span class="source-line-no">093</span><span id="line-93"> }</span> |
| <span class="source-line-no">094</span><span id="line-94"> }</span> |
| <span class="source-line-no">095</span><span id="line-95"> }</span> |
| <span class="source-line-no">096</span><span id="line-96"></span> |
| <span class="source-line-no">097</span><span id="line-97"> @Override</span> |
| <span class="source-line-no">098</span><span id="line-98"> public Procedure<?> getExclusiveLockOwnerProcedure() {</span> |
| <span class="source-line-no">099</span><span id="line-99"> return exclusiveLockOwnerProcedure;</span> |
| <span class="source-line-no">100</span><span id="line-100"> }</span> |
| <span class="source-line-no">101</span><span id="line-101"></span> |
| <span class="source-line-no">102</span><span id="line-102"> @Override</span> |
| <span class="source-line-no">103</span><span id="line-103"> public int getSharedLockCount() {</span> |
| <span class="source-line-no">104</span><span id="line-104"> return sharedLock;</span> |
| <span class="source-line-no">105</span><span id="line-105"> }</span> |
| <span class="source-line-no">106</span><span id="line-106"></span> |
| <span class="source-line-no">107</span><span id="line-107"> // ======================================================================</span> |
| <span class="source-line-no">108</span><span id="line-108"> // try/release Shared/Exclusive lock</span> |
| <span class="source-line-no">109</span><span id="line-109"> // ======================================================================</span> |
| <span class="source-line-no">110</span><span id="line-110"></span> |
| <span class="source-line-no">111</span><span id="line-111"> /** Returns whether we have succesfully acquired the shared lock. */</span> |
| <span class="source-line-no">112</span><span id="line-112"> public boolean trySharedLock(Procedure<?> proc) {</span> |
| <span class="source-line-no">113</span><span id="line-113"> if (hasExclusiveLock() && !hasLockAccess(proc)) {</span> |
| <span class="source-line-no">114</span><span id="line-114"> return false;</span> |
| <span class="source-line-no">115</span><span id="line-115"> }</span> |
| <span class="source-line-no">116</span><span id="line-116"> // If no one holds the xlock, then we are free to hold the sharedLock</span> |
| <span class="source-line-no">117</span><span id="line-117"> // If the parent proc or we have already held the xlock, then we return true here as</span> |
| <span class="source-line-no">118</span><span id="line-118"> // xlock is more powerful then shared lock.</span> |
| <span class="source-line-no">119</span><span id="line-119"> sharedLock++;</span> |
| <span class="source-line-no">120</span><span id="line-120"> return true;</span> |
| <span class="source-line-no">121</span><span id="line-121"> }</span> |
| <span class="source-line-no">122</span><span id="line-122"></span> |
| <span class="source-line-no">123</span><span id="line-123"> /** Returns whether we should wake the procedures waiting on the lock here. */</span> |
| <span class="source-line-no">124</span><span id="line-124"> public boolean releaseSharedLock() {</span> |
| <span class="source-line-no">125</span><span id="line-125"> // hasExclusiveLock could be true, it usually means we acquire shared lock while we or our</span> |
| <span class="source-line-no">126</span><span id="line-126"> // parent have held the xlock. And since there is still an exclusive lock, we do not need to</span> |
| <span class="source-line-no">127</span><span id="line-127"> // wake any procedures.</span> |
| <span class="source-line-no">128</span><span id="line-128"> return --sharedLock == 0 && !hasExclusiveLock();</span> |
| <span class="source-line-no">129</span><span id="line-129"> }</span> |
| <span class="source-line-no">130</span><span id="line-130"></span> |
| <span class="source-line-no">131</span><span id="line-131"> public boolean tryExclusiveLock(Procedure<?> proc) {</span> |
| <span class="source-line-no">132</span><span id="line-132"> if (isLocked()) {</span> |
| <span class="source-line-no">133</span><span id="line-133"> return hasLockAccess(proc);</span> |
| <span class="source-line-no">134</span><span id="line-134"> }</span> |
| <span class="source-line-no">135</span><span id="line-135"> exclusiveLockOwnerProcedure = proc;</span> |
| <span class="source-line-no">136</span><span id="line-136"> return true;</span> |
| <span class="source-line-no">137</span><span id="line-137"> }</span> |
| <span class="source-line-no">138</span><span id="line-138"></span> |
| <span class="source-line-no">139</span><span id="line-139"> /** Returns whether we should wake the procedures waiting on the lock here. */</span> |
| <span class="source-line-no">140</span><span id="line-140"> public boolean releaseExclusiveLock(Procedure<?> proc) {</span> |
| <span class="source-line-no">141</span><span id="line-141"> if (</span> |
| <span class="source-line-no">142</span><span id="line-142"> exclusiveLockOwnerProcedure == null</span> |
| <span class="source-line-no">143</span><span id="line-143"> || exclusiveLockOwnerProcedure.getProcId() != proc.getProcId()</span> |
| <span class="source-line-no">144</span><span id="line-144"> ) {</span> |
| <span class="source-line-no">145</span><span id="line-145"> // We are not the lock owner, it is probably inherited from the parent procedures.</span> |
| <span class="source-line-no">146</span><span id="line-146"> return false;</span> |
| <span class="source-line-no">147</span><span id="line-147"> }</span> |
| <span class="source-line-no">148</span><span id="line-148"> exclusiveLockOwnerProcedure = null;</span> |
| <span class="source-line-no">149</span><span id="line-149"> // This maybe a bit strange so let me explain. We allow acquiring shared lock while the parent</span> |
| <span class="source-line-no">150</span><span id="line-150"> // proc or we have already held the xlock, and also allow releasing the locks in any order, so</span> |
| <span class="source-line-no">151</span><span id="line-151"> // it could happen that the xlock is released but there are still some procs holding the shared</span> |
| <span class="source-line-no">152</span><span id="line-152"> // lock.</span> |
| <span class="source-line-no">153</span><span id="line-153"> // In HBase, this could happen when a proc which holdLock is false and schedules sub procs which</span> |
| <span class="source-line-no">154</span><span id="line-154"> // acquire the shared lock on the same lock. This is because we will schedule the sub proces</span> |
| <span class="source-line-no">155</span><span id="line-155"> // before releasing the lock, so the sub procs could call acquire lock before we releasing the</span> |
| <span class="source-line-no">156</span><span id="line-156"> // xlock.</span> |
| <span class="source-line-no">157</span><span id="line-157"> return sharedLock == 0;</span> |
| <span class="source-line-no">158</span><span id="line-158"> }</span> |
| <span class="source-line-no">159</span><span id="line-159"></span> |
| <span class="source-line-no">160</span><span id="line-160"> public boolean isWaitingQueueEmpty() {</span> |
| <span class="source-line-no">161</span><span id="line-161"> return queue.isEmpty();</span> |
| <span class="source-line-no">162</span><span id="line-162"> }</span> |
| <span class="source-line-no">163</span><span id="line-163"></span> |
| <span class="source-line-no">164</span><span id="line-164"> public Procedure<?> removeFirst() {</span> |
| <span class="source-line-no">165</span><span id="line-165"> return queue.removeFirst();</span> |
| <span class="source-line-no">166</span><span id="line-166"> }</span> |
| <span class="source-line-no">167</span><span id="line-167"></span> |
| <span class="source-line-no">168</span><span id="line-168"> public void addLast(Procedure<?> proc) {</span> |
| <span class="source-line-no">169</span><span id="line-169"> queue.addLast(proc);</span> |
| <span class="source-line-no">170</span><span id="line-170"> }</span> |
| <span class="source-line-no">171</span><span id="line-171"></span> |
| <span class="source-line-no">172</span><span id="line-172"> public int wakeWaitingProcedures(ProcedureScheduler scheduler) {</span> |
| <span class="source-line-no">173</span><span id="line-173"> int count = queue.size();</span> |
| <span class="source-line-no">174</span><span id="line-174"> // wakeProcedure adds to the front of queue, so we start from last in the waitQueue' queue, so</span> |
| <span class="source-line-no">175</span><span id="line-175"> // that the procedure which was added first goes in the front for the scheduler queue.</span> |
| <span class="source-line-no">176</span><span id="line-176"> scheduler.addFront(queue.descendingIterator());</span> |
| <span class="source-line-no">177</span><span id="line-177"> queue.clear();</span> |
| <span class="source-line-no">178</span><span id="line-178"> return count;</span> |
| <span class="source-line-no">179</span><span id="line-179"> }</span> |
| <span class="source-line-no">180</span><span id="line-180"></span> |
| <span class="source-line-no">181</span><span id="line-181"> @SuppressWarnings("rawtypes")</span> |
| <span class="source-line-no">182</span><span id="line-182"> public Stream<Procedure> filterWaitingQueue(Predicate<Procedure> predicate) {</span> |
| <span class="source-line-no">183</span><span id="line-183"> return queue.stream().filter(predicate);</span> |
| <span class="source-line-no">184</span><span id="line-184"> }</span> |
| <span class="source-line-no">185</span><span id="line-185"></span> |
| <span class="source-line-no">186</span><span id="line-186"> @Override</span> |
| <span class="source-line-no">187</span><span id="line-187"> public String toString() {</span> |
| <span class="source-line-no">188</span><span id="line-188"> return new ToStringBuilder(this, ToStringStyle.SHORT_PREFIX_STYLE)</span> |
| <span class="source-line-no">189</span><span id="line-189"> .appendSuper(describeLockStatus()).append("waitingProcCount", queue.size()).build();</span> |
| <span class="source-line-no">190</span><span id="line-190"> }</span> |
| <span class="source-line-no">191</span><span id="line-191">}</span> |
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| </pre> |
| </div> |
| </main> |
| </body> |
| </html> |
