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| <pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a> |
| <span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a> |
| <span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a> |
| <span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a> |
| <span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a> |
| <span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a> |
| <span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a> |
| <span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a> |
| <span class="sourceLineNo">009</span> *<a name="line.9"></a> |
| <span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a> |
| <span class="sourceLineNo">011</span> *<a name="line.11"></a> |
| <span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a> |
| <span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a> |
| <span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a> |
| <span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a> |
| <span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a> |
| <span class="sourceLineNo">017</span> */<a name="line.17"></a> |
| <span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.util;<a name="line.18"></a> |
| <span class="sourceLineNo">019</span><a name="line.19"></a> |
| <span class="sourceLineNo">020</span>import java.io.IOException;<a name="line.20"></a> |
| <span class="sourceLineNo">021</span>import java.io.InterruptedIOException;<a name="line.21"></a> |
| <span class="sourceLineNo">022</span>import java.util.concurrent.ConcurrentHashMap;<a name="line.22"></a> |
| <span class="sourceLineNo">023</span>import java.util.concurrent.ConcurrentMap;<a name="line.23"></a> |
| <span class="sourceLineNo">024</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.24"></a> |
| <span class="sourceLineNo">025</span>import org.slf4j.Logger;<a name="line.25"></a> |
| <span class="sourceLineNo">026</span>import org.slf4j.LoggerFactory;<a name="line.26"></a> |
| <span class="sourceLineNo">027</span><a name="line.27"></a> |
| <span class="sourceLineNo">028</span>import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;<a name="line.28"></a> |
| <span class="sourceLineNo">029</span><a name="line.29"></a> |
| <span class="sourceLineNo">030</span>/**<a name="line.30"></a> |
| <span class="sourceLineNo">031</span> * Allows multiple concurrent clients to lock on a numeric id with a minimal memory overhead. The<a name="line.31"></a> |
| <span class="sourceLineNo">032</span> * intended usage is as follows:<a name="line.32"></a> |
| <span class="sourceLineNo">033</span> *<a name="line.33"></a> |
| <span class="sourceLineNo">034</span> * <pre><a name="line.34"></a> |
| <span class="sourceLineNo">035</span> * IdLock.Entry lockEntry = idLock.getLockEntry(id);<a name="line.35"></a> |
| <span class="sourceLineNo">036</span> * try {<a name="line.36"></a> |
| <span class="sourceLineNo">037</span> * // User code.<a name="line.37"></a> |
| <span class="sourceLineNo">038</span> * } finally {<a name="line.38"></a> |
| <span class="sourceLineNo">039</span> * idLock.releaseLockEntry(lockEntry);<a name="line.39"></a> |
| <span class="sourceLineNo">040</span> * }<a name="line.40"></a> |
| <span class="sourceLineNo">041</span> * </pre><a name="line.41"></a> |
| <span class="sourceLineNo">042</span> */<a name="line.42"></a> |
| <span class="sourceLineNo">043</span>@InterfaceAudience.Private<a name="line.43"></a> |
| <span class="sourceLineNo">044</span>public class IdLock {<a name="line.44"></a> |
| <span class="sourceLineNo">045</span><a name="line.45"></a> |
| <span class="sourceLineNo">046</span> private static final Logger LOG = LoggerFactory.getLogger(IdLock.class);<a name="line.46"></a> |
| <span class="sourceLineNo">047</span><a name="line.47"></a> |
| <span class="sourceLineNo">048</span> /** An entry returned to the client as a lock object */<a name="line.48"></a> |
| <span class="sourceLineNo">049</span> public static final class Entry {<a name="line.49"></a> |
| <span class="sourceLineNo">050</span> private final long id;<a name="line.50"></a> |
| <span class="sourceLineNo">051</span> private int numWaiters;<a name="line.51"></a> |
| <span class="sourceLineNo">052</span> private boolean locked = true;<a name="line.52"></a> |
| <span class="sourceLineNo">053</span> private Thread holder;<a name="line.53"></a> |
| <span class="sourceLineNo">054</span><a name="line.54"></a> |
| <span class="sourceLineNo">055</span> private Entry(long id, Thread holder) {<a name="line.55"></a> |
| <span class="sourceLineNo">056</span> this.id = id;<a name="line.56"></a> |
| <span class="sourceLineNo">057</span> this.holder = holder;<a name="line.57"></a> |
| <span class="sourceLineNo">058</span> }<a name="line.58"></a> |
| <span class="sourceLineNo">059</span><a name="line.59"></a> |
| <span class="sourceLineNo">060</span> @Override<a name="line.60"></a> |
| <span class="sourceLineNo">061</span> public String toString() {<a name="line.61"></a> |
| <span class="sourceLineNo">062</span> return "id=" + id + ", numWaiter=" + numWaiters + ", isLocked=" + locked + ", holder="<a name="line.62"></a> |
| <span class="sourceLineNo">063</span> + holder;<a name="line.63"></a> |
| <span class="sourceLineNo">064</span> }<a name="line.64"></a> |
| <span class="sourceLineNo">065</span> }<a name="line.65"></a> |
| <span class="sourceLineNo">066</span><a name="line.66"></a> |
| <span class="sourceLineNo">067</span> private ConcurrentMap<Long, Entry> map = new ConcurrentHashMap<>();<a name="line.67"></a> |
| <span class="sourceLineNo">068</span><a name="line.68"></a> |
| <span class="sourceLineNo">069</span> /**<a name="line.69"></a> |
| <span class="sourceLineNo">070</span> * Blocks until the lock corresponding to the given id is acquired.<a name="line.70"></a> |
| <span class="sourceLineNo">071</span> * @param id an arbitrary number to lock on<a name="line.71"></a> |
| <span class="sourceLineNo">072</span> * @return an "entry" to pass to {@link #releaseLockEntry(Entry)} to release the lock<a name="line.72"></a> |
| <span class="sourceLineNo">073</span> * @throws IOException if interrupted<a name="line.73"></a> |
| <span class="sourceLineNo">074</span> */<a name="line.74"></a> |
| <span class="sourceLineNo">075</span> public Entry getLockEntry(long id) throws IOException {<a name="line.75"></a> |
| <span class="sourceLineNo">076</span> Thread currentThread = Thread.currentThread();<a name="line.76"></a> |
| <span class="sourceLineNo">077</span> Entry entry = new Entry(id, currentThread);<a name="line.77"></a> |
| <span class="sourceLineNo">078</span> Entry existing;<a name="line.78"></a> |
| <span class="sourceLineNo">079</span> while ((existing = map.putIfAbsent(entry.id, entry)) != null) {<a name="line.79"></a> |
| <span class="sourceLineNo">080</span> synchronized (existing) {<a name="line.80"></a> |
| <span class="sourceLineNo">081</span> if (existing.locked) {<a name="line.81"></a> |
| <span class="sourceLineNo">082</span> ++existing.numWaiters; // Add ourselves to waiters.<a name="line.82"></a> |
| <span class="sourceLineNo">083</span> while (existing.locked) {<a name="line.83"></a> |
| <span class="sourceLineNo">084</span> try {<a name="line.84"></a> |
| <span class="sourceLineNo">085</span> existing.wait();<a name="line.85"></a> |
| <span class="sourceLineNo">086</span> } catch (InterruptedException e) {<a name="line.86"></a> |
| <span class="sourceLineNo">087</span> --existing.numWaiters; // Remove ourselves from waiters.<a name="line.87"></a> |
| <span class="sourceLineNo">088</span> // HBASE-21292<a name="line.88"></a> |
| <span class="sourceLineNo">089</span> // There is a rare case that interrupting and the lock owner thread call<a name="line.89"></a> |
| <span class="sourceLineNo">090</span> // releaseLockEntry at the same time. Since the owner thread found there<a name="line.90"></a> |
| <span class="sourceLineNo">091</span> // still one waiting, it won't remove the entry from the map. If the interrupted<a name="line.91"></a> |
| <span class="sourceLineNo">092</span> // thread is the last one waiting on the lock, and since an exception is thrown,<a name="line.92"></a> |
| <span class="sourceLineNo">093</span> // the 'existing' entry will stay in the map forever. Later threads which try to<a name="line.93"></a> |
| <span class="sourceLineNo">094</span> // get this lock will stuck in a infinite loop because<a name="line.94"></a> |
| <span class="sourceLineNo">095</span> // existing = map.putIfAbsent(entry.id, entry)) != null and existing.locked=false.<a name="line.95"></a> |
| <span class="sourceLineNo">096</span> if (!existing.locked && existing.numWaiters == 0) {<a name="line.96"></a> |
| <span class="sourceLineNo">097</span> map.remove(existing.id);<a name="line.97"></a> |
| <span class="sourceLineNo">098</span> }<a name="line.98"></a> |
| <span class="sourceLineNo">099</span> throw new InterruptedIOException("Interrupted waiting to acquire sparse lock");<a name="line.99"></a> |
| <span class="sourceLineNo">100</span> }<a name="line.100"></a> |
| <span class="sourceLineNo">101</span> }<a name="line.101"></a> |
| <span class="sourceLineNo">102</span><a name="line.102"></a> |
| <span class="sourceLineNo">103</span> --existing.numWaiters; // Remove ourselves from waiters.<a name="line.103"></a> |
| <span class="sourceLineNo">104</span> existing.locked = true;<a name="line.104"></a> |
| <span class="sourceLineNo">105</span> existing.holder = currentThread;<a name="line.105"></a> |
| <span class="sourceLineNo">106</span> return existing;<a name="line.106"></a> |
| <span class="sourceLineNo">107</span> }<a name="line.107"></a> |
| <span class="sourceLineNo">108</span> // If the entry is not locked, it might already be deleted from the<a name="line.108"></a> |
| <span class="sourceLineNo">109</span> // map, so we cannot return it. We need to get our entry into the map<a name="line.109"></a> |
| <span class="sourceLineNo">110</span> // or get someone else's locked entry.<a name="line.110"></a> |
| <span class="sourceLineNo">111</span> }<a name="line.111"></a> |
| <span class="sourceLineNo">112</span> }<a name="line.112"></a> |
| <span class="sourceLineNo">113</span> return entry;<a name="line.113"></a> |
| <span class="sourceLineNo">114</span> }<a name="line.114"></a> |
| <span class="sourceLineNo">115</span><a name="line.115"></a> |
| <span class="sourceLineNo">116</span> /**<a name="line.116"></a> |
| <span class="sourceLineNo">117</span> * Blocks until the lock corresponding to the given id is acquired.<a name="line.117"></a> |
| <span class="sourceLineNo">118</span> * @param id an arbitrary number to lock on<a name="line.118"></a> |
| <span class="sourceLineNo">119</span> * @param time time to wait in ms<a name="line.119"></a> |
| <span class="sourceLineNo">120</span> * @return an "entry" to pass to {@link #releaseLockEntry(Entry)} to release the lock<a name="line.120"></a> |
| <span class="sourceLineNo">121</span> * @throws IOException if interrupted<a name="line.121"></a> |
| <span class="sourceLineNo">122</span> */<a name="line.122"></a> |
| <span class="sourceLineNo">123</span> public Entry tryLockEntry(long id, long time) throws IOException {<a name="line.123"></a> |
| <span class="sourceLineNo">124</span> Preconditions.checkArgument(time >= 0);<a name="line.124"></a> |
| <span class="sourceLineNo">125</span> Thread currentThread = Thread.currentThread();<a name="line.125"></a> |
| <span class="sourceLineNo">126</span> Entry entry = new Entry(id, currentThread);<a name="line.126"></a> |
| <span class="sourceLineNo">127</span> Entry existing;<a name="line.127"></a> |
| <span class="sourceLineNo">128</span> long waitUtilTS = EnvironmentEdgeManager.currentTime() + time;<a name="line.128"></a> |
| <span class="sourceLineNo">129</span> long remaining = time;<a name="line.129"></a> |
| <span class="sourceLineNo">130</span> while ((existing = map.putIfAbsent(entry.id, entry)) != null) {<a name="line.130"></a> |
| <span class="sourceLineNo">131</span> synchronized (existing) {<a name="line.131"></a> |
| <span class="sourceLineNo">132</span> if (existing.locked) {<a name="line.132"></a> |
| <span class="sourceLineNo">133</span> ++existing.numWaiters; // Add ourselves to waiters.<a name="line.133"></a> |
| <span class="sourceLineNo">134</span> try {<a name="line.134"></a> |
| <span class="sourceLineNo">135</span> while (existing.locked) {<a name="line.135"></a> |
| <span class="sourceLineNo">136</span> existing.wait(remaining);<a name="line.136"></a> |
| <span class="sourceLineNo">137</span> if (existing.locked) {<a name="line.137"></a> |
| <span class="sourceLineNo">138</span> long currentTS = EnvironmentEdgeManager.currentTime();<a name="line.138"></a> |
| <span class="sourceLineNo">139</span> if (currentTS >= waitUtilTS) {<a name="line.139"></a> |
| <span class="sourceLineNo">140</span> // time is up<a name="line.140"></a> |
| <span class="sourceLineNo">141</span> return null;<a name="line.141"></a> |
| <span class="sourceLineNo">142</span> } else {<a name="line.142"></a> |
| <span class="sourceLineNo">143</span> // our wait is waken, but the lock is still taken, this can happen<a name="line.143"></a> |
| <span class="sourceLineNo">144</span> // due to JDK Object's wait/notify mechanism.<a name="line.144"></a> |
| <span class="sourceLineNo">145</span> // Calculate the new remaining time to wait<a name="line.145"></a> |
| <span class="sourceLineNo">146</span> remaining = waitUtilTS - currentTS;<a name="line.146"></a> |
| <span class="sourceLineNo">147</span> }<a name="line.147"></a> |
| <span class="sourceLineNo">148</span> }<a name="line.148"></a> |
| <span class="sourceLineNo">149</span><a name="line.149"></a> |
| <span class="sourceLineNo">150</span> }<a name="line.150"></a> |
| <span class="sourceLineNo">151</span> } catch (InterruptedException e) {<a name="line.151"></a> |
| <span class="sourceLineNo">152</span> // HBASE-21292<a name="line.152"></a> |
| <span class="sourceLineNo">153</span> // Please refer to the comments in getLockEntry()<a name="line.153"></a> |
| <span class="sourceLineNo">154</span> // the difference here is that we decrease numWaiters in finally block<a name="line.154"></a> |
| <span class="sourceLineNo">155</span> if (!existing.locked && existing.numWaiters == 1) {<a name="line.155"></a> |
| <span class="sourceLineNo">156</span> map.remove(existing.id);<a name="line.156"></a> |
| <span class="sourceLineNo">157</span> }<a name="line.157"></a> |
| <span class="sourceLineNo">158</span> throw new InterruptedIOException("Interrupted waiting to acquire sparse lock");<a name="line.158"></a> |
| <span class="sourceLineNo">159</span> } finally {<a name="line.159"></a> |
| <span class="sourceLineNo">160</span> --existing.numWaiters; // Remove ourselves from waiters.<a name="line.160"></a> |
| <span class="sourceLineNo">161</span> }<a name="line.161"></a> |
| <span class="sourceLineNo">162</span> existing.locked = true;<a name="line.162"></a> |
| <span class="sourceLineNo">163</span> existing.holder = currentThread;<a name="line.163"></a> |
| <span class="sourceLineNo">164</span> return existing;<a name="line.164"></a> |
| <span class="sourceLineNo">165</span> }<a name="line.165"></a> |
| <span class="sourceLineNo">166</span> // If the entry is not locked, it might already be deleted from the<a name="line.166"></a> |
| <span class="sourceLineNo">167</span> // map, so we cannot return it. We need to get our entry into the map<a name="line.167"></a> |
| <span class="sourceLineNo">168</span> // or get someone else's locked entry.<a name="line.168"></a> |
| <span class="sourceLineNo">169</span> }<a name="line.169"></a> |
| <span class="sourceLineNo">170</span> }<a name="line.170"></a> |
| <span class="sourceLineNo">171</span> return entry;<a name="line.171"></a> |
| <span class="sourceLineNo">172</span> }<a name="line.172"></a> |
| <span class="sourceLineNo">173</span><a name="line.173"></a> |
| <span class="sourceLineNo">174</span> /**<a name="line.174"></a> |
| <span class="sourceLineNo">175</span> * Must be called in a finally block to decrease the internal counter and remove the monitor<a name="line.175"></a> |
| <span class="sourceLineNo">176</span> * object for the given id if the caller is the last client.<a name="line.176"></a> |
| <span class="sourceLineNo">177</span> * @param entry the return value of {@link #getLockEntry(long)}<a name="line.177"></a> |
| <span class="sourceLineNo">178</span> */<a name="line.178"></a> |
| <span class="sourceLineNo">179</span> public void releaseLockEntry(Entry entry) {<a name="line.179"></a> |
| <span class="sourceLineNo">180</span> Thread currentThread = Thread.currentThread();<a name="line.180"></a> |
| <span class="sourceLineNo">181</span> synchronized (entry) {<a name="line.181"></a> |
| <span class="sourceLineNo">182</span> if (entry.holder != currentThread) {<a name="line.182"></a> |
| <span class="sourceLineNo">183</span> LOG.warn("{} is trying to release lock entry {}, but it is not the holder.", currentThread,<a name="line.183"></a> |
| <span class="sourceLineNo">184</span> entry);<a name="line.184"></a> |
| <span class="sourceLineNo">185</span> }<a name="line.185"></a> |
| <span class="sourceLineNo">186</span> entry.locked = false;<a name="line.186"></a> |
| <span class="sourceLineNo">187</span> if (entry.numWaiters > 0) {<a name="line.187"></a> |
| <span class="sourceLineNo">188</span> entry.notify();<a name="line.188"></a> |
| <span class="sourceLineNo">189</span> } else {<a name="line.189"></a> |
| <span class="sourceLineNo">190</span> map.remove(entry.id);<a name="line.190"></a> |
| <span class="sourceLineNo">191</span> }<a name="line.191"></a> |
| <span class="sourceLineNo">192</span> }<a name="line.192"></a> |
| <span class="sourceLineNo">193</span> }<a name="line.193"></a> |
| <span class="sourceLineNo">194</span><a name="line.194"></a> |
| <span class="sourceLineNo">195</span> /**<a name="line.195"></a> |
| <span class="sourceLineNo">196</span> * Test whether the given id is already locked by the current thread.<a name="line.196"></a> |
| <span class="sourceLineNo">197</span> */<a name="line.197"></a> |
| <span class="sourceLineNo">198</span> public boolean isHeldByCurrentThread(long id) {<a name="line.198"></a> |
| <span class="sourceLineNo">199</span> Thread currentThread = Thread.currentThread();<a name="line.199"></a> |
| <span class="sourceLineNo">200</span> Entry entry = map.get(id);<a name="line.200"></a> |
| <span class="sourceLineNo">201</span> if (entry == null) {<a name="line.201"></a> |
| <span class="sourceLineNo">202</span> return false;<a name="line.202"></a> |
| <span class="sourceLineNo">203</span> }<a name="line.203"></a> |
| <span class="sourceLineNo">204</span> synchronized (entry) {<a name="line.204"></a> |
| <span class="sourceLineNo">205</span> return currentThread.equals(entry.holder);<a name="line.205"></a> |
| <span class="sourceLineNo">206</span> }<a name="line.206"></a> |
| <span class="sourceLineNo">207</span> }<a name="line.207"></a> |
| <span class="sourceLineNo">208</span><a name="line.208"></a> |
| <span class="sourceLineNo">209</span> void assertMapEmpty() {<a name="line.209"></a> |
| <span class="sourceLineNo">210</span> assert map.isEmpty();<a name="line.210"></a> |
| <span class="sourceLineNo">211</span> }<a name="line.211"></a> |
| <span class="sourceLineNo">212</span><a name="line.212"></a> |
| <span class="sourceLineNo">213</span> public void waitForWaiters(long id, int numWaiters) throws InterruptedException {<a name="line.213"></a> |
| <span class="sourceLineNo">214</span> for (Entry entry;;) {<a name="line.214"></a> |
| <span class="sourceLineNo">215</span> entry = map.get(id);<a name="line.215"></a> |
| <span class="sourceLineNo">216</span> if (entry != null) {<a name="line.216"></a> |
| <span class="sourceLineNo">217</span> synchronized (entry) {<a name="line.217"></a> |
| <span class="sourceLineNo">218</span> if (entry.numWaiters >= numWaiters) {<a name="line.218"></a> |
| <span class="sourceLineNo">219</span> return;<a name="line.219"></a> |
| <span class="sourceLineNo">220</span> }<a name="line.220"></a> |
| <span class="sourceLineNo">221</span> }<a name="line.221"></a> |
| <span class="sourceLineNo">222</span> }<a name="line.222"></a> |
| <span class="sourceLineNo">223</span> Thread.sleep(100);<a name="line.223"></a> |
| <span class="sourceLineNo">224</span> }<a name="line.224"></a> |
| <span class="sourceLineNo">225</span> }<a name="line.225"></a> |
| <span class="sourceLineNo">226</span>}<a name="line.226"></a> |
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| </div> |
| </body> |
| </html> |