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https://issues.apache.org/jira/browse/HADOOP-12908?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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John Zhuge updated HADOOP-12908:
--------------------------------
Fix Version/s: 2.8.0
Status: Patch Available (was: Open)
This patch will work better when AbstractService is restartable, i.e., allowing
state transition from STOPPED to STARTED.
> Make JvmPauseMonitor a singleton
> --------------------------------
>
> Key: HADOOP-12908
> URL: https://issues.apache.org/jira/browse/HADOOP-12908
> Project: Hadoop Common
> Issue Type: Improvement
> Affects Versions: 2.7.2
> Reporter: John Zhuge
> Assignee: John Zhuge
> Priority: Minor
> Fix For: 2.8.0
>
> Attachments: HADOOP-12908-001.patch
>
>
> Make JvmPauseMonitor a singleton just as JvmMetrics because there is no use
> case to run multiple instances per JVM. No need for
> {{TestMetrics$setPauseMonitor}} any more. Initialization code can be
> simplified.
> For example, this code segment
> {noformat}
> pauseMonitor = new JvmPauseMonitor();
> addService(pauseMonitor);
> jm.setPauseMonitor(pauseMonitor);
> {noformat}
> becomes
> {noformat}
> addService(JvmPauseMonitor.INSTANCE);
> {noformat}
> And this code segment
> {noformat}
> pauseMonitor = new JvmPauseMonitor();
> pauseMonitor.init(config);
> pauseMonitor.start();
> metrics.getJvmMetrics().setPauseMonitor(pauseMonitor);
> {noformat}
> becomes
> {noformat}
> pauseMonitor.INSTANCE.init(config);
> pauseMonitor.INSTANCE.start();
> {noformat}
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