On Thu, 6 May 2021 20:41:40 GMT, Kevin Walls <[email protected]> wrote:
> This is a merge request to fix the issue where a running jstatd does not see
> JVMs in docker containers started since the jstatd itself started.
>
> jstatd was using the set of temp directories gathered on startup to scan for
> VMs, by reading their perfdata file. That includes existing running VMs in
> docker instances using tmp dirs such as /proc/PID/root/tmp/. But it needs to
> re-evaluate that set of temp dirs continually to see new VMs in docker
> containers. Rescanning also means it "forgets" about tmp dirs which have
> disappeared, for containers that have shutdown, and it will now not be
> scanning those directories forever.
>
> Have been testing this manually, watching jps connecting to jstatd and show
> newly created JVMs in docker containers come and go. Running existing tests
> OK so far.
src/jdk.internal.jvmstat/share/classes/sun/jvmstat/perfdata/monitor/protocol/local/LocalVmManager.java
line 79:
> 77: public LocalVmManager(String user) {
> 78: this.userName = user;
> 79: setTempDirs();
Is this call necessary? It looks like we don't need to hold `tmpdirs` anymore.
Can we remove `tmpdirs` from class member and can call
`PerfDataFile.getTempDirectories()` directly at L138?
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PR: https://git.openjdk.java.net/jdk/pull/3908
