Hi David and Serguei,

Please review a new version of the fix that for Linux platform uses the proc 
filesystem to retrieve the main class name for the running Java process. 

Webrev: http://cr.openjdk.java.net/~dtitov/8205654/webrev.02/
Bug: https://bugs.openjdk.java.net/browse/JDK-8205654 

Thanks,
Daniil

On 11/29/18, 4:52 PM, "David Holmes" <[email protected]> wrote:

    Hi Daniil,
    
    On 30/11/2018 7:30 am, Daniil Titov wrote:
    > Thank you, David!
    > 
    > The proposed fix didn't help. It still hangs at some occasions.  
Additional tracing showed that when jcmd is invoked with the main class name it 
iterates over all running Java processes and temporary attaches to them to 
retrieve the main class name. It hangs while trying to attach to one of the 
running Java processes. There are numerous Java processes running at the host 
machine some associated with the test framework itself and another with the 
tests running in parallel. It is not clear what exact is this particular 
process since the jcmd hangs before retrieving the process' main class name, 
but after all tests terminated the process with this id is no longer running.  
I have to revoke this review since more investigation is required.
    
    That sounds like an unsolvable problem for the test. You can't control 
    other Java processes on the machine, and searching by name requires 
    asking each of them in turn.
    
    How do we get the list of Java processes in the first place? Perhaps we 
    need to do some /proc/<pid>/cmdline peeking?
    
    Cheers,
    David
    
    > 
    > Best regards,
    > Daniil
    > 
    > 
    > 
    > On 11/11/18, 1:35 PM, "David Holmes" <[email protected]> wrote:
    > 
    >      Hi Daniil,
    >      
    >      I took a quick look at this one ... two minor comments
    >      
    >      The static class names could just be "Process" as they will acquire 
the
    >      enclosing class name as part of their own name anyway. As it is this
    >      gets repeated eg:
    >      
    >      HelpTest$HelpTestProcess
    >      InvalidCommandTest$InvalidCommandTestProcess
    >      
    >      TestJavaProcess.java:
    >      
    >      39     public static void main(String argv[]) {
    >      
    >      Nit: Should be "String[] argv" in Java style
    >      
    >      Thanks,
    >      David
    >      
    >      On 10/11/2018 3:18 PM, Daniil Titov wrote:
    >      > Please review the change that fixes 
serviceability/dcmd/framework/* tests from a time out. The fix for JDK-8166642 
made serviceability/dcmd/framework/* tests non-concurrent to ensure that they 
don't interact with each other and there are no multiple tests running 
simultaneously since all they do share the common main class name 
com.sun.javatest.regtest.agent.MainWrapper. However, it looks like the  tests 
from other directories still might run in parallel with these tests and they 
also have com.sun.javatest.regtest.agent.MainWrapper as a main class.
    >      >
    >      > The fix  ensures that each serviceability/dcmd/framework/* test 
uses a Java process with a unique main class name when connecting to this 
process with jcmd and the main class name.
    >      >
    >      > Bug: https://bugs.openjdk.java.net/browse/JDK-8205654
    >      > Webrev: http://cr.openjdk.java.net/~dtitov/8205654/webrev.001/
    >      >
    >      > Best regards,
    >      > Daniil
    >      >
    >      >
    >      
    > 
    > 
    


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