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  1. Jenkins
  2. JENKINS-5413

SCM polling getting hung


    • Icon: Bug Bug
    • Resolution: Unresolved
    • Icon: Critical Critical
    • remoting
    • None

      This is to track the problem originally reported here: http://n4.nabble.com/Polling-hung-td1310838.html#a1310838
      The referenced thread is relocated to http://jenkins.361315.n4.nabble.com/Polling-hung-td1310838.html

      What the problem boils down to is that many remote operations are performed synchronously causing the channel object to be locked while a response returns. In situations where a lengthy remote operations is using the channel, SCM polling can be blocked waiting for the monitor on the channel to be released. In extreme situations, all the polling threads can wind up waiting on object monitors for the channel objects, preventing further processing of polling tasks.

      Furthermore, if the slave dies, the locked channel object still exists in the master JVM. If no IOException is thrown to indicate the termination of the connection to the pipe, the channel can never be closed because Channel.close() itself is a sychronized operation.

        1. DUMP1.txt
          57 kB
        2. hung_scm_pollers_02.PNG
          145 kB
        3. thread_dump_02.txt
          92 kB
        4. threads.vetted.txt
          163 kB

            Unassigned Unassigned
            dty Dean Yu
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