Very long safepoint pauses for RevokeBias

[Christopher Berner]

I work on the Presto project, which is a distributed SQL engine, and
intermittently (roughly once an hour) I see very long application stopped
times (as reported by
   -XX:+PrintGCApplicationStoppedTime). I enabled safepoint statistics, and
see that the pause seems to be coming from a RevokeBias safepoint.

Any suggestions as to how I can debug this? I already tried adding
-XX:+PerfDisableSharedMem, in case this was related to
https://bugs.openjdk.java.net/browse/JDK-8076103

See below for safepoint statistics:

         vmop                    [threads: total initially_running
wait_to_block]    [time: spin block sync cleanup vmop] page_trap_count

2528.893: RevokeBias                       [     872          0
  6    ]      [     0 12826 13142  6476  8177    ]  0