On Thu, 7 Jul 2022 06:01:58 GMT, Ioi Lam <ik...@openjdk.org> wrote: > Some Kubernetes setups share the /tmp directory across multiple containers. > On rare occasions, the JVM may crash when it tries to write to > `/tmp/hsperfdata_<user>/<pid>` when a process in a separate container decides > to do the same thing (because they happen to have the same namespaced pid). > > This patch avoids the crash by using `flock()` to allow only one of these > processes to write to the file. All other competing processes that fail to > grab the lock will give up the file and run with PerfMemory disabled. We will > try to enable PerfMemory for the failed processes in a follow-up RFE: > [JDK-8289883](https://bugs.openjdk.org/browse/JDK-8289883) > > Thanks to Vitaly Davidovich and Nico Williams for coming up with the idea of > using `flock()`. > > I kept the use of `kill()` for stale file detection to be compatible with > older JVMs. > > I also took the opportunity to clean up the comments and remove dead code. > The old code was using "shared memory resources" which sounds unclear and > odd. I changed the terminology to say "shared memory file" instead.
This pull request has now been integrated. Changeset: 84f23149 Author: Ioi Lam <ik...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/84f23149e22561173feb0e34bca31a7345b43c89 Stats: 324 lines in 3 files changed: 267 ins; 27 del; 30 mod 8286030: Avoid JVM crash when containers share the same /tmp dir Reviewed-by: stuefe, sgehwolf ------------- PR: https://git.openjdk.org/jdk/pull/9406
