On Tue, 11 Aug 2026 10:09:47 GMT, Ivan Bereziuk <[email protected]> wrote:
> Please review this PR that makes "failcount" case of
> `TestDockerMemoryMetrics.java` more robust.
> The "failcount" case is failing in some environments (OL9+ in my case).
>
> With this change I am trying to address several issues:
> * the test was not setting swap-space, and assumed OS will map mirror
> `--memory` in size. 128MiB for the test was not always enough for a
> successful run.
> * updated the test with additional `--memory-swap` flat to control the
> swap headroom in container so that failcount gets more chances to be
> incremented while main memory is full. It may also be that some OSes are more
> eager the others to update counters in cgroup-fs. This tweak helps.
> * the `new byte[1 MiB]` allocations alone reserves heap space for the
> application space but may leave the memory uncommitted. It can be that 512
> MiB Java heap fills up and throws OutOfMemoryError before RSS crosses the
> 128MiB limit.
> * fix by dirtying the chunks after we allocate them.
> * removed `catch`'ing `java.lang.OutOfMemoryError` errors to avoid secondary
> `OutOfMemoryError`.
> * The test inherits JVM flags set externally and so `-Xmx` is often passed to
> the JVM running in a container.
> * Make `-Xmx` flag set from within the test to *win* over the one set
> externally (e.g. by our make scripts for task definition).
>
> * the additional logs help seeing the dynamics of the test, Example OL9:
>
> Initial memory fail count: 0
> Allocated: 0M, Memory usage: 42M, Memory and swap: 42M
> .......Allocated: 8M, Memory usage: 72M, Memory and swap: 72M
> .......Allocated: 16M, Memory usage: 88M, Memory and swap: 88M
> .......Allocated: 24M, Memory usage: 106M, Memory and swap: 106M
> .......Allocated: 32M, Memory usage: 123M, Memory and swap: 123M
> .......Allocated: 40M, Memory usage: 127M, Memory and swap: 142M
> .......Allocated: 48M, Memory usage: 127M, Memory and swap: 163M
> .......Allocated: 56M, Memory usage: 97M, Memory and swap: 185M
> .......Allocated: 64M, Memory usage: 113M, Memory and swap: 200M
> .......Allocated: 72M, Memory usage: 127M, Memory and swap: 215M
> .......Allocated: 80M, Memory usage: 127M, Memory and swap: 251M
> .......Allocated: 88M, Memory usage: 127M, Memory and swap: 249M
> .......Allocated: 96M, Memory usage: 127M, Memory and swap: 266M
> .......Allocated: 104M, Memory usage: 125M, Memory and swap: 287M
> .
> DEBUG: Bytes allocation length 1: 1048576
> Final memory fail count: 1
> TEST PASSED!!!
> ```
>
> Tested `TestDockerMemoryMetrics.java` on
> * Ubuntu 24.04 x {Podman, Docker}
> * OL9,10 + Pod...
This pull request has now been integrated.
Changeset: c2e49da8
Author: Ivan Bereziuk <[email protected]>
Committer: Casper Norrbin <[email protected]>
URL:
https://git.openjdk.org/jdk/commit/c2e49da8f6391a0a3447fc5b1349bebd3b7f2e23
Stats: 75 lines in 2 files changed: 27 ins; 1 del; 47 mod
8390065: TestDockerMemoryMetrics.java fails in MetricsMemoryTester failcount
Reviewed-by: cnorrbin
-------------
PR: https://git.openjdk.org/jdk/pull/32300
