RFR: JDK-8324287: Record total and free swap space in JFR [v6]

[Erik Gahlin]

On Tue, 30 Jan 2024 16:17:49 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> Total and free swap space should be recorded in JFR, because it is important to know e.g. in case of memory shortages.
>> 
>> Currently we only have a container related event (ContainerMemoryUsage) that provides some info but no general event.
>> PhysicalMemory could be enhanced or a new event added.
>> 
>> There is already some coding (see Java_com_sun_management_internal_OperatingSystemImpl_getTotalSwapSpaceSize0 and
>> Java_com_sun_management_internal_OperatingSystemImpl_getFreeSwapSpaceSize0) for the swap space info retrieval.
>
> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
> 
>   some Linux container related adjustments

JFR part looks good. Could use try-with-resources in the test, i.e try (Recording r = ...). Have not reviewed OS related code.

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Marked as reviewed by egahlin (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17581#pullrequestreview-1852152646