On Fri, 14 Nov 2025 15:11:02 GMT, Severin Gehwolf <sgehwolf@openjdk.org> wrote:
Please review this revised version of getting rid of `jlong` and `julong` in internal HotSpot code. The single remaining usage is using `os::elapsed_counter()` which I think is still ok. This refactoring is for the container detection code to (mostly) do away with negative return values.
It gets rid of the trifold-use of return value: 1.) error, 2) unlimited values 3) actual numbers/values/limits. Instead, all container related values are now being read from the interface files as `uint64_t` and afterwards interpreted in the way that make sense for the API implementations. For example, `cpu` values will essentially be treated as `int`s as before, potentially returning a negative value `-1` for unlimited. For memory sizes the type `physical_memory_size_type` has been chosen. When there is no limit for a specific memory size a value `value_unlimited` is being returned.
All error cases have been changed to returning `false` in the API functions (and no value is being set in the passed in reference for the value). The effect of this is that all container related functions now return a `bool` and require a reference to be passed in for the `value` that is being asked for.
All usages of the API have been changed to use the revised API. There is no more usages for `OSCONTAINER_ERROR` (`-2) in HotSpot code.
While working on this, I've noticed that there are still some calls deep in the cgroup subsystem code to query "machine" info (e.g. `os::Linux::active_processor_count()`). I've filed [JDK-8369503](https://bugs.openjdk.org/browse/JDK-8369503) to get this cleaned-up as this patch was already getting large.
Testing (looking good): - [x] GHA - [x] All container tests (including problem listed ones) on Linux x86_64 with cg v1 and cg v2. See [this comment](https://github.com/openjdk/jdk/pull/27743#issuecomment-3390060127) below. - [x] Some ad-hoc manual testing in containers using JFR (`jdk.SwapSpace` event) and `VM.info` diagnostic command.
Thoughts? Opinions?
Severin Gehwolf has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 25 commits:
- Merge branch 'master' into jdk-8365606-jlong-julong-refactor - Add space in trace log - Merge branch 'master' into jdk-8365606-jlong-julong-refactor - One more comment fix - Extract OSContainer::available_swap_in_bytes() - Simplify os::used_memory() - Fix os::active_processor_count() - os::free_memory => use 'value' directly - os::available_memory() => use 'value' directly - Fix pids_max printing in VM.info - ... and 15 more: https://git.openjdk.org/jdk/compare/5d65c23c...9a5f3eb5
Marked as reviewed by cnorrbin (Committer). ------------- PR Review: https://git.openjdk.org/jdk/pull/27743#pullrequestreview-3465404828