metric/system/cgroup: introduce cache for cgroup v2

florianl commented 7 months ago

What does this PR do?

Reintroduce the improvements from https://github.com/elastic/elastic-agent-system-metrics/pull/103. This PR got reverted with https://github.com/elastic/elastic-agent-system-metrics/pull/113 because of https://github.com/elastic/elastic-agent-system-metrics/issues/109. The issue, that got reported in https://github.com/elastic/elastic-agent-system-metrics/issues/109, was fixed with https://github.com/elastic/elastic-agent-system-metrics/pull/116.

So its time to bring back the performance improvements by reintroducing the cache for cgroup v2.

Why is it important?

Checklist

[x] My code follows the style guidelines of this project
[x] I have commented my code, particularly in hard-to-understand areas
[ ] ~~I have added tests that prove my fix is effective or that my feature works~~
[ ] ~~I have added an entry in CHANGELOG.md~~

florianl commented 7 months ago

sorry - but making linter happy seems to be impossible ...

pierrehilbert commented 6 months ago

@cmacknz should we just force merge this one?

cmacknz commented 6 months ago

If the linter is the only problem we can force merge this, at least for me the linter is not even a blocking step (the squash and merge button is available) so there is no force merge required.

elastic / elastic-agent-system-metrics