Improved Memory Accounting for cgroups v2 to Exclude Page Cache

Why it matters

This feature addresses inaccurate memory usage reporting in cgroups v2 by excluding the memory used by the page cache, providing more precise and meaningful memory accounting for ClickHouse processes running under cgroup management.

How to use it

This improvement is applied automatically when ClickHouse runs under cgroups v2. No additional configuration is required from users.