Re: [PATCH v18 0/3] Improve proc RSS accuracy

On Fri, 27 Feb 2026 10:37:27 -0500 Mathieu Desnoyers [off-list ref] wrote:

This series introduces the hierarchical tree counter (hpcc) to increase
accuracy of approximated RSS counters exposed through proc interfaces.

With a test program hopping across CPUs doing frequent mmap/munmap
operations, the upstream implementation approximation reaches a 1GB
delta from the precise value after a few minutes, compared to a 80MB
delta with the hierarchical counter. The hierarchical counter provides a
guaranteed maximum approximation inaccuracy of 192MB on that hardware
topology.

This series is based on tag v7.0-rc1.

The main changes since v17:
- Fix patch series bissectability.
- Export GPL symbols for kunit tests.
- Improve kunit tests coverage.
- Fix kunit tests wait queue head reinit bug.
- Fix an out-of-bound on bootup on configurations where nr_cpu_ids is
  close to NR_CPUS.

Updated, thanks.

Andrew, this series targets 7.1.

Some review would be useful.  Can you think of someone we could ask to
undertake this?