refactor(memtrack): rename track-rmap toggle to track-physical

[not-matthias]

What

Renames the memtrack physical-memory tracking toggle so it names the capability rather than the underlying mechanism:

• Env var: CODSPEED_MEMTRACK_TRACK_RMAP -> CODSPEED_MEMTRACK_TRACK_PHYSICAL
• Field: TrackerOptions.rmap -> TrackerOptions.physical

Physical (resident) memory is reconstructed from the folio rmap fentry hooks, so physical describes the intent while the internal rmap mechanism layer (RmapSupport, MemtrackBpf::new_with_rmap, for_each_rmap_*, the BPF C) keeps its accurate name.

Behavior

Unchanged. Tracking stays opt-in (enable with =1); the builder default remains false. The full folio rmap hook set only exists on newer kernels, and RmapSupport::detect() still gates what actually attaches per kernel — so the default is not flipped to on.

Notes

• Only the env-var/field names change; callers and the rmap_only_options() test helper are updated accordingly.
• cargo check --tests -p memtrack passes (crate + test targets compile). The privileged rss/c integration tests are GITHUB_ACTIONS-gated and skipped locally, so they were not executed here.

Closes COD-3468

[greptile-apps]

Greptile Summary

The PR renames memtrack’s opt-in physical-memory tracking field and environment variable while retaining the existing rmap-based implementation and default-off behavior.

• Renames TrackerOptions.rmap to TrackerOptions.physical.
• Replaces CODSPEED_MEMTRACK_TRACK_RMAP with CODSPEED_MEMTRACK_TRACK_PHYSICAL.
• Updates the rmap-focused test helper to use the renamed builder option.

Confidence Score: 5/5

The PR appears safe to merge with no concrete regressions identified.

The renamed option remains default-off, is passed unchanged into the existing rmap implementation, and has no stale consumers in the primary or related repositories.

Important Files Changed

Filename	Overview
crates/memtrack/src/ebpf/tracker.rs	Consistently renames the public option and environment-variable plumbing while preserving defaults and BPF attachment behavior.
crates/memtrack/tests/shared.rs	Updates the physical-memory test helper to use the renamed builder setter.

_{Reviews (1): Last reviewed commit: "refactor(memtrack): rename track-rmap to..." | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

Using the Walltime instrument on standard Hosted Runners will lead to inconsistent data.

For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 17 untouched benchmarks

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_{Comparing cod-3468-convert-track-rmap-toggle-into-physical-memory-toggle (15002cf) with main (6ecb3c0)}