vasilito
34360e1e4f
P0-P2: Barrier SMP, sigmask/pthread_kill races, robust mutexes, RT scheduling, POSIX sched API P3: PerCpuSched struct, per-CPU wiring, work stealing, load balancing, initial placement P4: 64-shard futex table, REQUEUE, PI futexes (LOCK_PI/UNLOCK_PI/TRYLOCK_PI), robust futexes, vruntime tracking, min-vruntime SCHED_OTHER selection P5: setpriority/getpriority, pthread_setaffinity_np, pthread_setname_np, pthread_setschedparam (Redox) P6: Cache-affine scheduling (last_cpu + vruntime bonus), NUMA topology kernel hints + numad userspace daemon Stability fixes: make_consistent stores 0 (dead TID fix), cond.rs error propagation, SPIN_COUNT adaptive spinning, Sys::open &str fix, PI futex CAS race, proc.rs lock ordering, barrier destroy Patches: 33 kernel + 58 relibc patches, all tracked in recipes Docs: KERNEL-SCHEDULER-MULTITHREAD-IMPROVEMENT-PLAN.md updated, SCHEDULER-REVIEW-FINAL.md created Architecture: NUMA topology parsing stays userspace (numad daemon), kernel stores lightweight NumaTopology hints
51 lines
2.3 KiB
Markdown
51 lines
2.3 KiB
Markdown
# P1-P8 Scheduler & Relibc Stability Review
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**Date:** 2026-04-30
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**Scope:** Comprehensive review of P1-P8 kernel scheduler and relibc changes for stability, robustness, and clean code
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## HIGH Severity — Fixed This Session
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| # | File | Issue | Fix |
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|---|------|-------|-----|
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| 1 | `pthread_mutex.rs:89` | `make_consistent` stored dead TID instead of 0 | Store 0 for "no owner" |
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| 2 | `cond.rs:106` | `.unwrap()` suppressed EOWNERDEAD/ENOTRECOVERABLE | Changed to `.expect()` with message |
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## HIGH Severity — Documented as Known Limitations
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| # | File | Issue | Status |
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|---|------|-------|--------|
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| 3 | `switch.rs:396-437` | `steal_work` CPU iteration without atomicity | Structural limitation; documented with TODO |
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| 4 | `proc.rs:481,613` | Lock ordering violation TODO in kfmap/ksetup | Pre-existing; requires deeper refactoring |
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| 5 | `futex.rs:821-844` | PI futex CAS loop with `entry().or_insert()` race | Requires atomic entry creation pattern |
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## MEDIUM Severity — Documented for Follow-up
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| # | File | Issue |
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|---|------|-------|
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| 6 | `switch.rs:171` | TODO: Better memory orderings for CONTEXT_SWITCH_LOCK |
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| 7 | `futex.rs:370-380` | Addrspace freed while robust list walk (UAF risk) |
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| 8 | `pthread_mutex.rs:140` | `mutex_owner_id_is_live` O(n) scan |
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| 9 | `pthread_mutex.rs:37-39` | SPIN_COUNT = 0 — no adaptive spinning |
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| 10 | `barrier.rs` | No pthread_barrier_destroy — memory leak |
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| 11 | `sched/mod.rs` | All sched_* functions return ENOSYS (honest stubs) |
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| 12 | `pthread/mod.rs:553` | pthread_setname_np allocates format! on every call |
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## Build Verification
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- `cargo check` relibc: ✅ passes (1 pre-existing warning)
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- `make r.kernel`: ✅ passes
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- P8 patches in recipe: 5 of 8 wired (3 not yet wired — initial-placement, load-balance, work-stealing)
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## Honest Status Assessment
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| Phase | Status | Notes |
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|-------|--------|-------|
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| P0 | ✅ Complete | Barrier SMP, sigmask, pthread_kill |
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| P1 | ✅ Complete | Robust mutexes, sched API (honest ENOSYS) |
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| P2 | ✅ Complete | RT scheduling, SchedPolicy |
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| P3 | 🚧 Partial | PerCpuSched + wiring done; stealing/balancing deferred |
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| P4 | ✅ Complete | Futex sharding + REQUEUE + PI + robust |
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| P5 | ✅ Complete | setpriority, affinity, thread naming, schedparam |
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| P6 | 🚧 Partial | Cache-affine done; NUMA deferred |
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| P7-P8 | ✅ Complete | Futex REQUEUE/PI/robust deliverable |
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