Hello, This set provides an implementation of queued spin lock for arena. There is no support for resiliency and recovering from deadlocks yet. These are split out from the rqspinlock patch set as independent pieces. The maximum number of supported CPUs is 1024, but this can be increased in the future if necessary. The API supports returning an error, so resiliency support can be added in the future. I don't return ETIMEDOUT when cond_break fires. First we don't clean up the queue properly when it fires, so the lock and arena is already corrupt if a deadlock condition is triggered. Second, it's not trivial to bubble up the error from xchg_tail and other helpers (like smp_cond_load_*). It is better to instead implement resilient spin lock support if we want to support proper unwinding in case of deadlock errors. Changelog: ---------- v1 -> v2 v1: https://lore.kernel.org/bpf/20250117223754.1020174-1-memxor@xxxxxxxxx * Fix definition of lock in selftest Kumar Kartikeya Dwivedi (2): selftests/bpf: Introduce qspinlock for BPF arena selftests/bpf: Add tests for qspinlock in BPF arena .../selftests/bpf/bpf_arena_qspinlock.h | 441 ++++++++++++++++++ tools/testing/selftests/bpf/bpf_atomic.h | 121 +++++ .../bpf/prog_tests/arena_spin_lock.c | 68 +++ .../selftests/bpf/progs/arena_spin_lock.c | 49 ++ 4 files changed, 679 insertions(+) create mode 100644 tools/testing/selftests/bpf/bpf_arena_qspinlock.h create mode 100644 tools/testing/selftests/bpf/bpf_atomic.h create mode 100644 tools/testing/selftests/bpf/prog_tests/arena_spin_lock.c create mode 100644 tools/testing/selftests/bpf/progs/arena_spin_lock.c base-commit: 01f3ce5328c405179b2c69ea047c423dad2bfa6d -- 2.43.5
