[PATCH 0/2] sched_ext: Update demo schedulers and selftests for deprecated APIs

[Cheng-Yang Chou <yphbchou0911@gmail.com>]

Two sets of sched_ext APIs have been deprecated:

- Direct writes to p->scx.dsq_vtime in favor of 
  scx_bpf_task_set_dsq_vtime()
- ops.cpu_acquire/release() in favor of handling CPU preemption via the
  sched_switch tracepoint

This series updates the demo schedulers (scx_simple, scx_flatcg,
scx_qmap) and selftests (select_cpu_vtime, maximal) to use the new
APIs, keeping them in sync with current best practices.

Patch 1 uses bpf_ksym_exists() to fall back to direct assignment on
older kernels that don't have scx_bpf_task_set_dsq_vtime(), preserving
backwards compatibility.

Patch 2 removes the cpu_acquire/release stubs and the
__COMPAT_scx_bpf_reenqueue_local_from_anywhere() compat guard from
scx_qmap, unconditionally relying on the sched_switch TP.

Thanks,
Cheng-Yang

---

Cheng-Yang Chou (2):
  sched_ext: Update demo schedulers and selftests to use
    scx_bpf_task_set_dsq_vtime()
  sched_ext: Update demo schedulers and selftests to drop
    ops.cpu_acquire/release()

 tools/sched_ext/scx_flatcg.bpf.c              | 21 ++++++++++++++-----
 tools/sched_ext/scx_qmap.bpf.c                | 15 ++-----------
 tools/sched_ext/scx_simple.bpf.c              | 12 +++++++++--
 .../testing/selftests/sched_ext/maximal.bpf.c | 15 ++++++-------
 .../sched_ext/select_cpu_vtime.bpf.c          | 13 ++++++++++--
 5 files changed, 45 insertions(+), 31 deletions(-)

-- 
2.48.1