Merge tag 'sched_ext-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext

Pull sched_ext updates from Tejun Heo:

 - scx_bpf_now() added so that BPF scheduler can access the cached
   timestamp in struct rq to avoid reading TSC multiple times within a
   locked scheduling operation.

 - Minor updates to the built-in idle CPU selection logic.

 - tool/sched_ext updates and other misc changes.

* tag 'sched_ext-for-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
  sched_ext: fix kernel-doc warnings
  sched_ext: Use time helpers in BPF schedulers
  sched_ext: Replace bpf_ktime_get_ns() to scx_bpf_now()
  sched_ext: Add time helpers for BPF schedulers
  sched_ext: Add scx_bpf_now() for BPF scheduler
  sched_ext: Implement scx_bpf_now()
  sched_ext: Relocate scx_enabled() related code
  sched_ext: Add option -l in selftest runner to list all available tests
  sched_ext: Include remaining task time slice in error state dump
  sched_ext: update scx_bpf_dsq_insert() doc for SCX_DSQ_LOCAL_ON
  sched_ext: idle: small CPU iteration refactoring
  sched_ext: idle: introduce check_builtin_idle_enabled() helper
  sched_ext: idle: clarify comments
  sched_ext: idle: use assign_cpu() to update the idle cpumask
  sched_ext: Use str_enabled_disabled() helper in update_selcpu_topology()
  sched_ext: Use sizeof_field for key_len in dsq_hash_params
  tools/sched_ext: Receive updates from SCX repo
  sched_ext: Use the NUMA scheduling domain for NUMA optimizations

Author: torvalds

Documentation/scheduler/sched-ext.rst

@@ -242,9 +242,9 @@ The following briefly shows how a waking task is scheduled and executed.
    task was inserted directly from ``ops.select_cpu()``). ``ops.enqueue()``
    can make one of the following decisions:
 
-   * Immediately insert the task into either the global or local DSQ by
-     calling ``scx_bpf_dsq_insert()`` with ``SCX_DSQ_GLOBAL`` or
-     ``SCX_DSQ_LOCAL``, respectively.
+   * Immediately insert the task into either the global or a local DSQ by
+     calling ``scx_bpf_dsq_insert()`` with one of the following options:
+     ``SCX_DSQ_GLOBAL``, ``SCX_DSQ_LOCAL``, or ``SCX_DSQ_LOCAL_ON | cpu``.
 
    * Immediately insert the task into a custom DSQ by calling
      ``scx_bpf_dsq_insert()`` with a DSQ ID which is smaller than 2^63.

kernel/sched/core.c

@@ -793,6 +793,7 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
 void update_rq_clock(struct rq *rq)
 {
 	s64 delta;
+	u64 clock;
 
 	lockdep_assert_rq_held(rq);
 
@@ -804,11 +805,14 @@ void update_rq_clock(struct rq *rq)
 		SCHED_WARN_ON(rq->clock_update_flags & RQCF_UPDATED);
 	rq->clock_update_flags |= RQCF_UPDATED;
 #endif
+	clock = sched_clock_cpu(cpu_of(rq));
+	scx_rq_clock_update(rq, clock);
 
-	delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
+	delta = clock - rq->clock;
 	if (delta < 0)
 		return;
 	rq->clock += delta;
+
 	update_rq_clock_task(rq, delta);
 }