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The task leaves the BPF > scheduler's custody when it is inserted into the destination local DSQ and > ops.dequeue() should be called at that point, just like for same-rq > dispatches. > > Add a dequeue_remote test that exercises this path. All tasks are put > into custody from ops.enqueue() and moved to the local DSQ of whichever > CPU runs ops.dispatch(), so that most moves cross CPUs. Two variants are > covered, selected by test_use_move_to_local: > > - false: tasks are queued in a BPF queue and dispatched with > scx_bpf_dsq_insert(SCX_DSQ_LOCAL_ON | cpu), going through > dispatch_to_local_dsq(), > > - true: tasks are queued on a user DSQ and consumed with > scx_bpf_dsq_move_to_local(), going through consume_remote_task(). > > The BPF scheduler tracks each task's custody state and triggers > scx_bpf_error() if: > > - ops.dequeue() is called with SCX_DEQ_CORE_SCHED_EXEC, meaning that > the custody exit was missed on insertion into the local DSQ and > deferred to set_next_task_scx(), > > - a task starts running without ops.dequeue() having been called since > its last ops.enqueue(), > > - ops.dequeue() is called for a task that isn't in custody, or > ops.enqueue() for a task that is. > > Core scheduling can legitimately pick tasks straight out of custody, so > the test is skipped if any task has a core scheduling cookie when it > starts. > > The test currently fails: > > sched_ext: dequeue_remote: dequeue_remote.bpf.c:143: 156 (runner): late ops.dequeue() with SCX_DEQ_CORE_SCHED_EXEC (enq_cpu=1 cpu=3 seq=1) > ... > ops_dequeue+0x114/0x170 > set_next_task_scx+0x104/0x1e0 > __pick_next_task+0xc7/0x180 > __schedule+0x154/0x1870 > > so don't add it to auto-test-targets yet. It will be enabled once the > underlying bug is fixed. > > Assisted-by: Claude:claude-opus-5.5 > Signed-off-by: Kuba Piecuch We can probably fold the this into PATCH 3. Thanks, -Andrea