selftests/sched_ext: Add a test for ops.dequeue() on remote local DSQ moves

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Add a dequeue_remote test that makes moves of tasks in the BPF
scheduler's custody to another CPU's local DSQ the common case, both via
SCX_DSQ_LOCAL_ON dispatch and via scx_bpf_dsq_move_to_local(). The BPF
scheduler tracks each task's custody state and triggers scx_bpf_error()
if a custody period doesn't end with exactly one ops.dequeue() before
the task runs, or if it ends with an SCX_DEQ_CORE_SCHED_EXEC dequeue of
a task without a core cookie.

Without the previous patch, the test fails with:

  sched_ext: dequeue_remote: dequeue_remote.bpf.c:141: 15 (rcu_preempt): late ops.dequeue() with SCX_DEQ_CORE_SCHED_EXEC (enq_cpu=3 cpu=2 seq=1)
     ...
     ops_dequeue+0x114/0x170
     set_next_task_scx+0x104/0x1e0
     __pick_next_task+0xc7/0x180
     __schedule+0x154/0x1870

Reviewed-by: Andrea Righi <arighi@nvidia.com>
Assisted-by: Claude:claude-opus-5.5
Signed-off-by: Kuba Piecuch <jpiecuch@google.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

...

This commit is contained in:

Kuba Piecuch 2026-09-30 14:23:59 +00:00 • committed by Tejun Heo

parent af701b8d32

commit cc07fae1de

3 changed files with 475 additions and 0 deletions

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1

tools/testing/selftests/sched_ext/Makefile

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270

tools/testing/selftests/sched_ext/dequeue_remote.bpf.c

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204

tools/testing/selftests/sched_ext/dequeue_remote.c

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