sched_ext: Add select_cpu kfuncs to scx_kfunc_ids_unlocked

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select_cpu_from_kfunc() has an extra scx_kf_allowed_if_unlocked() branch
that accepts calls from unlocked contexts and takes task_rq_lock() itself
- a "callable from unlocked" property encoded in the kfunc body rather
than in set membership. That's fine while the runtime check is the
authoritative gate, but the upcoming verifier-time filter uses set
membership as the source of truth and needs it to reflect every context
the kfunc may be called from.

Add the three select_cpu kfuncs to scx_kfunc_ids_unlocked so their full
set of callable contexts is captured by set membership. This follows the
existing dual-set convention used by scx_bpf_dsq_move{,_vtime} and
scx_bpf_dsq_move_set_{slice,vtime}, which are members of both
scx_kfunc_ids_dispatch and scx_kfunc_ids_unlocked.

While at it, add brief comments on each duplicate BTF_ID_FLAGS block
(including the pre-existing dsq_move ones) explaining the dual
membership.

No runtime behavior change: the runtime check in select_cpu_from_kfunc()
remains the authoritative gate until it is removed along with the rest
of the scx_kf_mask enforcement in a follow-up.

v2: Clarify dispatch-set comment to name scx_bpf_dsq_move*() explicitly so it
    doesn't appear to cover scx_bpf_sub_dispatch() (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

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This commit is contained in:

Tejun Heo 2026-04-10 07:54:06 -10:00

parent 9b5501d3c9

commit a37e134317

2 changed files with 10 additions and 0 deletions

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6

kernel/sched/ext.c

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4

kernel/sched/ext_idle.c

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