From b38332be61a8a76cf77586fb769849257ff217ae Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 9 Jul 2026 12:06:11 -1000 Subject: [PATCH] sched_ext: Make scx_bpf_kick_cid() return void scx_bpf_kick_cid() returned an error code, but the value conveys nothing actionable and no caller consumes it. The kick is asynchronous, so a successful return only means it was queued. An invalid @cid is already reported through scx_error() by scx_cid_to_cpu(), and a missing scheduler leaves nothing to kick. Make scx_bpf_kick_cid() return void to match scx_bpf_kick_cpu(). The cid-form kfuncs are not in practical use yet, so the ABI change is safe. Signed-off-by: Tejun Heo Reviewed-by: Andrea Righi --- kernel/sched/ext/ext.c | 11 +++++------ tools/sched_ext/include/scx/common.bpf.h | 2 +- 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c index fedda8f9ebe3..80cc7f68a3cd 100644 --- a/kernel/sched/ext/ext.c +++ b/kernel/sched/ext/ext.c @@ -8560,10 +8560,10 @@ __bpf_kfunc void scx_bpf_kick_cpu(s32 cpu, u64 flags, const struct bpf_prog_aux * @flags: %SCX_KICK_* flags * @aux: implicit BPF argument to access bpf_prog_aux hidden from BPF progs * - * cid-addressed equivalent of scx_bpf_kick_cpu(). Return 0 on success, - * -errno otherwise. + * cid-addressed equivalent of scx_bpf_kick_cpu(). An invalid @cid aborts the + * scheduler via scx_cid_to_cpu(). */ -__bpf_kfunc s32 scx_bpf_kick_cid(s32 cid, u64 flags, const struct bpf_prog_aux *aux) +__bpf_kfunc void scx_bpf_kick_cid(s32 cid, u64 flags, const struct bpf_prog_aux *aux) { struct scx_sched *sch; s32 cpu; @@ -8571,12 +8571,11 @@ __bpf_kfunc s32 scx_bpf_kick_cid(s32 cid, u64 flags, const struct bpf_prog_aux * guard(rcu)(); sch = scx_prog_sched(aux); if (unlikely(!sch)) - return -ENODEV; + return; cpu = scx_cid_to_cpu(sch, cid); if (cpu < 0) - return cpu; + return; scx_kick_cpu(sch, cpu, flags); - return 0; } /** diff --git a/tools/sched_ext/include/scx/common.bpf.h b/tools/sched_ext/include/scx/common.bpf.h index bd51986c4c42..e7b3ba491c5e 100644 --- a/tools/sched_ext/include/scx/common.bpf.h +++ b/tools/sched_ext/include/scx/common.bpf.h @@ -104,7 +104,7 @@ void scx_bpf_events(struct scx_event_stats *events, size_t events__sz) __ksym __ s32 scx_bpf_cpu_to_cid(s32 cpu) __ksym __weak; s32 scx_bpf_cid_to_cpu(s32 cid) __ksym __weak; void scx_bpf_cid_topo(s32 cid, struct scx_cid_topo *out) __ksym __weak; -s32 scx_bpf_kick_cid(s32 cid, u64 flags) __ksym __weak; +void scx_bpf_kick_cid(s32 cid, u64 flags) __ksym __weak; s32 scx_bpf_task_cid(const struct task_struct *p) __ksym __weak; s32 scx_bpf_this_cid(void) __ksym __weak; struct task_struct *scx_bpf_cid_curr(s32 cid) __ksym __weak;