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Introduce set_task_slice() and route the existing direct writes > through it. No functional change - the helper only assigns p->scx.slice. > > Signed-off-by: Tejun Heo > --- > kernel/sched/ext/ext.c | 32 +++++++++++++++++++------------- > 1 file changed, 19 insertions(+), 13 deletions(-) > > diff --git a/kernel/sched/ext/ext.c b/kernel/sched/ext/ext.c > index 9fa4cfbc75c8..ff997ba881b0 100644 > --- a/kernel/sched/ext/ext.c > +++ b/kernel/sched/ext/ext.c > @@ -1153,6 +1153,12 @@ static void touch_core_sched_dispatch(struct rq *rq, struct task_struct *p) > #endif > } > > +/* set @p's slice, every write to p->scx.slice goes through here */ nit: maybe we should say all "BPF-triggered writes to p->scx.slice", or something along these lines, just for clarity, update_curr_scx() still decrements curr->scx.slice directly. Thanks, -Andrea > +static void set_task_slice(struct task_struct *p, u64 slice) > +{ > + p->scx.slice = slice; > +} > + > static void update_curr_scx(struct rq *rq) > { > struct task_struct *curr = rq->curr; > @@ -1238,7 +1244,7 @@ static void dsq_dec_nr(struct scx_dispatch_q *dsq, struct task_struct *p) > > static void refill_task_slice_dfl(struct scx_sched *sch, struct task_struct *p) > { > - p->scx.slice = READ_ONCE(sch->slice_dfl); > + set_task_slice(p, READ_ONCE(sch->slice_dfl)); > __scx_add_event(sch, SCX_EV_REFILL_SLICE_DFL, 1); > } > > @@ -1333,7 +1339,7 @@ static void rq_owned_post_enq(struct scx_sched *sch, struct rq *rq, > > if ((enq_flags & SCX_ENQ_PREEMPT) && p != rq->curr && > rq->curr->sched_class == &ext_sched_class) { > - rq->curr->scx.slice = 0; > + set_task_slice(rq->curr, 0); > resched_curr(rq); > } > } > @@ -2039,7 +2045,7 @@ static void yield_task_scx(struct rq *rq) > if (SCX_HAS_OP(sch, yield)) > SCX_CALL_OP_2TASKS_RET(sch, yield, rq, p, NULL); > else > - p->scx.slice = 0; > + set_task_slice(p, 0); > } > > static bool yield_to_task_scx(struct rq *rq, struct task_struct *to) > @@ -3273,7 +3279,7 @@ static void task_tick_scx(struct rq *rq, struct task_struct *curr, int queued) > * we can't trust the slice management or ops.core_sched_before(). > */ > if (scx_bypassing(sch, cpu_of(rq))) { > - curr->scx.slice = 0; > + set_task_slice(curr, 0); > touch_core_sched(rq, curr); > } else if (SCX_HAS_OP(sch, tick)) { > SCX_CALL_OP_TASK(sch, tick, rq, curr); > @@ -3412,7 +3418,7 @@ static void scx_disable_task(struct scx_sched *sch, struct task_struct *p) > * control, after ops.disable() has observed their final values. > */ > p->scx.dsq_vtime = 0; > - p->scx.slice = 0; > + set_task_slice(p, 0); > > /* > * Verify the task is not in BPF scheduler's custody. If flag > @@ -7033,7 +7039,7 @@ static void scx_root_enable_workfn(struct kthread_work *work) > queue_flags |= DEQUEUE_CLASS; > > scoped_guard (sched_change, p, queue_flags) { > - p->scx.slice = READ_ONCE(sch->slice_dfl); > + set_task_slice(p, READ_ONCE(sch->slice_dfl)); > p->sched_class = new_class; > } > } > @@ -7671,7 +7677,7 @@ static bool kick_one_cpu(s32 cpu, struct scx_sched_pcpu *pcpu, struct rq *this_r > !sched_class_above(cur_class, &ext_sched_class)) { > if (cpumask_test_cpu(cpu, pcpu->cpus_to_preempt)) { > if (cur_class == &ext_sched_class) > - rq->curr->scx.slice = 0; > + set_task_slice(rq->curr, 0); > cpumask_clear_cpu(cpu, pcpu->cpus_to_preempt); > } > > @@ -8021,9 +8027,9 @@ __bpf_kfunc bool scx_bpf_dsq_insert___v2(struct task_struct *p, u64 dsq_id, > return false; > > if (slice) > - p->scx.slice = slice; > + set_task_slice(p, slice); > else > - p->scx.slice = p->scx.slice ?: 1; > + set_task_slice(p, p->scx.slice ?: 1); > > scx_dsq_insert_commit(sch, p, dsq_id, enq_flags); > > @@ -8047,9 +8053,9 @@ static bool scx_dsq_insert_vtime(struct scx_sched *sch, struct task_struct *p, > return false; > > if (slice) > - p->scx.slice = slice; > + set_task_slice(p, slice); > else > - p->scx.slice = p->scx.slice ?: 1; > + set_task_slice(p, p->scx.slice ?: 1); > > p->scx.dsq_vtime = vtime; > > @@ -8233,7 +8239,7 @@ static bool scx_dsq_move(struct bpf_iter_scx_dsq_kern *kit, > if (kit->cursor.flags & __SCX_DSQ_ITER_HAS_VTIME) > p->scx.dsq_vtime = kit->vtime; > if (kit->cursor.flags & __SCX_DSQ_ITER_HAS_SLICE) > - p->scx.slice = kit->slice; > + set_task_slice(p, kit->slice); > > /* execute move */ > locked_rq = move_task_between_dsqs(sch, p, enq_flags, src_dsq, dst_dsq); > @@ -8628,7 +8634,7 @@ __bpf_kfunc bool scx_bpf_task_set_slice(struct task_struct *p, u64 slice, > if (unlikely(!sch || !scx_task_on_sched(sch, p))) > return false; > > - p->scx.slice = slice; > + set_task_slice(p, slice); > return true; > } > > -- > 2.54.0 >