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sched_ext: Always use SMP versions in kernel/sched/ext.c

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Simplify the scheduler by making formerly SMP-only primitives and data
structures unconditional.

tj: Updated subject for clarity.

Signed-off-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
This commit is contained in:
Cheng-Yang Chou 2025-06-11 21:54:01 +08:00 committed by Tejun Heo
parent 9ec5e0be0e
commit 165af41516
1 changed files with 1 additions and 25 deletions
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26
kernel/sched/ext.c
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@ -1778,12 +1778,10 @@ static void run_deferred(struct rq *rq)
process_ddsp_deferred_locals(rq);
}
#ifdef CONFIG_SMP
static void deferred_bal_cb_workfn(struct rq *rq)
{
run_deferred(rq);
}
#endif
static void deferred_irq_workfn(struct irq_work *irq_work)
{
@ -1806,7 +1804,6 @@ static void schedule_deferred(struct rq *rq)
{
lockdep_assert_rq_held(rq);
#ifdef CONFIG_SMP
/*
* If in the middle of waking up a task, task_woken_scx() will be called
* afterwards which will then run the deferred actions, no need to
@ -1824,7 +1821,7 @@ static void schedule_deferred(struct rq *rq)
deferred_bal_cb_workfn);
return;
}
#endif
/*
* No scheduler hooks available. Queue an irq work. They are executed on
* IRQ re-enable which may take a bit longer than the scheduler hooks.
@ -2528,7 +2525,6 @@ static void move_local_task_to_local_dsq(struct task_struct *p, u64 enq_flags,
p->scx.dsq = dst_dsq;
}
#ifdef CONFIG_SMP
/**
* move_remote_task_to_local_dsq - Move a task from a foreign rq to a local DSQ
* @p: task to move
@ -2695,11 +2691,6 @@ static bool consume_remote_task(struct rq *this_rq, struct task_struct *p,
return false;
}
}
#else /* CONFIG_SMP */
static inline void move_remote_task_to_local_dsq(struct task_struct *p, u64 enq_flags, struct rq *src_rq, struct rq *dst_rq) { WARN_ON_ONCE(1); }
static inline bool task_can_run_on_remote_rq(struct scx_sched *sch, struct task_struct *p, struct rq *rq, bool enforce) { return false; }
static inline bool consume_remote_task(struct rq *this_rq, struct task_struct *p, struct scx_dispatch_q *dsq, struct rq *task_rq) { return false; }
#endif /* CONFIG_SMP */
/**
* move_task_between_dsqs() - Move a task from one DSQ to another
@ -2872,9 +2863,7 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
{
struct rq *src_rq = task_rq(p);
struct rq *dst_rq = container_of(dst_dsq, struct rq, scx.local_dsq);
#ifdef CONFIG_SMP
struct rq *locked_rq = rq;
#endif
/*
* We're synchronized against dequeue through DISPATCHING. As @p can't
@ -2888,7 +2877,6 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
return;
}
#ifdef CONFIG_SMP
if (src_rq != dst_rq &&
unlikely(!task_can_run_on_remote_rq(sch, p, dst_rq, true))) {
dispatch_enqueue(sch, find_global_dsq(p), p,
@ -2948,9 +2936,6 @@ static void dispatch_to_local_dsq(struct scx_sched *sch, struct rq *rq,
raw_spin_rq_unlock(locked_rq);
raw_spin_rq_lock(rq);
}
#else /* CONFIG_SMP */
BUG(); /* control can not reach here on UP */
#endif /* CONFIG_SMP */
}
/**
@ -3274,10 +3259,8 @@ static void set_next_task_scx(struct rq *rq, struct task_struct *p, bool first)
static enum scx_cpu_preempt_reason
preempt_reason_from_class(const struct sched_class *class)
{
#ifdef CONFIG_SMP
if (class == &stop_sched_class)
return SCX_CPU_PREEMPT_STOP;
#endif
if (class == &dl_sched_class)
return SCX_CPU_PREEMPT_DL;
if (class == &rt_sched_class)
@ -3290,14 +3273,12 @@ static void switch_class(struct rq *rq, struct task_struct *next)
struct scx_sched *sch = scx_root;
const struct sched_class *next_class = next->sched_class;
#ifdef CONFIG_SMP
/*
* Pairs with the smp_load_acquire() issued by a CPU in
* kick_cpus_irq_workfn() who is waiting for this CPU to perform a
* resched.
*/
smp_store_release(&rq->scx.pnt_seq, rq->scx.pnt_seq + 1);
#endif
if (!(sch->ops.flags & SCX_OPS_HAS_CPU_PREEMPT))
return;
@ -3494,8 +3475,6 @@ bool scx_prio_less(const struct task_struct *a, const struct task_struct *b,
}
#endif /* CONFIG_SCHED_CORE */
#ifdef CONFIG_SMP
static int select_task_rq_scx(struct task_struct *p, int prev_cpu, int wake_flags)
{
struct scx_sched *sch = scx_root;
@ -3625,7 +3604,6 @@ static void rq_offline_scx(struct rq *rq)
rq->scx.flags &= ~SCX_RQ_ONLINE;
}
#endif /* CONFIG_SMP */
static bool check_rq_for_timeouts(struct rq *rq)
{
@ -4285,14 +4263,12 @@ DEFINE_SCHED_CLASS(ext) = {
.put_prev_task = put_prev_task_scx,
.set_next_task = set_next_task_scx,
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_scx,
.task_woken = task_woken_scx,
.set_cpus_allowed = set_cpus_allowed_scx,
.rq_online = rq_online_scx,
.rq_offline = rq_offline_scx,
#endif
.task_tick = task_tick_scx,