sched: Move sched_class::prio_changed() into the change pattern
Move sched_class::prio_changed() into the change pattern.
And while there, extend it with sched_class::get_prio() in order to
fix the deadline sitation.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 48df1c9..5de31c3 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2143,12 +2143,6 @@ inline int task_curr(const struct task_struct *p)
return cpu_curr(task_cpu(p)) == p;
}
-void check_prio_changed(struct rq *rq, struct task_struct *p, int oldprio)
-{
- if (oldprio != p->prio || dl_task(p))
- p->sched_class->prio_changed(rq, p, oldprio);
-}
-
void wakeup_preempt(struct rq *rq, struct task_struct *p, int flags)
{
struct task_struct *donor = rq->donor;
@@ -7219,9 +7213,6 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
p->sched_class = next_class;
p->prio = prio;
}
-
- if (!(queue_flag & DEQUEUE_CLASS))
- check_prio_changed(rq, p, oldprio);
out_unlock:
/* Avoid rq from going away on us: */
preempt_disable();
@@ -10631,6 +10622,13 @@ struct sched_change_ctx *sched_change_begin(struct task_struct *p, unsigned int
.running = task_current(rq, p),
};
+ if (!(flags & DEQUEUE_CLASS)) {
+ if (p->sched_class->get_prio)
+ ctx->prio = p->sched_class->get_prio(rq, p);
+ else
+ ctx->prio = p->prio;
+ }
+
if (ctx->queued)
dequeue_task(rq, p, flags);
if (ctx->running)
@@ -10657,6 +10655,10 @@ void sched_change_end(struct sched_change_ctx *ctx)
if (ctx->running)
set_next_task(rq, p);
- if ((ctx->flags & ENQUEUE_CLASS) && p->sched_class->switched_to)
- p->sched_class->switched_to(rq, p);
+ if (ctx->flags & ENQUEUE_CLASS) {
+ if (p->sched_class->switched_to)
+ p->sched_class->switched_to(rq, p);
+ } else {
+ p->sched_class->prio_changed(rq, p, ctx->prio);
+ }
}
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index d9d5a70..3dbf036 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -3054,24 +3054,25 @@ static void switched_to_dl(struct rq *rq, struct task_struct *p)
}
}
+static u64 get_prio_dl(struct rq *rq, struct task_struct *p)
+{
+ return p->dl.deadline;
+}
+
/*
* If the scheduling parameters of a -deadline task changed,
* a push or pull operation might be needed.
*/
-static void prio_changed_dl(struct rq *rq, struct task_struct *p,
- int oldprio)
+static void prio_changed_dl(struct rq *rq, struct task_struct *p, u64 old_deadline)
{
if (!task_on_rq_queued(p))
return;
+ if (p->dl.deadline == old_deadline)
+ return;
+
#ifdef CONFIG_SMP
- /*
- * This might be too much, but unfortunately
- * we don't have the old deadline value, and
- * we can't argue if the task is increasing
- * or lowering its prio, so...
- */
- if (!rq->dl.overloaded)
+ if (dl_time_before(old_deadline, p->dl.deadline))
deadline_queue_pull_task(rq);
if (task_current_donor(rq, p)) {
@@ -3094,11 +3095,8 @@ static void prio_changed_dl(struct rq *rq, struct task_struct *p,
resched_curr(rq);
}
#else
- /*
- * We don't know if p has a earlier or later deadline, so let's blindly
- * set a (maybe not needed) rescheduling point.
- */
- resched_curr(rq);
+ if (dl_time_before(old_deadline, p->dl.deadline))
+ resched_curr(rq);
#endif
}
@@ -3135,6 +3133,7 @@ DEFINE_SCHED_CLASS(dl) = {
.task_tick = task_tick_dl,
.task_fork = task_fork_dl,
+ .get_prio = get_prio_dl,
.prio_changed = prio_changed_dl,
.switched_from = switched_from_dl,
.switched_to = switched_to_dl,
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index a6a911356..7bc4fb7 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -3654,7 +3654,7 @@ static void reweight_task_scx(struct rq *rq, struct task_struct *p,
SCX_CALL_OP_TASK(SCX_KF_REST, set_weight, p, p->scx.weight);
}
-static void prio_changed_scx(struct rq *rq, struct task_struct *p, int oldprio)
+static void prio_changed_scx(struct rq *rq, struct task_struct *p, u64 oldprio)
{
}
@@ -4496,9 +4496,6 @@ static void scx_ops_disable_workfn(struct kthread_work *work)
p->sched_class = new_class;
}
- if (!(queue_flags & DEQUEUE_CLASS))
- check_prio_changed(task_rq(p), p, p->prio);
-
scx_ops_exit_task(p);
}
scx_task_iter_stop(&sti);
@@ -5212,9 +5209,6 @@ static int scx_ops_enable(struct sched_ext_ops *ops, struct bpf_link *link)
p->scx.slice = SCX_SLICE_DFL;
p->sched_class = new_class;
}
-
- if (!(queue_flags & DEQUEUE_CLASS))
- check_prio_changed(task_rq(p), p, p->prio);
}
scx_task_iter_stop(&sti);
percpu_up_write(&scx_fork_rwsem);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 579b0ca..7cc9648 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -13074,11 +13074,14 @@ static void task_fork_fair(struct task_struct *p)
* the current task.
*/
static void
-prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
+prio_changed_fair(struct rq *rq, struct task_struct *p, u64 oldprio)
{
if (!task_on_rq_queued(p))
return;
+ if (p->prio == oldprio)
+ return;
+
if (rq->cfs.nr_running == 1)
return;
@@ -13090,8 +13093,9 @@ prio_changed_fair(struct rq *rq, struct task_struct *p, int oldprio)
if (task_current_donor(rq, p)) {
if (p->prio > oldprio)
resched_curr(rq);
- } else
+ } else {
wakeup_preempt(rq, p, 0);
+ }
}
#ifdef CONFIG_FAIR_GROUP_SCHED
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 53c21e8..e3d2dab 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -500,8 +500,11 @@ static void switching_to_idle(struct rq *rq, struct task_struct *p)
}
static void
-prio_changed_idle(struct rq *rq, struct task_struct *p, int oldprio)
+prio_changed_idle(struct rq *rq, struct task_struct *p, u64 oldprio)
{
+ if (p->prio == oldprio)
+ return;
+
BUG();
}
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 01480484..ea9a1da 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2482,11 +2482,14 @@ static void switched_to_rt(struct rq *rq, struct task_struct *p)
* us to initiate a push or pull.
*/
static void
-prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
+prio_changed_rt(struct rq *rq, struct task_struct *p, u64 oldprio)
{
if (!task_on_rq_queued(p))
return;
+ if (p->prio == oldprio)
+ return;
+
if (task_current_donor(rq, p)) {
#ifdef CONFIG_SMP
/*
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index e54b77b..0aa6da2 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2424,8 +2424,10 @@ struct sched_class {
void (*reweight_task)(struct rq *this_rq, struct task_struct *task,
const struct load_weight *lw);
+
+ u64 (*get_prio) (struct rq *this_rq, struct task_struct *task);
void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
- int oldprio);
+ u64 oldprio);
unsigned int (*get_rr_interval)(struct rq *rq,
struct task_struct *task);
@@ -3898,8 +3900,6 @@ extern void set_load_weight(struct task_struct *p, bool update_load);
extern void enqueue_task(struct rq *rq, struct task_struct *p, int flags);
extern bool dequeue_task(struct rq *rq, struct task_struct *p, int flags);
-extern void check_prio_changed(struct rq *rq, struct task_struct *p, int oldprio);
-
#ifdef CONFIG_SMP
extern struct balance_callback *splice_balance_callbacks(struct rq *rq);
extern void balance_callbacks(struct rq *rq, struct balance_callback *head);
@@ -3917,6 +3917,7 @@ static inline void balance_callbacks(struct rq *rq, struct balance_callback *hea
#endif
struct sched_change_ctx {
+ u64 prio;
struct task_struct *p;
int flags;
bool queued;
diff --git a/kernel/sched/stop_task.c b/kernel/sched/stop_task.c
index 2c7a5f9..b3ab1dd 100644
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -82,8 +82,11 @@ static void switching_to_stop(struct rq *rq, struct task_struct *p)
}
static void
-prio_changed_stop(struct rq *rq, struct task_struct *p, int oldprio)
+prio_changed_stop(struct rq *rq, struct task_struct *p, u64 oldprio)
{
+ if (p->prio == oldprio)
+ return;
+
BUG(); /* how!?, what priority? */
}
diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c
index 8e1364a..e5c0e87 100644
--- a/kernel/sched/syscalls.c
+++ b/kernel/sched/syscalls.c
@@ -95,12 +95,6 @@ void set_user_nice(struct task_struct *p, long nice)
old_prio = p->prio;
p->prio = effective_prio(p);
}
-
- /*
- * If the task increased its priority or is running and
- * lowered its priority, then reschedule its CPU:
- */
- p->sched_class->prio_changed(rq, p, old_prio);
}
EXPORT_SYMBOL(set_user_nice);
@@ -720,9 +714,6 @@ int __sched_setscheduler(struct task_struct *p,
}
}
- if (!(queue_flags & DEQUEUE_CLASS))
- check_prio_changed(rq, p, oldprio);
-
/* Avoid rq from going away on us: */
preempt_disable();
head = splice_balance_callbacks(rq);
