Change the function signature of sched_class::dequeue_task() to return
a boolean, allowing future patches to 'fail' dequeue.
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
---
kernel/sched/core.c | 7 +++++--
kernel/sched/deadline.c | 4 +++-
kernel/sched/fair.c | 4 +++-
kernel/sched/idle.c | 3 ++-
kernel/sched/rt.c | 4 +++-
kernel/sched/sched.h | 2 +-
kernel/sched/stop_task.c | 3 ++-
7 files changed, 19 insertions(+), 8 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2119,7 +2119,10 @@ static inline void enqueue_task(struct r
sched_core_enqueue(rq, p);
}
-static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags)
+/*
+ * Must only return false when DEQUEUE_SLEEP.
+ */
+static inline bool dequeue_task(struct rq *rq, struct task_struct *p, int flags)
{
if (sched_core_enabled(rq))
sched_core_dequeue(rq, p, flags);
@@ -2133,7 +2136,7 @@ static inline void dequeue_task(struct r
}
uclamp_rq_dec(rq, p);
- p->sched_class->dequeue_task(rq, p, flags);
+ return p->sched_class->dequeue_task(rq, p, flags);
}
void activate_task(struct rq *rq, struct task_struct *p, int flags)
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -1842,7 +1842,7 @@ static void enqueue_task_dl(struct rq *r
enqueue_pushable_dl_task(rq, p);
}
-static void dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
+static bool dequeue_task_dl(struct rq *rq, struct task_struct *p, int flags)
{
update_curr_dl(rq);
@@ -1852,6 +1852,8 @@ static void dequeue_task_dl(struct rq *r
dequeue_dl_entity(&p->dl, flags);
if (!p->dl.dl_throttled && !dl_server(&p->dl))
dequeue_pushable_dl_task(rq, p);
+
+ return true;
}
/*
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6828,7 +6828,7 @@ static void set_next_buddy(struct sched_
* decreased. We remove the task from the rbtree and
* update the fair scheduling stats:
*/
-static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
+static bool dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
{
struct cfs_rq *cfs_rq;
struct sched_entity *se = &p->se;
@@ -6896,6 +6896,8 @@ static void dequeue_task_fair(struct rq
dequeue_throttle:
util_est_update(&rq->cfs, p, task_sleep);
hrtick_update(rq);
+
+ return true;
}
#ifdef CONFIG_SMP
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -486,13 +486,14 @@ struct task_struct *pick_next_task_idle(
* It is not legal to sleep in the idle task - print a warning
* message if some code attempts to do it:
*/
-static void
+static bool
dequeue_task_idle(struct rq *rq, struct task_struct *p, int flags)
{
raw_spin_rq_unlock_irq(rq);
printk(KERN_ERR "bad: scheduling from the idle thread!\n");
dump_stack();
raw_spin_rq_lock_irq(rq);
+ return true;
}
/*
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -1493,7 +1493,7 @@ enqueue_task_rt(struct rq *rq, struct ta
enqueue_pushable_task(rq, p);
}
-static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
+static bool dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
@@ -1501,6 +1501,8 @@ static void dequeue_task_rt(struct rq *r
dequeue_rt_entity(rt_se, flags);
dequeue_pushable_task(rq, p);
+
+ return true;
}
/*
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2278,7 +2278,7 @@ struct sched_class {
#endif
void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
- void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
+ bool (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
void (*yield_task) (struct rq *rq);
bool (*yield_to_task)(struct rq *rq, struct task_struct *p);
--- a/kernel/sched/stop_task.c
+++ b/kernel/sched/stop_task.c
@@ -57,10 +57,11 @@ enqueue_task_stop(struct rq *rq, struct
add_nr_running(rq, 1);
}
-static void
+static bool
dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
sub_nr_running(rq, 1);
+ return true;
}
static void yield_task_stop(struct rq *rq)