[PATCH 3/3] sched/core: update preempt_notifier_key to modern api

From: Davidlohr Bueso
Date: Sun Mar 25 2018 - 15:23:48 EST


No changes in refcount semantics -- key init is false; replace

static_key_slow_inc|dec with static_branch_inc|dec
static_key_false with static_branch_unlikely

Signed-off-by: Davidlohr Bueso <dbueso@xxxxxxx>
---
kernel/sched/core.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 757d5a251ca4..311451e58c3c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2462,17 +2462,17 @@ void wake_up_new_task(struct task_struct *p)

#ifdef CONFIG_PREEMPT_NOTIFIERS

-static struct static_key preempt_notifier_key = STATIC_KEY_INIT_FALSE;
+DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);

void preempt_notifier_inc(void)
{
- static_key_slow_inc(&preempt_notifier_key);
+ static_branch_inc(&preempt_notifier_key);
}
EXPORT_SYMBOL_GPL(preempt_notifier_inc);

void preempt_notifier_dec(void)
{
- static_key_slow_dec(&preempt_notifier_key);
+ static_branch_dec(&preempt_notifier_key);
}
EXPORT_SYMBOL_GPL(preempt_notifier_dec);

@@ -2482,7 +2482,7 @@ EXPORT_SYMBOL_GPL(preempt_notifier_dec);
*/
void preempt_notifier_register(struct preempt_notifier *notifier)
{
- if (!static_key_false(&preempt_notifier_key))
+ if (!static_branch_unlikely(&preempt_notifier_key))
WARN(1, "registering preempt_notifier while notifiers disabled\n");

hlist_add_head(&notifier->link, &current->preempt_notifiers);
@@ -2511,7 +2511,7 @@ static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)

static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
{
- if (static_key_false(&preempt_notifier_key))
+ if (static_branch_unlikely(&preempt_notifier_key))
__fire_sched_in_preempt_notifiers(curr);
}

@@ -2529,7 +2529,7 @@ static __always_inline void
fire_sched_out_preempt_notifiers(struct task_struct *curr,
struct task_struct *next)
{
- if (static_key_false(&preempt_notifier_key))
+ if (static_branch_unlikely(&preempt_notifier_key))
__fire_sched_out_preempt_notifiers(curr, next);
}

--
2.13.6