[PATCH 1/2] sched: Move __task_rq_{, un}lock() to kernel/sched/sched.h

From: Kirill Tkhai
Date: Tue Feb 17 2015 - 05:47:04 EST



Place it in sched.h, because dl_task_timer() needs it.
Also remove lockdep check, which is not fit to this
function.

Similar to idea of Josh Poimboeuf for task_rq_{,un}lock():
https://lkml.org/lkml/2015/2/9/476

Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
CC: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
---
kernel/sched/core.c | 28 ----------------------------
kernel/sched/deadline.c | 12 +++---------
kernel/sched/sched.h | 26 ++++++++++++++++++++++++++
3 files changed, 29 insertions(+), 37 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0466e61..fc12a1d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -307,28 +307,6 @@ __read_mostly int scheduler_running;
int sysctl_sched_rt_runtime = 950000;

/*
- * __task_rq_lock - lock the rq @p resides on.
- */
-static inline struct rq *__task_rq_lock(struct task_struct *p)
- __acquires(rq->lock)
-{
- struct rq *rq;
-
- lockdep_assert_held(&p->pi_lock);
-
- for (;;) {
- rq = task_rq(p);
- raw_spin_lock(&rq->lock);
- if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
- return rq;
- raw_spin_unlock(&rq->lock);
-
- while (unlikely(task_on_rq_migrating(p)))
- cpu_relax();
- }
-}
-
-/*
* task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
*/
static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
@@ -351,12 +329,6 @@ static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
}
}

-static void __task_rq_unlock(struct rq *rq)
- __releases(rq->lock)
-{
- raw_spin_unlock(&rq->lock);
-}
-
static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags)
__releases(rq->lock)
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 29ae704..e008b51 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -512,14 +512,8 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
dl_timer);
struct task_struct *p = dl_task_of(dl_se);
struct rq *rq;
-again:
- rq = task_rq(p);
- raw_spin_lock(&rq->lock);
- if (rq != task_rq(p) || task_on_rq_migrating(p)) {
- /* Task was move{d,ing}, retry */
- raw_spin_unlock(&rq->lock);
- goto again;
- }
+
+ rq = __task_rq_lock(p);

/*
* We need to take care of several possible races here:
@@ -574,7 +568,7 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
push_dl_task(rq);
#endif
unlock:
- raw_spin_unlock(&rq->lock);
+ __task_rq_unlock(rq);

return HRTIMER_NORESTART;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 0870db2..f65f57c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1020,6 +1020,32 @@ static inline int task_on_rq_migrating(struct task_struct *p)
return p->on_rq == TASK_ON_RQ_MIGRATING;
}

+/*
+ * __task_rq_lock - lock the rq @p resides on.
+ */
+static inline struct rq *__task_rq_lock(struct task_struct *p)
+ __acquires(rq->lock)
+{
+ struct rq *rq;
+
+ for (;;) {
+ rq = task_rq(p);
+ raw_spin_lock(&rq->lock);
+ if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
+ return rq;
+ raw_spin_unlock(&rq->lock);
+
+ while (unlikely(task_on_rq_migrating(p)))
+ cpu_relax();
+ }
+}
+
+static inline void __task_rq_unlock(struct rq *rq)
+ __releases(rq->lock)
+{
+ raw_spin_unlock(&rq->lock);
+}
+
#ifndef prepare_arch_switch
# define prepare_arch_switch(next) do { } while (0)
#endif



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