sched,dl: Remove return value from pull_dl_task()

In order to be able to use pull_dl_task() from a callback, we need to
do away with the return value.

Since the return value indicates if we should reschedule, do this
inside the function. Since not all callers currently do this, this can
increase the number of reschedules due rt balancing.

Too many reschedules is not a correctness issues, too few are.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: ktkhai@parallels.com
Cc: rostedt@goodmis.org
Cc: juri.lelli@gmail.com
Cc: pang.xunlei@linaro.org
Cc: oleg@redhat.com
Cc: wanpeng.li@linux.intel.com
Cc: umgwanakikbuti@gmail.com
Link: http://lkml.kernel.org/r/20150611124742.859398977@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Peter Zijlstra 2015-06-11 14:46:42 +02:00 committed by Thomas Gleixner
parent fd7a4bed18
commit 0ea60c2054

View File

@ -298,9 +298,8 @@ static inline bool need_pull_dl_task(struct rq *rq, struct task_struct *prev)
return false; return false;
} }
static inline int pull_dl_task(struct rq *rq) static inline void pull_dl_task(struct rq *rq)
{ {
return 0;
} }
static inline void queue_push_tasks(struct rq *rq) static inline void queue_push_tasks(struct rq *rq)
@ -1041,7 +1040,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
resched_curr(rq); resched_curr(rq);
} }
static int pull_dl_task(struct rq *this_rq); static void pull_dl_task(struct rq *this_rq);
#endif /* CONFIG_SMP */ #endif /* CONFIG_SMP */
@ -1472,15 +1471,16 @@ static void push_dl_tasks(struct rq *rq)
; ;
} }
static int pull_dl_task(struct rq *this_rq) static void pull_dl_task(struct rq *this_rq)
{ {
int this_cpu = this_rq->cpu, ret = 0, cpu; int this_cpu = this_rq->cpu, cpu;
struct task_struct *p; struct task_struct *p;
bool resched = false;
struct rq *src_rq; struct rq *src_rq;
u64 dmin = LONG_MAX; u64 dmin = LONG_MAX;
if (likely(!dl_overloaded(this_rq))) if (likely(!dl_overloaded(this_rq)))
return 0; return;
/* /*
* Match the barrier from dl_set_overloaded; this guarantees that if we * Match the barrier from dl_set_overloaded; this guarantees that if we
@ -1535,7 +1535,7 @@ static int pull_dl_task(struct rq *this_rq)
src_rq->curr->dl.deadline)) src_rq->curr->dl.deadline))
goto skip; goto skip;
ret = 1; resched = true;
deactivate_task(src_rq, p, 0); deactivate_task(src_rq, p, 0);
set_task_cpu(p, this_cpu); set_task_cpu(p, this_cpu);
@ -1548,7 +1548,8 @@ skip:
double_unlock_balance(this_rq, src_rq); double_unlock_balance(this_rq, src_rq);
} }
return ret; if (resched)
resched_curr(this_rq);
} }
/* /*
@ -1704,8 +1705,7 @@ static void switched_from_dl(struct rq *rq, struct task_struct *p)
if (!task_on_rq_queued(p) || rq->dl.dl_nr_running) if (!task_on_rq_queued(p) || rq->dl.dl_nr_running)
return; return;
if (pull_dl_task(rq)) pull_dl_task(rq);
resched_curr(rq);
} }
/* /*