Changes since v1:
- cover letter BLURB added :)
- forgotten Suggested-by Oleg field added to patch 1
- raw_smp_processor_id() returned instead of mistaken smp_processor_id()
- kbuild excess function parameter 'cpu' description warning fixed
Alexander Gordeev (2):
sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
sched/core: Get rid of 'cpu' variable in __schedule()
kernel/sched/core.c | 7 ++-----
kernel/workqueue.c | 5 ++---
kernel/workqueue_internal.h | 2 +-
3 files changed, 5 insertions(+), 9 deletions(-)
--
1.8.3.1
Given that wq_worker_sleeping() could only be called for a
CPU it is running on, we do not need passing a CPU ID as an
argument.
Suggested-by: Oleg Nesterov <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>
---
kernel/sched/core.c | 2 +-
kernel/workqueue.c | 5 ++---
kernel/workqueue_internal.h | 2 +-
3 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9503d59..4e56a4d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3257,7 +3257,7 @@ static void __sched notrace __schedule(bool preempt)
if (prev->flags & PF_WQ_WORKER) {
struct task_struct *to_wakeup;
- to_wakeup = wq_worker_sleeping(prev, cpu);
+ to_wakeup = wq_worker_sleeping(prev);
if (to_wakeup)
try_to_wake_up_local(to_wakeup);
}
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 7ff5dc7..2fa8d26 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -858,7 +858,6 @@ void wq_worker_waking_up(struct task_struct *task, int cpu)
/**
* wq_worker_sleeping - a worker is going to sleep
* @task: task going to sleep
- * @cpu: CPU in question, must be the current CPU number
*
* This function is called during schedule() when a busy worker is
* going to sleep. Worker on the same cpu can be woken up by
@@ -870,7 +869,7 @@ void wq_worker_waking_up(struct task_struct *task, int cpu)
* Return:
* Worker task on @cpu to wake up, %NULL if none.
*/
-struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
+struct task_struct *wq_worker_sleeping(struct task_struct *task)
{
struct worker *worker = kthread_data(task), *to_wakeup = NULL;
struct worker_pool *pool;
@@ -886,7 +885,7 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu)
pool = worker->pool;
/* this can only happen on the local cpu */
- if (WARN_ON_ONCE(cpu != raw_smp_processor_id() || pool->cpu != cpu))
+ if (WARN_ON_ONCE(pool->cpu != raw_smp_processor_id()))
return NULL;
/*
diff --git a/kernel/workqueue_internal.h b/kernel/workqueue_internal.h
index 4521587..8635417 100644
--- a/kernel/workqueue_internal.h
+++ b/kernel/workqueue_internal.h
@@ -69,6 +69,6 @@ static inline struct worker *current_wq_worker(void)
* sched/core.c and workqueue.c.
*/
void wq_worker_waking_up(struct task_struct *task, int cpu);
-struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu);
+struct task_struct *wq_worker_sleeping(struct task_struct *task);
#endif /* _KERNEL_WORKQUEUE_INTERNAL_H */
--
1.8.3.1
'cpu' variable is only used to acquire the current runqueue.
By using this_rq() instead, we can get rid of that variable.
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Alexander Gordeev <[email protected]>
---
kernel/sched/core.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 4e56a4d..82206f0 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3205,10 +3205,8 @@ static void __sched notrace __schedule(bool preempt)
struct task_struct *prev, *next;
unsigned long *switch_count;
struct rq *rq;
- int cpu;
- cpu = smp_processor_id();
- rq = cpu_rq(cpu);
+ rq = this_rq();
prev = rq->curr;
/*
@@ -3280,7 +3278,6 @@ static void __sched notrace __schedule(bool preempt)
trace_sched_switch(preempt, prev, next);
rq = context_switch(rq, prev, next); /* unlocks the rq */
- cpu = cpu_of(rq);
} else {
lockdep_unpin_lock(&rq->lock);
raw_spin_unlock_irq(&rq->lock);
--
1.8.3.1
On Tue, Mar 01, 2016 at 01:01:42PM +0100, Alexander Gordeev wrote:
> 'cpu' variable is only used to acquire the current runqueue.
> By using this_rq() instead, we can get rid of that variable.
Does not apply to tip/sched/core