sched/core: Cleanup leftovers in __schedule()
cover sched/core: Cleanup leftovers in __schedule()
*** BLURB HERE ***
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 | 4 ++-- kernel/workqueue_internal.h | 2 +- 3 files changed, 5 insertions(+), 8 deletions(-)
Signature · 1 line
1.8.3.1
PATCH 1/2 sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
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.
--- kernel/sched/core.c | 2 +- kernel/workqueue.c | 4 ++-- kernel/workqueue_internal.h | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-)
kernel/sched/core.c +1 -1
@@ -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); }
kernel/workqueue.c +2 -2
@@ -870,7 +870,7 @@ 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 +886,7 @@ 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 !=smp_processor_id ()))return NULL ;/*
kernel/workqueue_internal.h +1 -1
@@ -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 */
Signature · 1 line
1.8.3.1
kbuild test robot
build botRe: [PATCH 1/2] sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
All warnings (new ones prefixed by >>):
Hi Alexander,
[auto build test WARNING on wq/for-next]
[also build test WARNING on v4.5-rc6 next-20160226]
[cannot apply to tip/sched/core]
[if your patch is applied to the wrong git tree, please drop us a note to help improving the system]
url: https://github.com/0day-ci/linux/commits/Alexander-Gordeev/sched-core-Cleanup-leftovers-in-__schedule/20160229-004522 base: https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-next reproduce: make htmldocs
All warnings (new ones prefixed by >>):
include/linux/init.h:1: warning: no structured comments found
>> kernel/workqueue.c:874: warning: Excess function parameter 'cpu' description in 'wq_worker_sleeping'
kernel/sys.c:1: warning: no structured comments found drivers/dma-buf/seqno-fence.c:1: warning: no structured comments found drivers/dma-buf/reservation.c:1: warning: no structured comments found include/linux/reservation.h:1: warning: no structured comments found include/linux/spi/spi.h:540: warning: No description found for parameter 'max_transfer_size'
vim +874 kernel/workqueue.c
0fcb78c22f Rolf Eike Beer 2006-07-30 858 /**
e22bee782b Tejun Heo 2010-06-29 859 * wq_worker_sleeping - a worker is going to sleep
e22bee782b Tejun Heo 2010-06-29 860 * @task: task going to sleep
e22bee782b Tejun Heo 2010-06-29 861 * @cpu: CPU in question, must be the current CPU number
^1da177e4c Linus Torvalds 2005-04-16 862 *
e22bee782b Tejun Heo 2010-06-29 863 * This function is called during schedule() when a busy worker is
e22bee782b Tejun Heo 2010-06-29 864 * going to sleep. Worker on the same cpu can be woken up by
e22bee782b Tejun Heo 2010-06-29 865 * returning pointer to its task.
^1da177e4c Linus Torvalds 2005-04-16 866 *
e22bee782b Tejun Heo 2010-06-29 867 * CONTEXT:
e22bee782b Tejun Heo 2010-06-29 868 * spin_lock_irq(rq->lock)
^1da177e4c Linus Torvalds 2005-04-16 869 *
d185af300f Yacine Belkadi 2013-07-31 870 * Return:
e22bee782b Tejun Heo 2010-06-29 871 * Worker task on @cpu to wake up, %NULL if none.
^1da177e4c Linus Torvalds 2005-04-16 872 */
479b9d020d Alexander Gordeev 2016-02-28 873 struct task_struct *wq_worker_sleeping(struct task_struct *task)
^1da177e4c Linus Torvalds 2005-04-16 @874 {
e22bee782b Tejun Heo 2010-06-29 875 struct worker *worker = kthread_data(task), *to_wakeup = NULL;
111c225a5f Tejun Heo 2013-01-17 876 struct worker_pool *pool;
f293ea9200 Oleg Nesterov 2007-05-09 877
111c225a5f Tejun Heo 2013-01-17 878 /*
111c225a5f Tejun Heo 2013-01-17 879 * Rescuers, which may not have all the fields set up like normal
111c225a5f Tejun Heo 2013-01-17 880 * workers, also reach here, let's not access anything before
111c225a5f Tejun Heo 2013-01-17 881 * checking NOT_RUNNING.
111c225a5f Tejun Heo 2013-01-17 882 */:::::: The code at line 874 was first introduced by commit :::::: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Linux-2.6.12-rc2
:::::: TO: Linus Torvalds <[email protected]> :::::: CC: Linus Torvalds <[email protected]>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
Re: [PATCH 1/2] sched/core: Get rid of 'cpu' argument in wq_worker_sleeping()
In reply to Alexander Gordeevkernel/workqueue.c struct task_struct *wq_worker_sleeping(struct task_struct *task, int cpu) · line 890
Quoted 13 lines · Alexander Gordeev
kernel/workqueue.c +2
-2-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 +886,7 @@ 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 !=smp_processor_id ()))return NULL ;
I think both changes are fine, but perhaps it would be better to keep raw_smp_processor_id(). Unless you did this on purpose, but then it makes sense to add a note into the changelog.
Oleg.
PATCH 2/2 sched/core: Get rid of 'cpu' variable in __schedule()
In reply to Alexander Gordeev'cpu' variable is only used to acquire the current runqueue. By using this_rq() instead, we can get rid of that variable.
--- kernel/sched/core.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)
kernel/sched/core.c +1 -4
@@ -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);
Signature · 1 line
1.8.3.1