Commit-ID: 3472eaa1f12e217e2b8b0ef658ff861b2308cbbd
Gitweb: http://git.kernel.org/tip/3472eaa1f12e217e2b8b0ef658ff861b2308cbbd
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Sun, 21 Sep 2014 21:33:38 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 24 Sep 2014 14:47:03 +0200
sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()
1. read_lock(tasklist_lock) does not need to disable irqs.
2. ->mm != NULL is a common mistake, use PF_KTHREAD.
3. The second ->mm check can be simply removed.
4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) +
__task_rq_lock().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Kirill Tkhai <tkhai@xxxxxxxxx>
Cc: Mike Galbraith <umgwanakikbuti@xxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20140921193338.GA28621@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/sched/core.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0abfb7e..d65566d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7220,12 +7220,12 @@ void normalize_rt_tasks(void)
unsigned long flags;
struct rq *rq;
- read_lock_irqsave(&tasklist_lock, flags);
+ read_lock(&tasklist_lock);
for_each_process_thread(g, p) {
/*
* Only normalize user tasks:
*/
- if (!p->mm)
+ if (p->flags & PF_KTHREAD)
continue;
p->se.exec_start = 0;
@@ -7240,20 +7240,16 @@ void normalize_rt_tasks(void)
* Renice negative nice level userspace
* tasks back to 0:
*/
- if (task_nice(p) < 0 && p->mm)
+ if (task_nice(p) < 0)
set_user_nice(p, 0);
continue;
}
- raw_spin_lock(&p->pi_lock);
- rq = __task_rq_lock(p);
-
+ rq = task_rq_lock(p, &flags);
normalize_task(rq, p);
-
- __task_rq_unlock(rq);
- raw_spin_unlock(&p->pi_lock);
+ task_rq_unlock(rq, p, &flags);
}
- read_unlock_irqrestore(&tasklist_lock, flags);
+ read_unlock(&tasklist_lock);
}
#endif /* CONFIG_MAGIC_SYSRQ */
--
To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
|