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authorOleg Nesterov <oleg@redhat.com>2014-09-21 21:33:38 +0200
committerIngo Molnar <mingo@kernel.org>2014-09-24 14:47:03 +0200
commit3472eaa1f12e217e2b8b0ef658ff861b2308cbbd (patch)
treec231d968cc0a6a696ae8f3e008f979899bf52b45 /kernel
parent8651c65844e93af44554272b7e0d2b142837b244 (diff)
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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@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/core.c16
1 files changed, 6 insertions, 10 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0abfb7ec9e62..d65566d07fcf 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 */