From: Oleg Nesterov <oleg@tv-sign.ru>
To: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org
Subject: [PATCH] do_sched_setscheduler: don't take tasklist_lock
Date: Sun, 13 Aug 2006 21:03:40 +0400 [thread overview]
Message-ID: <20060813170340.GA1913@oleg> (raw)
We don't need to take tasklist_lock or disable irqs for
find_task_by_pid() + get_task_struct(). Use RCU locks
instead.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 2.6.18-rc3/kernel/sched.c~1_dss 2006-07-16 01:53:08.000000000 +0400
+++ 2.6.18-rc3/kernel/sched.c 2006-08-13 20:19:02.000000000 +0400
@@ -4156,14 +4156,15 @@ do_sched_setscheduler(pid_t pid, int pol
return -EINVAL;
if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
return -EFAULT;
- read_lock_irq(&tasklist_lock);
+
+ rcu_read_lock();
p = find_process_by_pid(pid);
- if (!p) {
- read_unlock_irq(&tasklist_lock);
+ if (p)
+ get_task_struct(p);
+ rcu_read_unlock();
+ if (!p)
return -ESRCH;
- }
- get_task_struct(p);
- read_unlock_irq(&tasklist_lock);
+
retval = sched_setscheduler(p, policy, &lparam);
put_task_struct(p);
next reply other threads:[~2006-08-13 12:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-13 17:03 Oleg Nesterov [this message]
2006-08-13 17:21 ` [PATCH] do_sched_setscheduler: don't take tasklist_lock Oleg Nesterov
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