From: Oleg Nesterov <oleg@redhat.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Chris Mason <chris.mason@oracle.com>,
Frank Rowand <frank.rowand@am.sony.com>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Mike Galbraith <efault@gmx.de>, Paul Turner <pjt@google.com>,
Jens Axboe <axboe@kernel.dk>, Yong Zhang <yong.zhang0@gmail.com>,
linux-kernel@vger.kernel.org
Subject: Re: [RFC][PATCH 11/18] sched: Add p->pi_lock to task_rq_lock()
Date: Wed, 5 Jan 2011 19:46:44 +0100 [thread overview]
Message-ID: <20110105184644.GA28306@redhat.com> (raw)
In-Reply-To: <20110104150102.862431889@chello.nl>
On 01/04, Peter Zijlstra wrote:
>
> This makes task_rq_lock() acquire both locks, and have
> __task_rq_lock() validate that p->pi_lock is held.
... and kills task_is_waking(), good ;)
So TASK_WAKING is only means "do not try to wakeup", this greatly
simplifies things.
One purely cosmetic nit,
> @@ -4902,8 +4898,7 @@ static int __sched_setscheduler(struct t
>
> check_class_changed(rq, p, prev_class, oldprio, running);
> }
> - __task_rq_unlock(rq);
> - raw_spin_unlock_irqrestore(&p->pi_lock, flags);
> + task_rq_unlock(rq, p, &flags);
__sched_setscheduler() has a couple more instances of
__task_rq_unlock(rq);
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
return EXXX;
above.
> @@ -5691,8 +5685,7 @@ int set_cpus_allowed_ptr(struct task_str
> return 0;
> }
> out:
> - __task_rq_unlock(rq);
> - raw_spin_unlock_irqrestore(&p->pi_lock, flags);
> + task_rq_unlock(rq, p, &flags);
the same.
Hmm, and normalize_rt_tasks(), it could just do task_rq_lock/task_rq_unlock.
And why it does read_lock_irqsave(tasklist), btw? _irqsave looks unneeded.
Oleg.
next prev parent reply other threads:[~2011-01-05 18:54 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-04 14:59 [RFC][PATCH 00/18] sched: Reduce runqueue lock contention -v4 Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 01/18] sched: Always provide p->on_cpu Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 02/18] mutex: Use p->on_cpu for the adaptive spin Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 03/18] sched: Change the ttwu success details Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 04/18] sched: Clean up ttwu stats Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 05/18] sched: Provide p->on_rq Peter Zijlstra
2011-01-05 8:13 ` Yong Zhang
2011-01-05 9:53 ` Peter Zijlstra
2011-01-29 0:10 ` Frank Rowand
2011-01-04 14:59 ` [RFC][PATCH 06/18] sched: Serialize p->cpus_allowed and ttwu() using p->pi_lock Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 07/18] sched: Drop the rq argument to sched_class::select_task_rq() Peter Zijlstra
2011-01-06 13:57 ` Peter Zijlstra
2011-01-06 14:23 ` Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 08/18] sched: Remove rq argument to sched_class::task_waking() Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 09/18] sched: Delay task_contributes_to_load() Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 10/18] sched: Also serialize ttwu_local() with p->pi_lock Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 11/18] sched: Add p->pi_lock to task_rq_lock() Peter Zijlstra
2011-01-05 18:46 ` Oleg Nesterov [this message]
2011-01-05 19:33 ` Peter Zijlstra
2011-01-29 0:21 ` Frank Rowand
2011-02-03 17:16 ` Peter Zijlstra
2011-02-03 17:49 ` Frank Rowand
2011-01-04 14:59 ` [RFC][PATCH 12/18] sched: Drop rq->lock from first part of wake_up_new_task() Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 13/18] sched: Drop rq->lock from sched_exec() Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 14/18] sched: Remove rq->lock from the first half of ttwu() Peter Zijlstra
2011-01-06 16:29 ` Peter Zijlstra
2011-01-29 1:05 ` Frank Rowand
2011-02-03 17:16 ` Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 15/18] sched: Remove rq argument from ttwu_stat() Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 16/18] sched: Rename ttwu_post_activation Peter Zijlstra
2011-01-29 1:08 ` Frank Rowand
2011-01-04 14:59 ` [RFC][PATCH 17/18] sched: Move the second half of ttwu() to the remote cpu Peter Zijlstra
2011-01-05 21:07 ` Oleg Nesterov
2011-01-06 15:09 ` Peter Zijlstra
2011-01-07 15:22 ` Oleg Nesterov
2011-01-18 16:38 ` Peter Zijlstra
2011-01-19 19:37 ` Oleg Nesterov
2011-01-29 0:04 ` Frank Rowand
2011-02-03 17:16 ` Peter Zijlstra
2011-01-04 14:59 ` [RFC][PATCH 18/18] sched: Sort hotplug vs ttwu queueing Peter Zijlstra
2011-01-05 20:47 ` Oleg Nesterov
2011-01-06 10:56 ` Peter Zijlstra
2011-01-04 15:16 ` [RFC][PATCH 00/18] sched: Reduce runqueue lock contention -v4 Ingo Molnar
2011-01-29 1:20 ` Frank Rowand
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