From: Frank Rowand <frank.rowand@gmail.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Chris Mason <chris.mason@oracle.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
Mike Galbraith <efault@gmx.de>, Oleg Nesterov <oleg@redhat.com>,
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: Thu, 03 Feb 2011 09:49:13 -0800 [thread overview]
Message-ID: <4D4AEA99.1040001@am.sony.com> (raw)
In-Reply-To: <1296753410.26581.463.camel@laptop>
On 02/03/11 09:16, Peter Zijlstra wrote:
> On Fri, 2011-01-28 at 16:21 -0800, Frank Rowand wrote:
>> On 01/04/11 06:59, Peter Zijlstra wrote:
< snip >
>>> @@ -2646,9 +2647,9 @@ void sched_fork(struct task_struct *p, i
>>> *
>>> * Silence PROVE_RCU.
>>> */
>>> - rcu_read_lock();
>>> + raw_spin_lock_irqsave(&p->pi_lock, flags);
>>> set_task_cpu(p, cpu);
>>> - rcu_read_unlock();
>>> + raw_spin_unlock_irqrestore(&p->pi_lock, flags);
>>
>> Does "* Silence PROVE_RCU." no longer apply after remove rcu_read_lock() and
>> rcu_read_unlock()?
>
> I think the locking is still strictly superfluous, I can't seem to
> recollect why I changed it from RCU to pi_lock, but since the task is
> fresh and unhashed it really cannot be subject to concurrency.
Sorry, my comment was not very clear. I meant to ask: should the
comment "* Silence PROVE_RCU." also be removed?
-Frank
next prev parent reply other threads:[~2011-02-03 17:49 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
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 [this message]
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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