From: Peter Zijlstra <peterz@infradead.org>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: yong.zhang0@gmail.com, paulmck@linux.vnet.ibm.com,
oleg@redhat.com, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, mingo@elte.hu, lizf@cn.fujitsu.com,
miaox@cn.fujitsu.com
Subject: Re: [PATCH v2 1/2] rcu: don't bind offline cpu
Date: Thu, 19 May 2011 10:55:01 +0200 [thread overview]
Message-ID: <1305795301.2466.7200.camel@twins> (raw)
In-Reply-To: <1305794078.2466.7193.camel@twins>
On Thu, 2011-05-19 at 10:34 +0200, Peter Zijlstra wrote:
> On Thu, 2011-05-19 at 15:06 +0900, KOSAKI Motohiro wrote:
> >
> > The right way is, explicit two phase cpu bindings (1) bind boot
> > (or any other online) cpu at CPU_UP_PREPARE (2) bind correct
> > target cpu at CPU_ONLINE. This patch does it.
>
> I'm not sure that is in-fact correct. From what I understood, RCU could
> have need of this thread before the ONLINE callback and expects it to be
> affine at that time.
Right, so we're waking that thread from the timer tick, so we must have
that thread set-up and ready _before_ we enable interrupts for the first
time. CPU_ONLINE is _WAAAAAY_ too late for that.
> What was wrong with delaying the wakeup to STARTING?
Hrmm right, so I thought STARTING was right after we marked the cpu
online, but its right before. Bummer.
Also Paul:
rcu_cpu_kthread()
rcu_process_callbacks()
__rcu_process_callbacks()
rcu_do_batch()
invoke_rcu_cpu_kthread()
Why wake the thread again if its already running?
next prev parent reply other threads:[~2011-05-19 8:55 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-28 14:20 [RFC PATCH] cpuset: fix cpuset_cpus_allowed_fallback() don't update tsk->rt.nr_cpus_allowed KOSAKI Motohiro
2011-04-28 16:11 ` Oleg Nesterov
2011-05-02 10:42 ` KOSAKI Motohiro
2011-05-02 10:55 ` [PATCH 1/2] " KOSAKI Motohiro
2011-05-11 16:05 ` Peter Zijlstra
2011-05-13 5:48 ` KOSAKI Motohiro
2011-05-13 6:42 ` Yong Zhang
2011-05-13 7:33 ` KOSAKI Motohiro
2011-05-13 7:43 ` Yong Zhang
2011-05-13 9:34 ` KOSAKI Motohiro
2011-05-13 17:02 ` Peter Zijlstra
2011-05-14 11:17 ` KOSAKI Motohiro
2011-05-16 13:37 ` Yong Zhang
2011-05-19 8:45 ` Peter Zijlstra
2011-05-19 8:54 ` Yong Zhang
2011-05-15 18:55 ` Paul E. McKenney
2011-05-16 13:26 ` Yong Zhang
2011-05-19 6:06 ` [PATCH v2 1/2] rcu: don't bind offline cpu KOSAKI Motohiro
2011-05-19 6:08 ` [PATCH v2 2/2] cpuset: fix cpuset_cpus_allowed_fallback() don't update tsk->rt.nr_cpus_allowed KOSAKI Motohiro
2011-05-28 16:35 ` [tip:sched/urgent] cpuset: Fix cpuset_cpus_allowed_fallback(), " tip-bot for KOSAKI Motohiro
2011-06-20 10:20 ` Peter Zijlstra
2011-06-21 9:54 ` KOSAKI Motohiro
2011-05-19 8:34 ` [PATCH v2 1/2] rcu: don't bind offline cpu Peter Zijlstra
2011-05-19 8:50 ` KOSAKI Motohiro
2011-05-19 9:41 ` Peter Zijlstra
2011-05-19 10:12 ` KOSAKI Motohiro
2011-05-19 11:41 ` Peter Zijlstra
2011-05-20 22:46 ` Paul E. McKenney
2011-05-19 8:55 ` Peter Zijlstra [this message]
2011-05-02 10:56 ` [PATCH 2/2] sched, cpuset: introduce do_set_cpus_allowed() helper function KOSAKI Motohiro
2011-05-02 12:58 ` [RFC PATCH] cpuset: fix cpuset_cpus_allowed_fallback() don't update tsk->rt.nr_cpus_allowed Paul E. McKenney
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