From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Stern <stern@rowland.harvard.edu>,
mingo@kernel.org, peterz@infradead.org, rusty@rustcorp.com.au,
paulmck@linux.vnet.ibm.com, namhyung@kernel.org, tj@kernel.org,
rjw@sisk.pl, nikunj@linux.vnet.ibm.com, linux-pm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Arjan van de Ven <arjan@infradead.org>
Subject: Re: [RFC PATCH 0/6] CPU hotplug: Reverse invocation of notifiers during CPU hotplug
Date: Thu, 26 Jul 2012 16:41:15 +0530 [thread overview]
Message-ID: <501125D3.9050705@linux.vnet.ibm.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1207261256030.32033@ionos>
On 07/26/2012 04:32 PM, Thomas Gleixner wrote:
> On Wed, 25 Jul 2012, Srivatsa S. Bhat wrote:
>> On 07/25/2012 10:00 PM, Thomas Gleixner wrote:
>>> While I thought about having a full dependency tracking system, I'm
>>> quite convinced by now, that hotplug is a rather linear sequence which
>>> does not provide much room for paralell setup/teardown.
>>>
>>
>> Pretty much, when considering hotplug of a single CPU.
>>
>> (But when considering booting, Arjan had proposed (while discussing
>> about his asynchronous booting patch) that it would be good to split
>> up physical vs logical parts of the booting/hotplug, so that the
>> physical part can happen in parallel with other CPUs, while the
>> logical online can be done serially, much later. Anyway, this is
>> slightly off-topic here, since we are mainly talking about hotplug
>> of a single cpu here. I just thought of putting a word about that
>> here, since we are discussing hotplug redesign anyways..)
>
> Well, the nice thing about having a proper state machine is that you
> can tell the code to advance the BP only to the "kick the other cpu"
> step, which is before the first sync point, so you can leave the state
> there and continue with "bring it fully online" later.
>
> So that feature comes basically for free. :)
>
Ah! Nice :-)
Regards,
Srivatsa S. Bhat
next prev parent reply other threads:[~2012-07-26 11:11 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-25 11:53 [RFC PATCH 0/6] CPU hotplug: Reverse invocation of notifiers during CPU hotplug Srivatsa S. Bhat
2012-07-25 11:53 ` [RFC PATCH 1/6] list, rcu: Introduce rcu version of reverse list traversal Srivatsa S. Bhat
2012-07-25 11:53 ` [RFC PATCH 2/6] notifiers: Convert notifier chain to circular doubly linked-list Srivatsa S. Bhat
2012-07-25 11:54 ` [RFC PATCH 3/6] notifiers: Add support for reverse invocation of notifier chains Srivatsa S. Bhat
2012-07-25 11:54 ` [RFC PATCH 4/6] sched, cpuset: Prepare scheduler and cpuset CPU hotplug callbacks for reverse invocation Srivatsa S. Bhat
2012-07-25 11:54 ` [RFC PATCH 5/6] sched, perf: Prepare migration and perf " Srivatsa S. Bhat
2012-07-25 11:55 ` [RFC PATCH 6/6] CPU hotplug: Invoke CPU offline notifiers in reverse order Srivatsa S. Bhat
2012-07-25 16:43 ` Tejun Heo
2012-07-25 14:57 ` [RFC PATCH 0/6] CPU hotplug: Reverse invocation of notifiers during CPU hotplug Alan Stern
2012-07-25 15:56 ` Srivatsa S. Bhat
2012-07-25 16:10 ` Alan Stern
2012-07-25 16:37 ` Srivatsa S. Bhat
2012-07-25 16:43 ` Paul E. McKenney
2012-07-25 19:44 ` Alan Stern
2012-07-25 16:30 ` Thomas Gleixner
2012-07-25 16:51 ` Srivatsa S. Bhat
2012-07-26 11:02 ` Thomas Gleixner
2012-07-26 11:11 ` Srivatsa S. Bhat [this message]
2012-07-25 18:22 ` Srivatsa S. Bhat
2012-07-26 10:55 ` Thomas Gleixner
2012-07-26 11:13 ` Srivatsa S. Bhat
2012-07-26 11:22 ` Srivatsa S. Bhat
2012-07-27 7:40 ` Rusty Russell
2012-08-01 7:10 ` Thomas Gleixner
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