From: Rusty Russell <rusty@rustcorp.com.au>
To: paulmck@linux.vnet.ibm.com
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
Arjan van de Ven <arjan@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
"akpm\@linux-foundation.org" <akpm@linux-foundation.org>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Milton Miller <miltonm@bga.com>, "mingo\@elte.hu" <mingo@elte.hu>,
Tejun Heo <tj@kernel.org>,
KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Linux PM mailing list <linux-pm@vger.kernel.org>
Subject: Re: CPU Hotplug rework
Date: Sat, 24 Mar 2012 09:57:32 +1030 [thread overview]
Message-ID: <877gya99uj.fsf@rustcorp.com.au> (raw)
In-Reply-To: <20120322224919.GW2450@linux.vnet.ibm.com>
On Thu, 22 Mar 2012 15:49:20 -0700, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> On Thu, Mar 22, 2012 at 02:55:04PM +1030, Rusty Russell wrote:
> > On Wed, 21 Mar 2012 10:01:59 +0100, Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> > > Thing is, if its really too much for some people, they can orchestrate
> > > it such that its not. Just move everybody in a cpuset, clear the to be
> > > offlined cpu from the cpuset's mask -- this will migrate everybody away.
> > > Then hotplug will find an empty runqueue and its fast, no?
> >
> > I like this solution better.
>
> As long as we have some way to handle kthreads that are algorithmically
> tied to a given CPU. There are coding conventions to handle this, for
> example, do everything with preemption disabled and just after each
> preempt_disable() verify that you are in fact running on the correct
> CPU, but it is easy to imagine improvements.
I don't think we should move per-cpu kthreads at all. Let's stop trying
to save a few bytes of memory, and just leave them frozen. They'll run
again if/when the CPU returns.
Cheers,
Rusty.
--
How could I marry someone with more hair than me? http://baldalex.org
next prev parent reply other threads:[~2012-03-23 23:28 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-19 14:44 CPU Hotplug rework Srivatsa S. Bhat
2012-03-19 14:48 ` Srivatsa S. Bhat
2012-03-20 11:28 ` Peter Zijlstra
2012-04-05 17:39 ` Paul E. McKenney
2012-04-05 17:55 ` Paul E. McKenney
2012-04-05 23:06 ` Paul E. McKenney
2012-04-06 20:15 ` Srivatsa S. Bhat
2012-04-09 16:46 ` Paul E. McKenney
2012-04-10 7:56 ` Nikunj A Dadhania
2012-04-06 19:52 ` Srivatsa S. Bhat
2012-04-09 17:13 ` Paul E. McKenney
2012-04-10 13:41 ` Srivatsa S. Bhat
2012-04-10 15:46 ` Paul E. McKenney
2012-04-10 17:26 ` Srivatsa S. Bhat
2012-04-11 0:09 ` Steven Rostedt
2012-04-11 0:28 ` Paul E. McKenney
2012-04-11 0:37 ` Steven Rostedt
2012-04-11 1:00 ` Paul E. McKenney
2012-04-11 6:02 ` Srivatsa S. Bhat
2012-04-11 12:28 ` Paul E. McKenney
2012-03-19 23:42 ` Rusty Russell
2012-03-20 10:42 ` Peter Zijlstra
2012-03-20 23:00 ` Rusty Russell
2012-03-21 9:01 ` Peter Zijlstra
2012-03-22 4:25 ` Rusty Russell
2012-03-22 22:49 ` Paul E. McKenney
2012-03-23 23:27 ` Rusty Russell [this message]
2012-03-24 0:23 ` Paul E. McKenney
2012-03-26 0:41 ` Rusty Russell
2012-03-26 8:02 ` Peter Zijlstra
2012-03-26 13:09 ` Steven Rostedt
2012-03-26 13:38 ` Peter Zijlstra
2012-03-26 15:22 ` Steven Rostedt
2012-03-26 16:13 ` Peter Zijlstra
2012-03-26 17:05 ` Steven Rostedt
2012-03-26 17:59 ` Peter Zijlstra
2012-03-27 1:32 ` Rusty Russell
2012-03-27 3:05 ` Steven Rostedt
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