From: Rusty Russell <rusty@rustcorp.com.au>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-arch@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Ingo Molnar <mingo@kernel.org>,
Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>,
Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [patch 00/18] SMP: Boot and CPU hotplug refactoring - Part 1
Date: Tue, 22 May 2012 10:23:47 +0930 [thread overview]
Message-ID: <87mx512fz8.fsf@rustcorp.com.au> (raw)
In-Reply-To: <alpine.LFD.2.02.1205211013440.3231@ionos>
On Mon, 21 May 2012 10:25:21 +0200 (CEST), Thomas Gleixner <tglx@linutronix.de> wrote:
> On Mon, 21 May 2012, Rusty Russell wrote:
>
> > On Fri, 20 Apr 2012 16:18:04 +0200 (CEST), Thomas Gleixner <tglx@linutronix.de> wrote:
> > > On Fri, 20 Apr 2012, Srivatsa S. Bhat wrote:
> > > The whole notifier business needs a redesign as well, because we don't
> > > have a way to express proper dependencies, we add random notifier
> > > points and the teardown path is ass backwards. The whole thing wants
> > > to be a tree which can be walked in either direction and from any
> > > point. Right now we cut the trunk first and keep the single limb up
> > > with a helicopter and start dismantling it.
> >
> > But there are two ways to do it. One is to eliminate the need for
> > callbacks. The other is to make a full dependency-based callback
>
> What do you mean with fully eliminating the need for callbacks. Do you
> want to put the necessary bringup/shutdown function calls just in the
> core code so we get rid of the notifiers or do you have something
> different in mind ?
Eliminate is probably too hard, but with park/unpark I can see it
getting less common. Maybe few enough that we can simplify.
> > Not sure whether calling notifiers in parallel is going to be a big win:
> > they'll end up fighting over the cpu we're taking down. But I could be
> > wrong.
>
> I'm not going to aim for parallel in the first place. That was just an
> idea and if we chose the right implementation then parallelism can be
> added later.
Parallel CPUs going offline/online is probably a bigger win. Both for
suspend/resume and powersaving.
> > The original concept of stopping the machine for cpu hotplug and trying
> > not to effect any other kernel code has jumped the shark: I think we
> > need to look seriously at a complete rewrite where we don't use
> > stop_machine.
>
> Yep. Working on it. :)
I thought you might be :)
I'd love to review once you've got something.
Cheers,
Rusty.
next prev parent reply other threads:[~2012-05-22 3:03 UTC|newest]
Thread overview: 82+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-20 13:05 [patch 00/18] SMP: Boot and CPU hotplug refactoring - Part 1 Thomas Gleixner
2012-04-20 13:05 ` [patch 01/18] m32r: Remove pointless function prototypes Thomas Gleixner
2012-04-20 13:05 ` [patch 02/18] smp: Add task_struct argument to __cpu_up() Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-23 7:58 ` Jesper Nilsson
2012-04-23 7:58 ` Jesper Nilsson
2012-04-20 13:05 ` [patch 03/18] smp: Add generic smpboot facility Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 20:07 ` Yinghai Lu
2012-04-20 20:07 ` Yinghai Lu
2012-04-21 2:07 ` Stephen Rothwell
2012-04-21 2:07 ` Stephen Rothwell
2012-04-20 13:05 ` [patch 04/18] smp: Provide generic idle thread allocation Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 16:21 ` Sam Ravnborg
2012-04-20 16:21 ` Sam Ravnborg
2012-04-20 18:55 ` Thomas Gleixner
2012-04-20 18:55 ` Thomas Gleixner
2012-04-21 2:20 ` Stephen Rothwell
2012-04-21 2:20 ` Stephen Rothwell
2012-04-21 2:25 ` Frank Rowand
2012-04-21 2:25 ` Frank Rowand
2012-04-20 13:05 ` [patch 05/18] x86: Add task_struct argument to smp_ops.cpu_up Thomas Gleixner
2012-04-20 13:05 ` [patch 06/18] x86: Use generic idle thread allocation Thomas Gleixner
2012-04-20 13:05 ` [patch 07/18] powerpc: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 13:05 ` [patch 08/18] ia64: " Thomas Gleixner
2012-04-20 13:05 ` [patch 09/18] arm: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 13:05 ` [patch 11/18] hexagon: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-24 16:47 ` Richard Kuo
2012-04-24 16:47 ` Richard Kuo
2012-04-20 13:05 ` [patch 10/18] mips: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 13:05 ` [patch 12/18] s390: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-23 7:09 ` Martin Schwidefsky
2012-04-23 7:09 ` Martin Schwidefsky
2012-04-20 13:05 ` [patch 13/18] blackfin: " Thomas Gleixner
2012-04-20 13:05 ` [patch 14/18] cris: " Thomas Gleixner
2012-04-23 7:57 ` Jesper Nilsson
2012-04-23 7:57 ` Jesper Nilsson
2012-04-20 13:05 ` [patch 15/18] sh: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-21 3:18 ` Paul Mundt
2012-04-20 13:05 ` [patch 16/18] alpha: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 13:05 ` [patch 17/18] parisc: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-20 13:05 ` [patch 18/18] sparc: " Thomas Gleixner
2012-04-20 13:05 ` Thomas Gleixner
2012-04-22 19:52 ` David Miller
2012-04-20 13:16 ` [patch 00/18] SMP: Boot and CPU hotplug refactoring - Part 1 Thomas Gleixner
2012-04-20 13:21 ` Peter Zijlstra
2012-04-20 13:47 ` Thomas Gleixner
2012-04-21 0:08 ` Suresh Siddha
2012-05-03 9:41 ` Thomas Gleixner
2012-05-03 9:41 ` Thomas Gleixner
2012-05-03 23:42 ` Suresh Siddha
2012-04-20 15:42 ` Tejun Heo
2012-04-20 15:49 ` Peter Zijlstra
2012-04-20 15:56 ` Thomas Gleixner
2012-04-20 13:56 ` Srivatsa S. Bhat
2012-04-20 14:18 ` Thomas Gleixner
2012-04-24 18:44 ` Konrad Rzeszutek Wilk
2012-05-21 1:42 ` Rusty Russell
2012-05-21 8:25 ` Thomas Gleixner
2012-05-21 8:25 ` Thomas Gleixner
2012-05-22 0:53 ` Rusty Russell [this message]
2012-04-20 14:06 ` richard -rw- weinberger
2012-04-20 14:06 ` richard -rw- weinberger
2012-04-20 14:19 ` Thomas Gleixner
2012-04-20 14:27 ` James Bottomley
2012-04-20 17:55 ` Paul E. McKenney
2012-04-20 23:11 ` Venki Pallipadi
2012-04-21 1:04 ` Frank Rowand
2012-04-21 1:55 ` Frank Rowand
2012-04-22 21:01 ` Chris Metcalf
2012-04-22 21:01 ` Chris Metcalf
2012-04-30 8:05 ` Santosh Shilimkar
2012-04-30 8:05 ` Santosh Shilimkar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87mx512fz8.fsf@rustcorp.com.au \
--to=rusty@rustcorp.com.au \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=nikunj@linux.vnet.ibm.com \
--cc=paulmck@linux.vnet.ibm.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=srivatsa.bhat@linux.vnet.ibm.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).