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From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	linux-arch@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Ingo Molnar <mingo@kernel.org>,
	"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Subject: Re: [patch 00/18] SMP: Boot and CPU hotplug refactoring - Part 1
Date: Fri, 20 Apr 2012 18:27:30 +0400	[thread overview]
Message-ID: <1334932050.13001.2.camel@dabdike> (raw)
In-Reply-To: <20120420122120.097464672@linutronix.de>

On Fri, 2012-04-20 at 13:05 +0000, Thomas Gleixner wrote:
> Dear all,
> 
> I'm working on refactoring the SMP boot and CPU hotplug implementation.
> 
> The current code has evolved over time into a conglomerate of
> warts. My main goals are to:
> 
>  - reduce the architecture code by moving repeating constructs to the
>    core
> 
>  - redesigning the handling of per cpu threads. There is no point to
>    tear down the threads just to create them again.
> 
>  - restructuring the notifier facility into a proper tree with
>    dependencies to avoid the gazillion of callbacks and moving
>    setup/teardown code into the context of the upcoming/dying cpu
> 
> The motivation behind this work is the cpu hotplug nightmare which we
> are facing in the RT kernel and the requests from several groups
> (e.g. ARM) to make hotplug more lightweight and faster.
> 
> This first part moves the idle thread management for non-boot cpus
> into the core. fork_idle() is called in a workqueue as it is
> implemented in a few architectures already. This is necessary when not
> all cpus are brought up by the early boot code as otherwise we would
> take a ref on the user task VM of the thread which brings the cpu up
> via the sysfs interface.
> 
> This converts all architectures except m32r, mn10300, tile and UM to
> the new core facility. These architecture are calling fork_idle() in
> the very early boot code in smp_prepare_cpus() for unknown reasons.
> I haven't analyzed yet, whether this is on purpose or can be moved
> over to the generic facility. It'd be nice if the responsible maintainers
> could look into that as well.

Do you have a git tree we can try?  If you do, I promise to test as soon
as I can get my parisc systems nursed back to health after their
apparently trying voyage across the atlantic.

James



  parent reply	other threads:[~2012-04-20 14:27 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-04-20 13:05 Thomas Gleixner
2012-04-20 13:05 ` [patch 01/18] m32r: Remove pointless function prototypes Thomas Gleixner
2012-04-28  9:01   ` [tip:smp/hotplug] " tip-bot for 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
2012-04-28  9:02   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
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
2012-04-28  9:04   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
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
2012-04-28  9:05   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 05/18] x86: Add task_struct argument to smp_ops.cpu_up Thomas Gleixner
2012-04-28  9:05   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 06/18] x86: Use generic idle thread allocation Thomas Gleixner
2012-04-28  9:06   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 07/18] powerpc: " Thomas Gleixner
2012-04-28  9:07   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-28 22:51     ` Benjamin Herrenschmidt
2012-04-20 13:05 ` [patch 08/18] ia64: " Thomas Gleixner
2012-04-28  9:08   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 09/18] arm: " Thomas Gleixner
2012-04-28  9:09   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 11/18] hexagon: " Thomas Gleixner
2012-04-24 16:47   ` Richard Kuo
2012-04-28  9:10   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 10/18] mips: " Thomas Gleixner
2012-04-28  9:10   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 12/18] s390: " Thomas Gleixner
2012-04-23  7:09   ` Martin Schwidefsky
2012-04-28  9:11   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 13/18] blackfin: " Thomas Gleixner
2012-04-28  9:13   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 14/18] cris: " Thomas Gleixner
2012-04-23  7:57   ` Jesper Nilsson
2012-04-28  9:12   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 15/18] sh: " Thomas Gleixner
2012-04-21  3:18   ` Paul Mundt
2012-04-28  9:14   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 16/18] alpha: " Thomas Gleixner
2012-04-28  9:15   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 17/18] parisc: " Thomas Gleixner
2012-04-28  9:16   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2012-04-20 13:05 ` [patch 18/18] sparc: " Thomas Gleixner
2012-04-22 19:52   ` David Miller
2012-04-28  9:15   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
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 23:42         ` Suresh Siddha
2012-05-03 17:43       ` [tip:smp/hotplug] smp, idle: Allocate idle thread for each possible cpu during boot tip-bot for Suresh Siddha
2012-04-20 15:42   ` [patch 00/18] SMP: Boot and CPU hotplug refactoring - Part 1 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
2012-05-22  0:53         ` Rusty Russell
2012-04-20 14:06 ` richard -rw- weinberger
2012-04-20 14:19   ` Thomas Gleixner
2012-04-20 14:27 ` James Bottomley [this message]
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
2012-04-22 21:01   ` Chris Metcalf
2012-04-30  8:05 ` Santosh Shilimkar

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