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From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Peter Anvin <hpa@zytor.com>, Oleg Nesterov <oleg@redhat.com>,
	linux-arch@vger.kernel.org, Tejun Heo <tj@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Rafael Wysocki <rafael.j.wysocki@intel.com>,
	Arjan van de Ven <arjan@linux.intel.com>,
	Rik van Riel <riel@redhat.com>,
	"Srivatsa S. Bhat" <srivatsa@mit.edu>,
	Sebastian Siewior <bigeasy@linutronix.de>,
	Paul Turner <pjt@google.com>
Subject: Re: [patch 10/20] cpu/hotplug: Make target state writeable
Date: Sat, 27 Feb 2016 00:46:18 +0100	[thread overview]
Message-ID: <6355023.m2RKuauZef@vostro.rjw.lan> (raw)
In-Reply-To: <20160226182341.022814799@linutronix.de>

Hi Thomas,

On Friday, February 26, 2016 06:43:32 PM Thomas Gleixner wrote:
> Make it possible to write a target state to the per cpu state file, so we can
> switch between states.

One thing that potentially may be problematic here is that any kind of
"offline" operations needs to be carried out under device_hotplug_lock,
because there are cases in which devices (including CPUs) are taken
offline in groups and if one offline fails, the whole operation has to
be rolled back.

So if you put a CPU into one of the intermediate states manually and
something like the above happens in parallel with it, they may not
play well together IMO.

Thanks,
Rafael

  reply	other threads:[~2016-02-26 23:44 UTC|newest]

Thread overview: 69+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-02-26 18:43 [patch 00/20] cpu/hotplug: Core infrastructure for cpu hotplug rework Thomas Gleixner
2016-02-26 18:43 ` [patch 01/20] idle: Move x86ism out of generic code Thomas Gleixner
2016-02-27 20:29   ` Brian Gerst
2016-02-29 19:35     ` Thomas Gleixner
2016-02-29 19:48       ` Will Deacon
2016-02-29 20:06         ` Thomas Gleixner
2016-02-26 18:43 ` [patch 02/20] cpu/hotplug: Restructure FROZEN state handling Thomas Gleixner
2016-03-01 19:51   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 22:35     ` Srivatsa S. Bhat
2016-03-02 23:43     ` Srivatsa S. Bhat
2016-02-26 18:43 ` [patch 03/20] cpu/hotplug: Restructure cpu_up code Thomas Gleixner
2016-03-01 19:52   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 22:36     ` Srivatsa S. Bhat
2016-02-26 18:43 ` [patch 04/20] cpu/hotplug: Split out cpu down functions Thomas Gleixner
2016-03-01 19:52   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 22:37     ` Srivatsa S. Bhat
2016-02-26 18:43 ` [patch 05/20] cpu/hotplug: Add tracepoints Thomas Gleixner
2016-03-01 19:52   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 06/20] cpu/hotplug: Convert to a state machine for the control processor Thomas Gleixner
2016-03-01 19:53   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 11:23     ` Peter Zijlstra
2016-02-26 18:43 ` [patch 07/20] cpu/hotplug: Convert the hotplugged cpu work to a state machine Thomas Gleixner
2016-03-01 19:53   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 08/20] cpu/hotplug: Hand in target state to _cpu_up/down Thomas Gleixner
2016-03-01 19:54   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 09/20] cpu/hotplug: Add sysfs state interface Thomas Gleixner
2016-03-01 19:54   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 12:40     ` Peter Zijlstra
2016-02-26 18:43 ` [patch 10/20] cpu/hotplug: Make target state writeable Thomas Gleixner
2016-02-26 23:46   ` Rafael J. Wysocki [this message]
2016-02-27  7:39     ` Thomas Gleixner
2016-02-27 14:43       ` Rafael J. Wysocki
2016-02-28 14:49         ` Thomas Gleixner
2016-02-29 15:49           ` Thomas Gleixner
2016-03-01  1:53             ` Rafael J. Wysocki
2016-03-01 19:55   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 12:41     ` Peter Zijlstra
2016-03-02 19:57       ` Thomas Gleixner
2016-02-26 18:43 ` [patch 11/20] cpu/hotplug: Implement setup/removal interface Thomas Gleixner
2016-03-01 19:55   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 12/20] cpu/hotplug: Move scheduler cpu_online notifier to hotplug core Thomas Gleixner
2016-03-01 19:55   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 13/20] cpu/hotplug: Unpark smpboot threads from the state machine Thomas Gleixner
2016-03-01 19:56   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 14/20] cpu/hotplug: Split out the state walk into functions Thomas Gleixner
2016-03-01 19:56   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 15/20] cpu/hotplug: Create hotplug threads Thomas Gleixner
2016-03-01 19:57   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 16/20] cpu/hotplug: Move online calls to hotplugged cpu Thomas Gleixner
2016-03-01 19:57   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 17/20] arch/hotplug: Call into idle with a proper state Thomas Gleixner
2016-03-01 19:57   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 18/20] cpu/hotplug: Let upcoming cpu bring itself fully up Thomas Gleixner
2016-03-01 19:58   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 17:28   ` [patch 18/20] " Richard Cochran
2016-02-26 18:43 ` [patch 19/20] cpu/hotplug: Make wait for dead cpu completion based Thomas Gleixner
2016-03-01 19:58   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-02-26 18:43 ` [patch 20/20] rcu: Make CPU_DYING_IDLE an explicit call Thomas Gleixner
2016-02-27  2:14   ` Paul E. McKenney
2016-02-27  2:23     ` Paul E. McKenney
2016-02-27  7:47       ` Thomas Gleixner
2016-02-27 11:05         ` Paul E. McKenney
2016-02-27 11:30           ` Thomas Gleixner
2016-02-27 16:33             ` Paul E. McKenney
2016-03-01 19:58   ` [tip:smp/hotplug] " tip-bot for Thomas Gleixner
2016-03-02 20:11     ` Paul E. McKenney
2016-03-03  7:31       ` Thomas Gleixner
2016-03-03 10:03       ` [tip:smp/hotplug] cpu/hotplug: Plug death reporting race tip-bot for Thomas Gleixner
2016-03-03 14:11         ` Paul E. McKenney

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