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From: Frank Rowand <frank.rowand@am.sony.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	"linux-arch@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>,
	Matt Turner <mattst88@gmail.com>,
	Russell King <linux@arm.linux.org.uk>,
	Mike Frysinger <vapier@gentoo.org>,
	Jesper Nilsson <jesper.nilsson@axis.com>,
	Richard Kuo <rkuo@codeaurora.org>,
	Tony Luck <tony.luck@intel.com>,
	Hirokazu Takata <takata@linux-m32r.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	David Howells <dhowells@redhat.com>,
	"James E.J. Bottomley" <jejb@parisc-linux.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Paul Mundt <lethal@linux-sh.org>,
	"David S. Miller" <davem@davemloft.net>,
	Chris Metcalf <cmetcalf@tilera.com>,
	Richard Weinberger <richard@nod.at>,
	"x86@kernel.org" <x86@kernel.org>
Subject: Re: [patch 04/18] smp: Provide generic idle thread allocation
Date: Fri, 20 Apr 2012 19:25:25 -0700	[thread overview]
Message-ID: <4F921A95.3030805@am.sony.com> (raw)
In-Reply-To: <20120420124557.102478630@linutronix.de>

On 04/20/12 06:05, Thomas Gleixner wrote:
> All SMP architectures have magic to fork the idle task and to store it
> for reusage when cpu hotplug is enabled. Provide a generic
> infrastructure for it.
> 
> Create/reinit the idle thread for the cpu which is brought up in the
> generic code and hand the thread pointer to the architecture code via
> __cpu_up().
> 
> Note, that fork_idle() is called via a workqueue, because this
> guarantees that the idle thread does not get a reference to a user
> space VM. This can happen when the boot process did not bring up all
> possible cpus and a later cpu_up() is initiated via the sysfs
> interface. In that case fork_idle() would be called in the context of
> the user space task and take a reference on the user space VM.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Matt Turner <mattst88@gmail.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Mike Frysinger <vapier@gentoo.org>
> Cc: Jesper Nilsson <jesper.nilsson@axis.com>
> Cc: Richard Kuo <rkuo@codeaurora.org>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Hirokazu Takata <takata@linux-m32r.org>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: David Howells <dhowells@redhat.com>
> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Chris Metcalf <cmetcalf@tilera.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: x86@kernel.org
> ---
>  arch/Kconfig        |    3 +
>  kernel/cpu.c        |    2 -
>  kernel/sched/core.c |    2 +
>  kernel/smpboot.c    |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/smpboot.h    |   10 ++++++
>  5 files changed, 99 insertions(+), 1 deletion(-)
> 
> Index: linux-2.6/arch/Kconfig
> ===================================================================
> --- linux-2.6.orig/arch/Kconfig
> +++ linux-2.6/arch/Kconfig
> @@ -145,6 +145,9 @@ config HAVE_DMA_ATTRS
>  config USE_GENERIC_SMP_HELPERS
>  	bool
>  
> +config GENERIC_SMP_IDLE_THREAD
> +       bool

    ^^^^^  This _appears_ to be spaces instead of a tab.  Hopefully not a false alarm, I know
           my mail servers randomly change tabs to spaces, just to mess with me, but I double
           checked at the lkml archive.

> +
>  config HAVE_REGS_AND_STACK_ACCESS_API
>  	bool
>  	help

< snip >

- Frank


WARNING: multiple messages have this Message-ID
From: Frank Rowand <frank.rowand@am.sony.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
	"linux-arch@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>,
	Matt Turner <mattst88@gmail.com>,
	Russell King <linux@arm.linux.org.uk>,
	Mike Frysinger <vapier@gentoo.org>,
	Jesper Nilsson <jesper.nilsson@axis.com>,
	Richard Kuo <rkuo@codeaurora.org>,
	Tony Luck <tony.luck@intel.com>,
	Hirokazu Takata <takata@linux-m32r.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	David Howells <dhowells@redhat.com>,
	"James E.J. Bottomley" <jejb@parisc-linux.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Paul Mundt <lethal@linux-sh.org>,
	"David S. Miller" <davem@davemloft.net>,
	Chris
Subject: Re: [patch 04/18] smp: Provide generic idle thread allocation
Date: Fri, 20 Apr 2012 19:25:25 -0700	[thread overview]
Message-ID: <4F921A95.3030805@am.sony.com> (raw)
In-Reply-To: <20120420124557.102478630@linutronix.de>

On 04/20/12 06:05, Thomas Gleixner wrote:
> All SMP architectures have magic to fork the idle task and to store it
> for reusage when cpu hotplug is enabled. Provide a generic
> infrastructure for it.
> 
> Create/reinit the idle thread for the cpu which is brought up in the
> generic code and hand the thread pointer to the architecture code via
> __cpu_up().
> 
> Note, that fork_idle() is called via a workqueue, because this
> guarantees that the idle thread does not get a reference to a user
> space VM. This can happen when the boot process did not bring up all
> possible cpus and a later cpu_up() is initiated via the sysfs
> interface. In that case fork_idle() would be called in the context of
> the user space task and take a reference on the user space VM.
> 
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Matt Turner <mattst88@gmail.com>
> Cc: Russell King <linux@arm.linux.org.uk>
> Cc: Mike Frysinger <vapier@gentoo.org>
> Cc: Jesper Nilsson <jesper.nilsson@axis.com>
> Cc: Richard Kuo <rkuo@codeaurora.org>
> Cc: Tony Luck <tony.luck@intel.com>
> Cc: Hirokazu Takata <takata@linux-m32r.org>
> Cc: Ralf Baechle <ralf@linux-mips.org>
> Cc: David Howells <dhowells@redhat.com>
> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
> Cc: Paul Mundt <lethal@linux-sh.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Chris Metcalf <cmetcalf@tilera.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: x86@kernel.org
> ---
>  arch/Kconfig        |    3 +
>  kernel/cpu.c        |    2 -
>  kernel/sched/core.c |    2 +
>  kernel/smpboot.c    |   83 ++++++++++++++++++++++++++++++++++++++++++++++++++++
>  kernel/smpboot.h    |   10 ++++++
>  5 files changed, 99 insertions(+), 1 deletion(-)
> 
> Index: linux-2.6/arch/Kconfig
> ===================================================================
> --- linux-2.6.orig/arch/Kconfig
> +++ linux-2.6/arch/Kconfig
> @@ -145,6 +145,9 @@ config HAVE_DMA_ATTRS
>  config USE_GENERIC_SMP_HELPERS
>  	bool
>  
> +config GENERIC_SMP_IDLE_THREAD
> +       bool

    ^^^^^  This _appears_ to be spaces instead of a tab.  Hopefully not a false alarm, I know
           my mail servers randomly change tabs to spaces, just to mess with me, but I double
           checked at the lkml archive.

> +
>  config HAVE_REGS_AND_STACK_ACCESS_API
>  	bool
>  	help

< snip >

- Frank

  parent reply	other threads:[~2012-04-21  2:25 UTC|newest]

Thread overview: 87+ 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
2012-04-28  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 [this message]
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
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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