Messages in this thread | | | Date | Fri, 20 Apr 2012 19:25:25 -0700 | From | Frank Rowand <> | Subject | Re: [patch 04/18] smp: Provide generic idle thread allocation |
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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
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