Re: [PATCH RFC v2 0/3] add cpu physically hotplug driver

From: li guang
Date: Sun Jun 09 2013 - 20:38:08 EST


Hi, Rafael

å 2013-06-06åç 13:00 +0200ïRafael J. Wysockiåéï
> On Thursday, June 06, 2013 09:40:32 AM liguang wrote:
> > This patch-set try to support physically hot-plug/unplug
> > a cpu automatically, that is:
> > if you offline a cpu, it will automatically actually remove
> > a cpu, and if you hot-plug a cpu, then it will online this
> > cpu automatically.
>
> No and no.

Hmm... are you saying cpu online/offline designed to distinguish
with real cpu plug/unplug?
but, what the actual usage of online/offline?
forgive my foolish.

>
> Why do you need this?
>

e.g. for QEMU case, if hot-plug a cpu,
we have to online a cpu manually if there's
no user space support like udev to do it automatically.
and also, I think maybe online/offline should be naturally
integrated with real plug/unplug process of CPU.

>
>
> > so, offline is just like eject, but eject attribute seems not
> > available since recent kernel(can't figure out when), with
> > this driver, if allowed, it will trigger a eject cpu process.
> > and for automatically online, it was said there are objections,
> > don't know the reason, so, send this patch-set boldly.
> >
> > of course, this approach is for QEMU 's hotplug cpu emulation
> > only, but not limited, if someone like to explore ec space to
> > implment cpu hot-plug/unplug for real platform please
> > feel free to continue.
> >
> > Li Guang (3)
> > drivers/platform/x86: add cpu physically hotplug driver
> > ec: add ec space notifier
> > cpu_physic_hotplug: register handler for ec space notifier
> >
> > drivers/acpi/ec.c | 32 ++++++++++++++++++++++++++++++++
> > drivers/platform/x86/Kconfig | 8 ++++
> > drivers/platform/x86/Makefile | 1 +
> > drivers/platform/x86/cpu_physic_hotplug.c | 90 +++++++++++++++++++++++++++++
> > include/linux/acpi.h | 2 ++
> > 5 files changed, 130 insertions(+), 3 deletions(-)
> > create mode 100644 drivers/platform/x86/cpu_physic_hotplug.c


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