Messages in this thread | | | From | "Yu, Fenghua" <> | Date | Thu, 15 Dec 2011 10:38:20 -0800 | Subject | RE: [PATCH v4 0/7] x86: BSP or CPU0 online/offline |
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> We need a debug feature for this: CONFIG_DEBUG_BOOT_CPU_OFF=y or > such (disabled by default): this feature would offline the boot > CPU as soon as possible, and boot up userspace with the boot CPU > offlined.
I would think the earliest time when CPU0 can be offline is right after do_initcalls() because do_initcalls() installs some cpu hotplug notifier.
But this will change generic code (e.g. add arch hook in init/main.c or add a new initcall level which is after level 7s).
Another way is to offline CPU0 (or any CPU) in /etc/rc.local. By this way, we don't change kernel. And this is safe, but a bit later than in kernel.
Any comment?
Thanks.
-Fenghua
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