Thread (2 messages) 2 messages, 2 authors, 2011-07-06

Re: [PATCHv2] arm: platsmp: Allow secondary cpu hotplug with

From: Russell King - ARM Linux <hidden>
Date: 2011-07-06 22:56:11
Also in: linux-arm-kernel, linux-arm-msm, linux-omap, linux-samsung-soc, linux-tegra, lkml

On Tue, Jul 05, 2011 at 10:29:17AM -0700, Stephen Boyd wrote:
If an ARM system has multiple cpus in the same socket and the
kernel is booted with maxcpus=1, secondary cpus are possible but
not present due to how platform_smp_prepare_cpus() is called.
Since most typical ARM processors don't actually support physical
hotplug, initialize the present map to be equal to the possible
map in generic ARM SMP code. Also, always call
platform_smp_prepare_cpus() as long as max_cpus is non-zero (0
means no SMP) to allow platform code to do any SMP setup.

After applying this patch it's possible to boot an ARM system
with maxcpus=1 on the command line and then hotplug in secondary
cpus via sysfs. This is more in line with how x86 does things.
Ok - how about putting this in the patch system?

Thanks.
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