Messages in this thread | | | From | Jeff Moyer <> | Subject | Re: the maxcpus= boot parameter broke somewhere along the line | Date | Mon, 02 Apr 2012 10:05:06 -0400 |
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"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> writes:
> Looking at the mention of udev above, and considering the commit you bisected > to, I think it would be good to see whether someone is writing 1 to > /sys/device/system/cpu/cpu*/online and hence the cpus are getting hot-added > towards the end of boot. Maybe that sounds stupid, but worth a try :) > > So can you try the debug patch below? It applies on latest linux-3.3-rc6+
Sorry it took me so long to get back to you. You're patch did, in fact, trigger:
udev: starting version 147 CPU 3 online initated from userspace SMP alternatives: switching to SMP code WARNING! power/level is deprecated; use power/control instead Booting Node 0 Processor 3 APIC 0x3 NMI watchdog: enabled, takes one hw-pmu counter. CPU 1 online initated from userspace Booting Node 0 Processor 1 APIC 0x2 NMI watchdog: enabled, takes one hw-pmu counter. CPU 2 online initated from userspace Booting Node 0 Processor 2 APIC 0x1 NMI watchdog: enabled, takes one hw-pmu counter. CPU 1 online initated from userspace CPU 3 online initated from userspace CPU 2 online initated from userspace
Checking through udev rules, I found this in /lib/udev/rules.d/40-redhat.rules (this is a RHEL 6 install, btw):
ACTION=="add", KERNEL=="cpu[0-9]*", RUN+="/bin/bash -c 'echo 1 > /sys/devices/system/cpu/%k/online'"
So, what do you suppose is the right way to fix this?
Cheers, Jeff
Kay, you can read up on the rest of the thread here: https://lkml.org/lkml/2012/3/6/242
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