Messages in this thread | | | Date | Mon, 02 Apr 2012 20:02:49 +0530 | From | "Srivatsa S. Bhat" <> | Subject | Re: the maxcpus= boot parameter broke somewhere along the line |
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On 04/02/2012 07:35 PM, Jeff Moyer wrote:
> "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 >
Aha! Just like I thought! So there is no kernel bug with respect to the maxcpus= boot parameter :-)
Regards, Srivatsa S. Bhat
> 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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