From: Jeff Moyer <jmoyer@redhat.com>
To: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Sasha Levin <levinsasha928@gmail.com>,
Nick Bowler <nbowler@elliptictech.com>,
linux-kernel@vger.kernel.org, Kay Sievers <kay.sievers@vrfy.org>
Subject: Re: the maxcpus= boot parameter broke somewhere along the line
Date: Mon, 02 Apr 2012 10:38:27 -0400 [thread overview]
Message-ID: <x49sjgmgpwc.fsf@segfault.boston.devel.redhat.com> (raw)
In-Reply-To: <4F79B891.8020704@linux.vnet.ibm.com> (Srivatsa S. Bhat's message of "Mon, 02 Apr 2012 20:02:49 +0530")
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> writes:
> 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 :-)
But this IS a change in behaviour (using older kernels, the maxcpus=
boot parameter works just fine). So, what exactly has changed is my
question, and what is the right way to fix it?
Cheers,
Jeff
next prev parent reply other threads:[~2012-04-02 14:38 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-06 14:59 Jeff Moyer
2012-03-06 15:17 ` Sasha Levin
2012-03-06 16:08 ` Jeff Moyer
2012-03-06 16:48 ` Nick Bowler
2012-03-06 17:15 ` Sasha Levin
2012-03-06 18:08 ` Jeff Moyer
2012-03-07 15:41 ` Srivatsa S. Bhat
2012-03-07 19:14 ` Jeff Moyer
2012-03-09 11:22 ` Srivatsa S. Bhat
2012-04-02 14:05 ` Jeff Moyer
2012-04-02 14:32 ` Srivatsa S. Bhat
2012-04-02 14:38 ` Jeff Moyer [this message]
2012-04-04 7:02 ` Srivatsa S. Bhat
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