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Subject: Re: [PATCH] x86/mce: Keep quiet in case of broadcasted mce after
 system panic
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From: Xunlei Pang <xpang@redhat.com>
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Date: Tue, 24 Jan 2017 10:33:26 +0800
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To: Borislav Petkov <bp@alien8.de>, "Luck, Tony" <tony.luck@intel.com>
Cc: Prarit Bhargava <prarit@redhat.com>, Kiyoshi Ueda <k-ueda@ct.jp.nec.com>, kexec@lists.infradead.org, x86@kernel.org, xlpang@redhat.com, linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>, Junichi Nomura <j-nomura@ce.jp.nec.com>, Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>, Dave Young <dyoung@redhat.com>

On 01/24/2017 at 02:14 AM, Borislav Petkov wrote:
> On Mon, Jan 23, 2017 at 10:01:53AM -0800, Luck, Tony wrote:
>> will ignore the machine check on the other cpus ... assuming
>> that "cpu_is_offline(smp_processor_id())" does the right thing
>> in the kexec case where this is an "old" cpu that isn't online
>> in the new kernel.
> Nice. And kdump did do the dumping on one CPU, AFAIR. So we should be
> good there.
>

"nr_cpus=N" will consume more memory, using very large N is almost
impossible for kdump to boot with considering the limited crash memory
reserved.

For some large machine, nr_cpus=1 might not be enough, we have to use
nr_cpus=4 or more, it is also helpful for the vmcore parallel dumping :-)

Regards,
Xunlei

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