From: Xunlei Pang <xpang@redhat.com>
To: Pratyush Anand <panand@redhat.com>,
Dave Young <dyoung@redhat.com>, Pingfan Liu <piliu@redhat.com>
Cc: kexec@lists.infradead.org, Baoquan He <bhe@redhat.com>,
kernelfans@gmail.com
Subject: Re: [PATCHv2 2/2] [fs] proc/vmcore: check the dummy place holder for offline cpu to avoid warning
Date: Wed, 21 Dec 2016 11:26:21 +0800 [thread overview]
Message-ID: <5859F65D.1060506@redhat.com> (raw)
In-Reply-To: <6691e874-e47a-0028-a2f8-59e431613d6f@redhat.com>
On 12/20/2016 at 11:38 PM, Pratyush Anand wrote:
>
>
> On Monday 19 December 2016 08:10 AM, Dave Young wrote:
>> Hi, Pingfan
>>
>> On 12/19/16 at 10:08am, Pingfan Liu wrote:
>>> > kexec-tools always allocates program headers for present cpus. But
>>> > when crashing, offline cpus have dummy headers. We do not copy these
>>> > dummy notes into ELF file, also have no need of warning on them.
>> I still think it is not worth such a fix, if you feel a lot of warnings
>> in case large cpu numbers, I think you can change the pr_warn to
>> pr_warn_once, we do not care the null cpu notes if it has nothing bad
>> to the vmcore.
>>
>
> I agree. Warning is more like information here. May be, we can count the number of times real_sz was 0, and then can print an info at the end in stead of warning, like..."N number of CPUs would have been offline, PT_NOTE entries was absent for them."
Well, OTOH the warning may also be due to some user-space misuse, we can't distinguish that without extra information added.
Another possible user-space fix would be: Firstly fix kexec-tools to add notes only for online cpus,
then utilize udev rules(cpu online/offline events) to automatically trigger kdump kernel reload.
Regards,
Xunlei
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next prev parent reply other threads:[~2016-12-21 3:25 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-19 2:08 [PATCHv2 1/2] kexec: add a dummy note for each offline cpu Pingfan Liu
2016-12-19 2:08 ` [PATCHv2 2/2] [fs] proc/vmcore: check the dummy place holder for offline cpu to avoid warning Pingfan Liu
2016-12-19 2:40 ` Dave Young
2016-12-20 15:38 ` Pratyush Anand
2016-12-21 3:26 ` Xunlei Pang [this message]
2016-12-21 3:57 ` Pratyush Anand
2016-12-21 4:52 ` Xunlei Pang
2016-12-21 7:15 ` Liu ping fan
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