Re: EFI kdump without acpi_rsdp

[Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On 08/02/2013 09:14 AM, Dave Young wrote:
> On 08/01/2013 09:27 PM, Vivek Goyal wrote:
>> On Thu, Aug 01, 2013 at 10:12:25AM +0800, Dave Young wrote:
>>> On 08/01/2013 04:55 AM, Vivek Goyal wrote:
>>>> On Wed, Jul 31, 2013 at 04:48:00PM -0400, Vivek Goyal wrote:
>>>>> On Wed, Jul 31, 2013 at 04:42:27PM -0400, Vivek Goyal wrote:
>>>>>
>>>>> [..]
>>>>>> This system is behaving strangely. Yesterday I tried everything and it 
>>>>>> did not work and today both 3.9 and 3.10 kernel seem to work (with
>>>>>> acpi_rsdp=). I am upgrading kexec-tools now and will try again. If
>>>>>> that works, then will try without acpi_rsdp.
>>>>>>
>>>>>> Well, with 3.10 kernel boots up device showsup but dump saving fails.
>>>>>> Looks like makedumpfile bailed out.
>>>>>>
>>>>>> Hopefully upgrading kexec-tools will fix it.
>>>>>
>>>>> Well now OOM killer trigger while loading selinux policy. Red flags,
>>>>> memory utilization of various components has gone up and even 128MB
>>>>> does not seem to be sufficient.
>>>>
>>>> I upgraded from kexec-tools-2.0.3-71.fc19.x86_64 to
>>>> kexec-tools-2.0.4-5.fc19.x86_64 and memory problem started happening. Have
>>>> we done any significant change in kexec-tools which contributes to this.
>>>
>>
>> [ CC harald and initramfs list]
>>> The main contribute is Harald enabled 98selinux. Chaowang said selinux
>>> will use ~50M memory as the peak for load_policy. That is too much..
>>
>> Hi Dave,
>>
>> Have few questions. 
>>
>> - I upgraded kexec-tools package and not dracut. So how did memory usage
>>   go up.
> 
> It's strange, I don't think we have anything which use much memory.
> 
>>
>> - Were we not always loading selinux polity in initramfs. Otherwise I will
>>   see relabeling happen when I boot back to first kernel. And In my
>>   testing I did not see any relabeling happen. (I will make sure I was
>>   not testing with selinux disabled).
> 
> Should always load selinux in initramfs unless rootfs mounting fails.
> 
>>
>> - 50MB for selinux policy sounds too much. In RHEL6 this usage was around
>>   30MB and I remember in early fedora days it had dropped down to 18MB.
>>   Daniel, Eric, does selinux policy load memory consumption has to be
>>   this much. We reserve 128MB and 50MB is a huge chunk of that.
>>
>>>
>>> Ccing selinux peole Daniel and Eric. I wonder if there's a way we can
>>> use in kdump initrd for minimum memory footprint. Because we will not
>>> switch_root, so it will not influence the normal 1st kernel selinux.
>>
>> I did not understand above statement Dave. Are you saying that we
>> can save vmcore on root filesystem without loading selinux policy and
>> still avoid relabeling in first kernel when it boots back. How?
> 
> Dracut will always mount rootfs so mostly we need not relabel in 1st
> kernel because chroot load_policy in 2nd kernel will work unless rootfs
> mounting fails.
> 
> I ever tested loading minimum policy in RHEL6, it use much less memory
> than targeted policy.  Our target is simply label like file
> /sysroot/var/crash/*/vmcore. I'm wondering if there's similar method we
> can reduce memory usage in capture kernel.

Clarify a bit this, I means if there's a minimum way to use in initramfs
to enable selinux without 'chroot load_policy'.

> 
>>
>> Thanks
>> Vivek
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> 
> 


-- 
Thanks
Dave